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Medical Gas Design GuideChapter 4 - Design

Continuing Education Publication

®

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Notes on Using this Pamphlet:

This pamphlet is presented as a service to systems designers working with medical gas and vacuum in medical facilities. The design process used in this booklet is detailed in Chapter 1 - Design Process.

This Guide is not in any way intended to be a substitute for a properly qualied engineer, and any pretence tobeing alone sucient for the proper design of any medical gas system is explicitly disclaimed.

It is BeaconMedæs’ intent that this book should only be used as one tool among many by properly qualiedengineers who are in a position by training and experience to know it’s applications and limitations.

You will nd in using the Guide that there are innumerable decisions, judgement calls, and subtleties in thedesign of medical gases which cannot be incorporated in any book, but serve to dramatically emphasize thevalue of the engineer’s expertise.

Fourth Edition May 2010Previous Edition April 2009

Notes

This Pamphlet in both print and electronic versions is Copyright 2010 BeaconMedæs. All Rights are Reserved, and noreproduction may be made of the whole or any part without permission in writing. Distribution of the Electronic version is

permitted only where the whole is transmitted without alteration, including this notice.

Comments on this booklet or on any aspect of medical gases are welcome and encouraged.Please send to [email protected]

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Page 3 Rev F 5/2010

Introduction

Design is the phase where objectsactually begin to go onto the plans.It might be better called the layoutphase, since that is the work productwhich emerges.

Dierent rms handle this phase in dierent ways.Some have the project engineer mark up paperdrawings which are then handed over to a CADoperator to detail, then returned to the engineer whocompletes the calculation work involved with pipe

sizing, etc. In other rms, the engineer will completethe CAD work themselves and concurrently engineerthe project. The ow of the various elements detailedhere in the Guide are also interchangeable. Forexample, we place valves before piping is run. Someengineers prefer to reverse these steps.

There is no one procedure which universally worksbetter than another. The detail of workow can safelybe left to the design team, provided simply that all of the segments detailed here receive attention.

Chapter 4Design

The Drawing Space

Practice varies on how medical gas is treated withindesign documents, but the clear trend is to setmedical gas out on it’s own set of drawings withinthe plumbing and mechanical drawings. We stronglyrecommend this practice. Medical gas drawingsare then typically designated “MG-X” or similar todistinguish them from the plumbing drawings.

The advent of Revit® and other three dimensionaldrawing packages and techniques may change someof the way we do medical gas design work - it is

already inuencing how we present our designs - butat this writing it has not had an eect on the basicprocedure.

You should start with a complete set of architecturaldrawings which must include:

• The room designations. Placement of outlets isdriven by occupancy, so the intended occupancyof each space is very important in successful layout.

• Locations of all doors, especially re doors.

• Location of re walls and designated re zones.

• If possible, the intended locations for ceiling serviceitems (e.g. columns, boom, pendants) in the O.R.,ICU or any other location.

• Elevations or details of headwalls and all ceilingservice equipment, by occupancy, if they exist.Sometimes this equipment passes through aniterative process wherein the engineer mustdetermine the medical gases prior to the detail of these products being nalized. If so, it is important

to know from the discovery process which areas areintended to be tted with headwalls and ceilingservices and which will be tted with standard in-wall outlets. It will be necessary in these cases tocoordinate with the architect on the nal design of these products.

• The intended location of the patient. Usually thiswill be shown by an outline of the “bed” on the

Revit is a trademark Of Autodesk Corporation.

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BeaconMedæs Medical Gas Design Guide

Chapter 4Page 4

OXYGEN MANIFOLDOM

MEDICAL GAS CEILING OUTLET

MEDICAL GAS STATION OUTLET

VACUUM INLET QC TYPE

OXYGEN OUTLET QC TYPE

IN LINE BALL VALVE

PRESSURE/VACUUM SENSOR

WASTE ANESTHESIA GAS DISPOSAL PIPINGW

CARBON DIOXIDE PIPINGC

INSTRUMENT AIR PIPINGIA

MAIN LINE GAUGE

VACUUM SWITCH

0-200 PSI (0-1380 KPA) PRESSURE SWITCH

0-100 PSI (0-690 KPA) PRESSURE SWITCH

LOCAL ALARM

EMERGENCY OXYGEN INLETEOI

NITROGEN CONTROL PANELNITROGEN CONTROL PANEL NCP

WASTE ANESTHETIC GAS DISPOSALWAGD

CEILING COLUMNCC

MGCO

MEDICAL GAS OUTLET IN MANUFACTURED ASSEMBLYMGHO

MGSO

CARBON DIOXIDE MANIFOLDCOM

NITROGEN MANIFOLDNM

MEDICAL AIR MANIFOLDAM

NITROUS OXIDE MANIFOLDNOM

DESCRIPTION

VACUUM EXHAUST PIPINGVE

MEDICAL VACUUM PIPINGV

OXYGEN PIPINGO

NITROUS OXIDE PIPINGNO

MEDICAL AIR PIPINGMA

MEDICAL AIR INTAKE PIPINGMA~IN

NITROGEN PIPINGN MEDICAL GAS VENT LINEVENT

OXYGEN 80 psi PIPINGO-80

AIR 80 psi PIPINGA-80

CARBON DIOXIDE 100 psi PIPINGC-100

VACUUM BOTTLE SLIDES

BULK OXYGEN SUPPLYBOS

MEDICAL VACUUM SYSTEMMVS

VALVE BOX (RECESSED) VALVE BOXVB

MASTER ALARM MASTER ALARM PANELMAP

AREA ALARM AREA ALARMAA

DESIGNATIONDESCRIPTIONSYMBOL

PRESSURE REGULATOR

VALVE FOR FUTURE

LOCKED OPEN IN LINE VALVE

LOCKED CLOSED IN LINE VALVE

PRESSURE RELIEF VALVE

CHECK VALVE

VACUUM INLET DISS TYPE

WAGD INLET DISS TYPE

OXYGEN OUTLET DISS TYPE

NITROGEN OUTLET DISS TYPE

MEDICAL AIR OUTLET DISS TYPEN20 OUTLET DISS TYPE

N2O OUTLET QC TYPE

INSTRUMENT AIR CONTROL PANELIACPINSTRUMENT AIR CONTROL PANEL

INSTRUMENT AIR OUTLET DISS TYPE

MEDICAL AIR OUTLET QC TYPE

CO2 OUTLET DISS TYPE

WAGD INLET QC TYPE

Detail 4.4 Medical Gas Symbology

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Design Page 5

architectural drawings, or may be obvious fromother information. In extreme cases determinationmay require a call to the client or the architect.

Symbols

Symbology also varies from rm to rm, and surprisinglythere does not seem to be any universal symbology for

medical gas. Detail 4.4 shows some of the symbolswe prefer at BeaconMedæs, but others may be equallyvalid provided they are unique for medical gas, clearlydrawn and properly tabulated.

Step One : Outlets

Proceeding room by room, outlets will now be placedin each occupancy required by applicable standards oras desired by the client. Detail 4.7 is partially drawn forn the 2010 edition of the “Guidelines for Designand Construction of Health Care Facilities”. These arethe minimum standards which should be observed.

However, we have found they are inadequate in severalimportant respects, principally in that the tables inthe Guidelines are limited to oxygen, air , vacuum and

WAGD, which are only four of the six to twelve gases amodern facility may require. A more comprehensivetable is reproduced in Detail 4.7.

Where U.K. standards prevail, the HTM 2022 Table2 should be referenced rst, with Detail 4.7 as asecondary reference.

It is not uncommon for the outlets (number andlocation) to be predetemined by the architect andpresented to the engineer. This is particularly commonwhere headwalls are specied and may be reected onheadwall elevations but otherwise not appear on thearchitectural drawings. In any case where headwallsconsoles, ceiling services, or other architecturaequipment will be used to organize the outlets, thisequipment should be detailed with elevations. Theseelevations are used as the primary reference for theoutlet locations and numbers. For the mechanicaplans, references to the detail(s) may be preferable toactual outlet-by-outlet notation.

If the architect has predetermined outlet locations andnumbers, one may skip the following.

Based on the occupancy, determine what outletsshould be placed in the room.

Locate these outlets on either side of the patient’shead. Where multiple outlets of a single type arerequired, they should be divided more or less evenlybetween the two sides. Detail 4.5.1 shows some

typical outlet placement schemes (please note theseare only examples - there are no requirements which

Low Acuity Patient Room

High Acuity Patient Room

Intensive Care Patient Room

V A C U U M

I N L E T

V A C U U M

S L I D E

O X Y G E N

O U T L E T

M E D

I C A L A I R

O U T L E T

S

S

SS S

S

S

Detail 4.5.1Typical Wall Outlet Placement Relative to the Patient

Slide

Slide

Vacuum

Oxygen

Medical Air

Slide

Vacuum

Oxygen

Other

Services

Other

Services

Slide

60"

(1,524 mm)

18-24”

(457-609 mm)

Detail 4.5.2Typical Wall Outlet Placement Relative to the Patient

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Chapter 4Page 6

Collecting Bottleon Cart

Suction

Tubing

Overflowtrap

CollectingBottle on Slide

SuctionTubing

Overflowtrap

CollectingBottle on Slide

SuctionTubing

Overflowtrap

apply and client preference may rule.) Detail 4.5.2shows the corresponding elevation detail (Trunking isillustrated, but an outlet arrangement in a headwall orin the wall should be similar).

Vacuum bottle slide brackets are a detail oftenoverlooked during design. It is important to includethese slides to support the heavy collecting bottleswhich are needed to prevent liquid from entering thepipeline. This weight can damage the latch mechanismin many outlets and in extreme cases results in the

outlet being separated from the wall. While the detailsof suction technique are outside the scope of thisGuide, a general diagram of a typical vacuum setup isshown in Detail 4.6, and an elevation correspondingto Detail 4.5 should be considered around the patientspace.

Although it is possible to place outlets in re walls, sucha practice is best avoided. If possible, outlets should beplaced in other walls. When outlets are placed in rewalls, the integrity of the re wall must be restored byboxing in the outlets with sheet rock or other methodwhich preserves the overall re rating for the wall.

Step Two

Although it is possible sometimes to interchangesteps two and three, we recommend the next stepbe to determine, at least in general terms where thesource equipment will be placed. Final placementmay require an iterative process, since at this stage theactual size of the equipment is not known and cannotbe nally determined until the sizing of the systems iscompleted and equipment is selected (which ideally

occurs in the engineering phase). Nevertheless, it isnecessary to choose a location for the equipment inorder to determine placement of other components.Usually the general location for the equipment willhave been determined by the architect and space willhave been assigned. If so, these will of course be thelocations used (if possible). In other cases, you may be forced to seek out an appropriate location. In eitherevent, it is possible to test various locations for theirsuitability based on the equipment you are interestedin placing there.

Some general suitability tests:

Bulk liquid tanks:

1. The intended location complies with Detail 4.8.

2. The location is out of doors, and meets the spacingdetails required under NFPA 55 (see Detail 4.9.1)

3. Other siting requirements as set out by the tankmanufacturer or provider have been observed (you willneed to work with the facility’s gas supplier to obtain

this information).

Bulk oxygen installations located remote from thebuilding will require installation of an emergency lowpressure oxygen supply connection (EOSC) on theoutside of the building. This EOSC is a prefabricatedbox which will contain the necessary components.Locating the box requires taking account of:

1. The box must be located on the outside of thebuilding.

Detail 4.6Typical Suction Setups

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Design Page 7

Detail 4.7 Medical Gas Terminal Locations

Occupancy O2 Vac N2O Med Air N2 / IA CO2 WAGD

Autopsy 1 1

Blood Donors 1 1

Cardiac Catheterization 2 2 1

Critical Care:

Airborne Infectious Isolation in Critical Care (perbed)

3 3 1

Critical Care (general) / Intensive care (per bed) 3 3 1

Coronary Critical Care 3 2 1

Decontamination 1(l) (P) 1

Demonstration (Inservice) 1 1 1(a) 1 1(a) 1(a) 1(a)

Dental treatment (per station) (c) 1 1 1 1 1

Exam / Treatment / EEG / ECG / EMG 1 1

EENT 1 1

Emergency:

Holding/Initial Management (per bed) 1 1Triage (per bed) 1 1

Treatment / Trauma 2 3 1

Observation (per bed) 1 1

Cardiac treatment 2 3 1

Orthopedic/Cast Room 1 1 1

Imaging:

MRI / CT / PET 1 1 (a) 1 (e)

Other Radiology 1 1

Intermediate Care / Step down (per bed) 2 2 1

Isolation (Infectious disease) (per bed) 1 1 1

Laboratory (c) 1 (P) 1

Minor Procedures 1 2 1 1 1

Obstetrics:

Delivery Room (f) 2 4 (d) 1 1

Labor Room (f) 1 1 (d) 1 (e)

Labor/Delivery/Recovery (LDR) (f) 1 1 (e)

Labor/Delivery/Recovery/Postpartum (LDRP) (f) 1 1 (e)

Postpartum (per bed) 1 1

Postpartum Recovery 1 3 1 1(g)

Infant Resuscitation (per station) 3 3 3

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Chapter 4Page 8

2. Access for a truck or trailer must be available soconnection can be made to the box from a portablesource.

3. The ramp on which the truck will sit must beconstructed both for the surface load of a full tanker

Detail 4.7 Medical Gas Terminal Locations (continued)

Occupancy O2 Vac N2O Med Air N2 / IA CO2 WAGD

Operating Rooms:

Anesthesia Workroom (per station) 1 1(g) 1 1 1 (b) 1

Endo/cysto 2 3 1 1 1(a) 1

Induction Room / Holding 1 1 1 1 1

General O.R. (h) 2 4 1 1(k) 1 1(a) 1

Cardiac, Transplant, Neuro O.R. 2 5 1 1(k) 1(a) 1

Orthopedic O.R. (h) 2 4 1 1(k) 2 1(a) 1

Pediatric:

Pediatric Critical Care 3 3 1

Neonatal ICU (level 3/4) 3 3 3

Neonatal ICU (Level 1/2) 3 3 3

Nursery (i) 1/4 1/4 1/4

Pediatric and Adolescent 1 1 1

Pediatric nursery 1 1 1

Protective Environment 1 1

Psychiatric / Secure (g) (g) (g)

Recovery (PACU) (per bed) 2 3 1

Phase 2 recovery (separate from PACU) 1 3

Patient Room (single) 1 1 1

Patient Room (Double) 2 2 1

Respiratory Therapy 1 1 1

Sterilization / Central Supply (per station) 1(l) (P) 1

Seclusion (per bed) 1 1

Veterinary Applications (c) 1 2 (a) 1 (e)

Notes:Outlets are per bed or per station except where noted.(P) Indicates a prohibited use.(a) May be required depending on the intended procedures.(b) Include an outlet if this gas is piped into any Operating Room.(c) Dental, veterinary and laboratory systems are normally separate from medical systems.(d) Common option.(e) If Nitrous Oxide is piped.(f) Include outlets for infant resuscitation in separate location.(g) Optional, depending on the treatment or procedures intended.(h) Arrangement of the O.R. may dictate additional outlets to ensure all services are accessible for allprocedures.

(i) Up to four bassinets may share one outlet if it is accessible to them all.(k) BeaconMedaes recommendation for Air-Halogen anesthesia.(l) Controversial application

and to account for the possible spillage of liquid oxygen(no asphalt may be used).

4. When detailing the EOSC, remember that there areseveral other requirements which must be observed.Refer to Chapter 8 p. 26 and Detail 8.25.1 for moreinformation on the EOSC.

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Design Page 9

BulkCryogenic

GasStorage

Medical AirPlant

VacuumPlant

WAGDPlant

Instrument

AirPlant

Med gasManifolds,any type

Med Airheadersfor I.A.reserves

INDOORS

OUTDOORS

Using this detail:Look for a point which includes your intended locationand other equipment in the same location. If there issuch a point, the location is probably suitable. Thus amanifold may be located with a bulk storage unitoutdoors but never with an air plant. Graphic followsNFPA 99 5.1.3.3

Med gasCylinders

andContainers

in Storage

Med AirCylindersin Storage

Other equipment inthe same roome.g. boilers,airhandlers, etc.

Detail 4.8Source Location Exclusions

Gas and liquidmanifolds, headers andin-building emergency

reserves.

Ensure the intendedlocation has at least the following characteristics:

1. The intendedlocation complies withDetail 4.8.

2. It is possible andconvenient to movecylinders and containers

between the loadingdock and the intendedlocation.

3. There is at least oneoutside wall accessible for ventilation and forpiping vent lines to theoutside.

Public

Sidewalk

NearestParked

Vehicle

Detail 4.9.1

Bulk Station Location

Place of Public Assembly Wood Frame

Structure

NearestOpeningIn Wall

NearestNon-Ambulator

Patient

Building VentilationClearances

PropertyLine

50 ft15 meters 50 ft

15 meters

50 ft15 meters

As required bythe supplier

10 ft3 meters

10 ft3 meters

10 ft3 meters

5 ft1.5 meters

1 ft0.3 meters

(after NFPA 5.1.3.4.11.1note that local regulations may vary)

Medical Air Compressors, vacuum pumpsWAGD producers, and Instrument aicompressors.

Ensure the intended location has at leastthe following characteristics:

1. The intended location complies with

Detail 4.8. Note that except for gasesin cylinders and containers, there is nolimitation on the other equipment whichmay be located in the same space.

2. The location has sucient space fothe equipment itself and for maintenanceaccess. Since you have not yet sized oselected the equipment, knowing howmuch space to allocate is problematicbut with experience you can make a roughestimate of the equipment likely to berequired. Ideal maintenance access requires

three foot of open space on all sides of theequipment. This space can be reducedunder some circumstances, but at this stageof design, it is wise to allow the full envelopeif possible.

3. Installation access. It may be necessaryto examine the route the equipment musttravel to ensure it can be physically gotten

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Chapter 4Page 10

dicult steps in thedesign process.

Zone valves mustbe placed so as tocomply with all of the following rules whichapply:

1. No outlet/inlet can existwithout a zone valveon the same oor, orto put it another way,every outlet/inletmust be controlledby some zone valvelocated on the same oor. Therefore, itis possible to havea single valve to

control an entire oor

of outlets/inlets, but it is not allowed to have a oorwhich has outlets/inlets but has no zone valve on that

oor.

2. Each critical care or life support occupancy musthave it’s own zone valve. There are two equallytroublesome questions which must be answered: Whatis an occupancy and is a given occupancy a li fe supportarea?

The denition for an occupancy is “the use to whicha property is put”. Thus a simple test might be: isthis area under the control of a single body of sta

to the desired location. This is a particular problem forreplacement equipment.

3. Ventilation. The space must never exceed 105°F(40°C), under any circumstances, including when theequipment is running. Ventilation therefore mustbe sucient to carry away the heat generated by theequipment. It may be necessary in some climates toair condition the mechanical space.

4. Electrical service. If a location does not haveappropriate electrical service or will require electricalservices to be relocated, the expense of providingelectrical service may justify locating the equipmentelsewhere.

5. Access to water and chilled water (if required for thetechnology chosen).

Step Three

Place shuto valves as required by the standard. The

general rules for valves contained in NFPA 99 aresummarized in Detail 4.10.1.

It is possible to work from the source outward or fromthe outlets back towards the source. In this Guide wework from the outlets back. Therefore, the rst valvesyou will place will be the zone valves. Zone valves arethe one valve which is accessible to the oor sta, in abox with a cover which can be removed in an emergency.The rules for zone valve placement are relatively rigidand placing valves is one of the most complex and

N U R S E

S T A T I O N

Detail 4.10.2Zone Valves and Outlets

Riser Valve(s) Service Valve

Service Valve

Note: Single Service valves are shown,but multiple zones may branch off asingle Service Valve.

Outlet(s)/Inlet(s)Outlet(s)/Inlet(s)

Outlet(s)/

Inlet(s)

Service ValveFutureValve

ZoneValve

ZoneValve

Zone

ValveIndicates a Valve which must be secured

Non-critical areas, such asgeneral patient rooms

Anesthetising areas

Critical areas, such as Intensive Care

SourceValve

MainValve

Main Line

R i s e r

Detail 4.10.1Valve Placement(after NFPA 5.1.4)

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Design Page 11

members and used for similar forms of patient care?Thus, an ICU can be seen to be a single occupancybecause it is controlled by a distinct group of sta from a distinct location (the nurses station), and althe patients are receiving care of approximately similatype. By contrast two operating rooms would be seenas two separate occupancies, because the patientsare under the care of separate groups of sta, are

undergoing distinct procedures and there is probablynot a single central location which is always occupiedwhen procedures are underway.

Endoscopy rooms are an example of an area somewherebetween these two: patients are under the care ofdistinct groups of sta, but are undergoing roughlysimilar procedures. There may or may not be a centralocation for sta to monitor.

The question of life support is even more dicultWe want a clear test to apply, but the question isnot that simple. In the NFPA 99 Handbook there is a

test which may help: The test references back to the fundamental purpose for installing zone valves, whichis re control. So: if a re were to occur in the areaor room under consideration, could adjacent roomsbe evacuated without negative patient outcomes (i.ewould the patients being evacuated be injured or die?)If adjacent rooms would require time for their patientsto be stabilized and evacuated, then the area maybe considered critical care for the purpose of placingvalves. If on the other hand, the procedures couldbe terminated and patients could be evacuated (eitheunder their own power or by the sta) with minimal il

eect, then this area might be considered non-critical

3. Each anesthetizing location must have it’s ownzone valve located outside the room.

4. Certain local jurisdictions have specic rules onwhat constitutes a “critical care” or “life support”occupancy. For instance, zone valves are sometimesrequired for cystoscopy or endoscopy rooms by locarequirement but these do not always appear on listsof critical care occupancies. See the denitions fo“Critical Care” and “Invasive Procedure” in NFPA 992005. Also place any valves required by local rules.

5. You should otherwise place valves as necessaryto break the system into logical, discrete units foremergency shut o or service. Consider the number odependent patients which will be connected througha single zone valve. If that number is large (>10), it iswise to break the zone into multiple zones. 6. Zonevalves must be placed outside of the area they controlHaving determined that an occupancy must beprovided with a zone valve, then one must determinewhere the valve will be located. Finding and testing a

Outside Dimension”PW”

Cover Width327 mm (12 7/8 in.)

Cover Height“DH”

Box Height“H”

MountingFlange

Note:Valves must be piped to source on LEFT, to Patient on RIGHT

®

Box Width302 mm (11 7/8 in.)

Detail 4.11Installation Dimensions for Zone Valve Boxes

H DH

1 Valve Box10”

(254mm)11”

(279mm)

2 Valve Box with:

both valves 1” and smaller10”

(254mm)11”

(279mm)

either valve or both valves1 1/4” or larger

15 1/2”(394mm)

16 1/2”(419mm)

3 Valve Box15 1/2”

(394mm)16 1/2”

(419mm)

4 Valve Box20”

(508mm)21”

(533mm)

5 Valve Box with:

largest valve 1” or smaller26 1/2”

(674mm)

27 1/2”

(699mm)largest valve 1 1/4” orlarger

32”(788mm)

33”(839mm)

6 Valve Box32”

(788mm)33”

(839mm)

7 Valve Box36 1/2”

(902mm)37.5”

(953mm)

8 Valve Box41”

(1042mm)42”

(1067mm)

To calculate PW:PW (in inches) = 24.6 + 2((# valves -1) + Sum (all valvesnominal sizes in inches))Example: an 8 valve box containing 1/2”, 1/2”, 1/2”, 1/2”,

3/4”, 3/4”, 1 1/4”, 1 1/2” valves. PW = 24.6 + 2((8-1) +(.5+.5+.5+.5+.75+.75+1.25+1.5)) = 24.6 +2(7 + 5.25) = 49.1” PW (in mm) = 625 + 2(25((# valves -1) + Sum (all valvenominal sizes in inches)))Example: an 8 valve box containing 1/2”, 1/2”, 1/2”, 1/2”,3/4”, 3/4”, 1 1/4”, 1 1/2” valves. PW = 625 + 2(25((8-1) + (.5+.5+.5+.5+.75+.75+1.25+1.5)))= 625 + 2(25(7 + 5.25)) = 625 + 613 = 1,238mm

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Chapter 4Page 12

potential location involves these four steps:

• The ideal location for a zone valve is along the mostlogical exit path for the sta. That is to say: shouldthere be a re in the controlled occupancy, and thesta went to exit the occupancy, they should pass thevalve as they exit (see Detail 4.12.1). Consider that theymay be evacuating patients in beds or wheelchairs as

well, an exit route appropriate for a healthy personmay not be usable (a glance at the example in 4.12.1will show two problems of this type: a door too small for a stretcher or bed, and a stairwell)

• If, when standing at the valve, a person is withinthe same space as the outlets controlled, the valveis badly placed. A wall, a door or other physical, reand smoke resistive barrier must separate the outlets from the valve. As an example, if an ICU has individualrooms, the valve might be located inside the commonnurse’s station. If on the other hand, the ICU has onlycurtains, the valve needs to be located outside the ICU.In Detail 4.10.2, the valve is located outside the maindoorway instead of at the nurses station because even

though two of the beds are behind their own door, twoare only separated from the valve by curtains. Glasspartitions can be considered as walls, provided theyhave an adequate (usually 1 hour) re rating. Unratedpartitions must be considered as if they did not exist.

• Examine the swing of anynearby doors. If the valvelocation will end up behindthe door when the door isopened, a dierent locationmust be selected. It isunacceptable that a door

hides a valve, since of courseit cannot then be seen in anemergency. (see Detail 4.12)

• The valve should belocated where it is as secure

as possible. Ideally, they are located in busy corridorsor where visible to sta. Zone valves located in insecureand public areas may be turned o with maliciousintent or by persons ignorant of their function.

• There must be sucient wall space for the valve tophysically t in the location. Detail 4.11 gives valvesizes and ideal dimensions for the valve and associatedpiping. It is often possible to locate a valve in a smallerspace, but it requires a very expert installer to avoidburning the valves or damaging one joint while makinganother. Designing valves into tight spaces is very risky.

Don’t be surprised if you nd two or more of the abovepoints conict. Conict is unfortunately common, andthere are times when one or more of these principlesmust be compromised in order to have any zonevalve at all. In such cases, you must make your bestjudgement or discuss and agree with the client the bestlocation.

Step Four

The next stage of the process is to route the piping.Clearly, this is mostly a mechanical process of “connectthe dots”. Outlets route to branch lines, branch lines

route to zone valves, zone valves route to servicevalves, service valves route to riser or branch valves,riser valves route to mains, mains connect in turn to

SideBar On the Use of Ring Mains.

A Ring Main is where piping from multiple risers isconnected to a main pipeline which forms a loop, suchthat ow can come along either side of the loop or ringto that riser.

Particularly in vacuum systems, the ring main allowsfor less restriction to ow when the system is under heavy loading. This is more particularly true in older installations where you may be forced to utilize someold and inadequately sized piping to feed your new installation. The potential benets of a ring main in pressure gas piping is similar but typically less obvious.

While it is rare that the largest resistance to ow is inthe main lines, every little bit can help, and if the usersare messy and don’t keep the vacuum lines clean, theuse of a ring main may oer some additional insuranceagainst a blockage.

NFPA does not speak specically to the valving of aring main, but there is no reason a ring main cannot operate well if the standard valving rules, especially those for risers, are followed. The desirability of valveswithin the ring main is less clear, and would certainly require clear labelling if any were used. BeaconMedæsrecommends a ring main always be marked as such,so in future no one will be surprised when they shut avalve and the ow doesn’t stop!

Detail 4.12.2Zone Valves and Doors

v v

DN.DN.

NO. 1

STAIR

EXIT

E X I T

Detail 4.12.1

Zone Valves and Exit Path

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Design Page 13

main line valves. This process is usually quite simple.However, there are a few rules of thumb which willhelp make installation smoother:

1. It goes without saying that you should route piping

to make the runs as short as practical.

2. It is acceptable and commonly done to see singledrops to multiple outlets in the walls (e.g. when outletsare back to back) With pressure gases this is rarely aproblem, but this practice should be minimized whenworking with vacuum. No more than 2 vacuum outletsshould feed from a single 3/4 In. (15mm) drop.

3. Route piping down hallways rather than throughwalls wherever practical. If a wall is only a partition,and does not reach to the deck above (as is sometimesdone with patient rooms, intensive care areas, etc.) the

piping may be run over these walls. However, runninglines through re walls should be minimized to reducethe amount of restopping required.

4. Avoid drawing piping which cannot be installed.Occasionally an engineer will draw piping requiring ttings which cannot be obtained for medical gas.90’s, 45’s and tees are all fair game, but med gas pipingcannot be bent under NFPA 99 (although the practiceis common under other standards).

5. Try to route pipe so as to minimize ttings andturns. While some compromises with other tradesare unavoidable, medical gases, particularly medicavacuum should have an absolute minimum of turnsIf you know of possible conicts with ductworkstacks, electrical lines, etc., try to route the medicagas smoothly around these obstacles rather than havethe installer be forced to insert multiple ttings to get

around them.

6. With vacuum piping, avoid creating low spots or“U” traps in the pipe. The ideal vacuum layout wouldactually be sloped like a drain line towards the pumpto allow any liquid to run away from the inlets. Suchan ideal installation is usually impossible, but uiddrainage is a consideration to keep in mind whilerouting the pipe.

7. Standard practice with zone valves is to run fromthe source into the left side and to the outlets/inlets from the right. This convention comes from the

construction of the zone valve, with it’s guage on theright hand side. There are very, very few circumstanceswhere this rule can be violated without problems laterIt does sometimes require extra piping to accomplishthis arrangement, but it is very important your drawingsreect this orientation.

8. Zone valves may NEVER be connected in series suchthat one zone valve shuts down another.

9. Piping which must be run underground is requiredto meet specic requirements in the NFPA standard

Detail 4.13 summarizes good practice for buried pipes(although this is no longer strictly required by thestandard). It is permitted to run medical gas pipingwith other underground services, with no limitationsother than temperature and ventilation.

10. Although it is uncommon, there is no prohibitionagainst running medical gas piping out of doorsMedical Vacuum, WAGD and Medical Air pipelines aresubject to internal icing under some circumstances, soit is very risky to run these pipelines outside of heatedspaces. Any pipe run in the open must be protectedagainst damage.

11. Medical gas piping may not be run in areas withspecial hazards, specically: open ames (e.g. kitchens)elevator shafts or elevator machine rooms, or electricaenclosures containing 600 V or more.

Step 5

Locate the service valves. A service valve’s primary function is to permit work on the zone valve withouthaving to shut down the entire system. They are rarely

OriginalTrench

CleanFill

Sand andcrushedlimestone

Pipe

Split Conduit

(Lower half)

Split Conduit(Upper Half)

Drain hole

IndicatorTape at

1/2 depthof bury

Surface

Detail 4.13Buried Piping Requirements

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Chapter 4Page 14

used, because zone valves are very rarely serviced.In fact, most service valves will never be used.Nevertheless, they are required by the standard, andanyone who has undertaken a project involving addingor moving a zone valve is overjoyed to nd one.

The rules for service valves are (see Detail 4.10.1):

1. Where any line departs from a main line, riser orsignicant branch to serve zone valves, locate a servicevalve.

2. There can be no zone valve without a service valveon it’s source side. However, many zone valves mayshare a service valve.

3. Service valves must be on the same oor as the zonevalves they serve.

4. Service valves are located close to the main line,branch or riser, in secure spaces (i.e. accessible only to

maintenance sta) and in many facilities, locked open.If locks are required, be sure to designate the valve asrequiring a locking handle.

Step Six

Locate the Riser valves. Riser valves are something of an anachronism since many facilities today are singlestory, however they are still required under that namein the NFPA 99. More modern usage might be to callthem “branch” valves, which is a better way to think of them. The rules for placement are (see Detail 4.10.1):

1. At the base of each riser, before the riser passesinto the next oor. So, if the main line runs througha basement, the riser valve will physically be locatedin the basement at the point the line turns up. It isrequired where the main line turns up as well as beingrequired for every location where a riser tees o themain.

2. Although (1) above is the only requirementcontained in NFPA for these valves, if they are viewed asbranch valves, it makes sense to install them where anymajor branch separates from the main line. A simple

working denition of “major branch” would be a linewhich serves two of more zones.

3. Locate the valves in secure spaces (i.e. accessibleonly to maintenance sta) and close to the main line.If desired, lock them open.

Step Seven

Locate the Main Line valves and Source valves. Themain line valve is sometimes optional, but the source

valve never is. Therefore it may be easier to startwith the source valve. (Note that the source valve isINCLUDED with most BeaconMedæs equipment andthat it does not need to be separately called out. If specifying BeaconMedæs equipment, you may skipdown to the section below on Main Line valves).

The rules for the source valve are:

1. Every source must have a source valve. The sourcevalve functions to isolate the source and all it’sassociated equipment from the pipeline. Thus, byclosing the source valve you could remove the sourceequipment and replace it entire. It is also the dividingline between the source equipment with its particularrules and the pipeline with it’s own rules.

2. The Source valve will be located at or very near theequipment and within the same room. As this room orenclosure must be secure, there is no need to separatelysecure the source valve.

3. The source valve should be accessible to someoneworking on the equipment without a ladder or otherspecial equipment.

The rules for the Main line valve are:

1. If the source equipment is inside the building andprovided with a source valve, the main line valve maybe considered optional.

2. If the source equipment is outside the building,

the main line valve must be placed at the point wherethe pipe enters the building. A typical example is abulk oxygen system which is located remote fromthe building. The source valve is as required to beout on the pad with the equipment and a main linevalve is required at the point where the pipe enters thebuilding.

3. If the equipment is within the building physicallybut access can only be obtained by exiting the buildingand re-entering the source enclosure from the outside,the usual interpretation is that this case requires a mainline valve (but see 4 below)

4. If the equipment is physically mounted on anoutside wall (e.g. a manifold on the outside of thebuilding), the NFPA 99 permits the omission of themain line valve.

This allowance should only be implemented afterconsultation with the local authority having jurisdiction.

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Design Page 15

Outlet(s)/Inlet(s)Outlet(s)/Inlet(s)

Outlet(s)/ Inlet(s)

Non-critical areas, such asgeneral patient rooms

Anesthetising areas

Critical areas, such as Intensive Care

SourceValve

MainValve

Main Line

Area Alarm

Switch/Sensor

D.C.

Master Alarm

Switch/Sensor

D.C.D.C.

D.C. indicates a “Demand Check”

Area Alarm

Switch/Sensor

(alternate locations)

Detail 4.15

Alarm Sensor Placement (After NFPA 5.1.9)

Step Eight

Next, consider the placement of optional valves.Remember the old hospital engineer’s saw: “there is nosuch thing as too many valves”. NFPA 99 permits you toplace valves wherever desired for service or expansion,and the only requirement is that these valves mustbe secure (i.e. not visible or accessible to the public).

Many facilities would also want them locked open, butthat is optional under the standard.

Some guidance on in line valves:

1. If there are isolation rooms within a zone (burnunits, tuberculosis, infectious disease, etc.), insert inline valves to allow that room to be separated from thezone.

2. When a single zone controls multiple rooms,consider inserting them so as to allow each room to beisolated from the zone.

3. Consider inserting an in line valve wherever a systemmakes a natural break. An example might be an ICUwhich passes around a corner or a recovery room withan inpatient and an outpatient section.

4. Consider placing them wherever a distinctive pieceof equipment is installed. Some facilities like to putthem ahead of every headwall or power column.Equally, valves can usefully be placed ahead of ceilingcolumns, pendants, etc.

Step Nine

Consider placing Futures valves in any zone where it isknown or suspected that expansion or renovation wiloccur. These are typically placed at the end of a runclosed, locked and the end capped.

Futures valves should be considered at the ends of al

major lines, and at least one should be considered foeach oor. A particularly valuable version is a futurevalve on each oor right at the riser, which can actas the service valve should that oor ever requireadditional zones. It is amazing how much having sucha valve simplies renovation of a oor.

Step Ten (see also Chapter 10)

Alarms are placed next. There are three categories oalarms which must be located. Local alarms (see StepTwelve) are found with the medical air, instrument airvacuum and WAGD plants. A simplied version of the

local alarm (the “local signal”) may also be found withmanifolds and at the bulk gas station. Master alarms(see Step Eleven) are found in specic areas where the facility sta can see and react to them and Area alarmsare found in the patient care areas.

Area alarms are required in every location which isconsidered a critical care or life support area and in anyarea considered an anesthetizing location. Area alarmsinclude pressure and vacuum readouts displayingsystem pressure.

As with valves, determining where alarms are requiredcan be somewhat problematic. There is no mastelisting of critical careareas which caninfallibly guide you indeciding. The NFPAhandbook does oer anuseful if complex testIf the medical gasesor vacuum were to faiduring a procedure inthat occupancy, wouldthe procedure have to

terminate prematurely?Is it possible the patientoutcomes would benegatively impacted(i.e. would any patientbe injured or die?) Ifthe answer to either othese questions is “yes”then the area may beconsidered criticacare for the purpose of

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Chapter 4Page 16

alarms.

This test reminds us of the fundamental reason for analarm: to give the sta notication that a gas or vacuumsystem is failing, so they can in turn ensure the safetyof the patients.

A typical location for a panel is in the nurses station,

but that is not the only acceptable location nor is italways the best. The panel location should pass the following tests:

1. Is the proposed location one where a memberof the sta can reasonably be expected to be in theimmediate vicinity?

2. Is the proposed location always visible? Inparticular, is there any likelihood of the alarm beinghidden behind doors, parked equipment or otherobstructions?

3. Will the alarm be audible over all or most of thearea under it’s surveillance? This test precludes thealarm being placed in an oce where the door may beclosed and the alarm made inaccessible or inaudible.

It is entirely acceptable to combine multiple alarmsinto a single panel if the best location for their alarms isthe same. An example where this may be true is wherea central nurses station is provided for two dierentunits. Each unit has it’s own zone valve, but the bestlocation for both alarms is that shared nurses station.In such a case, a single panel with appropriate signals

and proper labelling would be ideal.

Anesthetizing locations have dierent, less stringentrequirements for Area alarms. Anesthetizing locationsare permitted to have a single alarm for a suite of zonesinstead of the single alarm for the zone required of critical care.

How many alarms to use will depend entirely on thelayout of the anesthetizing locations to be monitored.If, as is often true of Operating Rooms, the rooms areall grouped around a “core”, and controlled from acentral nurses station, all may be handled with a single

panel. If on the other hand the locations are spreadout, each having it’s own workspace for the sta andno central control station, for example as is sometimesdone in the design of birthing centers, multiple alarmsmay be required to ensure the rooms are adequatelymonitored.

Locating an area alarm for an anesthetizing locationtherefore includes determining where in the immediatevicinity of the anesthetizing locations to place thealarm. Eligible locations might include the control

room for the O.R., in the central sterile core, or at theO.R. supervisor’s desk. The location should pass the following tests:

1. Is the proposed location close to the anesthetizinglocations being monitored? Remember that when thealarm goes o, someone must go to each anesthetizinglocation and warn the sta, since each location will not

have an alarm of it’s own. If the distance is great, thetime taken will be long and patients may be at risk.

2. Is the proposed location one where a member of the sta should always be in the immediate vicinity(i.e. within earshot and sight line of the alarm)?

3. Is the proposed location always visible? Inparticular, is there any likelihood of the alarm beinghidden behind doors, parked equipment or otherobstructions?

4. Will the alarm be audible over a large area? Never

place an alarm in an oce where the door may beclosed and the alarm made inaccessible or inaudible.

Once the panels have been located, the alarm sensorsmust be placed. The actual location does not needto be precise, but it must be correct relative to thezone valve. Note that in line valves and service valvesmay be considered not to exist when placing alarmsensors under NFPA rules. (BeaconMedæs howeverrecommends that sensors always be placed on thepatient side of Service valves)

Detail 4.15 summarizes the rules for the placement of alarm sensors, which are:

1. In critical care locations, where an area alarm willmonitor a single zone, the sensor will be placed on thepatient side of the zone valve. Closing the valve willactivate the alarm.

2. In anesthetizing locations, where multiple zonesmay be monitored by a single area alarm, the sensorwill be placed on the source side of all the zone valves.Closing any zone valve or all the zone valves will notactivate the alarm. The alarm will only sound if there

is a source failure or closure of a valve closer to thesource. It is permitted to place the sensors on thepatient side of the valves as an alternate, but of coursethat will necessitate at least a separate set of signals foreach O.R., and probably will result in multiple panels.

3. If valves are placed at the owners discretion in non-critical care areas, such as general patient care oors,the sensor may be located at the owners discretion,but BeaconMedæs recommends they be placed on thepatient side of the zone valve.

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Design Page 17

4. Alarm sensors must be placed on gas specicdemand checks. A demand check is an automatic valve,keyed by gas for non-interchangeability, which allowsthe sensor to be removed for testing or replacementwithout shutting down the system.

Depending on the alarm system selected, the sensorsmay be located in the alarm and a small pipe run to the

panel, or the sensors may be located on the pipe andwired to the panel. Where the alarm gives the option,the decision can be made based on the coordinationbetween trades. Either way, it is important thespecication denes whose responsibility wiring thealarms is to be.

More information on Area Alarms is contained inChapter 10.

Step Eleven (see also Chapter 10)

Master alarms are sometimes also referred to as source

alarms, which is in many ways a more accurate term.Their function is to monitor the sources and give warningof issues developing with the source equipment itself.

There are two master alarm panels required:

1. One panel must be located in the “Principalworkspace of the person responsible for the systems.”This is usually dened as the engineering or facilitiesdepartment, and the alarm is commonly found inthe reception area or behind the dispatcher’s desk.However, this is certainly not the only location they

might be placed, nor necessarily the best. Alternativelocations might include the operating engineers ocein the boiler room, at the BMS main terminal, in therespiratory therapy department, in the anesthesiadepartment, or any other location which will bestensure that the alarm is seen and acted on by aresponsible person.

2. The second panel must be located in a place whichwill be occupied whenever “the facility is in operation”which for a hospital of course means 24 hours.

This used to be easy - this alarm went in the telephone

switchboard room. Now however, hospitals maynot have a switchboard any more. Other potentiallocations may include the security oce, reception,the room with the BMS central terminal, or any otherlocation which will ensure that an alarm is seen anda call is made to the right person to address it. Thereis an exception to this requirement which is made forLevel 2 (small) facilities, for which see Chapter 14.

Once the panels are located, the sensors for systempressure need to be placed. These will go on the

patient side of the main line valve if one exists, or onthe patient side of the source valve if no main line valveexists. (see Detail 4.14).

More information on Master Alarms is contained inChapter 10.

Step Twelve (see also Chapter 10)

(You may skip this section entirely if you intend tospecify BeaconMedæs equipment. Local alarms areincluded with all BeaconMedæs source equipment sono separate Local Alarm panel is needed.)

Local alarm panels are only required if the equipmentbeing installed is not properly compliant with NFPA99 as purchased. The panel serves to annunciatekey indicators of failure in the source equipmentand is placed in the same room or enclosure as theequipment itself. The panel should be located so asto be visible whenever a person is looking at the front

of the equipment. “Front” may best be dened as thecontrols for the equipment.

One signal on the panel will be required for eachmonitored condition. Provided there are adequateindicators available, and provided that the panel canbe seen from each source, it is permitted to combinemultiple sources into a single panel.

More information on Local Alarms is contained inChapter 10.

What Next?

At this point, you should have a nished layout includingall required valves, alarms, and the appropriate outletsin each patient location. Everything should be “hookedup” and therefore, on paper or the computer screenyou will have roughed out the medical gas pipelines.

The next stage is to calculate the sizes of each piece ofsource equipment, detail it, select the exact equipmentand then return to this drawing to conrm that whatyou estimated during the preceding layout process isstill valid. You may nd that some adjustments wil

need to be made (particularly as you check the physicasize of the selected equipment against the availablespace), but generally speaking what you have done wilbe reasonably close to the nal layout.

The next stages are system specic. They may be takenin any order, so here’s where to nd each:

Medical Air ~ Chapter 5,

Medical Vacuum ~ Chapter 6

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Chapter 4Page 18

Oxygen, Nitrous Oxide, Carbon Dioxide, and exotics~ Chapter 8

Nitrogen and Instrument Air ~ Chapter 9

After the sources are complete, the Alarms must bedetailed, which will take us through Chapter 10.

With all the components detailed, we will then turnto the sizing of the pipe in Chapter 11 - one of themost critical functions, and then to completing thespecication in Chapter 12.

7/28/2019 c4 design 5-10


®

1800 Overview Drive • Rock Hill, SC 29730 • Phone 1 888 4 MED GAS • Fax 803 817 5752www.beaconmedaes.com

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