[Roger Woodson] International Fuel Gas Code Compan(BookZZ.org)

INTERNATIONALFUEL GAS CODE

COMPANION:INTERPRETATION,

TACTICS, AND TECHNIQUES

http://dx.doi.org/10.1036/0071498966

About the Author

R. Dodge Woodson is a seasoned builder of as many as 60 single-family homes a year, a master remodeler, a master plumber, and a master gasfitter with over 30years of experience. He opened his first business in 1979 and is now the owner ofThe Masters Group, Inc., in Brunswick, Maine. In addition to operating this con-tracting company, Mr. Woodson has taught both code and apprentice classes inthe technical college system in Maine. Well known as a prolific author of manyMcGraw-Hill titles, his reputation and experience come together to offer readersa real-life view of professional practices.

Copyright © 2008 by The McGraw-Hill Companies, Inc. Click here for terms of use.

INTERNATIONALFUEL GAS CODE

COMPANION:INTERPRETATION,

TACTICS, ANDTECHNIQUES

R. Dodge Woodson

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http://dx.doi.org/10.1036/0071498966

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DOI: 10.1036/0071498966

http://dx.doi.org/10.1036/0071498966

This book is dedicated toAdam and Afton,

the two brightest stars in my life.Leona, Sadie, Ben, and Megan

make up the rest of my universe.

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vii

CONTENTS

Acknowledgments xvIntroduction xvii

CHAPTER 1: ADMINISTRATION 1.1

Piping Systems 1.2Gas Utilization Equipment 1.2Exceptions 1.2Other Fuels 1.4Minimum Standards 1.4Existing Installations 1.4Maintenance 1.5Additions 1.5Change in Occupancy 1.5Historic Designation 1.6Relocated Buildings 1.7Code Officer Appointment 1.7

Liability 1.7Authority 1.7Rules 1.8Applications and Permits 1.8Entry 1.8Records 1.9

Approval 1.9Modifications 1.9Alternative Options 1.10Testing 1.10

Permits 1.10Permit Application 1.11Permit Issuance 1.11Approved Construction Documents 1.11Validity 1.12Expiration 1.12Extensions 1.12Retention of Documents 1.13Working Without a Permit 1.13

Inspections 1.13Underground Inspections 1.14

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viii INTERNATIONAL FUEL GAS CODE COMPANION

Rough-In Inspections 1.14Final Inspections 1.14

Heating Equipment 1.14Prefabricated Construction 1.15

Follow-up Inspections 1.15Approval 1.16

Violations 1.16Punishment 1.17Stop-work Order 1.17Unsafe Conditions 1.17Condemned Installations 1.18Disconnection 1.18Reconnection 1.18

Appeal 1.18Membership of Board of Appeals 1.18Qualifications 1.19Board Organization 1.19

CHAPTER 2: DEFINITIONS 2.1

CHAPTER 3: GENERAL REGULATIONS 3.1

Labeling 3.1Plumbing 3.2Fuel Types 3.2Vibration 3.2Repair 3.2Wind 3.2Flooding 3.2Seismic Resistance 3.3Ducts 3.3Rodents 3.3Structural Safety 3.4Penetrations 3.4Cutting, Notching, and Boring Wood 3.4

Joists 3.4Studs 3.4Bored Holes 3.5

Trusses 3.5Steel 3.5

Structural-steel Framing 3.5Cold-formed Steel Framing 3.5Nonstructural Steel 3.6

Prohibited Appliance Locations 3.6Outdoor Locations 3.7Pit Locations 3.7Combustion, Ventilation, and Dilution Air 3.8

CONTENTS ix

Makeup Air 3.8Indoor Air 3.8Combined Spaces 3.9Outdoor Combustion Air 3.9Combination Air 3.10Mechanical Combustion-air Supply 3.11Louvers and Grilles 3.11Combustion-air Ducts 3.11Fumes and Gases 3.12

Installation 3.13Elevation of Ignition Source 3.13Parking Garages 3.14Public Garages 3.14Private Garages 3.14Grade Clearance 3.15Combustible Construction 3.15

Access and Service 3.15Attic Installations 3.15Under-floor Appliances 3.16Roofs and Elevated Structures 3.17

Permanent Ladders 3.17Sloped Roofs 3.18Guards 3.18

Condensate Disposal 3.18Clearance Reduction 3.20

Air-conditioning Equipment 3.20Furnace Plenums 3.20Supply Ducts 3.21Boilers and Furnaces 3.21

CHAPTER 4: GAS PIPING INSTALLATIONS 4.1

Identification 4.1Pipe Sizing 4.2

Branch Length 4.4Hybrid Pressure 4.4Pressure Drop 4.4Operating Pressure 4.5

LP Systems 4.5Sizing Tables 4.5

Piping Materials 4.62Anodeless Risers 4.63

Workmanship 4.64Threads 4.64Corrosive Action 4.64

Joints and Fittings 4.65Metallic Fittings 4.65Plastic Pipe Joints 4.66

Flanges and Flange Gaskets 4.66Piping-system Installation 4.67

Pipe Protection 4.67Solid Floors 4.68Above-ground Outdoor Piping 4.68Corrosion 4.69Outside Appliances 4.69Beneath Buildings 4.70Outlet Locations 4.70Plastic-pipe Limitations 4.71Tracers 4.71Changes in Direction 4.71

Testing 4.72Test Pressure and Duration 4.73

Servicing a System 4.74Pipe Support 4.74Wet Gas 4.75Shutoff Valves 4.76Flow Controls 4.77Manufactured-home Connections 4.78

Connector Length 4.78Gas-connector Prohibitions 4.79

Motor-vehicle Facilities 4.79LP-gas Fuel-dispensing Facilities 4.79Dispensing Devices 4.79Private Fueling 4.80Compressed-natural-gas Fuel-dispensing Facilities 4.80Location Exceptions 4.80Residential Applications 4.81Private Fueling Facilities 4.81Emergency Shutdown 4.82Closed Transfer System 4.82Vent Tube 4.82Air or Oxygen under Pressure 4.83Interconnections 4.83Support Intervals 4.83

Overpressure Protection 4.83Settings 4.86Unauthorized Operation 4.86Vents 4.87Size 4.87

CHAPTER 5: CHIMNEYS AND VENTS 5.1

Single Booster-type Automatic Instantaneous Water Heaters 5.2Requirements of Nonvented Appliances 5.2Residential and Low-heat Appliances 5.3

Category I Appliances 5.4

x INTERNATIONAL FUEL GAS CODE COMPANION

Existing Chimneys and Vents 5.4Vents 5.5

Insulation Shields 5.5Protection 5.5

Venting 5.6Mechanical Draft Systems 5.6Above-ceiling Systems 5.7

Masonry Chimneys 5.7Chimney Termination 5.8Chimney Sizing Limitations 5.8Chimney Inspections 5.10Liquid-fuel-burning Appliances 5.10Combination Appliances 5.10

Cleanouts 5.11Combustion Air 5.11Gas Vents 5.12

Terminating Gas Vents 5.12Vents for Category I Appliances 5.13Offsets 5.13Multistory Buildings 5.14

Sizing Connectors 5.14Labeling 5.15Single-Wall Pipe 5.15

Roof Penetration 5.15Installation Rules 5.16Single-wall Pipe Size 5.16

Venting Termination Locations 5.17Category II and IV Appliances 5.18

Unconditioned Areas 5.18Residential-type Appliance Connectors 5.18Low-heat Equipment 5.19Medium-heat Equipment 5.19Multiple Draft Hoods 5.20Multiple Appliances 5.21Joints 5.21Connector Length 5.21Chimney Connections 5.22Wall Penetration 5.22Vented Appliances 5.23Draft Hoods 5.24Table Definitions 5.25Venting Tables 5.26

Minimum Size 5.26Vent Offsets 5.26High Altitudes 5.27Multiple Inputs 5.27Liner Sizing 5.27

Vent Area and Diameter 5.27Chimney and Vent Locations 5.27

CONTENTS xi

xii INTERNATIONAL FUEL GAS CODE COMPANION

Component Commingling 5.28Conversion Accessories 5.28Vent Obstructions 5.28Connector Length 5.29Manifolds 5.29Fittings 5.29Vent Height 5.29Multistory Offsets 5.30Vertical Vent Maximum Size 5.31Liner Sizing and Connections 5.31Connector Maximum and Minimum Sizes 5.31Commercial Cooking Appliances 5.32Factory-built Chimneys 5.32

CHAPTER 6: SPECIFIC APPLIANCES 6.1

Decorative Appliances 6.1Fireplaces 6.2

Vented Gas Fireplaces 6.2Vented Wall Furnaces 6.2

Furnaces 6.3Floor Furnaces 6.3

Walls 6.3Thermostats 6.3Clearance 6.4

Duct Furnaces 6.4Air Heaters 6.4

Nonrecirculating Direct-fired Industrial Air Heaters 6.4Atmospheric Vents 6.5Relief Openings 6.5Recirculating Direct-fired Industrial Air Heaters 6.5Air Supply 6.6

Clothes Dryers 6.6Exhaust Systems 6.6Duct Penetrations 6.7Exhaust Installation 6.7Makeup Air 6.7Domestic Ducts 6.8Commercial Clothes Dryers 6.8

Sauna Heaters 6.9Air Intakes 6.9Controls 6.10Ventilation 6.10Forced-air Warm-air Furnaces 6.10Prohibited Sources 6.10

Unit Heaters 6.12Unvented Heaters 6.13

Cooking Appliances 6.14

Water Heaters 6.15Refrigerators 6.15Air Conditioning 6.15

Refrigeration Coils 6.16Boilers 6.17

Illuminating Appliances 6.17Infrared Radiant Heaters 6.18Boiler Standards 6.18Chimney Dampers 6.19

CHAPTER 7: GASEOUS HYDROGEN SYSTEMS 7.1

Generating and Refueling Operations 7.1Ventilation Types 7.2

Natural Ventilation 7.2Garage Openings 7.3Louvers and Grilles 7.3Mechanical Ventilation 7.3

Design 7.4Pressure Relief Devices 7.4

Valves 7.4Installation 7.4Sizing 7.5Protection 7.5

Configuration 7.6Piping 7.6

Identification 7.7Protection 7.8Outdoor Piping 7.8Joints 7.9Components 7.10

Shutoffs 7.10Containers 7.10Inspections 7.11

Testing Time 7.11Pressure Test 7.11Disconnection 7.12Leaks 7.12

Service 7.12Operation 7.12

Vent Outlets 7.13Suitable Locations 7.13

INDEX I.1

CONTENTS xiii


ACKNOWLEDGMENTS

I would like to thank the International Code Council, Inc. for its cooperation and permission to reprint certain illustrations and tables. This material was taken from material published by the International Code Council, Inc. Each appearance of the material is noted with appreciation.

xv



INTRODUCTION

R. Dodge Woodson has over 30 years of experience in the construction trades. He has built up to 60 single-family homes a year, has remodeled countless homes andbuildings, and is licensed as a master plumber and master gasfitter. As a seasonedauthor, Woodson is well known throughout the professional community. His writ-ing style and ability to turn complicated tasks into easy-to-understand termsmakes him and this book your guide to getting your code questions answered withless stress. Here is your ticket to simplifying the cryptic code that you work withon a daily basis. The code is large and can be complicated. Woodson translates itinto easy-to-use terms for people in the field. See the code as a real-world guideinstead of some foreign language that only some people can begin to sift through.This is your chance.

How important is understanding the code? It is essential for professionals inthe trade. Working without code compliance is an expensive mistake. Many goodgas workers mean well and still stray from the code. This is often due to the codebeing difficult to understand and follow. Not anymore. This book will walk youthrough the code requirements chapter by chapter.

Laid out in the same basic sequence as the code book, this book can be usedin conjunction with your code book. While this book is not a replacement for yourcode book, it is a strong enhancement to it. Use the books together as resources tomake your job or your business more productive.

Thumb through the pages here. Notice the code alert boxes. You will find thatsome key components of the code are highlighted in the alert boxes. Go ahead,take a peek. While you are at it, pick a few topics that you are either familiar withor confused about, and look them up. See for yourself how easy this book makesit to put your mind at ease on code issues.

You might find another book that attempts to do what this one does, but it wasnot written by R. Dodge Woodson. Another book might be a fine piece of work,but Woodson has a long-standing reputation as a best-selling author of code-related books for McGraw-Hill. If you are looking for one guide to the code thatyou can trust, this is it.

xvii



CHAPTER 1ADMINISTRATIVE

PROCEDURES

The administration of a compliance code is often overlooked by people in thetrades. Since this aspect is not usually dealt with by field installers, the elementsof administration are sometimes ignored. While this can sometimes work in thefield, it is not advisable to turn your back on any code requirement. If you are won-dering what the administration of a code involves, you are about to find out.

Our goal is to gain a full understanding of the International Fuel Gas Code. Wewill do this chapter by chapter. Administration is our primary focus in this chap-ter. If you don’t already have an official code book, get one. You will need a codebook to use in conjunction with this book.

Be aware that every code jurisdiction is permitted to amend the basic code re-quirements to meet local needs. Don’t overlook this fact. If you have any doubtsabout your local code requirements, check with your local code-enforcement of-ficer for clarification of the full code requirements in your region.

What does the International Fuel Gas Code apply to? Is it the same as theplumbing code? The gas code is not the same as the plumbing code. Areas cov-ered under the fuel-gas code include the following:

• The installation of fuel-gas piping systems

• Fuel-gas utilization equipment

• Gaseous-hydrogen systems

• Related accessories

There is an exception to the above. Detached one- and two-family dwellingsand multiple single-family dwellings such as townhouses that are not more thanthree stories high and that have separate means of egress, together with their ac-cessory structures, must comply with the International Residential Code.

1.1


1.2 INTERNATIONAL FUEL GAS CODE COMPANION

PIPING SYSTEMS

Natural-gas piping with an operating pressure of 125 pounds per square inchgauge (psig) or less is covered under this code. Liquid petroleum (LP) gas with anoperating pressure of 20 psig or less is also covered by this code. Requirements ofthe code apply from the point of delivery of gas to the outlet of the equipment shut-off valve for gas distribution. Piping-system requirements include:

• Design

• Materials

• Components

• Fabrication

• Assembly

• Installation

• Testing

• Inspection

• Operation

• Maintenance

GAS UTILIZATION EQUIPMENT

Requirements for gas-utilization equipment and related accessories are coveredunder the gas code. Such requirements include:

• Installation

• Combustion

• Ventilation air

• Venting

• Connections to piping systems

EXCEPTIONS

There are a number of situations where the fuel-gas code does not apply.Remember to check your local code requirements if there is any doubt in yourmind about the applicable requirements. These are the exceptions:

• Portable LP-gas equipment of all types that is not connected to a fixed fuel-pip-ing system

• Installation of farm equipment such as brooders, dehydrators, dryers, and irriga-tion equipment

• Raw material (feedstock) applications except for piping to special atmospheregenerators

• Oxygen-fuel gas cutting and welding systems

• Industrial gas applications using gases such as acetylene and acetylenic com-pounds, hydrogen, ammonia, carbon monoxide, oxygen, and nitrogen

• Petroleum refineries, pipeline compressor or pumping stations, loading termi-nals, compounding plants, refinery tank farms, and natural-gas processing plants

• Integrated chemical plants or portions of such plants where flammable or com-bustible liquids or gases are produced by or used in chemical reactions

• LP-gas installations at utility gas plants

• Liquefied-natural-gas (LNG) installations

• Fuel-gas piping in power and atomic-energy plants

• Proprietary items of equipment, apparatus, or instruments such as gas-generat-ing sets, compressors, and calorimeters

• LP-gas equipment for vaporization, gas mixing, and gas manufacturing

• Temporary LP-gas piping for buildings under construction or renovation thatwill not become part of the permanent piping system

• Installation of LP-gas systems for railroad-switch heating

• Installation of hydrogen-gas, LP-gas, and compressed-natural-gas (CNG) sys-tems on vehicles

• Except as referenced in Section 401.1.1 of the code, gas piping, meters, gas pres-sure regulators, and other appurtenances used by the serving gas supplier in thedistribution of gas other than undiluted LP gas

• Building design and construction, except as specified in the code

• Piping systems for mixtures of gas and air within the flammable range with anoperating pressure greater than 10 psig

• Portable fuel-cell appliances that are neither connected to a fixed piping systemnor interconnected to a power grid

ADMINISTRATIVE PROCEDURES 1.3

!CodealertA dwelling unit is a single unit providing complete, independent livingfacilities for one or more persons, including permanent provisions forsleeping, eating, cooking, and sanitation.

OTHER FUELS

The requirements for the design, installation, maintenance, alteration, and inspec-tion of mechanical systems operating with fuel other than fuel gas are regulatedby the International Mechanical Code.

MINIMUM STANDARDS

The code is used to establish minimum standards to protect life, limb, health,safety, property, and public welfare. This is done by controlling the design, con-struction, installation, material quality, location, operation, and maintenance oruse of fuel-gas systems. Without code requirements the installation of gas systemswould likely pose far greater risks.

EXISTING INSTALLATIONS

Existing installations are typically grandfathered. This simply means that coderequirements rarely force a person to bring existing conditions into a form thatwill pass modern code requirements. However, for this rule to apply, existing in-stallations must have complied with the code in use at the time the installationoccurred.


?Did you knowDid you know that provisions found in appendices of the code shall not applyunless they are specifically adopted by a jurisdiction? It is a fact.

TradetipIf a section, subsection, sentence, clause, or phrase of the code is for any rea-son deemed to be unconstitutional, this decision will not affect the validityof the remaining portions of the code.

MAINTENANCE

Proper maintenance is required for all installations, both new and existing. Theoperating condition of a system must be maintained in accordance with the origi-nal design and in a safe manner. This applies to devices and safeguards that are re-quired by code.

Who is responsible for required maintenance? Is it the installer? Are primarycontractors responsible for maintenance? No. The maintenance required for a sys-tem is the responsibility of the property owner or the owner’s designated agent. Itis within the rights of a code official to require an installation to be reinspected.

ADDITIONS

Additions, alterations, renovations, or repairs to installations must conform to therequirements of a new installation. This is not to say that existing portions of thesystem must be updated. The requirements of the modern code apply only to thenew work being done, so long as the original installation was in code complianceat the time of installation. Any work done to alter, repair, or add to an existing sys-tem must be performed in a manner that will not render the system unsafe, haz-ardous, or overloaded.

What happens if you have a minor repair to make to an existing system? Doesthat repair have to meet current code requirements? There are two answers. Theshort answer is that the work must meet current code requirements. However,there is an exception. When minor alterations, repairs, renovations, or additionsare made to an approved existing system, the work may be done in the same man-ner and arrangement as was allowed in the existing system so long as the workdoes not render the system hazardous.

CHANGE IN OCCUPANCY

Be careful when working with a building where there will be a change in occu-pancy. When a change of occupancy is desired, the change must be approved


TradetipAdditions, alterations, renovations, or repairs related to building or struc-tural issues are regulated by the International Building Code.

by a code official. Failure to seek approval before making such a change is unlawful.

Assuming that the building meets the intent of the provisions governing build-ing construction for the proposed change in occupancy without any risk of creat-ing a hazard to public health, safety, or welfare, the change should be approved.

HISTORIC DESIGNATION

How does the historic designation of a building affect the enforcement of thiscode? Historic buildings receive different treatment under the code requirements.To be considered a historic building, the building must be designated as historicby a state or local jurisdiction.

A code officer must be consulted to determine if a historic building is safe andin the public interest of health, safety, and welfare in its present condition follow-ing any work done to the building. If these conditions are met, a code officer canwaive normal code requirements for work to be done on historic buildings.


!CodealertRelocated buildings generally must meet present code requirements.There are, of course, exceptions. In general, a building that is movedinto or within a jurisdiction is required to comply with the provisionsfor new installations. This sometimes fools even experienced workers,so remember the rule well.

?Did you knowDid you know that a code officer can determine requirements that are notspecified in the code? Code officers must make rulings pertaining to publicsafety, health, and general welfare.

RELOCATED BUILDINGS

Relocated buildings generally must meet present code requirements. There are, ofcourse, exceptions. In general, a building that is moved into or within a jurisdic-tion is required to comply with the provisions for new installations. This some-times fools even experienced workers, so remember the rule well.

CODE OFFICER APPOINTMENT

Code-officer appointment is done by the chief appointing authority of a jurisdic-tion. A code official cannot be removed from office except for cause and after afull opportunity to be heard on specific and relevant charges by and before the ap-pointing authority. A code official has the authority to appoint a deputy code of-ficial, other related technical officers, inspectors, and other employees.

Liability

How does liability affect code officers? Code officials, code officers, and employ-ees charged with the enforcement of the code, while acting for the jurisdiction,cannot be rendered liable personally. They are relieved from all personal liabilityfor any damage accruing to persons or property as a result of an act required orpermitted in the discharge of official duties.

If a lawsuit is instituted against any officer or employee because of an act per-formed by that officer or employee in the lawful discharge of duties and under theprovisions of the code, the suit shall be defended by the legal representative of thejurisdiction until the final termination of the proceedings.

Code officials and subordinates must not be made liable for costs in an action,suit, or proceeding that is instituted in pursuance of the provisions of the code.Any officer of the Department of Inspection who is acting in good faith and with-out malice will be free of liability for acts performed under any of its provisionsor by reason of any act or omission in the performance of official duties in con-nection therewith.

Authority

How much authority does a code official have? Plenty, when it comes to code en-forcement. The code official is responsible for all aspects of enforcing code re-quirements. The following is a list of powers within the grasp of a code official:

• Rule-making authority

• Applications and permits

• Inspections


• Right of entry

• Identification

• Notices and orders

• Department records

Rules

When the rules of the code are involved, the code official is the ruler. Code offi-cials have full authority, as is necessary for public health, safety, and general wel-fare, to adopt and promulgate rules and regulations. The interpretation and imple-mentation of rules are within the control of a code official. However, a codeofficial cannot rule in a way that will waive structural or fire performance require-ments specifically provided for by the code.

Applications and Permits

Who is responsible for receiving applications and issuing permits? The code offi-cial is. Alterations covered by the code, inspection of premises where permitshave been issued, and enforcement of compliance are also the responsibility of thecode official.

Entry

Code officials have plenty of power to enter a premise. Entry must be provided toa code official whenever it is necessary to make an inspection to enforce the pro-visions of the code. When a code official has reasonable cause to believe that anyconditions or violations of the code that make a structure unsafe, dangerous, orhazardous in a building or on a premise exist, the code official shall have the au-thority to enter the building or premise at all reasonable times to inspect or to per-form the duties imposed upon the code official by the code.

When a code official feels the need to enter an occupied structure, the officialis required to show credentials to the occupant and request entry. Unoccupiedbuildings that are in need of being entered require the code official to make an at-tempt to locate the property owner or person in charge of the property. If entry fora code official is refused, there are options for the code official to seek remedy.


?Did you knowCode officials are required to carry proper identification when inspectingstructures or premises in the performance of duties under the code requirements.

Obtaining a proper inspection warrant or other remedy provided by law to secureentry will get the code official into a building.

Records

Code officers are required to keep accurate records. Some of the items that codeofficers are responsible for include:

• Applications received

• Permits

• Certificates issued

• Fees collected

• Reports of inspections

• Notices issued

• Orders issued

The records retained are to be kept as long as the building or structure towhich they apply remains in existence, unless otherwise provided for by otherregulations.

APPROVAL

Approval is another part of the job description for code officials. Most workers inthe trades think of inspectors when they think of code requirements. This is com-mon and on target. Let’s discuss some of the approval issues to be considered bycode officials.

Modifications

Practical difficulties can result in a code official’s decision to make a modificationin code requirements. Prior to such modification, a code official is required to findthat a special individual reason makes the strict letter of the code impractical. Any


!CodealertCode officials are required to issue all necessary notices or orders toensure compliance with the code.

modification must be in compliance with the intent and purpose of this code andmust not lessen health, life, and fire safety requirements. All details of any actiongranting modifications are required to be entered in the files of the Department ofInspection.

Alternative Options

Alternative options for methods and materials are allowed by code-enforcementofficers. However, the options must be approved. As long as the option is intendedto deliver the same intent of the code in an equal or better manner or quality, acode official may approve the alternate course.

Testing

Testing can be required by a code official when there is insufficient evidence ofcompliance with the provisions of the code. Test methods shall be as specified inthe code or other recognized test standards. If there are no recognized and ac-cepted test methods, the code official shall approve a testing procedure. All testsshall be performed by an approved agency. All reports of tests shall be retained bythe code official for the period required for retention of public records.

PERMITS

Permits are required in most instances for any type of new work. Property own-ers, authorized agents, or contractors who plan to erect, install, enlarge, alter, re-pair, remove, convert, or replace an installation regulated by the code or to causesuch work to be done require a permit. There is an exception: Where equipmentreplacements and repairs are required to be performed in an emergency situation,the permit application shall be submitted within the next working business day ofthe Department of Inspection.

Permits are not required for portable heating appliances. The replacement ofany minor component of equipment that does not alter the prior approval of suchequipment or make such equipment unsafe does not require a permit. When a per-


TradetipIf there are no recognized and accepted test methods, the code official shallapprove a testing procedure. All tests shall be performed by an approvedagency.

mit is not required, work performed must remain in compliance with the code andthe laws or ordinances of the jurisdiction.

Permit Application

Permit application requires a fee. The application and fee are filed with a code of-ficial on an official form provided for that purpose. The forms are available fromlocal code-enforcement offices. Applications must be signed by the propertyowner or an authorized agent. The proposed occupancy of all parts of a buildingmust be described in the permit application.

Unless waived by a code official, construction documents are required when apermit is applied for. Construction documents, engineering calculations, dia-grams, and other data may be required prior to the issuance of a permit. These doc-uments are generally required to be prepared by registered design professionals.

Permit Issuance

Code officials are required to issue permits when all application matters are com-plied with. Common requirements for the issuance of a permit include:

• Permit application

• Construction documents

• Diagrams

• Engineering calculations

• Related pertinent data

• Application fee

Approved Construction Documents

When a code official issues a permit for which construction documents are re-quired, the construction documents shall be endorsed in writing and stamped "AP-PROVED." Once the documents are approved and stamped, they may not bechanged in any way without approval from the code official. All work performedmust be done in accordance with the approved plans.


?Did you knowMaterials, equipment, and devices shall not be reused unless such elementshave been reconditioned, tested, placed in proper working condition and approved.

Validity

The issuance of a permit or approval of construction documents shall not be con-strued to be a permit for or an approval of any violation of any of the provisionsof the code or of other ordinances of the jurisdiction. A permit presuming to giveauthority to violate or cancel the provisions of the code shall be invalid.

If an error is made in the issuance of a permit by a code official, the code of-ficial has the right to correct any mistake that was made. A stop-work order canbe issued by the code official if the mistake is of such a type to warrant such dras-tic action.

Expiration

Permits come with time limits. Work must commence under the permit within 180days. If it does not, the permit will become null and void. Be aware that once workstarts, it must continue. If the work being done under a permit is suspended orabandoned for a period of 180 days or more at any time once the work has started,this can result in the loss of the permit. If a permit does expire, a new permit willbe required to resume work. Usually, the fee for the renewal permit is one-half thecost of the original permit. There are two exceptions: If work has been stopped formore than a year, the process of obtaining a permit goes back to the normal pro-cedure of getting a new permit; and,when work will deviate from the originalplans and specifications, a new permit process is required.

Extensions

Active permits that require more time for the completion of work can be used toapply for an extension. An extension may be approved for an additional 180 daysif there is reasonable cause for the request. Extensions are limited to a one-timeevent. Fees for extensions tend to be half the cost of a new permit.


?Did you knowCode officials shall have the authority to issue a permit for the construction ofpart of an installation before the construction documents for the entire instal-lation have been submitted or approved. There is, however, no guarantee thata permit for the entire project will be issued until all application documentsare in and approved. Acting with a partial permit is risky in the event that thefull project is not authorized.

Retention of Documents

One set of construction documents shall be retained by the code official until fi-nal approval of the work covered therein. One set of approved construction docu-ments shall be returned to the applicant, and said set shall be kept on the site of thebuilding or work at all times during which the work authorized thereby is inprogress.

Working Without a Permit

Working without a permit when a permit is required is not good business. Atthe very least, a person caught beginning work without a required permit is goingto have to pay a fee of 100 percent of the cost of a permit plus the cost of a permit.In other words, you will pay twice as much for a permit when you get one. Don’tbegin work without a required permit.

The refunding of permit fees may occur up to 180 days after a permit fee ispaid. Percentage amounts for the refunds vary from jurisdiction to jurisdiction.Check with your local code enforcement office for details on refund amounts.

INSPECTIONS

A permit holder is required to notify a code official when work is ready for a re-quired inspection. When a code official conducts a required inspection, the offi-


!CodealertCode officers are required to revoke permits or approvals issued underthe provisions of the code in cases where false information or facts inthe application or construction documents were provided.

?Did you knowA permit shall not be issued until the fees required by the code are paid. If anamendment to a permit is requested, it must not be issued until the requiredfee is paid.

cial must either allow work to proceed or identify violations that must be correctedbefore work progresses. There are three types of inspections required: under-ground inspections, rough-in inspections, and final inspections.

Underground Inspections

Underground inspection shall be made after trenches or ditches are excavated andbedded and piping is installed and before backfill is put in place. When excavatedsoil contains rocks, broken concrete, frozen chunks, and other rubble that woulddamage or break the piping or cause corrosive action it must not be used. Cleanbackfill shall be on the site.

Rough-In Inspections

Rough-in inspections are made after the roof, framing, fireblocking, and bracingare in place and components to be concealed are complete and prior to the instal-lation of wall or ceiling membranes.

Final Inspections

Final inspections take place upon the full completion of all work.

HEATING EQUIPMENT

Heating equipment installed to replace existing equipment serving an occupiedportion of a structure can be treated as an emergency action and does not requirea permit to be obtained prior to work being done, in the event that a request for in-spection of such heating equipment has been filed with the department not morethan 48 hours after replacement work is completed and before any portion of suchequipment is concealed by any permanent portion of the structure. Remember,though, that you must apply for all applicable permits within 48 hours of complet-ing the work.


TradetipThe code official shall accept reports of approved agencies, provided thatsuch agencies satisfy the requirements as to qualifications and reliability.

PREFABRICATED CONSTRUCTION

Prefabricated construction has become very popular. Since this type of construc-tion is done off the construction site and much of the work that would normally beinspected is concealed prior to placement on a building lot, how do you accountfor the inspection requirements? The process is actually quite simple. A manufac-turer of prefabricated construction must provide a code official with detailed sub-mittals for consideration. Once the documents are reviewed and approved, a per-mit can be issued. Several factors may be included in the submittals, some ofwhich include:

• Evaluation report

• Complete installation details

• A description of systems and components

• The basis upon which the system is being evaluated

• Test results

• Other data as specifically required

Follow-up Inspections

Follow-up inspections can be required, unless there is ready access provided to in-stallations, service equipment, and accessories. Code officials are required to con-


TradetipNew installations and parts of existing installations that have been altered,extended, renovated or repaired must be tested as prescribed by the code todisclose leaks and defects.

TradetipWhen an evaluation service is required, a code official shall designate theservice of an approved agency and review the agency’s evaluation report foradequacy and conformance to the code.

duct in-plant inspections as frequently as necessary to ensure performance com-plies with an approved evaluation report. At the discretion of a code official, anindependent inspection agency may be appointed by the code official. When anindependent inspection is done, a report of inspections must be furnished to thecode official upon request. Additionally, a label permanently affixed to the systemindicating that factory inspections have been performed is required.

Required test and inspection records must be made available to code officialsat all times during the fabrication of an installation and the erection of a building.Records required by a code official must be filed.

Approval

Once all required testing and inspection are done and prove the work to be in com-pliance with code requirements, a code official approves the work. This approvalis done in writing and filed.

Temporary connection to sources of energy can be approved by a code officialto allow the testing of an installation. It is also possible to obtain a temporary cer-tificate of occupancy at the discretion of a code official.

VIOLATIONS

Violations of code requirements can bring big trouble. The code is not to be takenlightly. It is a violation of law for a person, firm, or corporation to perform code-regulated work in violation of code requirements.


?Did you knowWhere any work or installation does not pass an initial test or inspection, thenecessary corrections shall be made so as to achieve compliance with thecode. Once corrections are made, the work must be resubmitted to the code of-ficial for inspection and testing.

?Did you knowTesting required by the code is done by the permit holder and observed by acode official. Apparatus, instruments, materials, and labor required for testingan installation or part thereof shall be furnished by the permit holder.

When a code violation is discovered, a code official is required to serve no-tice on the appropriate party that a code violation exists. The official order mustdirect the discontinuance of the illegal action or condition and the abatement ofthe violation.

The recipient of a violation notice must take corrective action promptly. If thisdoes not occur, a code official is required to press the matter with legal counsel ofthe jurisdiction being served. All remedies allowed by law may be brought to bearin an attempt to abate the code violation.

Punishment

What is the punishment for a code violation? It may be a simple fine, but somecode violations can result in imprisonment. In some cases, a fine and imprison-ment may both be handed out as a punishment. Each day that a violation contin-ues after due notice has been served shall be deemed a separate offense.

Stop-work Order

If a code official issues a stop-work order, all work must cease immediately. Thenotice must be in writing and given to the property owner, the owner’s agent, orthe person doing the work. A stop-work order must define the conditions underwhich work is authorized to resume. In the event of emergency circumstances, acode official is not required to provide written notice prior to stopping work.Failure to comply with a stop-work order is likely to result in a fine.

Unsafe Conditions

Unsafe conditions surrounding work are considered to be conditions in which thework is unsafe, constitutes a fire or health hazard, or is otherwise dangerous to hu-man life. Unsafe installations are considered to be a public nuisance that must beabated by repair, rehabilitation, demolition, or removal.


!CodealertWhat is the punishment for a code violation? It may be a simple fine,but some code violations can result in imprisonment. In some cases, afine and imprisonment may both be handed out as a punishment. Eachday that a violation continues after due notice has been served shall bedeemed a separate offense.

Condemned Installations

A code official can condemn a site when there is reasonable belief on the part ofthe official that any installation or portion thereof regulated by the code becomeshazardous to life, health, or property. When a site is condemned, a written noticeis presented that outlines what is required to abate the situation. The notice mustinclude a time limit for compliance to take place.

A person shall not use or maintain a defective installation after receiving suchnotice. If an installation is to be disconnected, written notice must be given. Incases of immediate danger to life or property, such disconnection shall be madeimmediately without such notice.

Disconnection

Code officers have the authority to have utilities disconnected from buildings andstructures when emergency conditions exist. If this is to be done, the utility servermust be notified. An attempt will be made to notify the property owner. If a prop-erty owner cannot be notified prior to disconnection, the property owner shall benotified in writing as soon as is practicable thereafter.

Reconnection

A person must not make energy-source connections to installations regulated bythe code that have been disconnected or ordered to be disconnected by the codeofficial. The use of an energy-source connection that has been shut down or or-dered shut down, until approved by a code official, is prohibited. In the event thatcompliance is not provided to an official order, the code official shall institute ap-propriate action to prevent, restrain, correct, or abate the violation.

APPEAL

A person has a right to appeal a decision made by a code official. This process be-gins with an application for appeal. The request must state that the appeal is basedon a claim that the true intent of the code or rules legally adopted under the codehas been interpreted incorrectly. An application for appeal must be filed on a formobtained by a code official within 20 days after the notice was served.

Membership of Board of Appeals

The board of appeals consists of five members. They are appointed by the chiefappointing authority. The members are appointed for staggered terms. The detailsare as follows:

• One for five years


• One for four years

• One for three years

• One for two years

• One for one year

• Thereafter, each new member shall serve for five years or until a successor hasbeen appointed

Qualifications

What are the qualifications needed to hold a place on the membership board? Thefive individuals who sit on the board must come from five different walks of life.Rules call for the following requirements:

• One member must be a registered design professional who is a registered archi-tect, builder, or superintendent of building construction. Ten years of experienceare required. Half of this experience must have been gained as the person incharge of work.

• One member must be a registered design professional with structural-engineer-ing or architectural experience.

• One member must be a registered design professional with fuel-gas and plumb-ing-engineering experience or a fuel-gas contractor with at least 10 years of ex-perience, with half of that experience gained while in charge of work.

• One member must be a registered design professional with fire-protection-engi-neering experience or a fire-protection contractor with at least 10 years of expe-rience, with half of that experience gained while in charge of work.

Board Organization

The board is required to select one of its members to serve as chairman once ayear. Members must not hear an appeal in which the members have a personal orprofessional interest in the proceeding. Selection of a qualified clerk to serve as


!CodealertThe chief appointing authority shall appoint two alternate members,who shall be called by the board chairman to hear appeals during theabsence or disqualification of a member. Alternate members shall pos-sess the qualifications required for board membership and shall be ap-pointed for five years or until a successor has been appointed.

secretary to the board is made by the chief administrative officer. Compensationfor members is determined by law.

The board shall meet upon notice from the chairman within 10 days of the fil-ing of an appeal or at stated periodic meetings. Hearings before the board shall beopen to the public. Anyone affected by an appeal has an opportunity to attend anopen hearing. The board must adopt and make available to the public through thesecretary procedures under which a hearing will be conducted. The proceduresshall not require compliance with strict rules of evidence but shall mandate thatonly relevant information be received.

An appeal hearing can be postponed if fewer than five board members arepresent. It takes a concurring vote of at least three board members to modify or re-verse a decision made by a code official. The decision of an appeal board must beby resolution. Certified copies shall be furnished to the appellant and to the codeofficial. It is then up to the code official to take immediate action in accordancewith the decision of the board.

Any person, whether or not a previous party to an appeal, shall have the rightto apply to the appropriate court for a writ of certiorari to correct errors of law.Application for review shall be made in the manner and time required by law fol-lowing the filing of the decision in the office of the chief administrative officer.

Well, there you have it. We are done with the administration section of thecode. Understanding definitions is next on our list, so let’s turn to Chapter 2 andget a clear understanding of the words, terms, and phrases used in the code.


CHAPTER 2DEFINITIONS

Definitions are important when interpreting the code. If you don’t have a clear un-derstanding of what words and phrases mean, you are going to have a rough ridetrying to read the code properly. This chapter is going to review the meaning ofterms as they are defined by the code.

When dealing with the code, words used in the present tense include the futuretense. Words in masculine gender include the feminine and neuter genders. A sin-gle number includes a plural number, and a plural number also indicates a singlenumber.

Terms that are not specifically defined in this section have ordinarily acceptedmeanings as the context implies. Terms defined in other codes carry the meaningsin those codes.

Definitions don’t require a lot of interpretation.. Don’t skip this chapter. Iknow it may seem senseless to put a lot of effort into learning definitions.However, you will not be able to do your best work with the code if you don’t un-derstand the definitions.

ACCESS (TO): That which enables a device, appliance, or equipment to be read-ily reached or by a means that first requires the removal or movement of a panel,door, or similar obstruction.

AIR CONDITIONER, GAS-FIRED: A gas-burning, automatically operatedappliance for supplying cooled and/or dehumidified air or chilled liquid.

AIR CONDITIONING: The treatment of air so as to control simultaneously thetemperature, humidity, cleanness, and distribution to meet the requirements of aspace.

AIR, EXHAUST: Air being removed from any space or piece of equipment andconveyed directly to the atmosphere by means of openings or ducts.

AIR-HANDLING UNIT: A blower or fan used for the purpose of distributingsupply air to a room, space, or area.

AIR, MAKEUP: Air provided to replace air being exhausted.

2.1



ALTERATION: A change in a system that involves an extension, addition, orchange to the arrangement, type, or purpose of the original installation.

ANODELESS RISER: A transition assembly in which plastic piping is installedand terminated above ground outside of a building.

APPLIANCE, AUTOMATICALLY CONTROLLED: Appliances equippedwith an automatic burner ignition, safety shutoff device, and other automatic de-vices that accomplish complete turn-on and shutoff of the gas to the main burneror burners and graduate the gas supply to the burner or burners, but do not affectcomplete shutoff of the gas.

APPLIANCE (EQUIPMENT): Any apparatus or equipment that utilizes gas as afuel or raw material to produce light, heat, power, refrigeration, or air conditioning.

APPLIANCE, FAN-ASSISTED COMBUSTION: An appliance equipped withan integral mechanical means to either draw or force products of combustionthrough a chamber or heat exchanger.

APPLIANCE, LOW-HEAT (RESIDENTIAL): Any appliance in which theproducts of combustion at the point of entrance to the flue under normal operatingconditions have a temperature of 1,000 degrees F.

APPLIANCE, MEDIUM-HEAT: Any appliance in which the products of com-bustion at the point of entrance to the flue under normal operating conditions havea temperature of more than 1000 degrees F, but not greater than 2000 degrees F.

APPLIANCE, UNVENTED: An appliance designed or installed in such a man-ner that the products of combustion are not conveyed by a vent or chimney directlyto the outside atmosphere.

APPLIANCE, VENTED: An appliance designed and installed in such a mannerthat all of the products of combustion are conveyed directly from the appliance tothe outside atmosphere through an approved chimney or vent system.

APPROVED: Acceptable to the code official or other authority having jurisdiction.

APPROVED AGENCY: An established and recognized agency that is accept-able to the code official and regularly engaged in conducting tests or furnishinginspection services.

ATMOSPHERIC PRESSURE: The pressure of the weight of air and water va-por on the surface of the earth, approximately 14.7 pounds per square inch (psi) atsea level.

AUTOMATIC IGNITION: Ignition of gas at the burner(s) when the gas-control-ling device is turned on, including reignition if the flames on the burner(s) havebeen extinguished by means other than by the closing of the gas-controlling device.

BAFFLE: An object placed in an appliance to change the direction of or retardthe flow of air, air-gas mixtures, or flue gases.

BAROMETRIC DRAFT REGULATOR: A balanced damper device at-

tached to a chimney, vent connector, breeching, or flue-gas manifold to protectcombustion equipment by controlling chimney draft. A double-acting baromet-ric draft regulator is one whose balancing damper is free to move in either di-rection to protect combustion equipment from both excessive draft and backdraft.

BOILER, HOT-WATER-HEATING: A boiler in which no steam is generated,from which hot water is circulated for heating purposes and then returned to theappliance and that operates at water pressures not exceeding 160 pounds per-square-inch gauge (psig) and at water temperatures not exceeding 250 degrees Fat or near the outlet.

BOILER, HOT-WATER-SUPPLY: A boiler completely filled with water thatfurnishes hot water to be used externally and that operates at water pressures notexceeding 160 psig and at water temperatures not exceeding 250 degrees F at ornear the outlet.

BOILER, LOW-PRESSURE: A self-contained appliance for supplying steamor hot water.

BOILER, STEAM-HEATING: A boiler in which steam is generated and thatoperates at a steam pressure not exceeding 15 psig.

BRAZING: A metal-joining process wherein coalescence is produced by the useof a nonferrous filler metal having a melting point above 1000 degrees F but lowerthan that of the base metal being joined. The filler material is distributed betweenthe closely fitted surfaces of the joint by capillary action.

BROILER: A general term including salamanders, barbecues, and other appli-ances cooling primarily by radiated heat, excepting toasters.

BTU: Abbreviation for British thermal unit, which is the quantity of heat requiredto raise the temperature of one pound of water 1 degree F.

BURNER: A device for the final conveyance of a gas or a mixture of gas and airto the combustion zone.

BURNER, INDUCED-DRAFT: A burner that depends on draft induced by a fanthat is an integral part of the appliance and is located downstream from the burner.

BURNER, POWER: A burner in which gas, air, or both are supplied at pressuresexceeding, for gas, the line pressure,, and, for air, atmospheric pressure, with thisadded pressure being applied at the burner.

CHIMNEY: A primarily vertical structure containing one or more flues for thepurpose of carrying gaseous products of combustion and air from an appliance tothe outside atmosphere.

CHIMNEY, FACTORY-BUILT: A listed and labeled chimney composed offactory-made components, assembled in the field in accordance with manufac-turer’s instructions and the conditions of the listing.

CHIMNEY, MASONRY: A field-constructed chimney composed of solid ma-

DEFINITIONS 2.3

sonry units, bricks, stones, or concrete.

CHIMNEY, METAL: A field-constructed chimney made of metal.

CLEARANCE: The minimum distance through air measured between the heat-producing surface of the mechanical appliance, device, or equipment and the sur-face of the combustible material or assembly.

CLOTHES DRYER: An appliance used to dry wet laundry by means of heated air.

CLOTHES DRYER, TYPE 1: A factory-built package in multiple production,primarily used in family living environments; usually the smallest unit physicallyand in function output.

CLOTHES DRYER, TYPE 2: A factory-built package in multiple production,used in public Laundromats; not designed for use in individual family living en-vironments.

CODE: Regulations, subsequent amendments thereto, or any emergency rule orregulation that the administrative authority having jurisdiction has lawfullyadopted.

CODE OFFICIAL: The officer or other designated authority charged with theadministration and enforcement of a code or a duly authorized representative.

COMBUSTION: In the context of this code, the rapid oxidation of fuel accom-panied by the production of heat or heat and light.

COMBUSTION AIR: Air necessary for complete combustion of a fuel, includ-ing theoretical air and excess air.

COMBUSTION CHAMBER: The portion of an appliance within which com-bustion occurs.

COMBUSTION PRODUCTS: Constituents resulting from the combustion of afuel with the oxygen of the air, including inert gases but excluding excess air

CONCEALED LOCATION: A location that cannot be accessed without damag-ing permanent parts of the building structure or finish surface. Spaces above, below,or behind readily removable panels or doors are not considered to be concealed.

CONCEALED PIPING: Piping that is located in an inaccessible location.

CONDENSATE: The liquid that condenses from a gas, including flue gas,caused by a reduction in temperature or an increase in pressure.

CONNECTOR, APPLIANCE (FUEL): A rigid metallic pipe and fittings, semi-rigid metallic tubing and fittings, or listed and laved device that connects an ap-pliance to the gas-piping system.

CONNECTOR, CHIMNEY OR VENT: The pipe that connects an appliance toa chimney or vent.

CONSTRUCTION DOCUMENTS: All of the written, graphic, and pictorialdocuments prepared or assembled for describing the design, location, and physi-cal characteristics of the elements of the project necessary for obtaining a permit.


CONTROL: A manual or automatic device designed to regulate the gas, air, wa-ter, or electrical supply to or operation of a mechanical system.

CONVERSION BURNER: A unit consisting of a burner and its controls for in-stallation in an appliance originally utilizing another fuel.

COUNTER APPLIANCES: Appliances such as coffee brewers and any appur-tenant water-heating equipment, food and dish warmers, hot plates, griddles, waf-fle bakers, and other appliances designed for installation on or in a counter.

CUBIC FOOT: The amount of gas that occupies 1 cubic foot at a temperature of60 degrees F, saturated with water vapor and under a pressure equivalent to thatof 30 inches of mercury.

DAMPER: A manually or automatically controlled device to regulate draft or therate of flow of air or combustion gases.

DECORATIVE APPLIANCE, VENTED: A vented appliance wherein the pri-mary function lies in the aesthetic effect of the flames.

DECORATIVE APPLIANCE, VENTED FIREPLACE: A vented appliancedesigned for installation within the fire chamber of a vented fireplace, wherein theprimary function lies in the aesthetic effect of the flames.

DEMAND: The maximum amount of gas input required per unit of time, usuallyexpressed in cubic feet per hour or BTU/h.

DESIGN-FLOOD ELEVATION: The elevation of the design flood includingwave height, relative to the datum specified on the community’s legally desig-nated flood hazard map.

DILUTION AIR: Air that is introduced into a draft hood and mixed with the fluegases.

DIRECT-VENT APPLIANCES: Appliances that are constructed and installedso that all air for combustion is derived directly from the outside atmosphere andall flue gases are discharged directly to the outside atmosphere.

DRAFT: The pressure difference existing between the equipment or any compo-nent part and the atmosphere, which causes a continuous flow of air and productsof combustion through the gas passages of the appliance to the atmosphere.

DRAFT HOOD: A nonadjustable device built into an appliance or made as partof the vent connector from an appliance, designed to (1) provide for ready escapeof the flue gases from the appliance in the event of no draft, back draft, or stop-page beyond the draft hood; (2) prevent a back draft from entering the appliance;and (3) neutralize the effect of stack action of the chimney or gas vent upon oper-ation of the appliance.

DRAFT, MECHANICAL OR INDUCED: The pressure difference created bythe action of a fan, blower, or ejector that is located between the appliance and thechimney or vent termination.

DRAFT, NATURAL: The pressure difference created by a vent or chimney due to

DEFINITIONS 2.5

its height and the temperature difference between the flue gases and the atmosphere.

DRAFT REGULATOR: A device that functions to maintain a desired draft inthe appliance by automatically reducing the draft to the desired value.

DRIP: The container placed at a low point in a system of piping to collect con-densate and from which the condensate is removable.

DRY GAS: A gas having a moisture and hydrocarbon dew point below any nor-mal temperature to which the gas piping is exposed.

DUCT FURNACE: A warm-air furnace normally installed in an air-distributionduct to supply warm air for heating. This definition shall apply only to a warm-airheating appliance that depends for air circulation on a blower not furnished as partof the furnace.

DUCT SYSTEM: A continuous passageway for the transmission of air that, inaddition to ducts, includes ducts fittings, dampers, plenums, fans, and accessoryair-handling equipment.

DWELLING UNIT: A single unit providing complete, independent living facil-ities for one or more persons, including permanent provisions for living, sleeping,eating, cooking, and sanitation.

EQUIPMENT: See “Appliance.”

FIREPLACE: A fire chamber and hearth constructed of noncombustible mate-rial for use with solid fuels and provided with a chimney.

FIREPLACE, FACTORY-BUILT: A fireplace composed of listed factory-builtcomponents assembled in accordance with the terms of listing to form the com-pleted fireplace.

FIREPLACE, MASONRY: A hearth and fire chamber of solid masonry unitssuch as bricks, stones, listed masonry units, or reinforced concrete, provided witha suitable chimney.

FIRING VALVE: A valve of the plug and barrel type designed for use with gasand equipped with a lever handle for manual operation and a dial to indicate thepercentage of opening.

FLAME SAFEGUARD: A device that will automatically shut off the fuel sup-ply to a main burner or group of burners when the means of ignition of such burn-ers becomes inoperative and when flame failure occurs on the burner or group ofburners.

FLOOD HAZARD AREA: The greater of the following two areas: (1) the areawithin a flood plain subject to a 1 percent or greater change of flooding in anygiven year or (2) the area designated as a flood hazard area on a community’sflood hazard map or otherwise legally designated.

FLOOR FURNACE: A completely self-contained furnace suspended from thefloor of the space being heated, taking air for combustion from outside such spaceand with means for observing flames and lighting the appliance from such space.


FLOOR FURNACE, FAN TYPE: A floor furnace equipped with a fan that pro-vides the primary means for circulating air.

FLOOR FURNACE, GRAVITY-TYPE: A floor furnace depending primarilyupon circulation of air by gravity. This classification also includes floor furnacesequipped with booster-type fans that do not materially restrict free circulation ofair by gravity flow when such fans are not in operation.

FLUE, APPLIANCE: The passage(s) within an appliance through which com-bustion products pass from the combustion chamber of the appliance to the draft-hood inlet opening equipped with a draft hood or to the outlet of the appliance onan appliance not equipped with a draft hood.

FLUE COLLAR: That portion of an appliance designed for the attachment of adraft hood, vent connector, or venting system.

FLUE GASES: Products of combustion plus excess air in appliance flues or heatexchangers.

FLUE LINER: A system or material used to form the inside surface of a flue ina chimney or vent for the purpose of protecting the surrounding structure from theeffects of combustion products and for conveying combustion products withoutleakage to the atmosphere.

FUEL GAS: A natural gas, manufactured gas, liquefied-petroleum gas, or mix-tures of these gases.

FUEL-GAS-UTILIZATION EQUIPMENT: See “Appliance.”

FURNACE: A completely self-contained heating unit that is designed to supplyheated air to spaces remote from or adjacent to the appliance location.

FURNACE, CENTRAL: A self-contained appliance for heating air by transferof the heat of combustion through metal to the air and designed to supply heatedair through ducts to a space remote from or adjacent to the appliance location.

FURNACE, DOWN-FLOW: A furnace designed with air-flow discharge verti-cally downward at or near the bottom of the furnace.

FURNACE, ENCLOSED: A specific heating or heating and ventilating fur-nace incorporating an integral total enclosure and using only outside air forcombustion.

FURNACE, FORCED-AIR: A central furnace equipped with a fan or blowerthat provides the primary means for circulation of air.

FURNACE, FORCED-AIR WITH COOLING UNIT: A single-package unit,consisting of a gas-fired forced-air furnace combined with an electrically or fuel-gas-powered summer air-conditioning system contained in a common casting.

FURNACE, GRAVITY WITH BOOSTER FAN: A furnace equipped with abooster fan that does not materially restrict free circulation of air by gravity flowwhen the fan is not in operation.

FURNACE, GRAVITY-TYPE: A central furnace depending primarily on circu-lation of air by gravity.

DEFINITIONS 2.7

FURNACE, HORIZONTAL FORCED-AIR: A furnace with air flow throughthe appliance essentially in a horizontal path.

FURNACE, MULTIPLE-POSITION: A furnace designed so that it can be in-stalled with the air-flow discharge in the up-flow, horizontal, or down-flow direction.

FURNACE PLENUM: An air compartment or chamber to which one or moreducts are connected and that forms part of an air-distribution system.

FURNACE, UP-FLOW: A furnace designed with air-flow discharge verticallyupward at or near the top of the furnace. This classification includes “highboy”furnaces with the blower mounted below the heating element and “lowboy” fur-naces with the blower mounted beside the heating element.

GAS CONVENIENCE OUTLET: A permanently mounted, manually operateddevice that provides the means for connecting an appliance to and disconnecting andappliance from the supply piping. The device includes an integral manually oper-ated valve with a nondisplaceable valve member designed so that disconnection ofan appliance only occurs when the manually operated value is in the closed position.

GAS PIPING: An installation of pipe, valves, or fittings installed on a premise orin a building and utilized to convey fuel gas.

GAS-UTILIZATION EQUIPMENT: An appliance that utilizes gas as a fuel,raw material, or both.

HAZARDOUS LOCATION: Any location considered to be a fire hazard forflammable vapors, dust, combustible fibers, or other highly combustible sub-stances. The location is not necessarily categorized in the building code as a high-hazard group.

HOUSE PIPING: See “Piping system.”

IGNITION PILOT: A pilot that operates during the lighting cycle and discontin-ues during main burner operations.

IGNITION SOURCE: A flame, spark, or hot surface capable of igniting flam-mable vapors or fumes. Such sources include appliance burners, burner igniters,and electrical switching devices.

INCINERATOR: An appliance used to reduce combustible refuse material toashes and manufactured, sold, and installed as a complete unit.

INDUSTRIAL AIR HEATERS, DIRECT-FIRED, NONRECIRCULAT-ING: A heater in which all the products of combustion generated by the burnersare released into the air stream being heated. The purpose of the heater is to offsetbuilding heat loss by heating only outdoor air.

INDUSTRIAL AIR HEATERS, DIRECT-FIRED RECIRCULATING: Aheater in which all the products of combustion generated by the burners are re-leased into the air stream being heated. Such heaters are of either the vented or un-vented type.


INFRARED RADIANT HEATER: A heater that directs a substantial amount ofits energy output in the form of infrared radiant energy into the area to be heated.Such heaters are of either the vented or unvented type.

JOINT, FLANGED: A joint made by bolting together a pair of flanged ends.

JOINT, FLARED: A metal-to-metal compression joint in which a conical spreadis made on the end of a tube that is compressed by a flare nut against a matingflare.

JOINT, MECHANICAL: A general form of gas-tight joint obtained by the join-ing of metal parts through a positive-holding mechanical construction, such as aflanged joint, threaded joint, flared joint, or compression joint.

JOINT, PLASTIC ADHESIVE: A joint made in thermoset plastic piping by theuse of an adhesive substance that forms a continuous bond between the matingsurfaces without dissolving either one of them.

JOINT, PLASTIC HEAT-FUSION: A joint made in thermoplastic piping byheating the parts sufficiently to permit fusion of the materials when the parts arepressed together.

JOINT, WELDED: A gas-tight joint obtained by the joining of metal parts in amolten state.

LABELED: Devices, equipment, appliances, or materials to which have been af-fixed a label, seal, symbol, or other identifying mark of a nationally recognizedtesting laboratory, inspection agency, or other organization concerned with prod-uct evaluation that maintains periodic inspection of the production of the above-labeled items and by whose label the manufacturer attests to compliance with ap-plicable nationally recognized standards.

LIMIT CONTROL: A device responsive to changes in pressure, temperature, orlevel for turning on, shutting off, or throttling the gas supply to an appliance.

LIQUEFIED-PETROLEUM GAS (LPG): A gas composed predominantly ofpropane, propylene, butanes or butylenes, or mixtures thereof that is gaseous un-der normal atmospheric conditions but is capable of being liquefied under moder-ate pressure at normal temperatures.

LISTED: Equipment, appliances, or materials included in a list published by a na-tionally recognized testing laboratory, inspection agency, or other organizationconcerned with product evaluation that maintains periodic inspection of produc-tion of listed equipment, appliances, or materials and whose listing states eitherthat the equipment, appliance, or material meets nationally recognized standardsor has been tested and found suitable for use in a specified manner. The means foridentifying listed equipment, appliances, or materials may vary for each testinglaboratory, inspection agency, or other organization concerned with product eval-uation, some of which do not recognize equipment, appliances, or materials aslisted unless they are also labeled. The authority having jurisdiction shall utilizethe system employed by the listing organization to identify a listed product.

DEFINITIONS 2.9

LIVING SPACE: Space within a dwelling unit utilized for living, sleeping, eat-ing, cooking, bathing, washing, and sanitation purposes.

LOG LIGHTER: A manually operated solid-fuel-ignition appliance for installa-tion in a vented solid-fuel-burning fireplace.

LUBRICATED PLUG-TYPE VALVE: A valve of the plug and barrel type pro-vided with a means for maintaining a lubricant between the bearing surfaces.

MAIN BURNER: A device or group of devices essentially forming an integralunit for the final conveyance of gas or a mixture of gas and air to the combustionzone and on which combustion takes place to accomplish the function for whichthe appliance is designed.

METER: The instrument installed to measure the volume of gas deliveredthrough it.

MODULATING: Also known as throttling, the action of a control from its max-imum to minimum position in either predetermined steps or increments of move-ment as caused by its actuating medium.

OCCUPANCY: The purpose for which a building or portion thereof is utilized oroccupied.

OFFSET (VENT): A combination of approved bends that makes two changes indirection, bringing one section of the vent out of line but into a line parallel withthe other section.

ORIFICE: The opening in a cap, spud, or other device whereby the flow of gasis limited and through which the gas is discharged to the burner.

OUTLET: A threaded connection or bolted flange in a pipe system to which agas-burning appliance is attached.

OXYGEN-DEPLETION SAFETY SHUTOFF SYSTEM (ODS): A systemdesigned to shut off the gas supply to the main and pilot burners if the oxygen inthe surrounding atmosphere is reduced below a predetermined level.

PILOT: A small flame that is utilized to ignite the gas at the main burner or burners.

PIPING: A pipe, tubing, or both. Pipe is a rigid conduit of iron, steel, copper, brass,or plastic. Tubing is a semirigid conduit of copper, aluminum, plastic, or steel.

PIPING SYSTEM: All fuel piping, valves, and fittings from the outlet of thepoint of delivery to the outlets of the equipment shutoff valves.

PLASTIC, THERMOPLASTIC: A plastic that is capable of being repeatedlysoftened by increase of temperature and hardened by decrease of temperature.

POINT OF DELIVERY: For natural gas systems, the outlet of the service-me-ter assembly or of the service regulator or service shutoff valve where a meter isnot provided. Where a value is provided at the outlet of the service-meter assem-bly, such valve shall be considered to be downstream of the point of delivery. Forundiluted liquefied-petroleum-gas systems, the point of delivery shall be consid-ered to be the outlet of the first regulator that reduces pressure to 2 psig or less.


PORTABLE FUEL-CELL APPLIANCE: A fuel-cell generator of electricitythat is not fixed in place. A portable fuel-cell appliance utilizes a cord and plugconnection to a grid-isolated load and has an integral fuel supply.

PRESSURE DROP: The loss in pressure due to friction or obstruction in pipes,valves, fittings, regulators, and burners.

PRESSURE TEST: An operation performed to verify the gas-tight integrity ofgas piping following its installation or modification.

PURGE: To free a gas conduit of air, gas, or a mixture of gas and air.

QUICK-DISCONNECT DEVICE: A hand-operated device that provides ameans for connecting and disconnecting an appliance or an appliance connectorto a gas supply and that is equipped with an automatic means to shut off the gassupply when the device is disconnected.

READY ACCESS (TO): That which enables a device, appliance, or equipmentto be directly reached without requiring the removal or movement of any panel,door, or similar obstruction.

REGISTERED DESIGN PROFESSIONAL: An individual who is registeredor licensed to practice a respective design profession as defined by the statutoryrequirements of the professional registration laws of the state or jurisdiction inwhich the project is to be constructed.

REGULATOR: A device for controlling and maintaining a uniform supply pres-sure, either pounds-to-inches water column (MP regulator) or inches-to-incheswater column (appliance regulator).

REGULATOR, GAS APPLIANCE: A pressure regulator for controlling pres-sure to the manifold of equipment.

REGULATOR, GAS APPLIANCE, LIMITED-ADJUSTMENT: A springtype limited adjustment in which the regulating force acting upon the diaphragmis derived principally from a spring, the loading of which is adjustable over arange of not more than 15 percent of the outlet pressure at the midpoint of the ad-justment range.

REGULATOR, GAS APPLIANCE, MULTISTAGE: A regulator for use witha single gas whose adjustment means is capable of being positioned manually orautomatically to two or more predetermined outlet pressure settings. Each of thesesettings shall be adjustable or nonadjustable. The regulator may modulate outletpressures automatically between its maximum and minimum predetermined out-let pressure settings.

REGULATOR, GAS APPLIANCE, NONADJUSTABLE, SPRING TYPE:A regulator in which the regulating force acting upon the diaphragm is derivedprincipally from a spring, the loading of which is not field-adjustable.

REGULATOR, GAS APPLIANCE, SPRING TYPE, STANDARD ADJUSTMENT: A regulator in which the regulating force acting upon the di-aphragm is derived principally from a spring, the loading of which is adjustable.

DEFINITIONS 2.11

The adjustment means shall be concealed.

REGULATOR, GAS APPLIANCE, WEIGHT TYPE: A regulator in whichthe regulating force acting upon the diaphragm is derived from a weight or com-bination of weights.

REGULATOR, LINE GAS-PRESSURE: A device placed in a gas line be-tween the service pressure regulator and the equipment for controlling, maintain-ing, or reducing the pressure in that portion of the piping system downstream ofthe device.

REGULATOR, MEDIUM-PRESSURE (MP): A line pressure regulator thatreduces gas pressure from the range of greater than 0.5 psig and less than or equalto 5 psig to a lower pressure.

REGULATOR, PRESSURE: A device placed in a gas line for reducing, control-ling, and maintaining the pressure in that portion of the piping system downstreamof the device.

REGULATOR, SERVICE PRESSURE: A device installed by the serving gassupplier to reduce and limit the service line pressure to delivery pressure.

RELIEF OPENING: The opening provided in a draft hood to permit the readyescape to the atmosphere of the flue products from the draft hood in the event ofno draft, back draft, or stoppage beyond the draft hood and to permit air into thedraft hood in the event of a strong chimney updraft.

RELIEF VALVE, DEVICE: A safety valve designed to forestall the develop-ment of a dangerous condition by relieving either pressure, temperature, or vac-uum in the hot-water-supply system.

RELIEF VALVE, TEMPERATURE, RESEATING OR SELF-CLOSINGTYPE: A resealing or self-closing automatic valve that opens and closes a reliefvent, depending on whether the temperature is above or below a predeterminedvalue.

RELIEF VALVE, TEMPERATURE, MANUAL RESET TYPE: A valve thatautomatically opens a relief vent at a predetermined temperature and that must bemanually returned to the closed position.

RELIEF VALVE, VACUUM: A valve that automatically opens and closes avent for relieving a vacuum within the hot-water-supply system, depending onwhether the vacuum is above or below a predetermined value.

RISER, GAS: A vertical pipe supplying fuel gas.

ROOM HEATER, UNVENTED: See “Unvented room heater.”

ROOM HEATER, VENTED: A free-standing heating unit used for direct heat-ing of the space in and adjacent to that in which the unit is located.

ROOM, LARGE, IN COMPARISON WITH SIZE OF EQUIPMENT: Aroom having a volume equal to at least 12 times the total volume of a furnace orair-conditioning appliance and at least 16 times the total volume of a boiler. Total


volume of the appliance is determined from its exterior dimensions and is to in-clude fan compartments and burner vestibules when used. When the actual ceil-ing height of a room is greater than 8 feet, the volume of the room is figured onthe basis of a ceiling height of 8 feet.

SAFETY SHUTOFF DEVICE: See “Flame safeguard.”

SHAFT: An enclosed space extending through on or more stories of a building,connecting vertical openings in successive floors or to a floor and the roof.

SLEEPING UNIT: A room or space in which people sleep; it can also includepermanent provisions for living, eating, and either sanitation or kitchen facilitiesbut not both. Such rooms and spaces that are also part of a dwelling unit are notsleeping units.

SPECIFIC GRAVITY: As applied to gas, the ratio of the weight of a given vol-ume to that of the same volume of air, both measured under the same condition.

STATIONARY FUEL-CELL POWER PLANT: A self-contained package orfactor-matched package that constitutes an automatically operated assembly of in-tegrated systems for generating electrical energy and recoverable thermal energyand is permanently connected and fixed in place.

THERMOSTAT, ELECTRIC-SWITCH TYPE: A device that senses changesin temperature and controls electrically, by means of separate components, theflow of gas to the burner(s) in order to maintain temperatures between predeter-mined limits and in which the thermal actuating element is an integral part of thedevice.

THERMOSTAT, GRADUATING: A thermostat in which the motion of thevalve is approximately in direct proportion to the effective motion of the thermalelement induced by temperature change.

THERMOSTAT, SNAP-ACTING: A thermostat in which the thermostaticvalve travels instantly from the closed to the open position and vice versa.

TRANSITION FITTINGS, PLASTIC TO STEEL: An adapter for joiningplastic pipe to steel pipe. The purpose of this fitting is to provide a permanent,pressure-tight connection between two materials that cannot be joined directly.

UNIT HEATER, HIGH-STATIC PRESSURE TYPE: A self-contained, auto-matically controlled, vented appliance having integral means for circulation of airagainst 0.2 inch or greater static pressure. Such an appliance is equipped with pro-visions for attaching an outlet air duct and, where the appliance is for indoor in-stallation remote from the space to be heated, is also equipped with provisions forattaching an inlet air duct.

UNIT HEATER, LOW-STATIC PRESSURE: A self-contained, automaticallycontrolled, vented appliance, intended for installation in the space to be heatedwithout the use of ducts, having integral means for circulation of air. Such unitsare allowed to be equipped with louvers or face extensions made in accordancewith the manufacturer’s specifications.

DEFINITIONS 2.13

UNLISTED BOILER: A boiler not listed by a nationally recognized testingagency.

UNVENTED ROOM HEATER: An unvented heating appliance designed forstationary installation and utilized to provide comfort heating. Such appliancesprovide radiant or convection heat by gravity or fan circulation directly from theheater and do not utilize ducts.

VALVE: A device used in piping to control the gas supply to any section of a sys-tem of piping or to an appliance.

VALVE, AUTOMATIC GAS-SHUTOFF: A valve used in conjunction with anautomatic gas-shutoff device to shut off the gas supply to a water-heating system.It can be constructed integrally with the gas-shutoff deice or a separate assembly.

VALVE, AUTOMATIC OR SEMIAUTOMATIC: A device consisting essen-tially of a valve and operator that control the gas supply to the burner(s) during op-eration of an appliance. The operator shall be actuated by application of gas pres-sure on a flexible diaphragm, by electrical means, by mechanical means, or by anyother approved means.

VALVE, EQUIPMENT SHUTOFF: A valve located in the piping system, usedto isolate individual equipment for purposes such as service or replacement.

VALVE, INDIVIDUAL MAIN BURNER: A valve that controls the gas supplyto an individual main burner.

VALVE, MAIN BURNER CONTROL: A valve that controls the gas supply tothe main burner manifold.

VALVE, MANUAL MAIN GAS-CONTROL: A manually operated valve in thegas line for the purpose of completely turning on or shutting off the gas supply tothe appliance, except to pilot or pilots that are provided with independent shutoff.

VALVE, MANUAL RESET: An automatic shutoff valve installed in the gas-supply piping and set to shut off when unsafe conditions occur. The device re-mains closed until manually reopened.

VALVE, SERVICE SHUTOFF: A valve, installed by the serving gas supplierbetween the service meter or source of supply and the customer piping system, toshut off the entire piping system.

VENT: A pipe or other conduit composed of factory-made components, contain-ing a passageway for conveying combustion products and air to the atmosphere,listed and labeled for use with a specific type or class of appliance.

VENT CONNECTOR: See “Connector.”

VENTED APPLIANCE CATEGORIES: Appliances that are categorized forthe purpose of vent selection into four categories.

VENTED APPLIANCE, CATEGORY I: An appliance that is operated with anonpositive vent static pressure and with a vent gas temperature that avoids exces-sive condensate production in the vent.


VENTED APPLIANCE, CATEGORY II: An appliance that is operated with anonpositive vent static pressure and with a vent gas temperature that is capable ofcausing excessive condensate production in the vent.

VENTED APPLIANCE, CATEGORY III: An appliance that operates with apositive vent static pressure and with a vent gas temperature that avoids excessivecondensate production in the vent.

VENTED APPLIANCE, CATEGORY IV: An appliance that is operated witha positive vent static pressure and with a vent gas temperature that is capable ofcausing excessive condensate production in the vent.

VENTED ROOM HEATER: A vented, self-contained, freestanding, nonre-cessed appliance for furnishing warm air to the space in which it is installed di-rectly from the heater without duct connections.

VENTED WALL FURNACE: A self-contained vented appliance complete withgrilles or the equivalent, designed for incorporation in or permanent attachment tothe structure of a building, mobile home, or travel trailer and furnishing heated aircirculated by gravity or by a fan directly into the space to be heated through open-ings in the casing. This definition excludes floor furnaces, unit heaters, and cen-tral furnaces.

VENTING SYSTEM: A continuous open passageway from the flue collar ordraft hood of an appliance to the outside atmosphere for the purpose of removingflue or vent gases. A venting system is usually composed of a vent or a chimneyand a vent connector, assembled to form the open passageway.

VENTING SYSTEM, FORCED-DRAFT: A portion of a venting system usinga fan or other mechanical means to cause the removal of flue or vent gases underpositive static vent pressure.

VENTING SYSTEM, INDUCED DRAFT: A portion of a venting system usinga fan or other mechanical means to cause the removal of flue or vent gases undernonpositive static vent pressure.

VENTING SYSTEM, MECHANICAL DRAFT: A venting system designed toremove flue or vent gases by mechanical means, consisting of an induced draftportion under nonpositive static pressure or a forced draft portion under positivestatic pressure.

VENTING SYSTEM, NATURAL DRAFT: A venting system designed to removeflue or vent gases under nonpositive static vent pressure entirely by natural draft.

VENT GASES: Products of combustion from appliances plus excess air and di-lution air in the vent connector, gas vent, or chimney above the draft hood or draftregulator.

VENT PIPING, BREATHER: Piping run from a pressure-regulating device tothe outdoors, designed to provide a reference to atmospheric pressure. If the de-vice incorporates an integral pressure-relief mechanism, a breather vent can alsoserve as a relief vent.

DEFINITIONS 2.15

VENT PIPING, RELIEF: Piping run from a pressure-regulating or pressure-limiting device to the outdoors, designed to provide for the safe venting of gas inthe event of excessive pressure in the gas piping system.

VENT, SPECIAL GAS: A vent listed and labeled for use with listed Category II,III, and IV appliances.

VENT, TYPE B: A vent listed and labeled for use with appliances with drafthoods and other Category I appliances that are listed fur use with Type B vents.

VENT, TYPE BW: A vent listed and labeled for use with wall furnaces.

VENT, TYPE L: A vent listed and labeled for use with appliances that are listedfor use with Type L or Type B vents.

WALL HEATER, UNVENTED: A room heater of the type designed for inser-tion in or attachment to a wall or partition. Such a heater does not incorporate con-cealed venting arrangements in its construction and discharges all products ofcombustion through the front into the room being heated.

WATER HEATER: Any heating appliance or equipment that heats potable wa-ter and supplies such water to the potable hot-water distribution system.

We have now covered all of the definitions needed to use your code book. Ournext topic pertains to general regulations, so let’s move to the next chapter and getstarted.


CHAPTER 3GENERAL REGULATIONS

Appliances regulated by the code must be listed and labeled for the application inwhich they are used. An exception is if an appliance is otherwise approved. Whohas the power to approve such a waiver in the code? The approval has to comefrom an acceptable engineering evaluation.

The evaluation of appliances is to be done by an approved agency, which testsa representative sample to the relevant standard or standards. Records of the test-ing are required to be kept and maintained by the testing agency. All test recordsmust provide sufficient detail to verify compliance with the test standard.

Periodic inspection of appliances is required by the code. These inspectionsshall be in-plant if necessary. Inspections are done to verify that labeled appli-ances are representative of the appliances that were approved.

Agencies to be approved must be objective and competent. To confirm its ob-jectivity, the agency shall disclose all possible conflicts of interest. Approvedagencies must have adequate equipment to perform all tests. Periodic calibrationof equipment is required. Personnel employed by an approved agency must be ex-perienced and educated in conducting, supervising, and evaluating tests.

LABELING

Permanent, factory-applied name plates are required to be affixed to appliancesthat are approved. Legible lettering on the nameplate is required to include the fol-lowing:

• Manufacturer’s name or trademark

• Model number

• Serial number

• Seal or mark of the testing agency

3.1



• The hourly rating in Btu/h

• The type of fuel approved for use with the appliance

• Minimum clearance requirements for the appliance

PLUMBING

Plumbing connections to appliances, whether for potable water supply or buildingdrainage, are regulated in accordance with the International Plumbing Code.

FUEL TYPES

Appliances must be designed for use with the type of fuel gas that will be sup-plied to them. Converting appliances to utilize different types of fuel is not ac-ceptable. However, conversions can be made if complete instructions are pro-vided in the installation manual provided by the serving gas supplier or theappliance manufacturer.

VIBRATION

There are times when appliances are installed in such a manner that vibration iso-lation is required. Under these circumstances, an approved means for support andrestraint of that appliance shall be provided.

REPAIR

When an appliance needs repair, it must be done with parts and practices that willpreserve the original approval or listing.

WIND

Appliances and supports that are exposed to wind shall be designed and installedto resist wind pressures as determined in the International Building Code.

FLOODING

Flooding can create serious problems. Any structure that is located in a flood-haz-

ard area is required to have appliances installed so that they are at or above the de-sign flood elevation and comply with the flood-resistant construction require-ments of the International Building Code.

As is often the case with code requirements, there is an exception to the floodrule. Appliance, equipment, and system installations regulated by the code can beinstalled below the design flood-level elevation if they are designed and installedto prevent water from entering or accumulating within the components and to re-sist hydrostatic and hydrodynamic loads and stresses, including the effects ofbuoyancy, during an occurrence of flooding. Installations must comply with theflood-resistant construction requirements of the International Building Code.

SEISMIC RESISTANCE

Earthquake loads have to be taken into consideration when working with the code.The International Building Code governs the requirements for earthquake loads.Supports must be designed and installed for seismic forces in accordance with thiscode.

DUCTS

All ducts required for the installation of systems regulated by the gas code shallbe designed and installed in accordance with the International Mechanical Code.

RODENTS

Rodents can pose a threat to appliances. Precautions must be taken to protect ap-pliances from rodent damage. The International Building Code dictates the re-quirements for rodent-proofing buildings and structures.

GENERAL REGULATIONS 3.3

!CodealertAppliances, equipment, and systems regulated by the gas code mustnot be located in elevator shafts.

STRUCTURAL SAFETY

The installation of gas piping must not weaken the structural safety of a building.During the installation or repair of gas piping, structural safety must be main-tained. Examples of elements to be protected are as follows:

• Finished floors

• Walls

• Ceilings

• Tile work

• Other parts of the structure that are to be changed or replaced

PENETRATIONS

Penetrations of floor, ceiling, and fire-resistance-rated assemblies are protected bythe International Building Code.

CUTTING, NOTCHING, AND BORING WOOD

There are a number of considerations to take into account when cutting, notching,or boring wood members. You must be aware of the type of wood that you areworking with. For example, engineered-wood structures normally may not be cut,notched, or bored. This applies to trusses, structural composite lumber, structuralglued-laminated members, and I-joists. Unless the manufacturer’s recommenda-tion or a registered design professional’s design specifically allows modificationto the wood members, consider engineered-wood products off limits for cutting.

Joists

Joists for ceilings and floors can be cut, drilled, or notched. But you must obey therules set forth by the IBC code. These rules include the following:

• Notching the ends of joist is allowed if the notching does not exceed one-fourththe joist depth.

• Holes drilled in joists must not be within 2 inches of the top and bottom of thejoist, and their diameter shall not exceed one-third the depth of the member.

• Notches in the top or bottom of a joist must not exceed one-sixth the depth andshall not be located in the middle one-third of the span.

Studs

When you are cutting studs, the rules change depending on whether the walls are


load-bearing or non-bearing. Exterior walls and bearing partitions can have theirstuds cut to a depth not exceeding 25 percent of the stud width. When cutting studsin non-bearing partitions, the cut cannot have a depth greater than 40 percent ofthe width of the stud.

Bored Holes

Bored holes that are not greater in diameter than 40 percent of a stud depth are al-lowed in any wood stud. Holes that are not greater than 60 percent of the studdepth are permissible in non-bearing studs. The 60-percent rule also applies inwalls where each bored stud is doubled, provided not more than two such succes-sive doubled studs are so bored. The edges of bored holes must not be nearer than5/8 inch to the edge of a stud. Bored holes shall not be located at the same sectionof a stud as a cut or notch.

TRUSSES

When working with trusses, you must not cut, drill, notch, splice, or alter themwithout written concurrence and approval of a registered design professional. Thisapplies to truss members and components. The approved load rating for trussesmust not be exceeded. For example, installing mechanical equipment that will besupported by trusses must be done only if the trusses are designed and approvedfor the load.

STEEL

Structural-steel Framing

A registered design professional must be consulted prior to cutting, notching, orboring holes in structural-steel framing. If such work is allowed, it must be donein compliance with the approved standards set forth by a registered design professional.

Cold-formed Steel Framing

The flanges and lips of load-bearing, cold-formed steel-framing members mustnot be cut or notched. Registered design professionals are responsible for estab-lishing approved procedures for cutting holes in cold-formed steel framing. Theseholes are allowed in the webs of load-bearing, cold-formed steel framing membersalong the centerline of the web of the framing member so long as they do not ex-ceed the dimensional limitations, penetration spacing, or minimum hole edge dis-tance as determined by a registered design professional. If cutting or notching is


needed in steel floor or roof decking, a registered design professional must ap-prove the procedure.

Nonstructural Steel

Nonstructural cold-formed-steel wall framing is allowed to have holes bored in it.Flanges and lips of nonstructural cold-formed-steel wall studs can be bored alongthe centerline of the web of the framing member. The holes shall not exceed 1 1/2inches in width or 4 inches in length. A minimum spacing of 24 inches from cen-ter to center of holes is required. Holes must not be located less than 10 inchesfrom the bearing end.

PROHIBITED APPLIANCE LOCATIONS

There are exceptions, which we will go over shortly, but as a rule of thumb appli-ances are prohibited from the following locations:

• Sleeping rooms

• Bathrooms

• Toilet rooms

• Storage closets

• Surgical rooms

• Spaces that open only into locations noted above

Now for the exceptions: Direct-vent appliances are allowed in prohibited lo-cations when they are installed in complete accordance with the conditions of thelisting and the manufacturer’s instructions.

Section 304.5 of the code pertains to the required volume criteria for roomsthat use vented appliances. If a room meets the requirements of Section 304.5, thefollowing types of appliances may be installed in otherwise prohibited locations:

• Vented room heaters

• Wall furnaces


!CodealertAppliances are not allowed to be located in hazardous locations unlessthey are listed and approved for the specific installations.

• Vented decorative appliances

• Vented gas fireplaces

• Vented gas fireplace heaters

• Decorative appliances for installation in vented solid fuel-burning fireplaces

A bathroom may have a single wall-mounted unvented room heater installedwhen the heater is equipped as specified in Section 621.6 of the code and has aninput rating not greater than 6000 Btu/h. In addition to Section 621.6, the bath-room must meet the required volume criteria of Section 304.5 of the code.

Bedrooms may have a single wall-mounted unvented room heater installed ifthe heater is equipped as specified in Section 621.6 of the code and has an inputrating not greater than 10,000 Btu/h. Additionally, the bedroom must meet the re-quired volume criteria of Section 304.5.

Another exception allows an appliance to be installed in a room or space thatopens only into a bedroom or bathroom if such a room or space is used for no otherpurpose and is provided with a solid, weather-stripped door that is equipped withan approved self-closing device. Combustion air must be taken directly from theoutdoors in accordance with Section 304.6 of the code.

OUTDOOR LOCATIONS

Equipment that is installed in outdoor locations must either be listed for outdoorinstallation or protected from outdoor environmental factors that influence the op-erability, durability, and safety of the equipment.

PIT LOCATIONS

Appliances installed in pits or excavations must not come into direct contact withthe surrounding soil. A minimum of 12 inches of clearance is required from thesides of a pit or excavation. The walls must be lined with concrete or masonry ifthe depth of the pit exceeds 12 inches in depth below the adjoining grade level.When a lining is required, it must extend a minimum of 4 inches above the adjoin-


?Did you knowAppliances must not be installed in a location where they may be impacted byvehicular damage, unless they are protected by an approved means.

ing grade level. Any pit used to hold equipment must have sufficient lateral-load-bearing capacity to resist collapse. Flood protection of an approved type is also re-quired for appliances located in pits or excavations.

COMBUSTION, VENTILATION, AND DILUTION AIR

Air for combustion, ventilation, and dilution of flue gases used in appliances in-stalled in building must be provided in accordance to Section 304.5 through 304.9of the code. If these requirements are not met, outdoor air must be introduced inaccordance with one of the methods detailed in sections 304.6 through 304.9.With the exception of Category I appliances, direct-vent appliances, gas appli-ances of other than natural draft design, and vented gas appliances must be pro-vided with combustion, ventilation, and dilution air in accordance with the appli-ance manufacturer’s instructions. A Type 1 clothes dryer that is provided withmakeup air in accordance with Section 614.5 of the code is exempt from theabove.

Makeup Air

Makeup air requirements for the operation of exhaust fans, kitchen ventilationsystems, clothes dryers, and fireplaces shall be considered in determining the ad-equacy of a space to provide combustion air requirements.

Indoor Air

Calculating indoor combustion air can be done in various ways. It is normallydone by requiring a minimum required volume of 50 cubic feet per 1,000 Btu/h ofthe appliance’s input rating. When the air infiltration rate of a structure is known,the minimum required volume can be determined with the use of an equation:

(Equation 3.1)

Use this equation when calculating the required volume for appliances that are not fan-assisted. For purposes of this calculation, an infiltration rate greater than 0.60 ACH shallnot be used in Equations 3.1 or 3.2.


TradetipAppliances must be located in such a way as not to interfere with proper cir-culation of combustion, ventilation, and dilution air.

(Equation 3.2)

Use this equation when calculating the required volume for fan-assisted appliances. Forpurposes of this calculation, an infiltration rate greater than 0.60 ACH shall not be used inEquations 3.1 or 3.2.

The total required volume shall be the sum of the required volume calculatedfor all appliances located within the space. Rooms communicating directly withthe space in which the appliances are installed through openings not furnishedwith doors and through combustion air openings sized and located in accordancewith Section 304.5.3 of the code are considered to be part of the required volume.

Combined Spaces

When spaces are combined on the same story, each opening is required to have aminimum free area of 1 square inch per 1000 Btu/h of the total input rating of allappliances housed in the space but not less than 100 square inches. One openingshall commence within 12 inches of the top, and one opening shall commencewithin 12 inches of the bottom of the enclosure. The minimum dimension of airopenings shall not be less than 3 inches.

The rules differ when combining spaces on different stories. Volumes ofspaces in different stories shall be considered as communicating spaces whensuch spaces are connected by one or more openings in doors or floor having a to-tal minimum free area of 2 square inches per 1000 Btu/h of total input rating ofall appliances.

Outdoor Combustion Air

Outdoor combustion air must be provided through openings to the outdoors. Theminimum dimension of air opening shall be not less than 3 inches. One way of do-ing this is with two permanent openings, one that commences within 12 inches ofthe top and one commencing within 12 inches of the bottom of the enclosure.These openings are required to communicate directly or by ducts with the out-doors or spaces that freely communicate with the outdoors.


?Did you knowA draft hood or barometric draft regulator shall be installed in the same roomor enclosure as the appliance served so as to prevent any difference in pres-sure between the hood or regulator and the combustion air supply.

In situations where openings communicate directly with the outdoors or wherecommunication is achieved with vertical ducts, each opening is required to have aminimum free area of 1 square inch per 4000 Btu/h of total input ratings of all ap-pliances in the enclosure.

If horizontal ducts are used to communicate with the outdoors, each openingis required to have a minimum free area of not less than 1 square inch per 2000Btu/h of total input rating of all appliances in the enclosure.

When one permanent opening is used for ventilation, the opening must beginwithin 12 inches of the top of the enclosure. Clearance is required for appliancesin these spaces. A minimum clearance of 1 inch is required from the sides andback of appliances. There must be a minimum of 6 inches of clearance in front ofan appliance. The opening must communicate directly with the outdoors orthrough a vertical or horizontal duct to the outdoors or a space that freely commu-nicates with the outdoors. A minimum free area of 1 square inch per 3,000 BTU/hof the total input rating of all appliances located in the enclosure is required. Theminimum free area of the opening shall not be less than the sum of the areas of allvent connectors in the space.

Combination Air

The use of a combination of both indoor and outdoor combustion air is allowedunder the requirements of the code in Sections 304.7.1 through 304.7.3. Indooropenings must meet the requirement of Section 304.5.3 of the code. Outdooropenings must be located in accordance with Section 304.6. We have alreadytalked about these requirements. Now let’s discuss the required opening sizes foroutdoor openings.

When sizing an outdoor opening, you must determine the ratio of interiorspaces. This ratio shall be the available volume of all communicating spaces di-vided by the required volume. The outdoor size-reduction factor is one minus theratio of interior spaces.

The minimum size of outdoor openings must be the full size of outdoor open-ings calculated in accordance with Section 304.6 of the code multiplied by the re-duction factor. The minimum dimension requirement for air openings is 3 inches.


!CodealertEngineered combustion-air installations must provide an adequate sup-ply of combustion, ventilation, and dilution air and must be approved.

Mechanical Combustion-air Supply

Mechanical combustion-air supply may provide all combustion air. When this isthe case, the air must come completely from the outdoors at an established rate.The rate required is not less than 0.35 cubic feet per minute per 1000 Btu/h of thetotal input rating of all appliances located within the space. Makeup air must beprovided to replace exhaust from exhaust fans.

When multiple appliances use a main burner, the appliances must be equippedwith an interlock. Each appliance shall be interlocked with the mechanical air-supply system to prevent main burner operation when the mechanical air-supplysystem is not in operation.

When combustion air is provided by the building’s mechanical ventilationsystem, the system shall provide the specified combustion-air rate in addition tothe required ventilation air.

Louvers and Grilles

The size of louver and grilles is based on the net free area of each opening. Thisprovides combustion, ventilation, and dilution air. If the free area through louversand grilles is not known, it must be calculated. To do this, you are allowed to as-sume that wood louvers have 24 percent free area and metal louvers and grilleshave 75 percent free area.

Screens used on louvers and grilles are to have a mesh with a size no smallerthan 1/4 inch. A grill or louver that is not motorized must be installed in a fixedopen position. Motorized louvers shall be interlocked with the appliance beingserved so that they are shown to be in the full open position prior to main burnerignition and during main burner operation. Safety devices are required to keep themain burner from igniting if the louvers fail to open during burner start-up. Thesystem must be installed to shut down the main burner if the louver fails to openduring operation.

Combustion-air Ducts

Galvanized steel, or a material having equivalent corrosion resistance, strength,and rigidity, is an acceptable material for the construction of air ducts. Dwelling


?Did you knowCombustion-air intake opening located on the exterior of a building shall havethe lowest side of each opening located not less than 12 inches vertically forthe adjoining grade level.

units can use unobstructed stud and joist spaces for conveying combustion air,provide that not more than one required fire block is removed. Ducts must termi-nate in unobstructed spaces allowing free movement of combustion air to appli-ances. Only one enclosure may be served by a single duct. If ducts end in an atticspace, they must not be screened.

Ducts shall not serve both upper and lower combustion-air openings in loca-tions where both such openings are used. The separation between ducts servingupper and lower combustion-air openings must be maintained to the source ofcombustion air. Horizontal upper combustion-air ducts are not allowed to slopedownward toward the source of combustion air.

Open air space around a chimney liner cannot be used to supply combustionair. The same is true of gas vents, special gas vents, or plastic piping that is in-stalled within a masonry, metal, or factory-built chimney. There is an exception:Direct-vent, gas-fired appliances designed for installation in a solid fuel-burningfireplace and installed in accordance with the manufacturer’s instruction are allowed.

Fumes and Gases

Protection from fumes and gases must be provided. This requires the safe removalof fumes or gases in an approved manner. The types of gases and fumes may in-clude any of the following:

• Carbon monoxide

• Hydrogen sulfide

• Ammonia

• Chlorine

• Halogenated hydrocarbons

Certain types of businesses generate corrosive or flammable products. Barbershop and beauty salons are examples of such businesses. The aerosol sprays usedfor hair care can produce dangerous fumes. Nondirect vent-type appliances shallbe located in a mechanical room separated or partitioned off from other areas withprovisions for combustion air and dilution air from the outdoors. Direct-vent ap-pliances must be installed in accordance with the appliance manufacturer’s in-structions.


TradetipHorizontal upper combustion-air ducts shall not slope downward toward thesource of combustion air.

INSTALLATION

The installation of appliances must comply with the code and the manufacturer’srecommendations. A copy of the manufacturer’s instructions for installation ofequipment must be available on the job site at the time of a code inspection. If youfind discrepancies between the code and the manufacturer’s recommendations forinstallation and the code is less restrictive, what should you do? You must installthe equipment in accordance with the manufacturer’s requirements.

Elevation of Ignition Source

Equipment and appliances installed in some locations must be installed so that theignition source sits at least 18 inches above the floor level. The types of locationswhere this rule comes into play include the following:

• Hazardous locations

• Public garages

• Private garages

• Repair garages

• Motor-fuel-dispensing facilities

• Parking garages

• Rooms or spaces that are not part of the living space of a dwelling unit and thatcommunicate directly with a private garage through openings


!CodealertCombustion-air intake openings located on the exterior of a buildingshall have the lowest side of such openings located not less than 1 footvertically from the adjoining grade level.

?Did you knowThe manufacturer’s instructions for installation of equipment must be avail-able on the job site at the time of a code inspection.

An exception: Elevation of an ignition source is not required for appliancesthat are listed as flammable-vapor-ignition-resistant.

Parking Garages

Connection of a parking garage with any room in which there is a fuel-fired appli-ance shall be by means of a vestibule providing a two-doorway separation, exceptthat a single door is permitted where the sources of ignition in the appliance areelevated in accordance with Section 305.3 of the code. Appliances that complywith Section 305.4 of the code are exempt from this ruling.

Public Garages

Appliances in public garages must be installed in a manner that will protect themfrom vehicle impact. Such appliances must be installed at least 8 feet above thefinished floor level in certain types of buildings. Some of these buildings includethe following:

• Public garages

• Motor-fuel-dispensing facilities

• Repair garages

• Areas frequented by motor vehicles

When motor vehicles exceed 6 feet in height and are capable of passing underan appliance, the appliance must be installed at least 2 feet higher above the fin-ished floor level than the height of the tallest vehicle. The only exception to theheight requirements is if the appliances are protected from vehicle impact.

Private Garages

If appliances are installed in private garages, they must be at least 6 feet above thefinished floor level. This rule does not apply if the appliance is protected from ve-hicle impact.


!CodealertEquipment and appliances that have an ignition source are not allowedto be installed in Group H occupancies or control areas where open use,handling, or dispensing of combustible, flammable, or explosive mate-rials occurs.

Grade Clearance

Grade clearance for equipment and appliances can be minimal if the unit is sup-ported on a level concrete slab or other approved material extending above adjoin-ing grade. When this is not the case, the equipment or appliance must be sus-pended a minimum of 6 inches above the adjoining grade.

Combustible Construction

Clearance for equipment and appliances from combustible construction must bemaintained. The amount of clearance is typically established by the manufacturerof the equipment or appliance. See Section 308 of the code if you are seeking a re-duction in clearance requirements. Devices such as door stops, limits, and closersare not allowed to provide required clearance. Some considerations for clearancerequirements include the following:

• Door swing

• Drawer pull

• Overhead projections

• Shelving

• Window swings

ACCESS AND SERVICE

Adequate access must be provided for equipment and appliances to be servicedwithout removing elements of permanent construction or disabling the function ofa required fire-resistance-rated assembly. The amount of clearance required mustbe adequate to allow for inspection, service, repair, or replacement of the equip-ment or appliance.

Attic Installations

Attic installations for appliances require access large enough to remove the appli-ance or equipment installed within the attic space. This access must not be less


!CodealertBoiler and furnace rooms must be protected in compliance with theInternational Building Code.

than 30 inches high and 22 inches wide and not more than 20 feet in length whenmeasured along the centerline of the passageway from the opening of the equip-ment. Continuous solid flooring is required in the passageway. This flooring mustnot be less than 24 inches wide. A level service space that is not less than 30 inchesdeep and 30 inches wide must exist at the front or service side of equipment or ap-pliances. Assuming that the appliance or equipment to be removed does not ex-ceed the minimum measurements, the minimum measurement of clear accessopenings is 20 inches by 30 inches.

As usual, there are some exceptions to access requirements in attic installa-tions. The passageway and level service space are not required where the appli-ance is capable of being serviced and removed through the required opening.When the passageway is not less than 6 feet high for its entire length, the passage-way shall be not greater than 50 feet in length.

Under-floor Appliances

Appliances may be installed under floors such as in crawl spaces. When this is thecase, suitable access to the appliance is required. At a minimum, the access spacemust be large enough to allow the removal and replacement of the appliance orequipment installed beneath a floor. A minimum width of 22 inches is required.Maximum width must not exceed 20 feet when measured along the centerline ofthe passageway. The minimum height requirement is 30 inches.

A level service space that is not less than 30 inches deep and 30 inches widemust exist at the front or service side of an appliance or equipment. When thedepth of a passageway or a service space exceeds 12 inches below the adjoininggrade, the walls of the passageway must be lined with concrete or masonry extend-ing 4 inches above the adjoining grade and have sufficient lateral-bearing capac-


!CodealertRooms containing appliances requiring access must be provided witha door and an unobstructed passageway measuring not less than 36inches wide and 80 inches high. Dwelling units offer an exception tothis rule. In such locations, the unobstructed passageway must be atleast 24 inches wide and large enough to allow removal of the largestappliance in the space, provided that a level service space of not lessthan 30 inches deep and the height of the appliance but not less than 30inches with the door open is present at the front or service side of theappliance.

ity to resist collapse. Minimum access dimensions for openings are 22 inches by30 niches, assuming that the opening is large enough to allow the removal of thelargest component of the appliance or equipment.

As you might expect, there are exceptions. A passageway is not requiredwhere a level service space is present when the access is open and the applianceis capable of being serviced and removed through the required opening. When thepassageway is not less than 6 feet high for its entire length, the passageway shallnot be limited in length.

A luminaire controlled by a switch located at the required passageway open-ing and a receptacle outlet shall be provided at or near the equipment location inaccordance with the ICC Electrical Code.

Roofs and Elevated Structures

It is not uncommon for appliances and equipment to be installed on roofs and el-evated structures. If the appliance or equipment may require access and is installedon a roof or elevated structure that is more than 16 feet high, there are special ac-cess rules to be considered. Here are some of the key points:

• Access must be provided by a permanent approved means of access.

• The extent of the access shall be from grade or floor level to the appliance- orequipment-level service space.

• The access must not require climbing over obstructions that are greater than 30inches high or walking on roofs having a slope greater than 4 units vertical in 12units horizontal. This amounts to a 33 percent roof slope.

Permanent Ladders

Permanent ladders may be used to provide access for rooftop and elevated equip-ment, but there are a number of factors that must meet minimum design criteria.Such factors include the following:

• Side railings must extend above the parapet or roof edge by not less than 30inches.


TradetipA luminaire controlled by a switch located at the required passageway open-ing and a receptacle outlet must be provided at or near the equipment loca-tion in an attic as required by the ICC Electrical Code.

• Ladders are required to have rung spacing that does not exceed 14 inches oncenter.

• Toe spacing for ladders shall not be less than 6 inches deep.

• A minimum of 18 inches is required between ladder rails.

• Ladder rungs must have a minimum diameter of 3/4 inch.

• Ladder rungs must be capable of supporting a minimum load of 300 pounds.

• When ladders extend more than 30 feet in height, they must be provided with off-set sections and landings that are capable of withstanding a load of 100 poundsper square inch.

• Ladders must be protected against corrosion by approved means.

Catwalks installed to provide access shall not be less than 24 inches wide andmust have railing as required for service platforms. Group R-3 occupancies are notrequired to abide by the regulations in this section.

Sloped Roofs

Appliances installed on roofs with a slope of 25 percent or more that have an edgemore than 30 inches above grade must provide a level platform on each side of theappliance to which access is required for service, repair, or maintenance. The plat-form must have minimum dimensions of 30 inches in all directions. Guards are re-quired around the platform. These guards are to extend at least 42 inches abovethe platform and shall be constructed so as to prevent the passage of a 21-inch-di-ameter sphere. The guards must meet the requirements set forth in theInternational Building Code.

Guards

When appliances or other components that require service and roof-hatch open-ings are located within 10 feet of a roof edge or open side of a walking surface andsuch edge or open side is located more than 30 inches above the floor, roof, orgrade below, guards must be provided. The guard must extend not less than 30inches beyond each end of any appliances, components, and roof-hatch openings,and the top of the guard shall be located not less than 42 inches above the elevatedsurface adjacent to the guard. Construction of the guard must be done to preventthe passage of a 21-inch-diameter sphere and shall comply with the loading re-quirements for guards specified in the International Building Code.

CONDENSATE DISPOSAL

Condensate disposal is required for equipment and appliances containing evapo-rators and cooling coils in accordance with the International Mechanical Code.


Condensate drains must be trapped as required by the equipment or appliancemanufacturer. Auxiliary drain pans are required for condensing appliances inCategory IV if damage can be expected if the condensate drain becomes stoppedup. Pans are not needed when the appliance is designed to shut down operation inthe event of a stoppage in the condensate system.

What does a condensate drain do? It collects and discharges the liquid-com-bustion byproducts of condensing appliances to approved plumbing fixtures. Acondensate drain must be made of an approved corrosion-resistant material andshall never be smaller than the drain connection that it is attached to. Like normaldrainage lines, condensate drains must be installed with a minimum grade, fall, orpitch. The minimum amount of grade allowable is a 1-percent slope. This amountsto 1/8 inch per foot of tubing or piping.

Drainage pipes for condensate drains may be constructed of any of the following:

• Cast iron

• Galvanized steel

• Copper

• Polybutylene

• Polyethylene

• ABS

• CPVC

• PVC

The minimum diameter for a condensate drain is 3/4 inch. Both pressure andtemperature ratings must be considered when designing a condensate drain. It isnot allowable to decrease the size of a condensate drain. It is acceptable to com-bine multiple condensate drains; however, the sizing of the drain must take intoaccount the full flow requirements based on the number of connections to thedrain.


!CodealertAn electrical receptacle outlet must be provided at or near the equip-ment location in accordance with the ICC Electrical Code.

CLEARANCE REDUCTION

There are times when the minimum required distance between an appliance and acombustible material can be reduced. These conditions are identified in Table 3.1.

Reduction of clearances with specified forms of protection, courtesy of the2006 International Fuel Gas Code.

If you have a situation that is not covered in Table 3.1, there are alternatives.The reduced clearance can be determined by linear interpolation between the dis-tances listed in the table. It is not acceptable to reduce clearances derived by ex-trapolation below the range of the table.

Air-conditioning Equipment

Air-conditioning equipment that is installed in locations that are not large in com-parison with the size of the equipment must be listed for the type of installationbeing done. For example, if the equipment is being used in a small entry hall, theappliance must be rated for that use. Installation must be done in full accordancewith the manufacturer’s recommendations. Listed clearances shall not be reducedby the protection methods described in the code, regardless of whether the enclo-sure is of combustible or noncombustible material.

When air-conditioning equipment is installed in rooms that are large in com-parison with the size of the appliance, it can be installed with reduced clearancesto combustible material, provided the combustible material or appliance is pro-tected as described in Table 3.1.

Furnace Plenums

Furnace plenums require clearance. A plenum that is adjacent to plaster on metallath or noncombustible material attached to combustible material requires theclearance to be measured to the surface of the plaster or other noncombustible fin-ish where the clearance specified is 2 inches or less.


!CodealertElectrical connections between equipment and the building wiring, in-cluding the grounding of the equipment, must comply with the ICCElectrical Code.

Supply Ducts

Supply ducts for air-conditioning appliances must have clearance within 3 feet ofa furnace plenum. At no time shall the clearance be less than what is listed for theappliance. Always check manufacturer’s recommendations before determining fi-nal clearance.

Boilers and Furnaces

Clearance for boilers and furnaces must be planned so as not to interfere with com-bustion air, draft-hood clearance and relief, and accessibility for servicing. All in-stallations have to be done in compliance with the manufacturer’s instructions.This type of equipment has to be listed for the intended purpose of the installation.Front clearance must be sufficient for servicing the burner and the furnace orboiler.

This concludes the review of general regulations. Now we are ready to talkabout installations. Let’s move to the next chapter and get into the meat of thesubject.



TYPE OF PROTECTION

APPLIED TO ANDCOVERING ALLSURFACES OF

COMBUSTIBLEMATERIAL

WITHIN THE DISTANCE

SPECIFIED AS THEREQUIRED

CLEARANCE WITHNO PROTECTION

(See Figure 3.1)

WHERE THE REQUIRED CLEARANCE WITH NO PROTECTION FROM APPLIANCE, VENT CONNECTOR,

OR SINGLE-WALL METAL PIPE IS: (inches)

36 18 12 9 6

Allowable clearances with specified protection (inches)

Use Column 1 for clearances above appliance or horizontal connector. Use Column 2 for clearances from appliance,

vertical connector, and single-wall metal pipe.

AboveCol. 1

Sidesandrear

AboveCol. 1

Sidesandrear

AboveCol. 1

Sidesandrear

AboveCol. 1

Sidesandrear

AboveCol. 1

Sidesandrear

1. 31/2-inch-thickmasonry wall withoutventilated airspace

— 24 — 12 — 9 — 6 — 5

2. 1/2-inch insulationboard over 1-inchglass fiber or mineralwood batts

24 18 12 9 9 6 6 5 4 3

3. 0.024-inch (nominal24 gage) sheet metalover 1-inch glass fiber or mineral woolbatts reinforced withwire on rear face withventilated airspace

18 12 9 6 6 4 5 3 3 3

4. 31/2-inch-thick ma-sonry wall withoutventilated airspace

— 12 — 6 — 6 — 6 — 6

5. 0.024-inch (nominal24 gage) sheet metalwith ventilated air-space

18 12 9 6 6 4 5 3 3 2

6. 1/2-inch insulationboard with ventilatedairspace

18 12 9 6 6 4 5 3 3 3

7. 0.024-inch (nominal24 gage) sheet metalwith ventilated air-space over 0.024-inch(nominal 24 gage)sheet metal with ventilated airspace

18 12 9 6 6 4 5 3 3 3

8. 1-inch glass fiber ormineral wool battssandwiched betweentwo sheets 0.024-inch(nominal 24 gage)sheet metal with ventilated airspace

18 12 9 6 6 4 5 3 3 3

TABLE 3.1 Reduction of clearances with specified forms of protection.a through k


For SI: 1 inch � 25.4 mm, °C � [(°F � 32)/1.8], 1 pound per cubic foot � 16.02 kg/m3, 1 Btu per inch per squarefoot per hour per °F � 0.144 W/m2 � K.a. Reduction of clearances from combustible materials shall not interfere with combustion air, draft hood clearance

and relief, and accessibility of servicing. b. All clearances shall be measured from the outer surface of the combustible material to the nearest point on the sur-

face of the appliance, disregarding any intervening protection applied to the combustible material.c. Spacers and ties shall be of noncombustible material. No spacer or tie shall be used directly opposite an appliance

or connector.d. For all clearance reduction systems using a ventilated airspace, adequate provision for air circulation shall be pro-

vided as described [see Figure 3.1(2) and Figure 3.1(3)].e. There shall be at least 1 inch between clearance reduction systems and combustible walls and ceilings for reduc-

tion systems using ventilated airspace. f. Where a wall protector is mounted on a single flat wall away from corners, it shall have a minimum 1-inch air gap.

To provide air circulation, the bottom and top edges, or only the side and top edges, or all edges shall be left open. g. Mineral wood batts (blanket or board) shall have a minimum density of 8 pounds per cubic foot and a minimum

melting point of 1,500°F.h. Insulation material used as part of a clearance reduction system shall have a thermal conductivity of 1.0 Btu per

inch per square foot per hour per °F or less.i. There shall be at least 1 inch between the appliance and the protector. In no case shall the clearance between the

appliance and the combustible surface be reduced below that allowed in this table.j. All clearances and thicknesses are minimum; larger clearances and thicknesses are acceptable.k. Listed single-wall connectors shall be installed in accordance with the manufacturer’s installation instructions.

TABLE 3.1 Reduction of clearances with specified forms of protection.a through k

(continued)

FIGURE 3.1 Wall-protector clearance-reduction system, courtesy of the 2006International Fuel Gas Code.


FIGURE 3.1 Wall-protector clearance-reduction system, courtesy of the 2006International Fuel Gas Code. (continued)


FIGURE 3.1 Wall-protector clearance-reduction system, courtesy of the 2006International Fuel Gas Code. (continued)


CHAPTER 4GAS PIPING INSTALLATIONS

The installation of gas piping is serious business. Mistakes made in the installa-tion can result in death. Following code requirements is essential to good businessand public safety. There are a number of rules and regulations to be consideredwhen installing gas piping. This is our topic for the moment, so let’s get to it.

When you consult your code book, you will see that the chapter on installa-tions pertains to design, installation, modification, and maintenance of gas sys-tems. The code covers work that begins at the connection point to an appliance orcomponent to the point of gas delivery. Other codes do come into play with gasinstallations. For example, the International Building Code regulates utility serv-ice piping that is located within buildings. The International Fire Code and NFPA58 cover the storage of liquefied-petroleum gas. All of the codes work together tomaintain safe installations.

IDENTIFICATION

Exposed gas piping, with the exception of steel piping, must be marked. This isdone with a yellow label that displays the word “Gas” in black letters. The label

4.1

!CodealertWhen adding an additional appliance, the existing gas piping must bechecked to confirm that it has adequate capacity for all the appliancesserved. Should the system be inadequate for the load, it must be up-graded to suitable specifications.



must appear along the piping at intervals of not more than 5 feet. There is an ex-ception: Piping that is installed in the same room as the equipment being served isnot required to be marked.

PIPE SIZING

Pipe sizing must be done in a manner to provide adequate supply for all appliancesserviced. This sizing must meet the maximum demand on the system without un-due loss of pressure between the point of delivery and the appliance.

The volume of gas to be provided, in cubic feet per hour, shall be determineddirectly from the manufacturer’s input ratings of the appliances served. In suchcases when an input rating is not indicated, one must be derived by the use of ta-bles in your code book, and there are a lot of them.

Hourly loads on a gas system for all demands attached to the system shall beused for pipe sizing, assuming that all appliances may be operating at full capac-ity simultaneously. In other words, size and design systems to meet the maximumdemands that may be put upon them. If a diversity of loads can be established, pipesizing shall be permitted to be based on such loads.

There are a few ways to size gas piping. The easy way, when it applies, is touse the sizing tables in your code book. Another way that is equally easy is to usethe sizing tables provided by equipment manufacturers. When all else fails, youhave to do the math. Or you can rely on an approved engineering design. Thereare equations that are used for sizing gas piping. Two of them are listed below:

(Equation 4.1)

?Did you knowWhen two or more gas meters are installed on the same premises to supplyseparate consumers, the piping systems shall not be interconnected on the out-let side of the meters. Piping from multiple meter installations must be markedwith an approved permanent identification by the installer so that the pipingsystem supplied by each meter is readily identifiable.

(Equation 4.2)

These equations can be used in connection with tables. When the equations areused to size piping or tubing, the pipe or tubing must have a smooth inside walland the length of the pipe shall be determined in accordance with Sections 402.4.1,402.4.2, or 402.4.3 of the code.

GAS PIPING INSTALLATIONS 4.3

APPLIANCEINPUT BTU/H

(Approx.)

Space Heating UnitsHydronic boiler

Single familyMultifamily, per unit

Warm-air furnaceSingle familyMulti-family, per unit

100,00060,000

100,00060,000

Space and Water Heating UnitsHydronic boiler

Single familyMultifamily, per unit

120,00075,000

Water Heating AppliancesWater heater, automatic instantaneous

Capacity at 2 gal./minuteCapacity at 4 gal./minuteCapacity at 6 gal./minute

Water heater, automatic storage, 30- to 40-gal. tankWater heater, automatic storage, 50-gal. tankWater heater, domestic, circulating or side-arm

142,800285,000424,40035,00050,00035,000

Cooking AppliancesBuilt-in oven or broiler unit, domesticBuilt-in top unit, domesticRange, free-standing, domestic

25,00040,00065,000

Other AppliancesBarbecueClothes dryer, Type 1 (domestic)Gas fireplace, direct-ventGas lightGas logRefrigerator

40,00035,00040,0002,50080,0003,000

For SI: 1 British thermal unit per hour = 0.293 W, 1 gallon = 3.785 L, 1 gallon per minute = 3.785 L/m.

TABLE 4.1 Approximate gas input for typical appliances, courtesy of the 2006International Fuel Gas Code.


Branch Length

Pipe sizing for each section of the longest pipe run from the point of delivery tothe most remote outlet shall be determined using the longest run of piping and theload of the section. The pipe size of each section of branch piping not previouslysized shall be determined using the length of piping from the point of delivery tothe most remote outlet in each branch and the load of the section.

Hybrid Pressure

Hybrid pressure has to do with higher-pressure gas piping. Sizing for this type ofsystem is a little different. The sizing must be done from the point of delivery tothe most remote line-pressure regulator. Then piping from the regulator to themost remote outlet served is used to determine the length for sizing.

Pressure Drop

Pressure drop must be factored into pipe sizing. The design pressure loss in a pip-ing system under the maximum probable flow conditions for the point of deliveryto the inlet connection of an appliance must be sized so that the supply pressure atthe appliance is greater than the minimum pressure required for proper and nor-

GAS

EQUATION FACTORS

Cr Y

Natural gas 0.6094 0.9992

Undiluted propane 1.2462 0.9910For SI: 1 cubic foot = 0.028 m3, 1 foot = 305 mm, 1-inch water column = 0.249 kPa, 1 pound per square inch =

6.895 kPa, 1 British thermal unit per hour = 0.293 W.

TABLE 4.2 C and Y values for natural gas and undiluted propane at standardconditions, courtesy of the 2006 International Fuel Gas Code.

!CodealertThe pipe size of each section of gas piping shall be determined usingthe longest length of piping from the point of delivery to the most re-mote outlet and the load of the section.


mal operation. Clearly put, the pipe sizing must be large enough to allow for pres-sure drops that might affect the performance of an appliance.

Operating Pressure

Under normal conditions, the maximum operating pressure for a gas system insidea building is 5 psig. When certain conditions exist, this ruling may be changed.Examples of the types of circumstances that can change the maximum operatingpressure include the following:

• Welded piping systems

• Piping that is located in a ventilated chase or otherwise enclosed for protectionagainst accidental gas accumulation

• Piping that is located inside buildings or separate areas of buildings used exclu-sively for industrial processing or heating

• Piping that is located inside buildings or separate areas of buildings used exclu-sively for research

• Piping that is located inside buildings or separate areas of buildings used exclu-sively for warehousing

• Piping that is located inside buildings or separate areas of buildings used exclu-sively for boiler or mechanical rooms

• Temporary piping for buildings under construction

LP SYSTEMS

What is the maximum operating pressure of an undiluted LP-gas system? The cor-rect answer is 20 psig. Temperature in a building can affect the use of an LP-gas sys-tem. For example, buildings with systems designed to operate below -5 degrees F orwith butane or a propane-butane mix are required to have a design that will eitheraccommodate liquid LP gas or prevent LP-gas vapor from condensing into a liquid.

What is the exception? There is one. It involves buildings or separate areas ofbuildings constructed in accordance with Chapter 10 of NFPA 58. The space mustbe used exclusively to house industrial processes, research, and experimental lab-oratories or equipment or processing with similar hazards.

Sizing Tables

Your code book contains sizing tables that will make sizing gas systems easier.Please see the tables on pages 31 through 63 of the 2006 International Fuel GasCode to illustrate the type of tables that you will be working with in your codebook. Always make sure that your local code does not have changes that are notlisted in standard code books.

4.6IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N

TABLE 4.3 Schedule 40 metallic pipe, courtesy of 2006 International Fuel Gas Code.

GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.7

4.8IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

NTABLE 4.4 Schedule 40 metallic pipe, courtesy of 2006 International Fuel Gas Code.

GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.9

4.10IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.11

4.12IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.13

4.14IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.15

4.16IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N

TABLE 4.8 Semirigid copper tubing, courtesy of 2006 International Fuel Gas Code.

GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.17

4.18IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.19

4.20IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.21

4.22IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.23

4.24IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.25

4.26IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

NTABLE 4.13 Semirigid copper tubing, courtesy of 2006 International Fuel Gas Code.

GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.27

4.28IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.29

4.30IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

NTABLE 4.15 Corrugated stainless-steel tubing (CSST), courtesy of 2006 International Fuel Gas Code.

GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.31TABLE 4.16 Corrugated stainless-steel tubing (CSST), courtesy of 2006 International Fuel Gas Code.

4.32IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.33TABLE 4.18 Corrugated stainless-steel tubing (CSST), courtesy of 2006 International Fuel Gas Code.

4.34IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.35TABLE 4.20 Polyethylene plastic pipe, courtesy of 2006 International Fuel Gas Code.

4.36IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

NTABLE 4.21 Polyethylene plastic pipe, courtesy of 2006 International Fuel Gas Code.


Gas Natural

Inlet Pressure Less than 2.0 psi

Pressure Drop 0.3 in w.c.

Specific Gravity 0.60

Plastic Tubing Size (CTS) (in.)

Nominal OD 1/23/4

Designation SDR 7.00 SDR 11.00

Actual ID 0.445 0.927

Length (ft) Capacity in Cubic Feet of Gas per Hour

10 54 372

20 37 256

30 30 205

40 26 176

50 23 156

60 21 141

70 19 130

80 18 121

90 17 113

100 16 107

125 14 95

150 13 86

175 12 79

200 11 74

225 10 69

250 NA 65

275 NA 62

300 NA 59

350 NA 54

400 NA 51

450 NA 47

500 NA 45For SI: 1 inch � 25.4 mm, 1 foot = 304.8 mm,1 pound per square inch = 6.895 kPa, 1-inch water column = 0.2488 kPa,1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m3/h,1 degree = 0.01745 rad.Notes:1. NA means a flow of less than 10 cfh.2. All entries have been rounded to three significant digits.

TABLE 4.22 Polyethylene plastic pipe, courtesy of 2006 International Fuel Gas Code.

4.38IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.39


Gas Natural

Inlet Pressure Less than 2.0 psi




Nominal OD 1/23/4


Actual ID 0.445 0.927


10 72 490

20 49 337

30 39 271

40 34 232

50 30 205

60 27 186

70 25 171

80 23 159

90 22 149

100 21 141

125 18 125

150 17 113

175 15 104

200 14 97

225 13 91

250 12 86

275 11 82

300 11 78

350 10 72

400 NA 67

450 NA 63

500 NA 59For SI: 1 inch � 25.4 mm, 1 foot = 304.8 mm,1 pound per square inch = 6.895 kPa, 1-inch water column = 0.2488 kPa,1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m3/h,1 degree = 0.01745 rad.Notes:1. NA means a flow of less than 10 cfh.2. All entries have been rounded to three significant digits.



Gas Undiluted propane

Inlet Pressure 11.0 in w.c.




Nominal OD 1/23/4


Actual ID 0.445 0.927


10 121 828

20 83 569

30 67 457

40 57 391

50 51 347

60 46 314

70 42 289

80 39 269

90 37 252

100 35 238

125 31 211

150 28 191

175 26 176

200 24 164

225 22 154

250 21 145

275 20 138

300 19 132

350 18 121

400 16 113

450 15 106

500 15 100For SI: 1 inch � 25.4 mm, 1 foot = 304.8 mm,1 pound per square inch = 6.895 kPa, 1-inch water column = 0.2488 kPa,1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m3/h,1 degree = 0.01745 rad.


4.42IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N

TABLE 4.26 Schedule 40 Metallic Pipe, courtesy of 2006 International Fuel Gas Code.

GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.43

4.44IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.45

4.46IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.47

4.48IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.49

4.50IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.51

4.52IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.53

4.54IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.55

4.56IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N

TABLE 4.33 Corrugated stainless-steel tubing, courtesy of 2006 International Fuel Gas Code.

GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.57


4.58IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N




4.60IN

TE

RN

AT

ION

AL

FU

EL

GA

S C

OD

E C

OM

PA

NIO

N


GA

S P

IPIN

G IN

ST

AL

LA

TIO

NS

4.61

Now let’s enter into the realm of piping materials.

PIPING MATERIALS

All piping materials must be in compliance with the code. Used materials cannotbe used again except when they are free of foreign materials and are determinedto be adequate for the service intended. Any material not covered by the code mustbe investigated and tested to determine suitability. Essentially, a manufacturermust say that the product is acceptable and a code official must approve its use.

When steel pipe is used, it must be of standard weight, which is Schedule 40,and it must comply with either ASME B 36.10, 10M; ASTM A 53; or ASTM A106. The same is true of wrought-iron piping.

Copper and brass piping are limited in their use for gas. Threaded copper,brass, and aluminum-alloy pipe cannot be used with corrosive gases. No copper


IRON PIPE SIZE(inches)

APPROXIMATE LENGTH OFTHREADED PORTION (inches)

APPROXIMATE NUMBEROF THREADS TO BE CUT

1/23/4 10

3/43/4 10

1 7/8 10

11/4 1 11

11/2 1 11

2 1 11

21/2 11/2 12

3 11/2 12

4 15/8 13

For SI: 1 inch � 25.4 mm, 1 foot = 304.8 mm,1 pound per square inch = 6.895 kPa, 1-inch water column = 0.2488 kPa,1 British thermal unit per hour = 0.2931 W, 1 cubic foot per hour = 0.0283 m3/h,1 degree = 0.01745 rad.

TABLE 4.38 Specifications for threading metallic pipe, courtesy of 2006 InternationalFuel Gas Code.

?Did you knowCast-iron pipe cannot be used as a gas-pipe material.

or brass pipe shall be used if the gas being transferred contains more than an av-erage of 0.3 grains of hydrogen sulfide per 100 standard cubic feet of gas.

When aluminum-alloy pipe is used for gas-piping applications, the pipe mustbe coated to protect it against external corrosion where it is in contact with ma-sonry, plaster, or insulation or subject to repeated wettings by such liquids as wa-ter, detergents, or sewage. This type of piping is not allowed for use in exterior lo-cations or in underground installations.

Copper and brass tubing that is used for gas piping must comply with StandardK or L of ASTM B 88 or ASTM B 280. These materials cannot be used for cor-rosive gases that contain more than 0.3 grains of hydrogen sulfide per 100 stan-dard cubic feet of gas.

Can plastic pipe be used to convey gas? Yes, as long as the plastic pipe andfittings are installed underground outdoors. The material must conform to ASTMD 2513. And the pipe must be marked as gas pipe and with the ASTM standardlabel.

Anodeless Risers

Plastic pipe, tubing, and anodeless risers must meet certain criteria. Manufacturersare required to recommend factory-assembled anodeless risers for the gas beingused. The components must be tested for leaks. This testing has to be done withinthe parameter of the manufacturer’s recommendations.

When a manufacturer produces a service-head adapter and field-assembledanodeless risers incorporating service-head adapters, the manufacturer must rec-ommend the gas used and the design must be in compliance with one or more ofthe following:

• Category I or ASTM D 2513

• U.S. Department of Transportation

• Code of Federal Regulations

• Title 49, Part 192.281 (e)


!CodealertSeamless copper, aluminum alloy, and steel tubing are not allowed totransport corrosive-gas materials.

WORKMANSHIP

Workmanship is a consideration in code inspection. Pipe, tubing, and fittingsused in gas systems must be free of cutting burrs and defects in structure orthreading. They must be brushed. Chips and scales must be removed. If defectsexist, they must be repaired. When repairing is not reasonable, replacement isrequired.

Threads

Metallic pipe threads and fittings must be taper pipe threads. The threads mustcomply with ASME B1.20.1. Pipe with threads that are stripped, chipped, cor-roded, or otherwise damaged shall not be used. Any weld that opens during the op-eration of cutting or threading makes the pipe unusable. Thread compounds, suchas sealing tape or pipe dope, must be resistant to the action of liquefied-petroleumgas or to any other chemical constituents of the gases to be conducted through thepiping.

Corrosive Action

Pipe and tubing must be protected against corrosive action. This is accomplishedwith protective coatings. The protective coating may be external or internal. Theuse of the protective coating is not to be considered as adding strength to the pipe.


!CodealertCorrugated stainless-steel tubing must be listed in accordance withANSI LC 1/CSA 6.26.

?Did you knowPlastic pipe, tubing, or fittings used in undiluted liquefied-petroleum-gas pip-ing systems must be in accordance with NFPA 58.

JOINTS AND FITTINGS

Joints and fittings used in gas piping have to meet tough requirements. They mustbe capable of withstanding maximum pressure and strength in the application. Alljoints must be tight and leakproof. Other requirements dictate that the piping,joints, and fittings must be able to withstand expansion, contraction, vibration, fatigue, and the weight of the pipe and its contents.

Pipe joints are to be threaded, flanged, brazed, or welded. On occasions whennonferrous pipe is brazed, the brazing material must have a melting point in ex-cess of 1000 degrees F. Phosphorus content in brazing materials must not exceedan amount of 0.05 percent.

When working with tubing, the joints must either be made with approved gas-tubing fittings or brazed with a material having a melting pong in excess of 1000degrees F. Again, the phosphorus contain must not exceed 0.05 percent.

Nonferrous pipe and tubing can use flared joints, but the joints must be ap-proved for the use. With metallic fittings there are numerous rules.

Metallic Fittings

Metallic fittings have to comply with a number of code requirements. To keep itsimple, I am putting the rules in a list for you:

• Unless special approval is retained, threaded fittings that are larger than 4 inchesare prohibited.

• The fittings used with steel or wrought-iron pipe must be made of steel, bronze,brass, malleable iron, or cast iron.

• Copper, brass, or bronze fittings must be used when the piping is copper or brass.

• Aluminum-alloy pipe requires the use of fittings that are of an aluminum alloy.

• Flanges are allowed with cast-iron fittings.

• Bushings are not allowed with the use of cast-iron fittings.

• When flammable gas-air mixtures are in use, cast-iron fittings are not allowed.


!CodealertPlastic pipe, tubing, and fittings used to connect regulator vents to re-mote vent terminations shall be made of PVC that conforms to UL 651.PVC vent piping cannot be installed indoors.

• Cast-iron fittings that are 4 inches or larger cannot be used indoors except wherethey are approved.

• Cast-iron fittings in excess of 6 inches are not to be used unless they are specif-ically approved for the use.

• Threads on aluminum-alloy fittings are not allowed to form a joint seal.

• You cannot use zinc-aluminum-alloy fittings in systems that contain a flamma-ble gas-air mixture.

• There are special fittings that can be used. They include couplings, proprietary-type joints, saddle tees, gland-type compression fittings, and flared, flareless, orcompression-type tubing fittings. These fittings must be used within the manufac-turer’s pressure-temperature recommendations. The fittings must be used withinthe service conditions with respect to vibration, fatigue, and thermal expansion orcontraction. They must be installed or braced to prevent separation of the joint bygas pressure or external physical damage, and they must be approved.

Plastic Pipe Joints

Plastic pipe joints, including plastic tubing joints, must be made in compliancewith the manufacturer’s recommendations. This typically requires the use of aprimer to clean the pipe or tubing and a solvent-weld glue. All joints must complywith code requirements.

Plastic joints must be designed and installed so that the longitudinal pull-outresistance of the joint will be at least equal to the tensile strength of the plastic pip-ing material.

Heat-fusion joints must be at least as strong as the pipe or tubing being joined.All heat-fusion fittings are to be labeled ASTM D 2513. The joints must be gas-tight when made.

Compression-type mechanical joints can be used to join plastic pipe and tub-ing. Gasket material in the fitting must be compatible with the pipe or tubing be-ing used and the gas being carried. Due to the nature of plastic pipe, a stiffenermust be flush with the end of the pipe or tubing and extend at least to the outsideend of the compression fitting when it is installed. The stiffener must be free ofrough or sharp edges and shall not be a force fit. You cannot use split tubular stiff-eners. When plastic pipe or tubing is used with LP-gas systems, it must meet therequirements of NFPA 58.

FLANGES AND FLANGE GASKETS

Flanges used with gas piping must meet the requirements of ASME B 16.1,ASME B 16.20, or MSS SP-6. Pressure and temperature ratings must equal or ex-ceed the requirements for the intended application. Standard facings are permitted


for use under the code. Where 150-pound pressure-rated steel flanges are boltedto Class 125 cast-iron flanges, the raised face on the steel flange shall be removed.

Can lapped flanges be used underground? No. They must only be used aboveground or in exposed locations, and they must be accessible for inspection.

Gasket material must be capable of withstanding the design temperature andpressure of the piping system and the chemical constituents of the gas being con-ducted without change to its chemical and physical properties. The materialmust be chosen with regard to fire exposure. Such materials can include the following:

• Metal

• Metal-jacketed asbestos (plain or corrugated)

• Asbestos

• Aluminum “O” rings

• Spiral-wound metal gaskets

If a flanged joint is opened, the gasket shall be replaced. Full-face gaskets shallbe used with all bronze and cast-iron flanges.

PIPING-SYSTEM INSTALLATION

How much do you know about piping system installations? Whatever your an-swer, you are about to learn more. We will start with prohibited locations. See thelist below for places not to install piping systems:

• Piping shall not be installed in or through a circulating-air duct.

• Piping shall not be installed in a laundry chute.

• Piping shall not be installed in a dumbwaiter.

• Piping shall not be installed in an elevator.

• Piping installed downstream of the point of delivery shall not extend through anytownhouse unit other than the unit served by such piping.

• Concealed piping is not allowed to be located in solid partitions or solid wallsunless installed in a chase or casing.

• Generally speaking, concealed piping is not allowed to be fitted with unions.

• Concealed piping is not allowed to be equipped with tubing fittings, right and leftcouplings, bushings, compression couplings, or swing joints made by combina-tions of fittings. There are two exceptions: tubing joined by brazing and fittingslisted for use in concealed locations.

Pipe Protection

Given the high risk for personal injury and property damage with a damaged gas


pipe, it should not come as any surprise that gas piping must be protected. Whenunderground piping is installed below grade and enters an outer foundation orbasement wall, the gas pipe must enter through a suitable sleeve. This sleeve is toprotect the pipe and is usually required to be two pipe diameters larger than thepipe conveying the gas. All annular space between gas pipe and a sleeve must besealed.

Gas pipe that is concealed must be protected. Black or galvanized-steel pipe isan exception that does not require special protection. Other types of pipe that areinstalled in wood studs, joists, rafters, or similar wood members that are less than1 1/2 inches from the nearest edge of the wood member must be protected. This istypically done with stud guards or nail plates. The plates are required to have aminimum thickness of 1/16 inch and be made of steel. This type of pipe shield isrequired to cover the area of the pipe where the member is notched or bored andmust extend a minimum of 4 inches above sole plates, below top plates, and toeach side of a stud, joist, or rafter.

Solid Floors

Pipe installed in solid floors must be laid in channels in the floor and covered in away that allows access to the piping with a minimum amount of damage to thestructure. Pipe protection must be provided to prevent damage from exposure, ex-cessive moisture, and corrosive substances. If it is not practical to install the pipein channels, the pipe can be installed in a conduit of Schedule 40 steel, wroughtiron, PVC, or ABS pipe with tightly sealed ends and joints. When conduit is used,both ends must extend no less than 2 inches beyond the point where the pipeemerges from the floor. Venting of the conduit is required. The vent must extendabove grade to the outdoors and must be installed so as to prevent the entry of wa-ter and insects.

Above-ground Outdoor Piping

When installing above-ground outdoor gas piping, the pipe must be installed atan elevation of not less than 3 1/2 inches above the ground. Gas pipe installed on


TradetipGas outlets that are not connected to appliances are required to be capped ina gas-tight seal. As you might expect, there is an exception: Listed and la-beled flush-mounted-type quick-disconnect devices and listed and labeledgas convenience outlets shall be installed in accordance with the manufac-turer’s instructions.

roof surfaces is also required to be elevated at least 3 1/2 inches above the sur-face. All outdoor piping must be installed so that it is supported and locatedwhere it will be protected from physical damage. Any gas pipe that passesthrough an outside wall must be protected against corrosion by coating or wrap-ping with an inert material. When pipe sleeves are used for protection, the annu-lar space must be sealed.

Corrosion

Corrosion protection is required for metallic pipe or tubing. This is required whensoil conditions or moisture is present and may cause a corrosive action. Zinc coat-ings, such as galvanizing, are not approved as a suitable protection when gas pipeis installed below ground. Any ferrous metal that is exposed to exterior conditionsmust be protected from corrosion. The mode of protection must be approved bythe code official. In events when dissimilar metals are joined below grade, an in-sulating coupling or fitting must be used. No gas piping is allowed to be laid incontact with cinders.

Outside Appliances

When outside appliances are serviced, the individual gas lines must be installed ata minimum of 8 inches below finished grade, provided that the installation is ap-


!CodealertUncoated, threaded, or socket-welded joints shall not be used in pipingin contact with soil or where internal or external crevices are known tooccur.

TradetipPipe protective coatings and wrappings must be approved for the applicationand must be factory-installed. There is an exception: As long as the protec-tive coating is installed in accordance with the manufacturer’s instructions,field application of coatings and wrappings is allowed. This applies to pipenipples, fittings, and locations where the factory coating or wrapping hasbeen damaged or necessarily removed at joints.

proved and installed in locations that are not susceptible to physical damage.Remember that normal cover for an underground pipe is 12 inches.

Beneath Buildings

Underground piping is generally not allowed beneath buildings. If the pipe is en-cased in a conduit of wrought iron, plastic pipe, or steel pipe designed to withstandsuperimposed loads, then installation can be done beneath buildings. When this isdone, the conduit must extend into the occupiable portion of the building. Whenthe conduit ends, the space between the conduit and the gas piping must be sealedto prevent the possible entrance of any gas leakage.

The end sealing of a conduit must be capable of withstanding the full pressureof gas pipe. This conduit must not extend less than 4 inches outside of a buildingand it must be vented above grade to the outdoors. The entrance of water or in-sects must be prevented at the termination of the conduit. Corrosion resistance isrequired for conduits, and they must be in accordance in 404.8.

Outlet Locations

Unthreaded portions of piping outlets must extend at least 1 inch through finishedceilings and walls; where it extends through floors or outdoor patios and slabs, theextensions must not be less than 2 inches above the penetration surface. All out-lets must be supported adequately. Typically, outlets are to be installed in theroom or space that contains the appliance or equipment being served.


?Did you knowA minimum depth of 12 inches is required for underground piping installa-tions unless there is a provision in Section 404.9.1 of the code that overrulesthe regulation.

!CodealertTrenches for gas piping must be graded so that the pipe has a firm, sub-stantially continuous bearing on the bottom of the trench.

Plastic-pipe Limitations

The only place where plastic pipe can be used for gas is outside underground. Itcannot be used in or under buildings or slabs. Maximum operating pressure forplastic gas piping must not exceed 100 psig for natural gas or 30 psig for LP gas.

Here are the exceptions: Plastic gas pipe is allowed to terminate above groundoutside of buildings where it is installed in premanufactured anodeless risers thatare in compliance with the manufacturer’s instructions. Plastic pipe is permittedto terminate with a wall head adapter within buildings where the pipe is insertedin a piping material for fuel-gas use in buildings.

Tracers

What are tracers? The most common type of tracer is a yellow insulated-copperwire. It can be some other type of approved conductor. The tracer is installedalongside nonmetallic gas piping. This allows the pipe to be found and traced elec-tronically. Ideally, tracer wires should terminate above ground at each end of apipe run. When this is not the case, the tracer must be installed so that it is acces-sible. A minimum conductor size of 18 AWG is required. And, the tracer must becovered in insulation that is approved for direct burial.

Changes in Direction

Changes of direction in gas piping are allowed when they are accomplished withthe use of fittings, factory bends, or field bends. Elbow fittings have to be factory-made welding elbows or transverse segments cut therefrom. The fitting requiresan arc length measured along the crotch at least 1 inch in pipe sizes 2 inches andlarger. Metallic-pipe bends must meet the following requirements:

• All bends must be made with bending tools and procedures that are intended forthe purpose.

• All bends must be smooth and free from buckling, cracks, or other evidence ofmechanical damage.

• Longitudinal welds of pipe must be near the neutral axis of the bend.

• The maximum arc for a bend must not exceed 90 degrees.


?Did you knowListed and labeled flush-mounted-type quick-disconnect devices and listedand labeled gas convenience outlets shall be installed in accordance with themanufacturer’s instructions.

• The inside radius of a bend shall be not less than six times the outside diameterof the pipe.

Plastic-pipe bends must comply with code requirements, which are noted below:

• At no time may the pipe be damaged during bending.

• The internal diameter of a pipe must not be effectively reduced.

• Joints are not allowed to be located in pipe bends.

• The radius of the inner curve of bends must not be less than 25 times the insidediameter of a pipe.

• If a manufacturer specifies the use of special bending tools or procedures, thetools and procedures must be used.

TESTING

Testing of a gas installation is required before the system is concealed or put intouse. There are different types of inspections that may be conducted. Examples ofthese inspections are noted below:

• Visual examination during manufacture

• Visual examination after manufacture

• Visual examination during fabrication

• Visual examination after fabrication


TradetipOutside and underground connections between metallic and plastic pipemust be made only with Category I transition fittings in accordance withASTM 2513.

!CodealertIt is not allowable to insert a device inside a pipe or fitting that will re-duce the cross-sectional area or obstruct the free flow of gas. The onlyexception to this rule is that approved gas filters are allowed.

• Visual examination during assembly

• Visual examination after assembly

• Pressure tests

• Supplementary types of nondestructive inspection techniques, such as magnetic-particle, radiographic, or ultrasonic are not required unless specifically listed inthe adopted code or in an engineering design.

• Repairs and additions to gas systems must be inspected. However, minor repairsand additions can be tested with a noncorrosive leak-detecting fluid instead of apressure test.

A pressure test is required on new branches that are installed to new appli-ances. Connections to existing piping can be tested with a noncorrosive leak-de-tecting fluid instead of a pressure test.

Piping systems can be tested as sections or as a whole. It is not permitted touse a valve in a line as a bulkhead between gas in one section of a piping systemand the test medium in an adjacent section unless two valves are installed in serieswith a valved “telltale” located between the valves. Only valves that are rated fortest pressure are allowed to be tested with pressure. Regulators and valve assem-blies fabricated independently of the piping system in which they are to be in-stalled can be tested with inert gas or air at the time of fabrication.

Oxygen cannot be used to test a gas system. Suitable testing mediums include:

• Air

• Nitrogen

• Carbon dioxide

• Inert gas

There are times when appliances are not intended to be tested with a gas sys-tem. If the appliances cannot be disconnected from the system during the testingprocedure, they can be isolated from the test. Blanks, blind flanges, or caps can beused for this purpose. Flanged joints at which blinds are inserted to blank off otherequipment during a test are not required to undergo additional testing. An appli-ance that is not rated for system test pressure must be isolated prior to a systemtest. This requires complete disconnection from the system. In cases where the ap-pliance has a valve that is rated for test pressure, the appliance can be isolated byclosing the valve prior to testing the gas system.

Test Pressure and Duration

Test pressure is measured with a manometer or a pressure-measuring device thatis designed and calibrated to read, record, or indicate a pressure loss caused byleakage during a test. The source of pressure shall be isolated before the pressuretests are made. Mechanical gauges used to measure test pressures must have arange whose highest end is not greater than five times the test pressure.


Test pressure must not be less than 3 psig. The pressure used must be no lessthan 1 1/2 times the proposed maximum working pressure. Test pressure exceed-ing 125 psig is not allowed. The test pressure must not exceed a value that pro-duces a hoop stress in the piping greater than 50 percent of the specified minimumyield strength of the pipe.

A pressure test is required to be maintained for a minimum of 30 minutes foreach 500 cubic feet of pipe volume or fraction thereof. Testing of a system with avolume less than 10 cubic feet or a system in a single-family dwelling shall be notless than 10 minutes. At no time shall the duration of a test be required to exceed24 hours.

If a leak is suspected, it must be found. The use of an approved gas meter or anoncorrosive leak-detection fluid is normally used. Never use a source of ignitionto seek leaks. In other words, don’t use a lit torch or match to find a gas leak. Oncea leak is found, it must be fixed and retested.

SERVICING A SYSTEM

When servicing a system that requires the gas piping to be opened, certain pro-cedures must be followed. The first step is turning off the gas, but that is not allthat is required. Gas in the piping system must be vented to the outdoors or aventilated area that is sufficient in size to prevent accumulation of flammablemixtures. Any remaining gas must be displaced with inert gas. See Table 4.39for details.

Once servicing is complete and a system is ready to be put back into operation,the system must be purged of air and inert gases. Some situations require the purg-ing of a system with inert gas. This is not required when air can be purged quicklywith fuel gas. The air must be purged to a point of discharge in free air. At no pointmay the site of purging be left unattended during the purging process. Once thepurging is complete, the vent must be closed securely. See Table 4.40 for pipingthat requires purging with inert gas.

PIPE SUPPORT

Pipe support is an essential part of a piping system. Components used for pipe sup-port must be of adequate strength and quality to support pipe properly. Acceptableforms of hangers may include the following:

• Pipe hooks

• Metal pipe straps

• Bands


• Brackets

• Hangers suitable for the size of the piping

Pipe support must be installed in such a way as to prevent excessive vibration.The intervals between supports must comply with local requirements. Section 415of the code deals with interval spacing, and we will talk about that later in thischapter. It must be determined that the pipe supports will not become disengagedby movement of the supported piping.

WET GAS

Wet gas is a type of gas that can allow liquid to accumulate in a piping system.Piping for a wet-gas system must be installed with a grade, or pitch, on it. The pip-


NOMINAL PIPE SIZE(inches)

LENGTH OF PIPINGREQUIRING PURGING

21/2 > 50 feet

3 > 30 feet

4 > 15 feet

6 > 10 feet

8 or larger Any lengthFor SI: 1 inch � 25.4 mm, 1 foot = 304.8 mm

TABLE 4.39 Length of piping requiring purging with inert gas for servicing ormodification, courtesy of 2006 International Fuel Gas Code.

NOMINAL PIPE SIZE(inches)

LENGTH OF PIPINGREQUIRING PURGING

3 > 30 feet

4 > 15 feet

6 > 10 feet

8 or larger Any lengthFor SI: 1 inch � 25.4 mm, 1 foot = 304.8 mm

TABLE 4.40 Length of piping requiring purging with inert gas before placing inoperation, courtesy of 2006 International Fuel Gas Code.

ing must slope downward at a rate of not less than 1/4 inch in 15 feet to preventthe need for trap installation.

Gas drips, usually called drip legs, are required at low points in a piping sys-tem. If condensation may accumulate, a drip is required. Outlets at gas meters re-quire gas drips. The drip must be installed to constitute a trap to collect any accu-mulation of condensation. The condensation shall then shut off the flow of gasbefore the condensate can run back into the gas meter. Drips must be installed tobe readily accessible and to be protected from freezing.

Sediment traps must be installed downstream of equipment shutoff valves asclose to the inlet of equipment as practical when a sediment trap is not incorpo-rated as part of the gas utilization equipment. Tee fittings can be used to make asediment trap. This usually means a tee fitting, a 8-inch nipple, and a cap.Illuminating appliances, ranges, clothes dryers, and outdoor grills do not requiresediment traps.

SHUTOFF VALVES

Shutoff valves are required on gas piping systems. Valves used must be of an ap-proved type. They may not be installed in concealed locations or furnace plenums.Access must be provided for valves. All gas meters require valves. The valvesmust be located on the supply side of the meters.

When a single meter is used to supply gas to multiple locations, each supplymust be equipped with its own shutoff valve. A common piping system that sup-plies multiple buildings with gas must have shutoff valves installed outdoors ateach building. Shutoff valves used to isolate multiple supply lines must be plainlymarked with an identification tag attached by the installer so that the valve can bereadily identified for which supply line it controls.

When an MP regulator is used, a shutoff valve must be installed immediatelyahead of the regulator. Shutoff valves are to be provided for each appliance sup-plied with gas. This valve must be in the same room as the appliance being servedand not more than 6 feet from the appliance. The valve cannot be installed up-stream from a union, connector, or quick disconnect device that it is serving.


TradetipWhen a gas system has been shut down and turned back on, it must bechecked for leaks.

Valves for decorative appliances in vented fireplaces are not prohibited frombeing installed in an area remote from the appliance if such valves are providedwith ready access. The valves must be permanently identified, and they are not al-lowed to serve additional equipment. Piping from the shutoff valve to within 3 feetof the appliance connection shall be sized in accordance with Section 402. Shutoffvalves that are located in a firebox or a fireplace must be installed in accordancewith the appliance manufacturer’s instructions.

FLOW CONTROLS

Flow controls can be necessary to maintain a proper rate of gas flow. Line=pres-sure regulators are used to keep operating pressure lower than supply pressure.Access is required for the regulators, and they must be protected from physicaldamage. If regulators are installed in outdoor locations, they must be approved forthe installation. There are a number of rules that apply to MP pressure regulators.They are noted below:

• Must be approved and suitable for the inlet and outlet gas pressure for the application

• Must maintain a reduced outlet pressure under lockup conditions

• Must have a capacity that is adequate to supply the appliances served

• Must be accessible

• If indoors, must be vented to the outdoors or equipped with a leak-limiting device

• Must be equipped with a sediment trap

• Require a gas drip within 10 pipe diameters downstream of the regulator outlet

Vent piping cannot be smaller than the vent connection on the pressure-regu-lating device. Piping that is run for relief vents and combination relief and breathervents must be run independently to the outdoors, and they must serve no more thanone device vent. When vent piping is serving only breather vents, it may be con-nected in a manifold arrangement sized in accordance with an approved designthat minimizes back pressure in the event of diaphragm rupture.


?Did you knowThe discharging of purged gases must be done into spaces that are not con-fined and that do not contain sources of ignition, unless precautions are takento perform the purging in a safe manner by ventilating the space, controllingthe purging rate, and eliminating any hazardous conditions.

MANUFACTURED-HOME CONNECTIONS

The rules for connecting appliances in manufactured home are not difficult to un-derstand, but they are important. Under normal conditions these types of connec-tions must be done by one of the following methods:

• Rigid metallic pipe and fittings

• Corrugated stainless-steel tubing in compliance with the manufacturer’s recom-mendations

• Semirigid metallic tubing and metallic fittings not more than 6 feet long and lo-cated entirely in the same room as the appliance being served (Do not use semi-rigid metallic tubing in a motor-operated appliance through an unprotectedknockout opening.)

• Listed and labeled appliance connectors that comply with ANSI Z21.24 if lo-cated entirely in the same room as the appliance being served

• Listed and labeled convenience outlets in conjunction with listed and labeled ap-pliance connectors

• Listed and labeled appliance connectors complying with ANSI Z21.69 and listedfor use with food-service equipment having casters or otherwise subject tomovement for cleaning, and other large, movable equipment

• Listed and labeled outdoor appliance connectors in compliance with ANSIZ21.75/CSA 6.27 and installed in accordance with the manufacturer’s instructions

When appliances have to be moved for cleaning, such as commercial cookingappliances, the appliances must be connected to the piping system with an appli-ance connector that is listed for compliance with ANSI Z21.69.

Connector Length

Gas connectors that are not made of rigid metallic piping are limited in length.Most appliance connectors are required to be no more than 3 feet in length.However, connectors for ranges and domestic clothes dryers can have a maximumlength of 6 feet. If rigid metallic pipe is used as a connector, it can have a longerlength so long as the piping is sized properly for the distance of the piping run. Allmeasurements are to be made along the centerline of the connector.


?Did you knowPressure regulators that require venting must be vented to the outdoors andprotected from the entrance of insects, water, and foreign objects. Regulatorsthat do not require venting must be labeled as such.

Gas-connector Prohibitions

Gas connectors must not be concealed within or extended through walls, floors,partitions, ceilings, or appliance housings. The exception to this is fireplace insertsthat are factory equipped with grommets, sleeves, or other means of protection inaccordance with the listing of the appliance.

MOTOR-VEHICLE FACILITIES

LP-gas Fuel-dispensing Facilities

The International Fire Code is used to govern the use of LP-gas motor-vehiclefuel-dispensing facilities. Components, containers, storage, and devices must beapproved. Hoses, hose connections, vehicle fuel connections, dispensers, LP-gaspumps, and electrical equipment used for LP gas must be listed.

Fuel-dispensing facilities are governed by the International Fire Code, butthere is more to be considered. The point of transfer for dispensing operationsmust be 25 feet or more from buildings having combustible exterior wall sur-faces; buildings having noncombustible exterior wall surfaces that are not part ofa 1-hour fire-resistance-rated assembly; buildings having combustible over-hangs; or property built on public streets, sidewalks, or railroads and at least 10feet from driveways and buildings having noncombustible exterior wall surfacesthat are part of a fire-resistance-rated assembly with a rating of 1 hour or more.That was a mouthful, and there is more. Here comes the exception: The point oftransfer for dispensing operations is not required to be separated from canopiesthat provide weather protection for dispensing equipment constructed in accor-dance with the International Building Code.

Dispensing Devices

Dispensing systems are required to have a manual shutoff valve and an excessflow-control check valve. The valves are to be installed in the liquid line betweenthe pump and the dispenser inlet where the dispensing device is installed at a re-mote location and is not part of a complete storage and dispensing unit mountedon a common base.

An excess flow-control valve is required, or an emergency shutoff-valve mustbe installed in or on the dispenser at the point at which the dispenser hose is con-nected to the liquid piping. A differential back-pressure valve shall be consideredequivalent protection. Listed shutoff valves must be located at the discharge endof the transfer hose.

Hydrostatic relief valves are required for hoses and piping used to dispense LPgas. The maximum allowable length for the hose is 18 feet. The hose must be pro-tected from mechanical damage.


Private Fueling

Self-service LP-gas-dispensing systems are not to be open to the public. They arelimited to the filling of permanently mounted fuel containers on LP-gas-poweredvehicles. Self-service status applies to keys, codes, and card-lock dispensing sys-tems. An emergency shutoff switch must be located within 100 feet of but not lessthan 20 feet from the dispenser, and the owner of the dispensing facility must en-sure the safe operation of the system and the training of users.

Compressed-natural-gas Fuel-dispensing Facilities

Compressed natural gas (CNG) motor-vehicle fuel-dispensing facilities are gov-erned by the International Fire Code. In general, storage vessels and equipmentused for the storage, compression, or dispensing of CNG must be approved orlisted in accordance with Sections 413.2.1 and 413.2.3 of the code. All contain-ers, compressors, pressure-relief devices, pressure-relief valves, pressure regula-tors, and piping used for CNG must be approved. Hoses, hose connections, dis-pensers, gas-detection systems, and electrical equipment used for CNG must belisted.

Location Exceptions

There are location exceptions, but generally compression, storage, and dispensingequipment is required to be above ground and outside. The exceptions are as fol-lows:

• When buildings are made of noncombustible construction as approved by theInternational Building Code and are unenclosed for three-quarters or more of theperimeter, they are allowed to have compression, storage, or dispensing equip-ment in the building.

• When installed in accordance with the International Fire Code, compression,storage, and dispensing equipment can be installed indoors or in vaults.

• If an equipment manufacturer authorizes it, residential fueling appliances andequipment can be installed indoors.


!CodealertConnectors for gas appliances must have the capacity required for thetotal demand of the connected appliances.

Compression, storage, and dispensing equipment not located in vaults thatcomply with the International Fire Code, other than residential fueling appliances,shall not be installed in the following locations:

• Beneath power lines

• Less than 10 feet from the nearest building or property line, public street, side-walk, or source of ignition (Remember, dispensing equipment does not need tobe separated from canopies that provide weather protection for the dispensingequipment when the structure is built in accordance with the InternationalBuilding Code.)

• Less than 25 feet from the nearest rail of any railroad track

• Less than 50 feet from the nearest rail of any railroad main track or any railroador transit line where power for train propulsion is provided by an outside electri-cal source, such as a third rail or overhead catenary.

• Less than 50 feet from the vertical plane below the nearest overhead wire of atrolley bus line.

Residential Applications

Residential fueling appliances must be connected in a way that will not causedamage to the premises. When installed outdoors, they must be located on firm,noncombustible surfaces.

Interior installations require venting to the outdoors. Additionally, a gas detec-tor must be installed in the same room or space housing the appliance. The detec-tor must be capable of operating at one-fifth of the lower limit of flammability ofnatural gas. This detector must be located within 6 inches of the highest point inthe room or space. In case of a system failure, the detector shall stop the operationof the appliance and activate an audible or visual alarm.

Private Fueling Facilities

Self-service CNG-dispensing systems, including key, code, and card-lock dis-pensing systems, must be limited to the filling of permanently mounted fuel con-tainers on CNG-powered vehicles. Owners of such facilities must ensure the safeoperation of the facilities. Pressure regulators have to be designed and installed toassure proper operation. This means protecting the regulators from freezing rain,


TradetipVehicle-impact protection for LP-gas storage containers, pumps, and dis-pensers must be provided in accordance with the International Fire Code.

sleet, snow, ice, mud, or debris. The protection is allowed to be integral with theregulator. Piping to equipment must be provided with a manual shutoff valve, andthe valve must be accessible.

Emergency Shutdown

An emergency shutdown device is required to be located within 75 feet of but notless than 25 feet from dispensers and must also be provided in the compressorarea. In the case of an emergency and upon activation, the shutdown device is re-quired to shut down the system that it is monitoring. This includes shutting off thepower supply to the compressor and closing valves between the main gas supplyand the compressor and between storage containers and dispensers.

Closed Transfer System

The use of a closed transfer system must be approved by a code official.Documented procedures must be submitted to the code official for review. Theremust be a plan for handling a low-pressure or high-pressure natural-gas releaseduring a discharge. Complete drawings of the piping diagram must be submittedto a code official.

Cylinders used in the venting of CNG must be rigidly supported. There mustbe a minimum of two points of support. Horizontal and lateral movement of thevessel or cylinder is prohibited. Protection of the vessel must be provided for thehighest rated pressure volume of the vessel. It should be noted that the structureor appurtenance must be constructed of noncombustible materials. This structureor appurtenance used for stabilizing cylinders must be separated from site equip-ment, features, and exposures as noted in your local code book. See Table 4.41for an example.

Vent Tube

A vent tube that diverts gas flow to the atmosphere must be installed on cylindersprior to beginning the venting process or a purging operation. Vent-tube materialsmust comply with International Fire Code requirements. The minimum distancerequired for a vent tube to terminate above grade is 10 feet. A rain cap or other fea-


?Did you knowFueling appliances for residential use are limited to a maximum capacity of 5standard cubic feet of natural gas per minute and must be listed.

ture that would limit or obstruct gas flow is prohibited. A listed bidirectional det-onation flame arrester must be installed at the connection fitting of a vent tube anda CNG cylinder.

Air or Oxygen under Pressure

Air or oxygen under pressure must not be allowed to come in contact with gas inpiping. This is accomplished by the use of a back-pressure regulator and reliefvalve. If oxygen is used, the installation must be in accordance with NFPA 51.

Interconnections

A backflow preventer is required for interconnections where supplementary gasfor standby use is connected downstream from a meter or a service regulatorwhere a meter is not supplied. It is permissible to use a three-way valve to admita standby supply and at the same time to shut off the regular supply of gas.

Support Intervals

As I mentioned earlier, pipe supports are required at specified intervals. Please seeTable 4.42 for acceptable intervals of pipe supports.

OVERPRESSURE PROTECTION

Overpressure protection is required to prevent a piping system from exceeding apressure that would cause unsafe operation of any connected and properly ad-


EQUIPMENT OR FEATURE MINIMUM SEPARATION (feet)

Buildings 25

Building openings 25

Lot lines 15

Public ways 15

Vehicles 25

CNG compressor and storage vessels 25

CNG dispensers 25For SI: 1 foot = 304.8 mm

TABLE 4.41 Separation distance for atmospheric venting of CNG, courtesy of 2006International Fuel Gas Code.

justed appliances. This is accomplished with the use of a line-pressure regulatorand one other method. There are two options. The two devices used must be in-stalled so that if one of the devices fails, the other device prevents overpressuriza-tion of the downstream system. The other option is to use two devices, either ofwhich is capable of limiting pressure to the maximum working pressure of thedownstream system. Maintenance requirements must be met on overpressure-pro-tection devices. This can include periodic inspections.

Pressure-relieving or pressure-limiting devices are not always required. Thefollowing list shows such circumstances:

• When gas does not contain materials that could seriously interfere with the op-eration of a service or line-pressure regulator

• When the operating pressure is 60 psi or less

• When a service or pressure regulator contains acceptable features and charac-teristics

Service or line-pressure regulators that meet the criteria for not requiring dualprotection include the following:


TradetipA structure or appurtenance that is used to support a cylinder must begrounded in accordance with the ICC Electrical Code. Bonding of the cylin-der valve is required prior to venting operations.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm

TABLE 4.42 Support of piping, courtesy of 2006 International Fuel Gas Code.

STEEL PIPE,NOMINAL SIZE

OF PIPE (inches)

SPACING OF SUPPORTS

(feet)

NOMINAL SIZEOF TUBING

(SMOOTH-WALL)(inches O.D.)

SPACING OF SUPPORTS

(feet)

1/2 6 1/2 4

3/4 or 1 8 5/8 or 3/4 6

11/4 or larger(horizontal) 10

7/8 or 1(horizontal) 8

11/4 or larger(vertical) Every floor level

1 or larger(vertical) Every floor level

• Pipe connections to the service or line regulator do not exceed 2 inches in nom-inal diameter.

• A regulator is self-contained with no external static or control piping.

• A regulator has a single port valve with an orifice diameter not greater than thatrecommended by the manufacturer for the maximum gas pressure at the regula-tor inlet.

• The valve seat is made of resilient material that is designed to withstand abrasionof the gas, impurities in the gas, and cutting by the valve and to resist permanentdeformation where it is pressed against the valve port.

• A regulator is capable, under normal operating conditions, of regulating thedownstream pressure within the necessary limits of accuracy and of limiting thedischarge pressure under no-flow conditions to not more than 150 percent of thedischarge pressure maintained under flow conditions.

Pressure-relieving or pressure-limiting devices must be of a certain type.Acceptable types are listed below:

• A spring-loaded relief device

• A pilot-loaded back-pressure regulator used as a relief valve and designed so thatfailure of the pilot system or external control piping will cause the regulator re-lief valve to open

• A monitoring regulator installed in series with the service or line-pressure regulator


!CodealertThe discharge of CNG from motor-vehicle fuel cylinders shall be ac-complished through a closed transfer system or an approved method ofatmospheric venting in accordance with Section 413.9.1 or 413.9.2.

?Did you knowAn approved “No Smoking” sign must be posted within 10 feet of a cylindersupport structure or appurtenance. Another required sign is one that reads:“Cylinder Shall Be Bonded.” This, too, is to be displayed on the cylinder sup-port structure or appurtenance.

• A series regulator installed upstream from the service or line regulator and set tocontinuously limit the pressure on the inlet of the service or line regulator to themaximum working pressure of the downstream piping system

• An automatic shutoff device installed in series with the service or line-pressureregulator and set to shut off when the pressure on the downstream piping systemreaches the maximum working pressure or some other predetermined pressureless than the maximum working pressure; the device must be designed to remainclosed until manually reset

• A liquid-seal relief device that can be set to open accurately and consistently atthe desired pressure

• The devices can be installed either as an integral part of the service or line-pres-sure regulator or as separate units

Settings

Settings for pressure-relieving or pressure-limiting devices must be set so that thepressure does not exceed a safe level beyond the maximum allowable workingpressure for connected piping and appliances.

Unauthorized Operation

Unauthorized operation of shutoff valves must be prevented. Shutoff valves maynot be cut off while rendering pressure-relieving or pressure-limiting devices in-operative. So how do you accomplish this? One way is to have the valve lockedin an open position. Authorized personnel must be told to leave the shutoff valveopen. If there is a reason for closing the valve, an authorized person must be pres-ent to ensure that the valve is locked in an open position when feasible.

Another way around the problem is to use duplicate relief valves. Each valvemust have adequate capacity to protect the system being served. Isolating valvesand three-way valves must be arranged so that only one safety device can be ren-dered inoperative at a time.

TradetipExternal control piping must be protected from falling objects, excavations,and other causes of damage and designed and installed so that damage to anycontrol piping will not render both the regulator and the overpressure-pro-tection device inoperative.


Vents

Gas from discharge stacks, vents, and outlet parts for all pressure-relieving andpressure-limiting devices must be discharged outdoors. The terminal ends of thesevents must be protected from the entry of water, insects, or other foreign materialthat could cause a blockage. Discharge stacks and vent lines must be a minimumof the same size as the outlet of the pressure-relieving device.

Size

Size matters when it comes to fittings, pipe, and openings. Devices located be-tween the system to be protected and the pressure-relieving device must be sizedto prevent hammering of the valve and impairment of relief capacity.

Had enough? I have. Let’s move into the next chapter on chimneys and vents.It will be a good change of pace.


?Did you knowPressure-relieving and pressure-limiting devices must be made from materi-als that will not be impaired by corrosion of external parts by atmosphere orinternal parts by the gas being conveyed. The devices must be constructed toallow someone to operate the units to determine if the valves for the devicesare free. An additional requirement is that the devices must be made in such away that allows them to be tested to determine the pressure at which they willoperate and so that they can be examined for leakage when they are in a closedposition.


CHAPTER 5CHIMNEYS AND VENTS

Chimneys and vents are governed by three codes. This chapter describes the pro-visions of the 2006 International Fuel Gas Code. The other codes that come intoplay are the International Mechanical Code and the International Building Code.The mechanical code pertains to factory-built units. Masonry chimneys are regu-lated by the building code.

All appliances are required to discharge products of combustion to the out-doors, except for appliances that are exempted by Section 501.8 of the gas code.We will consider those later in the chapter. All abandoned inlet openings in chim-neys and vents must be closed by an approved method. They cannot be left open.

Appliances that are equipped with mechanical forced-draft systems createpositive pressure in the venting system. When these appliances are used, the vent-ing system must be designed for positive pressure.

Room air is not allowed to enter a flue. This is accomplished with the instal-lation of a noncombustible seal. Access must be provided to flues for inspectionand cleaning.

Appliances are not allowed to be connected to a flue serving a factory-builtfireplace unless the appliance is listed specifically for this use. Any connection ofthis type must be in strict compliance with the manufacturer’s recommendations.

When an appliance is connected to a flue that serves a masonry fireplace, theflue gases from the appliance must enter the flue directly. The connector and flueused for this type of application must be accessible or removable for inspectionand cleaning. All connectors are required to be installed according to their listing.

Not all appliances are required to be vented. The following list details appli-ances that do not require venting:

• Ranges

• Built-in domestic cooking units that are listed and marked for optional venting

• Hot plates

5.1



• Laundry stoves

• Type 1 clothes dryers

• Refrigerators

• Counter appliances

• Room heaters that are listed for unvented use

• Direct-fired make-up air heaters

• Other equipment listed for unvented use and not provided with flue collars

• Specialized equipment of limited input such as laboratory burners and gas lights

• Single booster-type automatic instantaneous water heaters under certain conditions

SINGLE BOOSTER-TYPE AUTOMATIC INSTANTANEOUSWATER HEATERS

Single booster-type automatic instantaneous water heaters that are designed andused solely for the sanitizing-rinse requirements of a dishwashing machine in acommercial kitchen with a mechanical exhaust system do not have to be vented.Draft hoods may be required for this type of installation. When they are required,the draft-hood outlet must not be less than 36 inches vertically and 6 inches hori-zontally from any surface other than the heater.

REQUIREMENTS OF NONVENTED APPLIANCES

Appliances in the list above do have installation requirements. If the aggregate in-put rating exceeds 20 Btu per hour per cubic foot of volume of a room or space inwhich the appliances are installed, one or more must be provided with a ventingsystem or other approved means for conveying the vent gases to the outdoor at-mosphere so that the aggregate input rating of the remaining unvented appliancesand equipment does not exceed the input maximum.

!CodealertConnectors connected to a masonry chimney flue must be connectednot less than 12 inches above the lowest portion of the interior of flue.

If the room where the appliances are located is connected to another spacewith an opening of comparable size that cannot be closed, the volume of that spacecan be used in calculating the requirements for ventilation.

When power exhausters are used, appliances connected to them must be con-nected on the inlet side of the exhauster. All joints on the positive pressure side ofthe exhauster must be sealed to prevent flue-gas leakage as required by the man-ufacturer’s installation instructions.

RESIDENTIAL AND LOW-HEAT APPLIANCES

There are only three types of flue lining systems that are approved for use with res-idential-type and low-heat appliances. They are as follows:

• Clay flue lining the meets or exceeds the requirements of ASTM C 315 or equiv-alent standard

• Listed chimney lining systems that comply with UL 1777

• Approved materials that will resist without cracking, softening, or corrosion fluegases and condensate at temperatures up to 1,800 degrees F

CHIMNEYS AND VENTS 5.3

!CodealertMasonry chimneys utilized to vent appliances shall be located, con-structed, and sized as specified in the manufacturer's installation in-structions for the appliances being vented and Section 503 of the code.

TradetipAppliances that fall into the classification of Category II, III, or IV systemsmust be installed in accordance with the appliance manufacturer’s instructions.

Category I Appliances

Flue lining systems for use with Category I appliances are limited to two choices.They must comply with Section 501.12 of the code, or the chimney lining systemsmust be listed and labeled for use with gas appliances with draft hoods and otherCategory I gas appliances listed and labeled for use with Type B vents.

EXISTING CHIMNEYS AND VENTS

Whether you are disconnecting an existing chimney or vent or attaching to it, thework must be in compliance with the code requirements. These requirements in-clude such elements as:

• Size

• Flue passageways

• Cleanout

• Clearances

Chimney or vent sizes must be resized as needed to control flue-gas conden-sation in the interior of the chimney or vent. They must also be sized to provideappliances with their required draft. Resizing requirements for Category I appli-ances are given in Section 502.

Flue-gas passageways must be kept free of obstructions and combustible de-posits. Cleaning is required of any existing chimney or vent that was used previ-ously for venting a solid or liquid fuel-burning appliance or fireplace.

Flue liners, chimney inner walls, and vent inner walls must be continuous andfree of cracks, gaps, perforations, or other damage or deterioration that would al-low the escape of combustion products, including gases, moisture, or creosote.

Clearance requirements for chimneys and vents are controlled by theInternational Building Code. The manufacturer’s installation instructions mustalso be followed. Noncombustible firestopping or fireblocking has to be demon-strated in accordance with the International Building Code. Some masonry chim-neys are not required to have clearance between combustible materials and exte-


?Did you knowMasonry chimney flues are required to be equipped with a cleanout openingthat has a minimum height of 6 inches. The upper edge of the opening must belocated not less than 6 inches below the lowest chimney-inlet opening. A tight-fitting, noncombustible cover must be provided for the cleanout opening.

rior surfaces. In order for this to be the case, the chimney must be equipped witha lining system that is tested and listed for installation in chimneys in contact withcombustible materials in accordance with UL 1777 and installed in accordancewith the manufacturer’s instructions.

VENTS

Vents are required to be listed and labeled, except for special provisions in Section503.7 of the code. Type B and BW vents must be tested and be in compliance withUL 441. Vents of the Type L type are required to meet the regulations for UL 641.Category II and III appliances must meet the requirements of UL 1738. Plasticvents, which are approved for Category IV appliances, are not required to be listedor labeled when the vents are specified by the appliance manufacturer and in-stalled in accordance with the manufacturer’s recommendations.

Insulation Shields

Insulation shields are required for vents that pass through insulated areas. Theshields are required to be not less than 26-gauge sheet metal. When installed, theshield must provide clear space between the vent and the insulation materials. Theamount of clearance required is determined by the manufacturer’s requirementsfor the vent material. Vents that go through attics require a shield that terminatesnot less than 2 inches above insulation materials.

Protection

Protection must be provided for vents that are in concealed locations and are sub-ject to physical damage. If a vent penetrates wood members closer than 1 1/2inches to the edge of the wood member, shield plates must be installed to preventthe vent from being harmed. Shield plates are required to be made of steel with aminimum thickness of 1/16 inch. The plates must cover the risk area and extend aminimum of 4 inches above sole plates, below top plates, and to each side of astud, joist, or rafter.


TradetipWhen appliances are not connected directly to a chimney or a vent, a con-nector must be installed. The specifications of the connectors must complywith Section 503 of the code.

VENTING

Venting for appliances is normally required. This can be accomplished in variousways. For example, exhaust systems and ventilating hoods can be used in com-mercial applications to vent industrial appliances, such as those in which theprocess itself requires fume disposal.

Industrial appliances that are in large, well-ventilated spaces may be allowedto discharge directly into the space. Listed direct-vent appliances are to be in-stalled in compliance with the manufacturer’s recommendations.

Mechanical Draft Systems

Mechanical draft systems are available in various configurations. Acceptable sys-tems include the following:

• Systems that are listed and installed in accordance with the manufacturer’s in-structions for both the draft system and the appliance being served

• With the exception of incinerators, appliances vented by means of a mechanicaldraft system or either forced or induced draft design

• Systems designed to prevent leakage of vent or flue gases into buildings

• Vent connectors that serve appliances vented by natural draft and not connectedto any portion of mechanical draft systems operating under positive pressure

• Exit terminals of mechanical draft systems not less than 7 feet above grade wherelocated adjacent to public walkways


?Did you knowVenting systems must satisfy the draft requirements of appliances beingserved and must be in compliance with the manufacturer’s requirements.

!CodealertNo portion of a venting system shall extend into or pass through anycirculating air duct or furnace plenum.

When automatically operated appliances are connected to ventilation hoods orexhaust hoods, the system is required to have a damper or a power means of ex-haust. Provisions must be made to allow the flow of gas to the main burners onlywhen the damper is open to a position to properly vent the appliance being servedand when the power means of exhaust is in operation.

Above-ceiling Systems

Venting systems that pass through an above-ceiling air-handling space or othernonducted portion of an air-handling system must comply with one of three rules:

• The system must be listed as a special gas vent, a system that serves Category IIIand IV appliances, or some positive-pressure type. All joints must be sealed incompliance with the appliance manufacturer’s instructions.

• The system can be installed so that it has no fittings or joints between sections inthe above-ceiling space.

• The system can be installed in a conduit or enclosure with sealed joints separat-ing the interior of the conduit or enclosure from the ceiling space.

MASONRY CHIMNEYS

Masonry chimneys are generally required to be lined with approved clay flue lin-ing, a listed chimney-lining system, or other approved material that will resist cor-rosion, erosion, softening, or cracking from vent gases at temperatures up to 1,800degrees F. These chimneys are to be installed in accordance with NFPA 211.There are exceptions:

• Masonry chimney flues serving listed gas appliances with draft hoods

• Masonry chimney flues serving Category I appliances

• Appliances that are listed for use with Type B vents

• Chimneys that have a lining that is specifically listed for use with an appliancethat is being served


TradetipPlastic piping that is used for venting appliances must be listed for the in-tended use and be approved. Special gas vents must be listed and installed inaccordance with the manufacturer’s instructions.

• Liners installed in accordance with the manufacturer’s recommendations

• A permanent identifying label attached at the point where the connection is tobe made to the chimney liner: “This chimney liner is for appliances that burngas only. Do not connect to solid or liquid-fuel-burning appliances or incinerators.”

Chimney Termination

Chimneys for residential-type, low-heat appliances must extend a minimum of 3feet above the highest point where they pass through a roof of a building. Theymust be at least 2 feet higher than any portion of a building within a horizontal dis-tance of 10 feet. See Figure 5.1 for an example of chimney terminations.

Chimneys that serve medium-heat appliances must extend a minimum of 10feet higher than any portion of any building within 25 feet. Chimneys must ex-tend at least 5 feet above the highest connected appliance draft-hood outlet or fluecollar.

Chimney Sizing Limitations

We will talk about sizing chimneys later in the chapter, but first you need toknow about limitations that will be applied when sizing chimneys. You can useany approved engineering method to size a chimney. Section 504 of the codepertains to sizing requirements. Venting systems that use mechanical draft mustbe sized in accordance with approved engineering methods. There are two otherconsiderations.

When sizing a chimney for a single appliance with a draft hood, the effectiveareas of the vent connector and chimney flue shall be not less than the area of theappliance flue collar or draft hood outlet but not greater than seven times the draft-hood-outlet area.

If two appliances with draft hoods are to be connected to a chimney, the effec-tive area of the chimney flue must not be less than the area of the larger draft-hoodoutlet plus 50 percent of the area of the smaller draft-hood outlet, but not greaterthan seven times the smallest draft-hood-outlet area.


?Did you knowDecorative shrouds cannot be installed at the termination of factory-builtchimneys unless the shrouds are listed and labeled for use with the specificchimney system.


FIGURE 5.1 Chimney terminations, courtesy of the 2006 International Fuel Gas Code.

Chimney Inspections

A chimney must be inspected before replacing an existing appliance or connect-ing a vent connector to it. The chimney must be free from obstructions. If thechimney has been used previously for venting solid or liquid fuel-burning appli-ances or fireplaces, it must be cleaned before appliance replacement or vent con-nection. The chimney lining must comply with NFPA 211. An exception is thatwhen the appliance being replaced is approximately the same type of appliancewith the same basic input rating and efficiency, the existing chimney can be usedin its existing condition so long as it is safe.

If a chimney is found to be unsafe, it must be repaired, rebuilt, lined, relined,or replaced to conform with NFPA 211, and it must be suitable for the appliancesto be vented. It is not permissible to combine connections for appliances of differ-ent fuel types. By this I mean that you cannot connect a gas appliance to a vent orchimney that also serves a device that burns solid fuel.

Liquid-fuel-burning Appliances

Flues that serve liquid-fuel-burning appliances and gas appliances must be con-nected through separate openings or through a single opening where joined by asuitable fitting located as close as practical to the chimney. If two or more open-ings are provided into a single chimney, the connection points must be at differ-ent levels. When appliances are automatically controlled, they must be equippedwith safety shutoff devices.

Combination Appliances

Can you connect a combination gas- and solid-fuel-burning appliance to a singlechimney? If it is equipped with a manual reset device to shut off gas to the mainburner in the event of sustained backdraft or flue gas spillage, it can be connected


!CodealertCan an incinerator be vented by a chimney that serves other appli-ances? Yes, but there are conditions. The gas input to the incineratorshall not be included in calculating chimney size, provided that thechimney flue diameter is not less than 1 inch larger in equivalent diam-eter than the diameter of the incinerator flue outlet.

on a single chimney. Additionally, the flue must be sized to properly vent the ap-pliance. This ruling also applies to gas- and oil-burning appliances.

CLEANOUTS

Cleanouts are required for chimneys that formerly carried flue products from liq-uid or solid fuel-burning appliances in order to be used with fuel-gas appliances.The cleanouts are to have tight-fitting covers and installed so that their upper edgeis at least 6 inches below the lower edge of the lowest chimney inlet opening.

COMBUSTION AIR

The remaining space surrounding a chimney liner, gas vent, special gas vent, orplastic piping installed within a masonry, metal, or factory-built chimney must notbe used to supply combustion air. However, the space can be used to supply com-bustion air to direct-vent appliances that are designed for installation in a solid-fuel-burning fireplace and installed in accordance with the manufacturer’s re-quirements.


TradetipChimneys need to be supported properly. To do so, you must take into ac-count the design and weight of the materials used. Factory-built chimneysmust be supported and spaced in accordance with the manufacturer’s instal-lation instructions.

?Did you knowThe space surrounding a chimney liner, gas vent, special gas vent, or plasticpiping installed within a masonry chimney flue cannot be used to vent anotherappliance. However, the insertion of another liner or vent within the chimney,as provided for in the code, is not prohibited.

GAS VENTS

Gas vents can be installed in masonry chimneys. They must be installed in accor-dance with the manufacturer’s recommendations. The vent must be identified witha permanent label installed at the point where the vent enters a chimney. This la-bel is required to read: “This gas vent is for appliances that burn gas. Do not con-nect to solid or liquid fuel-burning appliances or incinerators.”

Terminating Gas Vents

There are a number of requirements for terminating gas vents. A vent that is 12inches or less in size and located not less than 8 feet from a vertical wall or simi-lar obstruction shall terminate above the roof in accordance with Figure 5.2.

Gas vents that are over 12 inches in size or are located less than 8 feet from avertical wall or similar obstruction shall terminate not less than 2 feet above thehighest point where they pass through the roof and not less than 2 feet above anyportion of a building within 10 feet horizontally.

A Type B or L gas vent must terminate at least 5 feet in vertical height abovethe highest connected appliance draft hood or flue collar. A Type B-W gas ventmust terminate at least 12 feet in vertical height above the bottom of a wall furnace.

When going through a roof, vents must extend through the roof flashing, roofjack, or roof thimble and terminate with a listed cap or listed roof assembly.

Gas vents are required to terminate at least 3 feet above any forced-air inlet lo-cated within 10 feet of the vent.


TradetipGas vents are to be installed in accordance with the manufacturer’s installa-tion instructions.

?Did you knowGas vents that extend through an exterior wall are not allowed to terminate ad-jacent to the wall or below eaves or parapets, except as provided in Sections503.2.3 and 503.3.3 of the code.

Vents for Category I Appliances

Natural draft venting systems serving one or more listed appliances equipped witha draft hood or appliances listed for use with Type B gas vents installed in a sin-gle story of a building must comply with one of three conditions. The first optionis to work within the code requirements of Section 504. Another option is to ob-tain an approved engineering design. The third option is to size the vent as de-scribed below.

When sizing an individual gas vent for a single, draft-hood-equipped appli-ance, the effective area of the vent connector and the gas vent shall not be less thanthe area of the appliance draft hood outlet or greater than seven times the drafthood outlet area.

Gas vents connected to two appliances with draft hoods must be sized so thatthe effective area of the vent is not less than the area of the larger draft-hood out-let plus 50 percent of the area of the smaller draft-hood outlet but not greater thanseven times the smaller draft-hood-outlet areas.

Offsets

Type B and L vents that are sized in accordance with Item 2 or 3 of Section503.6.9.1 of the code must extend in a generally vertical direction with offsets notexceeding 45 degrees, except that a vent system with not more than one 60-degreeoffset is permitted. Angles of more than 45 degrees from vertical are consideredhorizontal. When calculating horizontal runs, the total horizontal distance of avent plus the horizontal vent connector serving draft-hood-equipped appliancesmust not be greater than 75 percent of the vertical height of the vent.


FIGURE 5.2 Locations for terminating gas vents, courtesy of the 2006 International FuelGas Code.

Multistory Buildings

Category I appliances can have a common gas vent in multistory installations ifthe system is of an approved engineering design. With this in mind, crawl spaces,basements, and attics are to be considered as floor levels. When appliances con-nected to a common vent must be located in rooms separated from occupiablespace, the rooms are required to have provisions for adequate combustion, venti-lation, and dilution air that is not supplied from an occupiable space. See Figure5.3 for an illustration of .

SIZING CONNECTORS

The sizing of connectors and common segments of multistory venting systemslisted for use with Type B double-wall gas vents is done with a table in your codebook. We will discuss that table later in the chapter; now, we are going to talkabout provisions that must be met in order for the table to be effective.

The available total height (H) for each segment of a multistory venting systemis the vertical distance between the level of the highest draft-hood outlet or fluecollar on that floor and the centerline of the next highest interconnection tee.

The appliance input rating and available connector rise are used to determinesizing. The size must not be smaller than the draft-hood outlet or flue-collar size.The input rating is also used to determine the size of common vertical segmentsand of the interconnection tee at the base of that segment.


FIGURE 5.3 Plan view of practical separation method for multistory gas venting, cour-tesy of the 2006 International Fuel Gas Code.

LABELING

A label is required where solid and liquid fuels are used extensively. The labelmust be applied permanently to identify gas vents. The signage can be mountedon a wall, ceiling, or at the point where a vent connector enters a gas vent. Exactplacement of the label is to be determined by a code official. Each label is requiredto read as follows: “This gas vent is for appliances that burn gas. Do not connectto solid or liquid fuel-burning appliances or incinerators.”

SINGLE-WALL PIPE

Single-wall pipe is required to be made of galvanized sheet steel that is not lessthan 0.0304 inches thick or other approved, noncombustible, corrosion-resistantmaterial. Uninsulated single-wall pipe can be installed outside when the climate iswarm enough. Exterior installation is not allowed in regions where the 99-percentwinter design temperature is below freezing (32 degrees F).

The requirements for terminating a single-wall pipe are as follows:

• At least 5 feet in vertical height above the highest connected appliance draft-hood outlet or flue collar

• At least 2 feet above the highest point where it passes through a roof of a building

• At least 2 feet higher than any portion of a building within a horizontal distanceof 10 feet

• Termination point equipped with an approved cap or roof assembly

Roof Penetration

When single-wall pipe penetrates a roof, it must extend without interruptionthrough the roof flashing, roof jack, or roof thimble. If the roof is made of com-bustible material, a noncombustible, nonventilating thimble must be provided atthe point of passage through the roof. This thimble must extend at least 18 inchesabove and 6 inches below the roof with the annular space open at the bottom andclosed on the top.


TradetipGas vents shall be supported and spaced in accordance with the manufac-turer’s installation instructions.

Installation Rules

There are some installation rules to be followed when working with single-wallpipe:

• The pipe must not originate in an unoccupied attic or concealed space.

• The pipe is not allowed to pass through an attic.

• The pipe is not allowed to pass through an inside wall.

• The pipe is not allowed to pass through a concealed space.

• The pipe is not allowed to pass through a floor.

• Penetrations of exterior combustible walls must comply with Section 503.10.15of the code.

• Single-wall pipe used to vent an incinerator must be exposed and readily exam-inable for its full length and shall have suitable clearances maintained.

• Clearances for single-wall pipe can be determined by Table 5.1.

Single-wall Pipe Size

Venting systems made from single-wall metal pipe can be sized in one of threemanners. As usual, an approved engineering design is acceptable. When this is notavailable, you can use Section 504 of the code for appliances equipped with drafthoods. Then there is the easy way. When you are working with a single appliancethat has a draft hood, the vent can be sized so that the areas of the connector andthe pipe are each not less than the area of the appliance flue cover or draft-hoodoutlet, whichever is smaller. The vent area must not be greater than seven timesthe draft-hood-outlet area.


!CodealertVent caps and roof assemblies must have a venting capacity that is notless than that of the pipe to which they are attached.

TradetipSingle-wall metal pipe must be supported for the design and weight of thematerial used and must have all portions supported.

VENTING TERMINATION LOCATIONS

Venting termination locations must comply with a number of code requirements.For example, a mechanical draft venting system must terminate at least 3 feetabove any forced-air inlet located within 10 feet. There are, as you might expect,two exceptions: The rule does not apply to the combustion air intake or to a direct-vent appliance. It also doesn’t apply to the separation of the integral outdoor airinlet and flue-gas discharge of listed outdoor appliances.

With the exception of direct-vent appliances, a mechanical draft venting sys-tem must terminate at least 4 feet below, 4 feet horizontally from, or 1 foot aboveany door, operable window, or gravity air inlet into any building. The bottom ofthe vent terminal must be located at least 12 inches above grade.

Vent terminals of direct-vent appliances with an input of 10,000 Btu per houror less shall be located at least 6 inches from any air opening into a building; ap-pliances with inputs over 10,000 Btu per hour but not over 50,000 Btu per hourmust be installed with a 9-inch vent termination clearance; and appliances with aninput over 50,000 Btu/h must have at least a 12-inch vent-termination clearance.The bottom of the vent terminal and the air intake must be located at least 12inches above grade.


APPLIANCE

MINIMUM DISTANCE FROM COMBUSTIBLE MATERIAL

Listed Type Bgas vent material

ListedType L vent

materialSingle-wallmetal pipe

Factory-builtchimneysections

Listed appliances with drafthoods and appliances listed foruse with Type B gas vents

As listed As listed 6 inches As listed

Residential boilers and fur-naces with listed gas conver-sion burner and with drafthood

6 inches 6 inches 9 inches As listed

Residential appliances listed for use with Type L vents

Notpermitted As listed 9 inches As listed

Listed gas-fired toiletsNot

permitted As listed As listed As listed

Unlisted residential appliancewith draft hood

Notpermitted 6 inches 9 inches As listed

Residential and low-heat appliances other than above

Notpermitted 9 inches 18 inches As listed

Medium-heat appliances Not

permittedNot

permitted 36 inches As listed

TABLE 5.1 Clearances for connectors, courtesy of 2006 International Fuel GasCode.

Category II and IV Appliances

Category II and IV appliances that use through-the-wall vents and noncategorizedcondensing appliances cannot terminate over public walkways or over areaswhere condensate or vapor could create a nuisance or hazard or be detrimental tothe operation of regulators, relief valves, or other equipment. In some cases, basedon local experience, appliances in Category I and III can be forced to meet thesesame criteria.

UNCONDITIONED AREAS

Vent connectors used for appliances with draft hoods or Category I appliances lo-cated in unconditioned areas, such as crawl spaces and attics, have to meet certaincriteria. The portion of the connector in the unconditioned area must be Type B,Type L, or listed vent material having equivalent insulation properties. There is anexception: Single-wall metal pipe within exterior walls of a building locatedwhere the local 99-percent winter design temperature is 5 degrees F or higher canbe used in unconditioned spaces other than attics and crawl spaces.

RESIDENTIAL-TYPE APPLIANCE CONNECTORS

Residential-type appliance connectors for appliances not installed in attics orother unconditioned spaces must be designed for listed appliances that have drafthoods. Appliances with draft hoods and equipped with listed conversion burners,as well as Category I appliances, must have connectors that meet the following re-quirements:

• Type B or L vent material

• Galvanized sheet steel that is not less than 0.018 inch thick

• Aluminum (1100 or 3003 alloy or equivalent) sheet that is not less than 0.027inch thick


!CodealertThe drainage of condensate systems must be designed to collect anddispose of condensate from venting systems serving Category II andIV appliances and noncategorized condensing appliances in accor-dance with Section 503.8, Item 4, of the code.

• Stainless-steel sheet not less than 0.012 inch thick

• Smooth interior-wall metal pipe having resistance to heat and corrosion equal toor greater than that of the specifications above

• A listed vent connector

• Vent connectors not allowed to be covered with insulation

• Listed insulated vent connectors installed according to the terms of their listing

LOW-HEAT EQUIPMENT

Low-heat equipment requires a factory-built chimney section or steel pipe havingresistance to heat and corrosion equivalent to that of the appropriate galvanizedpipe. See Table 5.2 for options. All joints on the chimneys must be made in accor-dance with the manufacturer’s instructions.

MEDIUM-HEAT EQUIPMENT

Medium-heat appliances and incinerators require vents that are rated for the pur-pose. This means that a factory-built, medium-heat chimney is needed. The thick-ness of the chimney can be determined by using Table 5.3.

Steel vent connectors for appliances with a vent-gas temperature in excess of1000 degrees F measured at the entrance to the connector must be lined withmedium-duty fire brick or an equivalent. The lining is required to be at least 2.5inches thick for a vent connector having a diameter or greatest cross-sectional di-mensions of 18 inches or less. It must be at least 4 1/2 inches thick laid on a 4 1/2-inch bed for a vent connector having a diameter or greatest cross-sectional dimen-


DIAMETER OF CONNECTOR(inches)

MINIMUM THICKNESS(inch)

Less than 6 0.019

6 to less than 10 0.023

10 to 12 inclusive 0.029

14 to 16 inclusive 0.034

Over 16 0.056

TABLE 5.2 Minimum thickness for galvanized-steel vent connectors for low-heatappliances, courtesy of 2006 International Fuel Gas Code.

For SI: 1 inch = 25.4 mm.

sion greater than 18 inches. Factory-built chimney sections, when used, must bejoined together in accordance with the chimney manufacturer’s instructions.

MULTIPLE DRAFT HOODS

Sometimes appliances are equipped with multiple draft hoods or flue collars.When this is the case, the manifold for the hoods must be constructed in accor-dance with the manufacturer’s instructions. In the event there are no instructionsavailable, an approved engineering design is required. Is there a practical in-the-field solution to sizing? Yes: You can build a manifold that has an effective areaequal to the combined area of the flue collars or draft-hood outlets, and the ventconnector must have a minimum of 1 foot in rise. Wasn’t that easy?


DIAMETER (inches)AREA

(square inches)MINIMUM THICKNESS

(inch)

Up to 14 Up to 154 0.053

Over 14 to 16 154 to 201 0.067

Over 16 to 18 201 to 254 0.093

Over 18 Larger than 254 0.123

TABLE 5.3 Minimum thickness for steel vent connectors for medium-heat appliancesand commercial and industrial incinerators vent-connector size, courtesy of 2006International Fuel Gas Code.

For SI: 1 inch = 25.4 mm, 1 square inch = 645.16 mm2.

TradetipWhen two or more appliances are vented through a common vent connectoror vent manifold, they must be located at the highest level consistent withavailable headroom and the required clearance to combustible materials andmust be sized in accordance with Section 504 of the code or some other ap-proved engineering method. As an alternative, when there are two draft-hood-equipped appliances, the effective area of the common vent connectoror vent manifold and all junction fittings must be not less than the area of thelarger vent connector plus 50 percent of the area of the smaller flue-collaroutlet.

MULTIPLE APPLIANCES

When multiple appliances are connected to a single vent, the smaller connectormust enter at the highest level consistent with the available headroom or clearanceto combustible material. It is not permissible for vent connectors serving CategoryI appliances to be connected to any portion of a mechanical draft system operat-ing under positive static pressure.

JOINTS

Joints between sections of connector piping and connections to flue collars anddraft-hood outlets must be fastened by an approved method. The methods includesheet-metal screws and listed materials that are installed in accordance with themanufacturer’s requirements.

CONNECTOR LENGTH

The maximum horizontal length of a single-wall connector must be 75 percent ofthe height of the chimney or vent except for engineered systems. It is desirable tokeep vent connectors as short as is practically possible. The maximum horizontal


!CodealertVent connectors have to be installed to avoid turns or other construc-tion features that create excessive resistance to flow of vent gases.

?Did you knowDid you know that vent connectors cannot be installed with dips or sags? Theconnectors are required to have a grade upward, toward the vent or chimney,of a minimum of 1/4 inch per foot. The only exception to this is a connectorattached to a mechanical draft system installed in accordance with the manu-facturer’s instructions.

length of a Type B double-wall connector must be 100 percent of the height of thechimney or vent except for engineered systems. In cases where multiple appli-ances are being vented by a single vent, the maximum length of an individual con-nector from the appliance outlet to the junction with the common vent or anotherconnector must be 100 percent of the height of the chimney or vent.

CHIMNEY CONNECTIONS

Vent connectors are not allowed to make chimney connections at the extreme bot-tom of the chimney in order to avoid stoppages. When an installation is made tofacilitate removal of a connector, the connector must be attached firmly.Connectors must not extend into chimneys to a point where they will restrict thespace between the connector’s end and the opposite end of the chimney flue.

WALL PENETRATION

Single-wall connectors passing through combustible walls must meet code crite-ria. This normally involves the installation of a thimble in the wall. If a thimble isnot used, all combustible material must be removed from around the pipe thatpasses through the wall. The clearance must meet code requirements, and materi-


!CodealertVent connectors are required to be supported for the design and weightof the material used, to maintain clearances, and to prevent physicaldamage and separation of joints. The entire length of a vent connectormust be provided with ready access for inspection, cleaning, and replacement.

?Did you knowVent connectors must not be connected to a chimney flue serving a fireplaceunless the fireplace flue opening is permanently sealed.

als used to fill the space around the pipe must be noncombustible. Since a thimbleis often the most practical answer, it is most common to install approved thimblesin the walls where single-wall pipes will pass through combustible walls. Notethat the thimble must be ventilated. Other rules to follow are listed below:

• Listed appliances with draft hoods and Type B gas vents require thimbles to beat least 4 inches larger in diameter than the vent connector. However, when thevent connector has a run of more than 6 feet visible between the draft hood out-let and the thimble, it is permissible for the thimble to be at least 2 inches largerin diameter than the vent connector.

• Unlisted appliances with draft hoods require a thimble that is not less than 6inches larger in diameter than the vent connector.

• Thimbles for residential and low-heat appliances are required to be at least 12inches larger in diameter than the vent connector.

VENTED APPLIANCES

Vented appliances are required to be installed with draft hoods. Exceptions to thisrule do exist. Vented appliances that do not require draft hoods are listed below:

• Dual oven-type combination ranges

• Incinerators

• Direct-vent appliances

• Fan-assisted combustion-system appliances

• Appliances requiring chimney draft for operation

• Single firebox boilers equipped with conversion burners with inputs greater than400,000 Btu per hour

• Appliances equipped with blast, power, or pressure burners that are not listed foruse with draft hoods

• Appliances designed for forced venting


!CodealertVent connectors for medium-heat appliances are not allowed to passthrough walls or partitions that are made of combustible material.

DRAFT HOODS

Draft hoods must be installed without alteration, exactly as furnished and speci-fied by the appliance manufacturer. If a required draft hood is not supplied by anappliance manufacturer , the hood installed must be listed or approved. If no in-structions are available, the hood must be the same size as the flue collar for theappliance. Draft hoods for conversion burners must be listed or approved.

All draft-control devices supplied by appliance manufacturers are to be in-stalled in accordance with the manufacturer’s recommendations. If instructionsare not provided, the device is to be attached to the flue collar of the appliance oras near to the appliance as is practical.

Draft hoods and barometric draft regulators have to be installed in the sameroom or enclosure as the appliance in such a manner as to prevent any differencein pressure between the hood or regulator and the combustion-air supply.

Draft hoods and draft regulators must be installed in the position for whichthey are designed with reference to the horizontal and vertical planes. They mustbe located so that the relief opening is not obstructed by any part of the applianceor adjacent construction. Relief openings must be accessible for checking vent op-eration.

Draft hoods must be located so that the relief openings are at least 6 inchesfrom any surface except that of the appliances served and the venting system towhich the hoods are connected. Check the label on the appliance for any specificinstructions for clearance and comply with it. Never reduce required clearances.

Devices that obstruct or retard the flow of vent gases must not be installed ina vent connector, chimney, or vent. The following list outlines conditions that arenot considered to be obstructions:

• Draft regulators and safety controls that are listed and installed in accordancewith the manufacturer’s instructions

• Draft regulators and safety controls that are installed in accordance with an ap-proved engineering design

• Listed reclaimers and automatically operated vent dampers that are installed ac-cording to the requirements of the manufacturer


TradetipManually operated dampers are not allowed to be installed in vent connec-tors for appliances. Fixed baffles are not considered manually operateddampers.

• Approved economizers, heat reclaimers, and recuperators installed in ventingsystems of appliances not required to be equipped with draft hoods, provided thatthe appliance manufacturer’s instructions cover the installation of such a devicein the venting system and performance is in compliance with the code

• Vent dampers serving listed appliances installed in accordance with the code orapproved engineering methods

TABLE DEFINITIONS

You will need to know certain definitions used in tables within the code. The ta-bles are required to obtain essential data when working with gas systems. To pre-pare you for working with gas tables, a listing of commonly used words, terms,and abbreviations is provided below.

Appliance categorized vent diameter/area: The minimum vent area/diameterpermissible for Category I appliances to maintain a nonpositive vent static pres-sure when tested in accordance with nationally recognized standards

Fan-assisted combustion system: An appliance equipped with an integral me-chanical means to either draw or force products of combustion through the com-bustion chamber or heat exchanger

Fan minimum: The minimum input rating of a Category I fan-assisted appli-ance attached to a vent or connector

Fan maximum: The maximum input rating of a Category I fan-assisted appli-ance attached to a vent or connector.

Nat maximum: The maximum input rating of a Category I draft-hood-equipped appliance attached to a vent or connector

Fan + fan: The maximum combined appliance input rating of two or moreCategory I fan-assisted appliances attached to the common vent

Fan + nat: The maximum combined appliance input rating of one or moreCategory I fan-assisted appliances and one or more Category I draft-hood-equipped appliances attached to the common vent

Na: Vent configuration is not allowed due to potential for condensate forma-tion or pressurization of the venting system or is not applicable due to physical orgeometric restraints

Nat + nat: The maximum combined appliance input rating of two or moreCategory I draft-hood-equipped appliances attached to the common vent

We are getting closer to the tables that will be used for much of your planningfor gas systems. At first glance, the tables can be intimidating. They are not to befeared. Once you understand the tables, they will make your work with gas sys-tems easier.


VENTING TABLES

Venting tables are not allowed to be used when obstructions are present. Ventsserving listed appliances with vent dampers must be installed in accordance withthe manufacturer’s instructions or in compliance with code requirements. Thecode requirements that I am referring to illustrate that the maximum capacity of avent system is to be determined using the Nat Max column in the venting table.

Minimum capacity is determined as if the appliance were a fan-assisted appli-ance, using the Fan Min column to determine the minimum capacity of a vent sys-tem. Where the corresponding Fan Min is Na, the vent configuration is not per-mitted and an alternative venting configuration must be utilized.

Minimum Size

There may be times when the size you arrive at using a table is smaller than theappliance hood outlet or flue collar. If this happens, can you use the smaller size?It would be logical to think that the vent must be at least as large as the appliancehood outlet or flue collar, but this is not always the case. When certain conditionsare met, the vent can be smaller than the hood outlet or flue color. When is this al-lowed? See the list below:

• The total vent height (H) is at least 10 feet

• Vents for appliance draft-hood outlets or flue collars 12 inches in diameter orsmaller not reduced more than one table size

• Vents for appliance draft-hood outlets or flue collars larger than 12 inches in di-ameter not reduced more than two table sizes

• The maximum capacity listed in the tables for a fan-assisted appliance reducedby 10 percent

• The draft-hood outlet is greater than 4 inches in diameter (It is not acceptable toconnect a 3-inch-diameter vent to a 4-inch draft hood outlet. This provision doesnot apply to fan-assisted appliances.)

Vent Offsets

Single-appliance venting configurations with zero lateral lengths are not allowedto have elbows in the venting system. Single-appliance venting configurations


TradetipConnections between chimney liners and listed double-wall connectors areto be made with adapters that are listed for the job at hand.

with lateral lengths include two 90-degree elbows. For each additional elbow upto and including 45 degrees, the maximum capacity listed in the venting tablesmust be reduced by 5 percent. Additional elbows that are greater than 45 degreesup to and including 90 degrees present the maximum capacity listed in the vent-ing tables and need to be reduced by 10 percent.

High Altitudes

Systems designed for high altitudes should be sized using sea-level input ratingsfor maximum capacity. However, actual input that is based on derated input forthe altitude is to be used when determining the minimum capacity.

Multiple Inputs

When you are sizing a system with multiple inputs, you should use an input ratebased on the lowest appliance input rating to establish minimum capacity.Maximum capacity is determined based on the highest appliance-rating input.

Liner Sizing

Corrugated metallic chimney-liner systems that are listed can be sized with the ta-bles in your code book. To do this, use the tables for Type B vents and reduce themaximum capacity by 20 percent. This reduction allows for one 90-degree bendat the bottom of the chimney. If the chimney has additional bends or offsets, ex-tra reduction is needed. This reduction was discussed above in the section on ventoffsets.

VENT AREA AND DIAMETER

Vertical vents that have larger diameters than the vent connectors must be sizedusing the connector diameter for maximum vent capacity. Flow area for a ventcannot exceed seven times the flow area of the listed appliance’s categorized ventarea, flue-collar area, or draft-hood outlet. One exception is a system with an ap-proved engineering design.

CHIMNEY AND VENT LOCATIONS

Tables cannot be used for chimneys and vents that are exposed to the outdoors be-low the roof line. Is a Type B vent or listed chimney-lining system passing throughan unused masonry chimney flue considered to be exposed to the outdoors? No, itis not. Neither is one that passes through an unventilated enclosure or chase insu-lated to a value of at least R8.


Clay-tile-lined exterior masonry chimneys that are sized with the tables mustmeet certain criteria, which are outlined below:

• The vent connector is a Type B double-wall device.

• The vent-connector length is limited to 18 inches for each inch of vent-connec-tor diameter.

• The appliance is equipped with a draft hood.

• The input rating is less than the maximum capacity listed in the table.

• For a space-heating appliance with an input rating greater than the minimum ca-pacity given in the table

• If the above cannot be met, an alternative venting design must be used.

• One exception is that of vents installed for listed appliances when the installationis done according to the manufacturer’s instructions.

COMPONENT COMMINGLING

A single run of vents or vent connectors with different diameters and types of ventand connector components is permitted. All of the sizes and types used must bepermitted by the tables in your code book.

CONVERSION ACCESSORIES

Draft-hood conversion accessories for use with masonry chimneys venting listedCategory I fan-assisted appliances must be listed and installed in accordance withthe manufacturer’s instructions.

VENT OBSTRUCTIONS

Venting tables cannot be used when vent obstructions exist. Vents serving listedappliances with vent dampers must be installed in accordance with the manufac-turer’s instructions or certain other code requirements. Alternate options includeusing vent tables and keeping the maximum capacity of the vent connector mustbe determined using the Nat Max column.

The maximum capacity of the vertical vent or chimney is to be determined us-ing the Fan + Nat column when the second appliance is a fan-assisted applianceor the Nat + Nat column when the second appliance is equipped with a draft hood.

When calculating minimum capacity, the appliance is to be treated as if it is afan-assisted appliance. Use the Fan Min column to determine the minimum capac-


ity of the vent connector. The Fan + Fan column is used when the second appli-ance is a fan-assisted appliance, and the Fan + Nat column is used when the sec-ond appliance is equipped with a draft hood in order to determine whether the ver-tical vent or chimney configuration is not permitted (Na). If the vent is notpermitted, an alternative method of venting will be required.

CONNECTOR LENGTH

The vent-connector length is to be kept as short as possible. A maximum lengthcan be determined by allowing 18 inches of connector length for each inch of di-ameter of the connector. If a longer length is essential, there are ways to accom-modate the need. See Table 5.4 for examples of maximum vent-connector length.

MANIFOLDS

When sizing vent manifolds, you must apply a 10-percent reduction to the com-mon vent capacity element of the common vent tables. The length of the commonvent-connector manifold must not exceed 18 inches for each inch of commonvent-connector-manifold diameter.

FITTINGS

Tee and wye fittings connecting to a common vent must be sized so that the fit-ting is equal to the size of the vent. It is acceptable for fittings to be reduced in sizewhere they connect to appliance vent connectors.

VENT HEIGHT

When there are multiple appliances all located on one floor, the available totalheight is to be measured from the highest draft-hood outlet or flue collar up to thelevel of the outlet of the common vent.


?Did you knowThe cross-sectional area of a common vent must be equal to or greater than thecross-sectional area of the largest connector.

Multistory installations require that the available total height be figured foreach segment of the system based on the vertical distance between the highestdraft-hood outlet or flue collar entering that segment and the centerline of the nexthigher interconnection tee. Multistory sizing for the lowest portion of a system isto be calculated with sizing tables.

MULTISTORY OFFSETS

Multistory offsets in common vents are limited to a single offset in each system.A system that has an offset must comply with code requirements. The offset mustnot exceed 45 degrees. Vents must not be reduced in size above the offset.Horizontal length of a vent must not exceed 18 inches per inch of the commonvent diameter. The section of venting that contains the offset must be sized with areduction factor of 20 percent.


DIAMETER OF CONNECTOR(inches)

MINIMUM THICKNESS(inch)

3 41/2

4 6

5 71/2

6 9

7 101/2

8 12

9 131/2

10 15

12 18

14 21

16 24

18 27

20 30

22 33

24 36

TABLE 5.4 Maximum vent connector length, courtesy of 2006 International Fuel GasCode.

For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm.

VERTICAL VENT MAXIMUM SIZE

There are times when two or more appliances are connected to a common vent orchimney. The vent or chimney must not be more than seven times the smallestlisted appliance categorized vent area, flue-collar area, or draft-hood-outlet areaunless there is an approved engineering design.

LINER SIZING AND CONNECTIONS

Liner sizing is done with code tables. Connections between chimney liners andlisted double-wall fittings must be made with listed adapter fittings designed forthe purpose. If double-wall connectors are required, tee and wye fittings used forthe connection to the common vent chimney liner must be made with double-wallfittings. See the list below for tips on sizing requirements:

• Type B vents have to be calculated with a reduction factor of 20 percent whendetermining maximum capacity.

• When using the 20-percent reduction factor, the use of one 90-degree elbow isallowed.

CONNECTOR MAXIMUM AND MINIMUM SIZES

Vent connectors must not be increased at a rate of more than two sizes greater thanthe listed-appliance categorized vent diameter, flue-collar diameter, or draft-hood-outlet diameter. When used with draft hoods, vent connectors must not bereduced to a size smaller than the diameter of the draft-hood outlet. Fan-assistedappliances are allowed, under certain conditions, to have a vent that is smaller thanthe flue-collar diameter. What are the conditions? The vent connector must havea smooth interior surface. The appliance must be equipped with a draft hood.There is also a condition that limits size reductions. Vent connectors for fan-as-sisted appliances that have flue collars with diameters of 12 inches or less cannotbe reduced more than one table size. Flue collars that are larger than 12 inches canbe reduced by up to two table sizes.


?Did you knowVertical common vents used in multistory systems must be Type B doublewall and installed with a listed vent cap.

COMMERCIAL COOKING APPLIANCES

A fan-powered exhaust system is required when commercial cooking appliancesare vented by means of Type I or II kitchen exhaust hoods. The exhaust system hasto be interlocked with the appliances to prevent appliance operation when the ex-haust-hood system is not operating. If a solenoid valve is installed in the gas pip-ing as part of an interlock system, the gas piping must not be installed to bypass thevalve. It is not allowable for dampers to be installed in the exhaust system.

What is the exception? The interlock is not required if heat sensors or other ap-proved methods automatically activate the exhaust-hood system when cookingoperations occur.

FACTORY-BUILT CHIMNEYS

Factory-built chimneys for heating appliances that produce flue gases having atemperature not greater than 1,000 degrees F, measured at the entrance to thechimney, must be listed and labeled in accordance with UL 103. The chimneysmust be installed and terminated in accordance with the manufacturer’s instruc-tions. Structural members that support factory-built chimneys have to be designedto support the additional weight of the chimney. This applies to joists, rafters, andsimilar building components.

When factory-built chimneys are used for medium-heat appliances that pro-duce flue gases having a temperature above 1,000 degrees F, measured at the en-trance to the chimney, they must be listed and labeled in compliance with UL 959.Installation and termination must be done in accordance with the manufacturer’srecommendations.


?Did you knowWhen appliances have more than one input rate, the minimum vent-connectorcapacity has to be determined from code tables. The sizing must be less thanthe lowest appliance input rating. Maximum vent-connector capacity is deter-mined from code tables and must be greater than the highest appliance inputrating.

CHAPTER 6SPECIFIC APPLIANCES

What are specific appliances? The technical answer is that they are those that thatthe code identifies as specific appliances. They can include appliance types fromlog lighters to incinerators. Furnaces and clothes dryers can also be included asspecific appliances. So what does this category mean to you? It means that thereare special provisions for specific appliances.

Much of what you will learn about specific appliances is that they have to beinstalled in accordance with manufacturer’s requirements. There are references tocode sections and approval agencies. Much of the material does not require greatexplanation. However, there are some sections that have meat on the bones, andthose are the ones that we are going to work with here.

DECORATIVE APPLIANCES

Decorative appliances that are designed to be installed in approved solid-fuel-burning fireplaces must be tested in accordance with ANSI21.60. Natural-gas dec-orative appliances that are lighted manually must be tested in accordance withANSI Z21.84. As you will find with most appliances in this category, they mustbe installed in accordance with the manufacturer’s instructions.

With the exception of the appliances tested in accordance with ANSI Z21.84,decorative appliances approved for installation in approved solid-fuel-burningfireplaces must utilize a direct ignition device—an ignitor or a pilot flame to ig-nite the fuel at the main burner—and must be equipped with a flame-safeguard de-vice. This device must automatically shut off the fuel supply to a main burner orgroup of burners when the means of ignition of such burners becomes inoperative.Decorative appliances for installation in fireplaces cannot be installed where pro-hibited by Section 303.3 of the code.

6.1



FIREPLACES

Vented Gas Fireplaces

Vented gas fireplaces are to be tested in accordance with ANSI Z21.50. These ap-pliances fall under code provisions found in Section 602.2 of the code. And, ofcourse, they must be installed in accordance with the manufacturer’s installationinstructions.

Access must be provided to these appliances. When panels, grilles, or accessdoors are required to be removed for normal servicing, they must not be attachedto the building.

Vented Wall Furnaces

Vented wall furnaces are required to be tested in accordance with ANSIZ21.86/CSA 2.32. They must be installed in compliance with the instructions ofthe manufacturer. Venting for these units must comply with Section 503 of thecode.

It is not permissible to install a vented wall furnace in a place where the unitwill become a fire hazard. If the furnace is installed between a bathroom and anadjoining room, the unit must not circulate air from the bathroom to other parts ofa building.

Clearance between an air inlet or outlet on a furnace and a door must be a min-imum of 12 inches. Doorstops and door closers may not be installed to obtain therequired clearance. Wall furnaces are not to be fitted with ducts. If a casing exten-sion boot is used, it must be listed as a part of the appliance.

!CodealertLog lighters must be tested in accordance with CSA 8 and installed inaccordance with the manufacturer’s instructions.

TradetipIncinerators and crematories must be installed in compliance with the man-ufacturer’s instructions.

Access must be provided for cleaning heating surfaces and removing burners.It is also required that access be present for the replacement, repair, or servicingof sections, motors, controls, filters, and other working parts.

FURNACES

Floor Furnaces

Floor furnaces are required to be tested with ANSI Z.86/CSA 2.32. As usual, theunits have to be installed in accordance with the manufacturer’s instructions.There are placement requirements that must also be followed for floor furnaces. Afurnace installed in a floor is prohibited from certain locations, which are notedbelow:

• Doorways

• Stairway landings

• Aisles

• Passageways of any enclosure

• Exits from any room or space

Walls

When the register of a floor furnace with a horizontal warm-air outlet is installed,it must not be closer than 6 inches to the nearest wall. Occupants of a buildingmust not be required to walk over the warm-air registers of floor furnaces. To ac-complish this, the code requires registers to be at least 18 inches from two adjoin-ing sides of the floor-furnace register to the walls. Remaining sides are permittedto be placed not closer than 6 inches to a wall. When wall-register models areused, the registers must not be placed closer than 6 inches to a corner.

Thermostats

Controlling thermostats for floor furnaces must be located within the same roomor space as the furnace that they serve. As an option, the thermostat can be locatedin a room or space that is adjacent to the one where the floor furnace is located solong as the thermostat space is permanently open to the furnace location.

SPECIFIC APPLIANCES 6.3

?Did you knowIncinerators for commercial-industrial uses must be built in accordance withNFPA 82.

Clearance

Clearance is an important factor in the installation of floor furnaces. The lowestportion of a floor furnace must not have less than 6 inches of clearance from gradelevel except where the lower 6-inch portion of the floor furnace is sealed by themanufacturer to prevent entrance of water, in which case the minimum clearanceshall not be less than 2 inches. There may be times when this clearance cannot beobtained. In such cases, the ground below and the sides of the furnace must be ex-cavated to form a pit under the furnace. This will allow the required clearance tobe obtained. There must be 12 inches of clearance around the sides of a furnace,except that there is a minimum requirement of 18 inches of clearance on the sideof the furnace where the control center is located.

Duct Furnaces

Duct furnaces must be installed on the positive pressure side of circulating airblowers. Removable access panels on both the upstream and downstream sides offurnaces are required. Controls, combustion-air inlets, and draft hoods must be lo-cated outside of ducts. When a draft hood is used, it must be located in the sameenclosure from which combustion air is taken. All duct furnaces must be tested inaccordance with ANSI Z83.8 or UL 795. As usual, they must be installed in ac-cordance with the manufacturer’s requirements.

AIR HEATERS

Nonrecirculating Direct-fired Industrial Air Heaters

Nonrecirculating direct-fired industrial air heaters must be listed to ANSIZ83.4/CSA 3.7. As you might imagine, they must be installed in accordance withthe manufacturer’s instructions. These units cannot be used to supply any areacontaining sleeping quarters. They can only be installed in industrial or commer-cial occupancies. The units are, however, permitted to supply ventilation air. Forclearance, consult the rating plate and the manufacturer’s instructions.


!CodealertFloor furnaces are not allowed to be installed in concrete floor con-struction that is built on grade.

Atmospheric Vents

Valve train components that are equipped with atmospheric vents, gas reliefs, orbleeds must have their discharge lead to the outdoors. The devices must be pro-tected from blockage of insects and foreign matter. In the event that a listed ventlimiter is installed on a valve train component, an atmospheric vent is not required.

Relief Openings

Nonrecirculating direct-fired industrial air heaters are required to operate at ratedcapacity without overpressurizing the space served by the heater. They accom-plish this by taking into account the structure’s designed infiltration proving,properly designed relief openings, an interlocked power exhaust system, or a com-bination of these methods. Louvers and counterbalanced gravity dampers are al-lowed to be treated as relief openings. Motorized dampers and closable louvers arepermitted when they are verified to be in their full open position prior to main-burner operation.

Recirculating Direct-fired Industrial Air Heaters

Recirculating direct-fired industrial air heaters must be listed to ANSI Z83.18,and, they must be installed in accordance with the manufacturer’s instructions.


!CodealertFloor furnaces that are installed in basements that are used as habitablespace must be enclosed in compliance with Section 609.6 of the codeand must project into a nonhabitable space.

TradetipFloor furnaces installed in upper stories of buildings must project into non-habitable space and must be separated from such space by an enclosure thatis made of noncombustible material. The furnace must be given access andclearance on all sides and the bottom of not less than 6 inches. Combustionair must be in accordance with Section 304 of the code.

These units can only be installed in industrial and commercial occupancies. Theyare not allowed to serve any area containing sleeping quarters or in hazardous lo-cations that contain flammable solids, liquids, or gases; explosive materials; orsubstances that can become toxic when exposed to heat or flame.

Air Supply

The air supply for direct-fired industrial air heaters must be taken from the build-ing, ducted directly from the outdoors, or a combination of both. These systemsmust incorporate a means to supply outside ventilation air to the space at a rate ofnot less than 4 cubic feet per minute per 1,000 Btu per hour of rated input of theheater. When separate air induction is used, it must provide an interlock to lockout the main-burner operation until the mechanical means is verified. Any outsideair dampers or closing louvers must be verified to be in the open position prior tomain-burner operation.

CLOTHES DRYERS

Exhaust Systems

Clothes-dryer exhaust systems must not be comingled with other types of exhaustsystems. These units must be exhausted in accordance with the manufacturer’srecommendations. All moisture and products of combustion must be conveyed tothe outside of the building that houses the appliance.


!CodealertWhen duct furnaces are installed so that supply ducts convey air to ar-eas outside the space containing the furnace, the return air shall also beconveyed by a duct sealed to the furnace casing and terminating out-side the space containing the furnace.

?Did you knowAll air handled by a nonrecirculating direct-fired industrial air heater, includ-ing combustion air, shall be ducted directly from the outdoors.

Duct Penetrations

Duct penetrations through fireblocking, draft stopping, walls, floors, ceilings, orother assemblies required to be fire-resistant-rated are determined by the nature ofthe duct. Galvanized steel and aluminum ducts are allowed for such penetrationswhen their thickness meets the minimum requirements of the local code-enforce-ment office.

Exhaust Installation

Exhaust installations for clothes dryers must terminate on the outside of the build-ing housing the appliance. Backdraft dampers are not allowed in these exhaustsystems. Screens must not be installed where ducts terminate. You cannot usescrews to install or connect the piping system if they will interfere with the airflow. It is against the code to connect these systems to a vent connector, a vent, ora chimney. Exhaust ducts are not allowed to extend into or through ducts orplenums.

Makeup Air

When working with systems that exhaust more than 200 cubic feet per minute(CFM), makeup air must be provided. Closets used to house clothes dryers musthave an opening that contains 100 square inches for makeup air, or makeup airmust be provided from some other approved source.


TradetipNonrecirculating direct-fired industrial air heaters must be provided withaccess for the removal of burners, the replacement of motors, the replace-ment of controls, the replacement of filters, and the replacement of otherworking parts. Access is also required for lubrication of parts that requiremaintenance.

?Did you knowDirect-fired industrial air heaters are allowed to provide fresh air ventilation.

Domestic Ducts

Exhaust ducts for domestic clothes dryers are to be made of metal with a smoothinterior finish. The minimal nominal size of these ducts is 4 inches in diameter.All of the ductwork is to be supported and secured in place. Male ends of ducts atoverlapped joints must extend in the direction of the air flow.

Transition ducts for clothes dryers used to connect the appliance to the exhaustduct system must be metal, are limited to a single length not to exceed 8 feet, andmust be listed and labeled for the application. Transition ducts must never be con-cealed in construction.

Exhaust ducts for clothes dryers cannot exceed 25 feet from the dryer locationto the outlet terminal. The maximum length of the duct must be reduced 30 inchesfor each 45-degree bend and 5 feet for each 90-degree bend. The maximum lengthof the exhaust duct does not include the transition duct. As you might expect, thereis an exception:

When the clothes dryer make and model number are known and the manufac-turer’s installation instructions can be provided to a code official, the exhaust duct,including any transition duct, may be installed in accordance with the manufac-turer’s requirements.

Commercial Clothes Dryers

Commercial clothes dryers with exhaust ducts serving Type 2 dryers must be in-stalled in compliance with the manufacturer’s recommendations. When exhaust-


TradetipDon’t install direct-fired industrial air heaters with a clearance that is lessthan what is listed on the label of the product and the manufacturer’s recom-mendations.

!CodealertClothes dryers must be tested in accordance with ANSI Z21.5.1 orANSI Z21.5.2. They must be installed in accordance with the manufac-turer’s recommendations.

fan motors are installed, they must be installed outside of the airstream. If multi-ple installations are involved, the fan shall either operate continuously or be inter-locked to operate when any individual unit is operating. A minimum clearance of6 inches is required between ducts and combustible materials.

SAUNA HEATERS

Sauna heaters must be installed in accordance with the manufacturer’s instruc-tions. They must be installed in locations that will minimize any possibility of ac-cidental contact by a person in the room. Guards can be used to prevent contactwith the heaters. They must have a low coefficient of thermal conductivity.Guards are not allowed to substantially affect the transfer of heat from the heaterto the room.

Air Intakes

Not all sauna heaters are of a direct-vent type, and those that are not have to befitted for air intake. This can be a draft hood and combustion-air intake locatedoutside of a sauna room. Sometimes these devices are placed in dressing roomsthat are adjacent to a sauna. When this is the case, provisions must be made notto physically block the combustion-air and draft-hood inlets and to preventphysical contact with the draft hood and vent assembly. Warning notices may berequired. If so, they must be posted in conspicuous places to prevent blockageof the air systems. Letters used on the warning notices are required to be a min-imum of 1/4 inch high and must contrast with the background of the warning notice.


TradetipAll vertical duct risers for dryers listed to ANSI Z21.5.2 must be providedwith a cleanout or other means for cleaning the interior of the duct.

?Did you knowFire dampers cannot be installed in clothes-dryer exhaust duct systems.

Controls

Heat and time controls are required for saunas. For example, sauna heaters requirea thermostat that will limit room temperature to 194 degrees F. When such a ther-mostat is not an integral part of a sauna heater, the heat-sensing element must belocated within 6 inches of the ceiling. Heat-sensing elements of the capillary tubeand bulb type must be attached to a wall or other support and must be protectedfrom physical damage.

Ventilation

Ventilation of sauna rooms must be provided for. The opening must not be lessthan 4 inches by 8 inches. This opening is required to be located near the top ofthe door into the sauna room.

With the exception of saunas in one- and two-family dwellings, a warning no-tice must be posted. The posting must be permanent and of an approved material.It is to be mechanically attached to the outside of the sauna room and to read asfollows: “WARNING: DO NOT EXCEED 30 MINUTES IN SAUNA. EXCES-SIVE EXPOSURE CAN BE HARMFUL TO HEALTH. ANY PERSON WITHPOOR HEALTH SHOULD CONSULT A PHYSICIAN BEFORE USINGSAUNA.” The letters must be not less than 1/4 inch high and must contrast withthe background of the warning notice.

Forced-air Warm-air Furnaces

Forced-air warm-air furnaces must be tested in accordance with ANSI Z21.47 orUL 795 and installed in accordance with the manufacturer’s instructions. Theminimum unobstructed total area of the outside and return-air ducts or openingsto a forced-air warm-air furnace shall not be less than 2 square inches for each1,000 Btu/h output rating capacity of the furnace and not less than that specifiedin the furnace manufacturer’s installation instructions. Minimum unobstructed to-tal area of supply ducts from a forced-air warm-air furnace shall not be less than2 square inches for each 1,000 Btu/h output rating capacity of the furnace and notless than that specified in the furnace manufacturer’s installation instructions. Theexception to this rule is that the total area of the supply-air, outside, and return-airducts shall not be required to be larger than the minimum size required by the fur-nace manufacturer’s installation instructions.

Prohibited Sources

There are many locations that are prohibited sources for outside or return air forforced-air heating systems:

• Locations that are 10 feet from an appliance vent outlet

• Locations that are 10 feet from the vent opening from a plumbing drainage system


• Locations that are 10 feet from the discharge outlet of an exhaust fan, unless theoutlet is 3 feet above the outside air inlet

• Locations where there is a presence of objectionable odors, fumes, or flammablevapors

• Locations that are less than 10 feet above the surface of any abutting public wayor driveway

• Locations at grade level by a sidewalk, street, alley, or driveway

• Locations that are considered to be hazardous or unsanitary

• Locations designated as refrigeration machinery rooms

• Locations whose volume is less than 25 percent of the entire volume served bysuch systems, except where the amount of return air taken from a room or spaceis less than or equal to the amount of supply air delivered to such rooms or spaces

• Locations where an appliance serves as the sole source of return air, with excep-tions as noted below

Exceptions to locations where appliances serve as the sole source of return airare numerous. Let’s work our way through this. If the appliance is a direct-ventappliance or an appliance not requiring a vent in accordance with Section 501.8,it is excepted. If the room or space complies with one of the following require-ments, it is excluded:

• The return air must be taken from a room or space having a volume exceeding 1cubic foot for each 10 Btu/h of combined input rating of all fuel-burning appli-ances therein.


!CodealertThe panels, grilles, and access doors required to be removed for nor-mal servicing operations must not be attached to the building in whichthe heater is installed.

TradetipCombustion air must not be taken from inside a sauna room. A heater that isnot of a direct-vent type must be provided with combustion-air inlets anddraft.

• The volume of supply air discharged back into the same space shall be approxi-mately equal to the volume of return air taken from the space.

• Return-air inlets must not be located within 10 feet of any appliance firebox ordraft hood in the same room or space.

• Rooms or spaces containing solid-fuel-burning appliances provided that return-air inlets are located not less than 10 feet from the firebox of such appliances.

• Closets, bathrooms, toilet rooms, kitchens, garages, mechanic rooms, boilerrooms, and furnace rooms are excluded.

UNIT HEATERS

Unit heaters must be tested in accordance with ANSI Z83.8. They are also re-quired to be installed in accordance with the manufacturer’s instructions. Supportprovided for the heaters must be adequate to support the weight and dynamic loadsassociated with the equipment. All hangers and brackets are to be made of non-combustible material. Ducts must not be connected to a unit heater unless theheater is listed for such installation.

Suspended-type unit heaters require a minimum of 18 inches of clearancefrom combustible materials when measured at the sides. A clearance of 12 inchesat the bottom and 6 inches above the top if the unit heater has an internal draft hoodor 1 inch above the top of the sloping side if the heater has a vertical draft hoodare required.

The clearance requirements for floor-mounted-type unit heaters are a little dif-ferent. Combustible materials must be kept at least 6 inches from the sides and


?Did you knowEquipment that is powered by internal-combustion engines and turbines andfixed permanently must be installed in accordance with the manufacturer’s in-stallation instructions and NFPA 37.

TradetipPool and spa heaters have to be tested in accordance with ANSI Z21.56 andmust be installed in accordance with the manufacturer’s instructions.

back of these heaters. If the unit is vented vertically, the measurement for clear-ance is to be made from the draft hood or vent instead of the rear wall of the heater.These heaters are not allowed to be installed on combustible flooring.

Servicing of equipment requires a minimum clearance that is in compliancewith the manufacturer’s installation instructions. A unit that is listed may be al-lowed to have reduced clearance if the manufacturer allows it in the installationinstructions.

Unvented Heaters

Unvented heaters have to be tested in accordance with ANSI Z21.11.2. They mustbe installed in accordance with the manufacturer’s recommendations. If theheaters are not using fuel gas, they fall under the regulations of the InternationalMechanical Code. Such heaters are not allowed to be used as the sole source ofcomfort heating in a dwelling unit. Places where they cannot be installed includeGroups A, E, and I.

The aggregate input rating of all unvented appliances installed in a room orspace cannot exceed 20 Btu/h per cubic foot of volume of such room or space.When the appliance is installed in a room or a space that is adjacent to another areathat has a permanent opening between the two spaces, the volume of the adjacentroom can be used for sizing purposes.

When unvented heaters are used, they must be equipped with an oxygen-de-pletion-sensitive safety shutoff. If oxygen depletion is detected, the system mustshut down the heater. The depletion level is based on the manufacturer’s recom-


?Did you knowVolume dampers must not be placed in the air inlet to a furnace in a mannerthat will reduce the required amount of air to reach the furnace.

!CodealertCirculating air for fuel-burning, forced-air-type, warm-air furnacesshall be conducted into the blower housing from outside the furnaceenclosure by continuous airtight ducts.

mendations, but it cannot fall lower than 18 percent. The safety shutoff cannot beadjustable in the field.

COOKING APPLIANCES

Most cooking appliances intended for permanent installation have to be tested inaccordance with ANSI Z21.1, ANSI Z21.58, or ANSI Z83.11 and installed incompliance with the manufacturer’s requirements. The types of cooking appli-ances that fall into this category are:

• Ranges

• Ovens

• Stoves

• Broilers

• Grills

• Fryers

• Griddles

• Hot plates

• Barbecues

Domestic ranges cannot be installed on combustible flooring unless they arepositioned on their own bases or legs. All domestic appliances are required to be


!CodealertOutdoor-air inlets that are required for residential portions of a build-ing must be covered with a screen having 1/4-inch openings. Inletsserving nonresidential portions of a building must be covered withscreens having openings larger than 1/4 inch and not more than 1 inch.

?Did you knowUnvented room heaters are not allowed to have an input rating in excess of40,000 Btu/h.

listed and labeled for domestic use. Unless listed for an exception, all domesticopen-top boilers are to be equipped with a ventilating hood. A minimum clearanceof 24 inches is required between the cooking top and the combustible materialabove the ventilating hood. The hood must be at least as wide as the open-topbroiler unit and centered over the unit.

WATER HEATERS

Water heaters are required to be tested in accordance with ANSI Z21.10.1 andANSI Z21.10.3. As usual, they must be installed in accordance with the manufac-turer’s guidelines. If the water heater is not fueled by gas, the installation is regu-lated by the International Mechanical Code. If a water heater is used in a combi-nation mode as both a potable hot-water source and a space heater, the appliancemust be listed and labeled for the dual use. This type of unit falls under the regu-lations of the International Plumbing Code.

REFRIGERATORS

Refrigerators have to be tested in accordance with ANSI Z21.19 and must be in-stalled in accordance with the manufacturer’s instructions. Clearance is requiredat the top and back of refrigerators. Use the manufacturer’s recommendations forclearance when they are available. If you are on your own, leave at least 2 inchesof clearance behind and at least 12 inches above the appliance.

AIR CONDITIONING

Air-conditioning units that are gas-fired have to be tested in compliance withANSI Z21.40.1 or ANSI Z21.40.2 and installed according to the manufacturer’sinstructions. Gas engines are not allowed to be connected rigidly to gas-supply


!CodealertVentless firebox enclosures used with unvented decorative roomheaters must be listed in compliance with ANSI Z21.91.

piping. This requirement is meant to protect against the effects of normal vibration.

The clearances required for cooling equipment are outlined in Sections 308.3of the code. When this type of equipment is installed in alcoves and closets, theclearances must comply with Table 308.2 of the code. All air-conditioning equip-ment is required to be installed in compliance with the manufacturer’s recommen-dations. Unless the equipment is listed otherwise, it is to be installed on a noncom-bustible surface. All ducts, both return and supply, must be placed to ensure propercirculation of air.

Where air-conditioning equipment is installed within a space separate fromthe spaces served by the equipment, the air circulated by the equipment shall beconveyed by ducts that are sealed to the casing of the equipment and that separatethe circulating air from the combustion and ventilation air.

Refrigeration Coils

Under normal conditions, a refrigeration coil is not to be installed in conjunctionwith a forced-air furnace when circulation of cooled air is provided by the furnaceblower. Furnaces must not be located upstream from cooling units unless the cool-ing unit is designed or equipped so as not to develop excessive temperature orpressure.


TradetipUnvented decorative room heaters are not allowed to be placed in factory-built fireplaces unless the fireplace system is specifically tested, listed, andlabeled for such use under the code.

!CodealertVented room heaters are to be tested in accordance with ANSIZ21.86/CSA 1.32 and must be designed and equipped as specified inSection 602.2 of the code. All installations must be done in compliancewith the manufacturer’s instructions.

The coils must be installed in parallel with or on the downstream side of cen-tral furnaces to avoid condensation in the heating element. An exception to this isa furnace that is listed for installation downstream. Means of control flow must besufficient to prevent any circulation of cooled air through a furnace.

Boilers

Can you imagine boilers and air conditioning working together? It can happen.When refrigeration systems are combined with boilers, they must be installed toallow the chilled medium to be piped parallel with the heating boiler. Valves haveto be installed to prevent commingling of the two systems. Flow-control valves orother automatic means are required to prevent gravity circulation of the boiler wa-ter during the cooling cycle.

ILLUMINATING APPLIANCES

Illuminating appliances have to be tested in accordance with ANSI Z21.42 and in-stalled in accordance with the manufacturer’s instructions.

When these devices are designed for walls or ceilings, they must be securelyattached to substantial structures so that they are not subject to dependence on gaspiping for support. Devices that are meant for mounting on posts have to be se-curely and rigidly attached, and the post itself must be rigidly attached.

Posts that are greater than 3 feet in height shall be at least equivalent to that ofa 2 1/2-foot-diameter post constructed of 0.064-inch-thick steel or a 1-inchSchedule 40 steel pipe. Posts 3 feet or less in height shall not be smaller than a 3/4-inch Schedule 40 pipe. When water may collect at the bottom of posts, a drainopening is required.


!CodealertCommercial cooking appliances, except those exempted by Section501.8 of the code, must be vented by connecting the appliance to a ventor chimney. The connection must meet the requirements of the codeand the manufacturer’s instructions. As an alternative, the appliancecan be vented in accordance with Section 505.1.1 of the code.

INFRARED RADIANT HEATERS

All infrared radiant heaters are to be tested in accordance with ANSI Z83.6 andinstalled within the guidelines of the manufacturer. These units are to be in a fixedposition independent of gas and electric supply lines. All hangers and brackets forthis equipment must be made of noncombustible products.

BOILER STANDARDS

Boiler standards are established by ANSI Z21.13 or UL 795. Other codes and re-quirements can come into play. For example, some boilers are required to meet thestandards of ASME CSD-1 or the ASME Boiler and Pressure Vessel Code. NFPA85 can also be a standard. Check boiler installations carefully.

The International Mechanical Code usually controls the installation of boil-ers. Operating instructions must be attached to a boiler by a permanent means.Controls are to be set, adjusted, and tested by installers. It is the job of an installerto provide a control diagram and boiler operating instructions. In all cases, boil-ers require the manufacturer’s rating data and a nameplate to be attached to the unit.


!CodealertGas-fired toilets—and, yes, they do exist—have to be tested in accor-dance with ANSI Z21.61. Installation is to be done in compliance withthe recommendations of the manufacturer. Clearance is required forready access for use, cleanout, and any needed servicing.

TradetipMeans must be provided for disposal of condensate and to prevent its drip-ping onto heating elements.

CHIMNEY DAMPERS

If an unlisted decorative appliance for a vented fireplace is installed, the fireplacedamper must have a permanent free opening equal to or greater than those identi-fied in Table 6.1.

We are about to move into the next chapter ont gaseous hydrogen systems.Take a break and when you are ready, let’s move on. We are almost done.


?Did you knowDid you know that gas pipe that serves a heating system can also serve cool-ing equipment? However, the two systems are not allowed to be operated simultaneously.

TradetipPressure regulators are not always provided for appliances. When this is thecase, you must provide one. Multiple installations require one regulator ofadequate capacity to serve the appliances.


?Did you knowStationary fuel-cell power systems that have a power output of more than10MW must be tested in accordance with ANSI CSA America FC1. They arerequired to be installed in accordance with the manufacturer's recommenda-tions and NFPA 853.

CHIMNEYHEIGHT

(feet)

MINIMUM PERMANENT FREE OPENING (square inches)a

8 13 20 29 39 51 64

Appliance input rating (Btu per hour)

6 7,800 14,000 23,200 34,000 46,400 62,400 80,000

8 8,400 15,200 25,200 37,000 50,400 68,000 86,000

10 9,000 16,800 27,600 40,400 55,800 74,400 96,400

15 9,800 18,200 30,200 44,600 62,400 84,000 108,800

20 10,600 20,200 32,600 50,400 68,400 94,000 122,200

30 11,200 21,600 36,600 55,200 76,800 105,800 138,600

TABLE 6.1 Free opening area of chimney damper for venting flue gases From unlisteddecorative appliances for installation in vented fireplaces, courtesy of 2006 InternationalFuel Gas Code.

For SI: 1 inch � 25.4 mm, 1 foot = 304.8, 1 square inch = 645.16m2, 1 British thermal unit per hour = 0.2931 W.a. The first six minimum permanent free openings (8 to 51 square inches) correspond approximately to the cross-

sectional areas of chimneys having diameters of 3 through 8 inches, respectively. The 64-square-inch opening cor-responds to the cross-sectional area of standard 8-inch by 8-inch chimney tile.

CHAPTER 7GASEOUS HYDROGEN

SYSTEMS

When working with gaseous-hydrogen systems, you must pay attention to theInternational Fire Code. Chapters 30 and 35 of that code apply to these systems.Compressed gases are covered in Chapter 27 of the 2006 International Fire Code.When permits are required, they are regulated by Section 106 and as required bythe International Fire Code.

What is a gaseous-hydrogen system? It is an assembly of piping, devices, andapparatus designed to generate, store, contain, distribute, or transport a nontoxic,gaseous-hydrogen mixture that contains at least 95 percent hydrogen gas by vol-ume and not more than 1 percent oxygen by volume. These systems can includethe following:

• Compressed-gas containers

• Reactors

• Appurtenances

• Pressure regulators

• Interconnecting piping

• Tubing

• Controls

GENERATING AND REFUELING OPERATIONS

Ventilation is required for hydrogen-generating and -refueling operations. Placeswhere these operations may occur include the following:

• Public garages

• Private garages

7.1



• Repair garages

• Automotive-motor-fuel-dispensing facilities

• Parking garages that contain hydrogen-generating appliances

• Refueling systems

Rooms and spaces that are not part of the living space of a dwelling unit andthat communicate directly with a private garage through openings must be consid-ered to be part of the private garage.

VENTILATION TYPES

Natural Ventilation

Natural ventilation is regulated by the code. An indoor location that is intended forhydrogen-generating or -refueling operations is limited to a maximum floor areaof 850 square feet, and it must communicate with the outdoors in order to be incompliance with the code. A hydrogen-generating appliance is limited to a maxi-mum output capacity of 4 standard cubic feet per minute of hydrogen for each 250square feet of floor area in such spaces.

A minimum cross-sectional dimension for air openings is 3 inches. Ducts thatare used must have the same cross-sectional area as the free area of the opening towhich they connect. Appliances with sources of ignition are required to be locatedwithin 12 inches of a ceiling.

TradetipA room or space that is intended exclusively to house a gaseous-hydrogensystem is known as a hydrogen cutoff room.

?Did you knowA self-contained or factory-matched package of integrated systems for gener-ating gaseous hydrogen is a hydrogen-generating appliance. It utilizes elec-trolysis, reformation, chemical, or other processes to generate hydrogen.

Garage Openings

A garage is required to have two permanent openings. The higher opening is re-quired to be located entirely within 12 inches of the ceiling of the garage. A loweropening must be located entirely within 12 inches of the floor of the same garage.The code requires both openings to be in the same exterior wall. They must com-municate directly with the outdoors and have a minimum free area of 1/2 squarefoot per 1,000 cubic feet of garage volume.

Louvers and Grilles

The size of louvers and grilles must be calculated. The size is based on the net freearea of each opening. When the free area is known, it is required to be used in cal-culating the size of opening required to provide the free area specified. When thefree area is not known, wood louvers must have 25 percent free area, and metallouvers and grilles must have 75 percent free area. They must be installed in afixed-open position.

Mechanical Ventilation

Mechanical ventilation is to be installed in accordance with the InternationalMechanical Code. When it is used, equipment and appliances with an ignitionsource have to be placed in such a way that the source of ignition is below the me-chanical-ventilation outlet.

GASEOUS HYDROGEN SYSTEMS 7.3

!CodealertThe necessary supply of air for ventilation and dilution of flammablegases must be provided by an approved engineered system if the designis not done within code guidelines.

TradetipCompressed-gas containers, cylinders, and tanks must comply withChapters 30 and 35 of the International Fire Code.

DESIGN

Compressed-gas containers, cylinders, and tanks are to be designed, constructed,and tested in accordance with Chapter 27 of the 2006 International Fire Code, theASME Boiler and Pressure Vessel Code (Section VIII) or DOTn49 CFR, Parts100-180.

PRESSURE RELIEF DEVICES

Valves

Valves, including shutoffs, check valves, and other mechanical restrictions mustnot be installed between the pressure-relief device and the container being pro-tected. A locked-open shutoff valve is required on containers equipped with mul-tiple pressure-relief-device installations; the arrangement of the valves must pro-vide the full required flow through the minimum number of required relief devicesat all times.

Installation

Valves and other mechanical restrictions are not allowed to be located betweenpressure-relief devices and the point of release to the atmosphere.


?Did you knowFlammable-gas cylinders in occupancies regulated by the InternationalResidential Code are not allowed to exceed 250 cubic feet at normal temper-ature and pressure (NTP).

TradetipPressure-relief devices must meet code requirements and be sized and selected in accordance with CGA S-1.1, CGA S-1.2, and CGA S-1.3.

Sizing

Sizing of pressure-relief devices is required to be done in accordance with thespecifications used to build the container. Its purpose is to prevent the maximumdesign pressure of the container from being exceeded. In other words, if the pres-sure rises to an unsafe level, the relief device relieves the pressure to maintainsafety.

Protection

Pressure-relief devices and all associated bent piping must be designed, installed,and located so that their operation will not be affected by water or other debris ac-cumulating inside or obstructing the vent.


!CodealertContainers must be provided with pressure-relief devices in accor-dance with the ASME Boiler and Pressure Vessel Code (Section VIII),DOTn 49 CFR, Parts 100-190, and Section 703.3.7 of the code.

?Did you knowVessels other than containers shall be protected with pressure-relief devices inaccordance with the ASME Boiler and Pressure Vessel Code (Section VIII) orDOTn 49 CFR, parts 100-180.

!CodealertCompressed-gas containers, cylinders, tanks, and systems have to beprotected from accidental movement in accordance with Chapter 30 ofthe 2006 International Fire Code. All electrical wiring is to be done tothe standards of the ICC Electrical Code.

CONFIGURATION

Pressure-relief devices must be situated to discharge in an unobstructed manner tothe outdoors. The International Fire Code regulates the installation. Discharge lo-cations must be arranged to avoid the following:

• Impingement of escaping gas on personnel

• Containers

• Equipment

• Adjacent structures

The introduction of escaping gas into enclosed spaces is not allowed.Discharges are not allowed to terminate under eaves or canopies. The require-ments do not apply to DOT-specified containers with an internal volume of 2 cu-bic feet or less.

PIPING

Piping, tubing, fittings, and valves that convey gaseous hydrogen must be in-stalled in accordance with code requirements, Chapter 27 of the 2006International Fire Code, and ASME B31.3. Cast-iron pipe, valves, and fittings arenot allowed for this use. Sizing must be done in accordance with approved engi-neering methods.

Compressed-gas-system controls have to be designed to prevent materialsfrom entering or leaving process or reaction systems at other than the intended


TradetipPressure-relief devices have to be located so that there is ready access for in-spection and repair.

?Did you knowRelief-device vents must terminate in an approved location that is in compli-ance with Section 2209 of the International Fire Code.

time, rate, or path. Automatic controls must be designed to be failsafe in accor-dance with accepted engineering practices.

Identification

Hydrogen systems must be marked in compliance with ANSI A13.1. The identi-fication must include the direction of flow and are required at the following loca-tions:

• At every valve location

• At wall penetrations

• At floor penetrations

• At ceiling penetrations

• At changes of direction

• At intervals that do not exceed 20 feet

Piping and tubing materials are to be 300 series stainless steel or materialslisted or approved for hydrogen service and the use intended through the full rangeof operating conditions to which they will be subjected. The design must allow forexpansion, contraction, vibration, settlement, and fire exposure.

Except for through penetrations, piping located inside of buildings must be in-stalled in exposed locations and provided with ready access for visual inspection.


!CodealertPiping must not be installed in or through a circulating air duct. It alsomust not be installed in or through a clothes chute, chimney, or gasvent. Dumbwaiters and elevator shafts must not have piping installedin or through them. Walls, floors, and ceilings must not conceal piping.

!CodealertPipe that passes through concrete or masonry walls has to be protectedagainst differential settlement.

When in an underground location, pipe, including joints and fittings, must be pro-tected from corrosion and installed in accordance with approved engineeringmethods. Underground piping is not allowed to penetrate the outer foundation orbasement wall of a building.

Protection

Protection is not required for stainless-steel piping, stainless-steel tubing, or blacksteel. Other types of piping or tubing must be protected when it is installed lessthan 1 1/2 inches from the edge of wood members, through holes or notches inwood studs, joists, rafters, and similar wood members. When protection is re-quired, it must be provided in the form of shield plates that have a minimum thick-ness of 1/16 inch. These plates must be made of steel and cover the area of the pipewhere the member is compromised. A shield plate is to extend a minimum of 4inches above sole plates, below top plates, and to each side of a stud, joist, orrafter.

Outdoor Piping

Outdoor piping that is installed above ground has to be supported securely andprotected from physical damage. Any piping that passes through an exterior wallrequires a protective sleeve. All annular space between the piping and the sleevemust be sealed from inside so that the sleeve is ventilated to the outdoors. Pipingmust be protected from corrosion when it is underground. Exterior-wall penetra-tions of pipe require protection from corrosion by either a coating or wrappingmade of an inert material.


?Did you knowBrazing alloys are required to have a melting point that is greater than 1,000degrees F.

!CodealertMechanical joints are required to maintain electrical continuitythrough the joint, or a bonding jumper must be installed around thejoint.

Joints

ASME B31.3 is the standard that joints must adhere to. These joints include fit-tings of the following types:

• Welded

• Brazed

• Flared

• Socket

• Slip

• Compression

Gaskets and sealants used in hydrogen service must be listed in compliancewith ASME B31.3. Threaded and flanged connections are not allowed for use inareas other than hydrogen-cutoff rooms and outdoors.


TradetipBrazing alloys must have a melting point greater than 1,000 degrees F.

?Did you knowMechanical joints are required to maintain electrical continuity through thejoint, or a bonding jumper must be installed around the joint.

!CodealertThe handling of compressed-gas containers, cylinders, and tanks mustcomply with Chapter 27 of the 2006 International Fire Code.

Components

Piping components, valves, and regulators are required to be listed or approvedfor hydrogen service. These devices must be accessible. All such devices have tobe designed and made to withstand the maximum pressure that they may encounter.

SHUTOFFS

Connections to storage containers and tanks require accessible shutoff valves. Theonly exception is the connection of a relief valve.

CONTAINERS

Compressed-gas containers, cylinders, and tanks, with the exception of those witha water volume of less than 1.3 gallons and those designed for use in a horizontalposition, must be installed in an upright position. To be considered in a verticalposition, the container, cylinder, or tank axis can be inclined as much as 45 de-grees from the vertical.


TradetipHydrogen compressed gas, used inside or outdoors, must comply with thematerial-specific provisions of Chapters 30 and 35 of the 2006 InternationalFire Code.

!CodealertDeionized water must be utilized to perform hydrostatic pressure test-ing and must be acquired from a potable source. When a pneumatic testis done, the test medium must be air, nitrogen, carbon dioxide, or an in-ert gas. Oxygen is not allowed for use in pneumatic testing.

INSPECTIONS

Inspections and approval are required prior to putting a system into operation. Apressure test is required. Visual inspection of the entire piping system while it isunder a pressure test is the normal requirement. A verified code official is neededfor the inspection of a system. However, if a code official approves the inspectionmethods outlined in ASME B31.1, an engineered system can be used.

Pneumatic test pressure must not be less than one-and-one-half times the max-imum working pressure for systems less than 125 psig and not less than 5 psig,whichever is greater. A pneumatic test pressure must not be less than 110 percentof the maximum working pressure.

Testing Time

A test is required to be maintained for a minimum of 30 minutes for a pipe vol-ume or fraction thereof of 500 cubic feet. For piping systems having a volume ofmore than 24,000 cubic feet, the maximum test duration is 24 hours.

Test gauges must be in compliance with code requirements. For example, teststhat require a pressure of 10 psig or less need a gauge that has increments of 0.10psi or less.

Hydrostatic test pressure must not be less than one-and-one-half times themaximum working pressure. The pressure must not be less than 100 psig. Whenthis is the case, the gauge must have increments of 1 psi or less.

Tests that require a pressure of more than 100 psig need a gauge that has in-crements of 2 psi or less. Measuring devices that have an equivalent level of ac-curacy and resolution are permitted where specified by a design engineer and ap-proved by a code official.

Pressure Test

Hydrostatic or pneumatic leak tests are required. The test procedures are outlinedin ASME B31.3; other methods are permitted, provided that the testing is done inaccordance with the minimum provisions called for in Sections 705.3.1 and705.4.1 of the code.


?Did you knowIf test pressure is to exceed 125 psig, the pressure must not exceed a value thatproduces hoop stress in piping greater than 50 percent of the specified mini-mum yield strength of the pipe.

Disconnection

Disconnection of appliances may be required prior to a test. If the appliances arenot rated to withstand maximum test pressures, they must be isolated during a test.This can mean disconnecting the appliance and capping the supply pipe. If the ap-pliances are designed to handle the test pressure, they can be left connected andhave their shutoff valves closed.

Leaks

Leaks are not acceptable during test conditions. When they are identified from areduction in the pressure gauge, they must be found and corrected. Once they arefixed, a new test is required. Purging of gaseous-hydrogen piping systems mustcomply with Section 705.5.1 through 705.5.4.

SERVICE

There are times when systems require service. When this is the case, the systemmust be isolated from the gas supply at the nearest convenient point. Line pres-sure must be vented outdoors. Remaining gas is required to be displaced with inert gas.

OPERATION

Putting a hydrogen system into operation requires the cleaning of the system. Thisis done by running inert gas through the system. The inert gas must be used untilair is removed. At this point hydrogen can be allowed into the system. All inertgas must be expelled. The point of discharge must be monitored during the cleans-ing process; then the vent opening is to be closed.

Purging operations are not allowed to discharge into confined spaces. Neithercan they discharge into areas where a source of ignition exists. However, with


!CodealertPipe joints, which include welded joints, must be left exposed for in-spection during a test for leaks.

proper ventilation the discharge into an ignition area may be allowed. But all riskof hazardous conditions must be removed.

Vent Outlets

Vent pipe outlets for purging are required to be placed so that inert and fuel gasare released outdoors not less than 8 feet above the adjacent ground level. The gasmust be discharged upward or horizontally away from adjacent walls to assist indispersion. Vents cannot be placed in such a way that leaves or other obstructionswill trap gas. The vents must be at least 5 feet from any building opening or lotline of a property.

SUITABLE LOCATIONS

Suitable locations for indoor gaseous-hydrogen systems are noted below:

• Inside a building in a hydrogen-cutoff room designed and constructed in accor-dance with Section 420 of the International Building Code

• Inside a building not in a hydrogen cutoff room where the system is listed and la-beled for indoor installation and installed in accordance with the manufacturer’sinstructions

• Inside a building in a dedicated hydrogen-fuel-dispensing area having an aggre-gate hydrogen delivery capacity not greater than 12 SCFM and designed andconstructed in accordance with Section 703.1


TradetipExpansion joints have to be provided with temporary restraints if requiredfor the additional thrust load under test.

TradetipGaseous-hydrogen systems and detection devices are governed by theInternational Fire Code and the manufacturer’s instructions.

There you have it. Now you know the gas code. We have reached the end ofour journey. I hope my work helps you in your career. The code is not that diffi-cult to follow once you understand it, and I hope that I have made this process eas-ier for you.


?Did you knowGaseous-hydrogen systems are required to be located outdoors in accordancewith Section 2209.3.2 of the International Fire Code.

I.1

INDEX

AAbove-ceiling systems, 5.7Above-ground outdoor piping, 4.68Access, 2.1, 3.15Action, corrosive, 4.64Additions, 1.5Air, combustion, 3.8, 5.11Air conditioner, gas-fired, 2.1, 6.15Air conditioning, 2.1Air-conditioning equipment, 3.20Air, dilution, 3.8Air, exhaust, 2.1Air-handling unit, 2.1Air heaters, 6.4, 6.5Air heaters, air supply, 6.6Air heaters, atmospheric vents, 6.5Air heaters, industrial, non-recirculating

direct fired, 6.4Air heaters, industrial recirculating direct

fired, 6.5Air, indoor, 3.8Air, makeup, 2.2, 3.8Air, combination, 3.10Air, outdoor combustion, 3.9Air supply, mechanical combustion, 3.11Air under pressure, 4.83Air, ventilation, 3.8Alteration, 2.2Anodeless riser, 2.2, 4.63

Appliance, automatically controlled, 2.2Appliance, category I, 5.4, 5.18Appliance, combination, 5.10Appliance connectors, residential-type, 5.18Appliance, cooking, 6.14Appliance, decorative, 6.1Appliance, equipment, 2.2Appliance, fan-assisted combustion, 2.2Appliance, gas fireplaces, 6.2Appliance, illuminating, 6.17Appliance, liquid-fuel-burning, 5.10Appliance, low-heat, 2.2, 5.3Appliance, multiple, 5.21Appliance, under-floor, 3.16Appliance, unvented, 2.2Appliance, vented, 5.23Appliance, vented wall furnace, 6.2Applications, residential, 4.81, 5.3Approved agency, 2.2Atmospheric pressure, 2.2Automatic ignition, 2.2Alternative options, 1.10Appliances, outside, 4.69Applications, 1.8Approval, 1.9, 1.16Approved construction documents, 1.11Areas, unconditioned, 5.18Attic installations, 3.15


BBaffle, 2.3Barometric draft regulator, 2.3Beneath buildings, 4.79Board organization, 1.19Boiler, hot-water-heating, 2.3Boiler, low-pressure, 2.3Boiler, steam-heating, 2.3Boiler standards, 6.18Boilers, 3.21, 6.17, 6.18Bored holes, 3.5Boring, 3.4Branch length, 4.4Brazing, 2.3Broiler, 2.3BTU, 2.3Buildings, beneath, 4.70Buildings, multistory, 5.14Buildings, relocated, 1.7Burner, 2.3

CCategory I appliances, 5.4Category II and IV appliances, 5.18Category I appliances, vents for, 5.13Change in occupancy, 1.5Changes in direction, 4.71Chimney, 2.3, 5.1Chimney connections, 5.22Chimney dampers, 6.19Chimney inspections, 5.10Chimney sizing limitations, 5.8Chimney termination, 5.8Cleanouts, 5.11Clearance, grade, 3.15Clearance reduction, 3.20Closed transfer system, 4.82Clothes dryer, 2.4, 6.6 Clothes dryer, commercial, 6.8Clothes dryer, domestic ducts, 6.8Clothes dryer, duct penetrations, 6.7Clothes dryer, exhaust installation, 6.7Clothes dryer, exhaust systems, 6.6Clothes dryer, makeup air, 6.7Clothes dryer, type 1, 2.4Code, 2.4Code official, 2.4Cold-formed steel framing, 3.5Coils, refrigeration, 6.16Combination air, 3.10Combination appliances, 5.10Combined spaces, 3.9Combustible construction, 3.15

Combustion, 2.4, 3.8Combustion air, 2.4, 3.8, 5.11Combustion-air ducts, 3.11Combustion chamber, 2.4Compressed-natural-gas fuel-dispensing

facilities, 4.80Concealed location, 2.4Concealed piping, 2.4Condemned installations, 1.18Condensate, 2.4Condensate disposal, 3.1Connections, chimney, 5.22Connections, manufactured-home, 4.78Connector, appliance, 2.5Conncetor, sizing, 5.14Connector, chimney or vent, 2.5 Connector length, 4.78, 5.21Construction, combustible, 3.15Construction, prefabricated, 1.15Construction documents, 1.11, 2.5Control, 2.5Controls, flow, 4.77Conversion burner, 2.5Cooking appliances, 6.14Corrosion, 4.69Corrosive action, 4.64Counter appliances, 2.5Cubic foot, 2.5Cutting, 3.4

DDamper, 2.5, 6.19Decorative appliance, vented, 2.5Definitions, table, 5.25Design-flood elevation, 2.5Devices, dispensing, 4.79Dilution air, 2.5, 3.8Direct-vent appliances, 2.5Direction, changes in, 4.71Disconnection, 1.18Dispensing devices, 4.7Disposal, condensate, 3.18Documents, construction, 1.11, 2.5Documents, retention of, 1.13Draft, 2.5Draft hood, 2.6, 5.23Draft, mechanical or induced, 2.6Draft regulator, 2.6Draft systems, mechanical, 5.6Drip, 2.6Drop, pressure, 4.4Dry gas, 2.6Duct furnace, 2.6

I.2 INTERNATIONAL FUEL GAS CODE COMPANION

Ducts, 3.3Ducts, combustion-air, 3.11Ducts, supply, 3.21

EElevated structures, 3.17Elevation of ignition source, 3.13Emergency shutdown, 4.82Equipment, 2.6Equipment, air-conditioning, 3.20Equipment, low-heat, 5.19Equipment, medium-heat, 5.19Exceptions, location, 4.80Existing chimneys, 5.4Existing installations, 1.4Existing vents, 5.4Expiration, 1.12Extensions, 1.12

FFacilities, LP-gas fuel-dispensing, 4.7Facilities, motor-vehicle, 4.79Fireplace, 2.6, 6.2Fireplace, factory-built, 2.6Firing valve, 2.6Fittings, 4.65Flame safeguard, 2.7Flange gaskets, 4.66Flanges, 4.66Flood hazard area, 2.7Flooding, 3.2Floor, solid, 4.68Floor furnace, 2.7Floor furnace, gravity-type, 2.7Flow controls, 4.77Flue, appliance, 2.7Flue collar, 2.7Flue gases, 2.7Flue liner, 2.7Fuel-dispensing facilities, compressed-

natural-gas, 4.80 Fuel gas, 2.7Fuel-gas-utilization equipment, 2.7Fuel types, 3.2Fueling, private, 4.80Fueling facilities, private, 4.81Fumes, 3.12Furnace, 2.7, 3.21, 6.3Furnace clearance, 6.4Furnace, duct, 6.4Furnace, enclosed, 2.8Furnace, floor, 6.3Furnace, forced-air, 2.8Furnace, gravity-type, 2.8

Furnace, horizontal forced-air, 2.8Furnace, multiple-position, 2.8Furnace plenum, 2.8, 3.20Furnace, thermostats, 6.3Furnace, up-flow, 2.8Furnace, wall, vented, 6.2, 6.3

GGarages, parking, 3.14Garages, public, 3.14Garages, private, 3.14Gas-connector prohibitions, 4.79Gas convenience outlet, 2.8Gas piping, 2.8Gas piping installations, 4.1Gas utilization equipment, 1.2, 2.8Gas, wet, 4.75Gas vents, 5.12Gas vents, terminating, 5.12Gaseous hydrogen systems, 7.1Gases, 3.12Grade clearance, 3.15Grilles, 3.11Guards, 3.18

HHazardous location, 2.8Heaters, radiant infrared, 6.18Heaters, sauna, 6.9Heaters, unit, 6.12Heaters, water, 6.15Heating equipment, 1.14Historic designation, 1.6Hoods, draft, 5.24Hoods, multiple draft, 5.20House piping, 2.8Hybrid pressure, 4.4

IIgnition pilot, 2.9Illuminating appliances, 6.17Incinerator, 2.9Indoor air, 3.8Industrial air heaters, direct-fired, non-

recirculating, 2.9Infrared radiant heater, 2.9, 6.18Inspections, chimney, 5.10Inspections, final, 1.14Installation, 3.13Installation rules, 5.16Installation shields, 5.5Installations, attic, 3.15Installations, condemned, 1.16Installations, existing, 1.4

INDEX I.3

Installations, gas piping, 4.1Installations, piping-system, 4.67Interconnections, 4.83Intervals, support, 4.83

JJoint, 2.9Joint, plastic pipe, 4.66Joint, welded, 2.9Joints, 4.65, 5.21Joists, 3.4

LLabeled, 2.9Labeling, 3.1, 5.15Ladders, permanent, 3.17Length, branch, 4.4Length, connector, 4.78, 5.21Liability, 1.7Limit control, 2.10Limitations, plastic-pipe, 4.71Liquefied-petroleum gas, 2.10Liquid-fuel-burning appliances, 5.10Living space, 2.10Locations, exceptions, 4.80Locations, outlet, 4.70Log lighter, 2.10Louvers, 3.11Low-heat appliances, 5.3Low-heat equipment, 5.19LP-gas fuel-dispensing facilities, 4.79LP systems, 4.5Lubricated plug-type valve, 2.10

MMain burner, 2.10Maintenance, 1.5Makeup air, 3.8Manufactured-home connections, 4.78Masonry chimneys, 5.7Materials, piping, 4.62Mechanical combustion-air supply, 3.11Mechanical draft systems, 5.6Medium-heat equipment, 5.19Metallic fittings, 4.65Meter, 2.10Minimum standards, 1.4Modifications, 1.9Modulating, 2.10Motor-vehicle facilities, 4.79Multiple appliances, 5.21Multiple draft hoods, 5.20Multistory buildings, 5.14

NNonstructural steel, 3.6Non-vented appliances, requirements of,

5.2Notching, 3.4

OOccupancy, 2.10Occupancy, change in, 1.5Offset vent, 2.10Offsets, 5.13Operating pressure, 4.5Operation, unauthorized, 4.86Options, alternative, 1.10Orifice, 2.10Outdoor combustion air, 3.9Outdoor locations, 3.7Outdoor piping, above-ground, 4.68Outlet, 2.11Outlet locations, 4.70Outside appliances, 4.69Overpressure protection, 4.83Oxygen under pressure, 4.83Oxygen-depletion safety shutoff system,

2.11

PParking garages, 3.14Penetrations, 3.4Penetrations, roof, 5.15Penetrations, wall, 5.22Permanent ladders, 3.17Permits, 1.8, 1.10Pilot, 2.11Pipe protection, 4.67Pipe, single-wall, 5.15Pipe sizing, 4.2Pipe support, 4.74Piping, 2.11Piping materials, 4.62Piping systems installation, 4.67Pit locations, 3.7Plastic, thermoplastic, 2.11Plastic pipe joints, 4.66Plastic pipe limitations, 4.71Plenums, furnace, 3.20Plumbing, 3.2Point of delivery, 2.11Portable fuel-cell appliance, 2.11Prefabricated construction, 1.15Pressure drop, 2.11, 4.4Pressure, hybrid, 4.4Pressure, operating, 4.5


Pressure test, 2.11Private fueling, 4.80Private fueling facilities, 4.81Private garages, 3.14Pressure, air under, 4.83Pressure, oxygen under, 4.83Prohibited appliance locations, 3.6Prohibitions, gas-connector, 4.79Protection, 5.5Protection, overpressure, 4.83Protection, pipe, 4.67Public garages, 3.14Punishment, 1.17Purge, 2.11

QQualifications, 1.19Quick-disconnect device, 2.11

RReady access, 2.11Reconnection, 1.18Records, 1.9Reduction, clearance, 3.20Refrigeration coils, 6.16Refrigerators, 6.15Registered design professional, 2.11Regulator, 2.12Relief opening, 2.12Relief valve, temperature, reseating or self-

closing type, 2.13Relief valve, vacuum, 2.12Relocated buildings, 1.7Repair, 3.2Requirements of non-vented appliances, 5.2Residential appliances, 5.3Residential applications, 4.81Residential type appliance connectors, 5.18Riser, gas, 2.13Risers, anodeless, 4.63Rodents, 3.3Roof penetration, 5.15Roofs, 3.17Roofs, sloped, 3.18Room heater, unvented, 2.13Room heater, vented, 2.13Rules, 1.8Rules, installation, 5.16

SSafety shutoff device, 2.13Sauna heaters, 6.9Sauna, prohibited sources, 6.10Sauna, ventilation, 6.10

Seismic resistance, 3.3Service, 3.15Servicing a system, 4.74Settings, 4.86Shaft, 2.13Shields, insulation, 5.5Shutdown, emergency, 4.82Shutoff valves, 4.76Single booster-type automatic

instantaneous water heaters, 5.2Single-wall pipe, 5.15, 5.16Size, 4.87Sizing connectors, 5.14Sizing limitations, chimney, 5.8Sizing, pipe, 4.2Sizing tables, 4.5Sleeping unit, 2.13Sloped roofs, 3.18Solid floors, 4.68Spaces, combined, 3.9Specific gravity, 2.13Standards, minimum, 1.4Stationary fuel-cell power plant, 2.13Steel, 3.5Stop-work order, 1.17Structural safety, 3.4Structural-steel framing, 3.5Structures, elevated, 3.17Studs, 3.4Supply ducts, 3.21Support intervals, 4.83Support, pipe, 4.74Systems, LP, 4.5Systems, piping, 1.2Systems, servicing, 4.74

TTable, definitions, 5.25Tables, sizing, 4.5Tables, venting, 5.26Termination, chimney, 5.8Termination, gas vents, 5.12Termination locations, venting, 5.17Test pressure and duration, 4.73Testing, 4.72Thermostat, electric-switch type, 2.14Thermostat, graduating, 2.14Thermostat, snap-acting, 2.14Threads, 4.64Tracers, 4.71Transfer system, closed, 4.82Transition fittings, plastic to steel, 2.14Trusses, 3.5Tube, vent, 4.82

INDEX I.5

UUnauthorized operation, 4.86Unconditioned areas, 5.18Under-floor appliances, 3.16Unit heaters, 6.12Unit heaters, high-static pressure type, 2.14Unit heaters, low static pressure, 2.14Unit heaters, unvented, 6.13Unlisted boiler, 2.14Unsafe conditions, 1.17Unvented room heater, 2.14

VValidity, 1.12Valve, 2.14Valve, automatic or semiautomatic, 2.14Valve, equipment shutoff, 2.15Valve, individual main burner, 2.15Valve, manual main gas-control, 2.15Valve, manual reset, 2.15Valve, service shutoff, 2.15Valve, shutoff, 4.76Vent, 2.15, 4.87, 5.1, 5.4Vent area, 5.27Vent, category 1 appliances, 5.13Vent, cooking appliances, 5.31Vent, component commingling, 5.28Vent, connector, 2.15, 5.29, 5.31Vent, conversion accessories, 5.28Vent, diameter, 5.27Vent, existing, 5.4Vent, factory built chimneys, 5.31Vent, fittings, 5.29Vent, gas, 5.12Vent gases, 2.16Vent height, 5.29Vent liner sizing and connections, 5.31Vent locations, 5.27Vent manifolds, 5.29Vent multistory offsets, 5.30Vent obstructions, 5.28Vent, offsets, 5.26Vent piping, breather, 2.16Vent piping, relief, 2.16Vent size, 5.31Vent, special gas, 2.16

Vent, terminating gas, 5.12Vent tube, 4.82Vent, type B, 2.16Vent, type BW, 2.16Vent, type L, 2.16Vent, vertical maximum size, 5.31Vented appliance categories, 2.15Vented appliance category I, 2.15Vented appliance category II, 2.15Vented appliance category III, 2.15Vented appliance category IV, 2.15Vented appliances, 5.23Vented gas fireplace, 6.2Vented room heater, 2.15Vented wall furnace, 2.15, 6.2Ventilation, air, 3.8Venting, 5.6Venting, high altitudes, 5.27Venting, liner sizing, 5.27Venting, minimum size, 5.26Venting, multiple inputs, 5.27Venting system, 2.16Venting system, forced-draft, 2.16Venting system, gaseous hydrogen

systems, 7.1Venting system, induced draft, 2.16Venting system, mechanical draft, 2.16Venting system, natural draft, 2.16Venting tables, 5.26Venting termination locations, 5.17Ventilation, 3.8Vibration, 3.2Violations, 1.16

WWall heater, unvented, 2.17Wall penetration, 5.22Water heater, 2.17, 6.15Water heaters, single booster-type

automatic instantaneous, 5.2Wind, 3.2Wet gas, 4.75Workmanship, 4.64


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