Arkansas STEPS Network Presentation - Classified Areas

Hot Work

Hot Work Program

Hot Work - Any operation or job which could provide,

become or create an ignition source for any flammable material:

Welding, Cutting, Brazing, Soldering Acetylene burning Arc welding Metal chipping, sand blasting Open flames Electrical driven power tools Or similar work (Cameras, flashlights,

and electronic equipment can create hazards in flammable atmospheres

Prevention – Hot Work Permit

Flammable Range

L.E.L.

10%

L.E.L.

L.F.L

U.E.L.

U.F.L

100%

Too Rich to Explode

0.5% 5% 15%Methane

Flammability / Explosive Range

• Hot Work• Move the welding/cutting or move the hazard

(SWN requires > 100ft well bore & not less than 50ft from vegetation or other combustibles)

• Remove combustible materials• Confine the heat, slag, sparks with guards• Protect combustibles that can’t be moved with fire blankets

• Fire Extinguishers-in a state of readiness

• Fire Watch-required by OSHA• Have extinguisher and be trained to use it• Required for minimum of 30 minutes after completion of

welding and cutting

Hot Work Permit

Do any of these cause a spark?

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CSB Dangers of Hot Work

Static Electricity Hazards

Explosion Kansas City

Hazardous (Classified) Locations

Jeremy Cox, CSPSWN

William Brown, CSPXTO

Presented By::

Training Objectives

By the end of this training, employee will be able to:

• Understand how to determine Hazardous (Classified) Locations• Understand the differences between Class I, II, III hazardous

locations• Understand the different kinds of conditions under which these

hazards are present• Understand the three types of ignition sources• Equipment design & construction considerations

Regulatory Agencies

• OSHA 1910.307• NEC, articles 500-504 & 510- 517• ANSI / API 500-1998

Hazardous Locations

• The National Electrical Code (NEC) defines hazardous locations as those areas "where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust, or ignitable fibers or flyings."

Petroleum Refinery

Grain Elevator

Lumber Mill

Tank Battery

Gas Gathering Facility

Well Servicing

3 Types of Class Locations

• Class I Locations

• Class II Locations

• Class III Locations

Class I Locations

• Class I Hazardous Location is one in which flammable gases or vapors may be present in the air in sufficient quantities to be explosive or ignitable.

Typical Class I Locations • Some typical Class I Locations are:

– Petroleum refineries, and gasoline storage and dispensing areas; – Dry cleaning plants where vapors from cleaning fluids can be present; – Spray finishing areas; – Aircraft hangars and fuel servicing areas; and – Utility gas plants, and operations involving storage and handling of

liquified petroleum gas or natural gas. – All of these are Class I . . . gas or vapor . . . hazardous locations. All

require special Class I hazardous location equipment.

Class II Locations

• Areas made hazardous by the presence of combustible dust.

Typical Class II Locations • Some typical Class II Locations are:

– Grain elevators; – Flour and feed mills; – Plants that manufacture, use or store magnesium or aluminum

powders; – Producers of plastics, medicines and fireworks; – Producers of starch or candies; – Spice-grinding plants, sugar plants and cocoa plants; and – Coal preparation plants and other carbon handling or processing

areas.

Class III Locations• Areas where there are

easily-ignitable fibers or flyings present, due to the types of materials being handled, stored, or processed.

Typical Class III Locations

• Some type III locations include:

– Textile mills, cotton gins; – Cotton seed mills, flax processing plants; and – Plants that shape, pulverize or cut wood and

create sawdust or flyings.

Divisions (Conditions)• In addition to the types of hazardous locations, the National

Electrical Code also concerns itself with the kinds of conditions under which these hazards are present. The Code specifies that hazardous material may exist in several different kinds of conditions which, for simplicity, can be described as:

– normal conditions– abnormal conditions.

Divisions

• Division 1 - normal conditions

• Division 2 - abnormal conditions

Class I Location Groups

• The groups deal with the nature of the hazardous substances.

• The gases and vapors of Class I Locations are broken into four groups by the Code: A,B,C,& D

• These materials are grouped according to the ignition temperature of the substance, its explosion pressure, and other flammable characteristics.

Group A

• The only substance in Group A is acetylene.• Acetylene makes up only a very small

percentage of hazardous locations. Consequently, little equipment is available for this type of location.

• Acetylene is a gas with extremely high explosion pressures.

• Acetylene is a well known fuel gas used almost universally in gas welding.

• Even though it is very common, this gas is an extremely dangerous material. Acetylene is so reactive, it should never be allowed to come into contact with certain metals such as unalloyed copper.

• Nor should it be stored or used at pressures greater than 15 psi.

Acetylene Cylinders

• Acetylene is so flammable, that the National Electric Code has a special designation (its most stringent) for using electrical equipment around acetylene.

No other substance falls into this classification!

• Acetylene leaks, no matter how small can have serious consequences.

The explosive range of the gas, when mixed with air, is from 2.5% to 82%, the widest of any commonly used gas.

Acetylene Cylinders

Group B

• Relatively small segment of classified areas.• Includes Hydrogen and other materials with

similar characteristics.

Group C & D• Are by far the most usual Class I groups.

• They comprise the greatest % of all Class I hazardous locations.

• Common Group D flammable substances include:– Butane, gasoline, natural gas, propane

Class II Groups

• Class II – “dust locations” contain:– Groups E, F, & G

– These groups are classified according to the ignition temperature and the conductivity of the hazardous substance.

– Conductivity is an important consideration in Class II location, especially metal dusts.

Group E

• Metal dusts are categorized in the Code as Group E.

• Included here are aluminum and magnesium dusts and other metal dusts of similar nature.

Group F & G

• Group F atmospheres contain such materials as– Carbon black, charcoal dust, coal and coke dusts

• Group G includes:– Grain dust, flour, starch, cocoa, and similar types

of materials

International Electrotechnical Commission (IEC)

• The IEC classification system, used throughout much of the world outside of North America, varies from the traditional NEC Class/Division system in that it recognizes three levels of probability that a flammable concentration of material might be present.

• These levels of probability are known as:– Zone 0, Zone 1, Zone 2

IEC Zone Definitions

• The Class definitions only apply to applications in the U.S.

• The Zone standard classify the types of flammable substances present as such:– Zone 0, Zone 1, and Zone 2 are zones where

hazardous vapors and gases are present– Zone 20, Zone 21, and Zone 22 are zones where

hazardous dusts or fibers are present


• The hazardous location areas are defined by taking into account the different dangers presented by potentially explosive atmospheres. This



This graphic is for illustration purposes only.

IEC Group Definitions

• The explosive characteristics of the air mixtures of gases, vapors, or dusts vary with the specific material involved. Materials have been placed in groups based on their ignition temperatures and explosion pressures. Electrical apparatus for potentially explosive atmospheres is divided into 2 groups per EN 50014:


• Group I — Electrical apparatus for mines susceptible to firedamp (for use underground)

• Group II — Electrical apparatus for places with a potentially explosive atmosphere, other than mines susceptible to firedamp


IEC Ignition Temperature Class

IEC Protective Methods

Markings Explained

Intrinsically Safe Device Markings

Sources of Ignition

1. Arcs and Sparks 2. High Temperatures 3. Electrical Equipment Failure

Arcs and Sparks• Use of electric, non-explosive tools, equipment and motors• Sandblasting• Breaking concrete• Drilling• Chipping, ripping, or cutting by impact• Soldering• Grinding & filing• Carrying cellular phones, pagers, radios, or any other

equipment not labeled as safe for use in hazardous atmospheres.

• Operation internal combustion engines – (portable air compressors, generator, heaters..)

• Metal Tools (shovels, chisels, etc.)

High Temperatures

• Heat-Producing Equipment

• Such as lamps and lighting fixtures

• Cutting Torch• Welding

Electrical Equipment Failure

• Shorting of an Electrical Tool

• Equipment Failure

Equipment Design & Construction

• All equipment must be designed and constructed to be suitable for the specific Hazardous Location Class that it will be installed in.

Equipment Design & Construction Cont…

• Tools and Equipment we use will be primarily Class I Division I or Class I Division II

• Tools and equipment may be constructed for either Class I Division I or Class I Division II or not rated at all.

Devices that are not rated…• Are Mag’s flashlights “explosion-proof” or “intrinsically

safe”? – Mag Instrument’s flashlights are general-purpose

flashlights. We have not had them tested or certified as safe for special-purpose uses under any “intrinsically safe” standard or under any of the various “explosion-proof” standards that exist. We do not label our flashlights “explosion proof” or “intrinsically safe” and we do not warrant that they would be safe if put to such a special-purpose use.

– Mag Flashlight Official Website


• Non-sparking hand tools we may use

LEL Bottle Rocket


• Brass shovel


• Measuring tools

Review of Three Types of Hazardous Locations

• Class I – gas or vapor

• Class II– combustible dust

• Class III– fibers and flyings

ReviewKinds of Conditions

• Division 1– Normal Conditions

• Division 2– Abnormal Conditions

Classify The Following

• Natural Gas Well Pad (under normal operations)– Class I Division II

• Natural Gas Well Pad (during well servicing activity)– Class I Division I

• Compressor Station – Class I Division II

• Pipeline Pigging Operations– Class I Division I


Class I Division I


Class I Division I

Questions

Atmospheric Monitoring

Definitions

• Hazardous atmosphere– Atmosphere that may expose employees to risk of

death, incapacitation, impairment of ability to self-rescue (i.e. unaided escape from permit space), injury or acute illness from one or more following causes:

• Flammable gas, vapor or mist in excess of 10% of Lower Flammable Limit (LFL)

Definitions

• Hazardous atmosphere– Airborne combustible dust at concentration that

meets or exceeds LFL– Note: concentration may be approximated as

condition in which dust obscures vision at distance of 5 ft or less

– Atmospheric oxygen concentration <19.5% or >23.5%

Definitions

• Hazardous atmosphere– Atmospheric concentration of any substance for

which dose or PEL could result in employee exposure in excess of dose or PEL

• Note: atmospheric concentration of any substance not capable of causing death, incapacitation, impairment of ability to self-rescue, injury or acute illness due to health effects is not covered

Definitions

• Hazardous atmosphere– Any other atmospheric condition that is IDLH– Note: for air contaminants which OSHA has no

dose or PEL, other sources of information, such as MSDSs that comply with 29 CFR 1910.1200, published information & internal documents can provide guidance in establishing acceptable atmospheric conditions

Definitions

• Immediately Dangerous to Life and Health (IDLH)– Condition that poses immediate or delayed threat

to life or cause irreversible adverse health effects or interfere with individual’s ability to escape unaided from permit space

Testing Protocol

• Before employee enters space, internal atmosphere shall be tested, with calibrated direct-reading instrument, for following conditions in order given– Oxygen content– Flammable gases & vapors– Potential toxic air contaminants


• Oxygen– An atmospheric

oxygen concentration below 19.5% (deficiency), or above 23.5% (enriched)


– Flammable gases & vapors• LEL / UEL• % LEL verses % Volume


• Toxic Gases– An atmosphere concentration of any toxic

compound above the permissible exposure limit established by OSHA, NIOSH or ACGIH


• Carbon Monoxide


• Hydrogen Sulfide


• Gas Monitor Alarms• Provide an alarm at the appropriate exposure

limits for the monitored substance(s). Real-Time concentrationShort-Term Exposure Limit (STEL)Time-Weighted Average (TWA)


• Types of Monitor Sensors– Electrochemical (EC) Oxygen Sensors– Catalytic (CAT) Oxidation Sensors– Infrared (IR) Sensors– Photo Ionization Detector (PID) Sensors


• Other Sensor Characteristics to Consider based on your workplace needs may include:

➤ Monitor design that allows gas intake from both the top and front of the monitor.

➤ The contaminant concentration measurement range, minimum detection limit and resolution.

➤ Environmental conditions during use (range of temperature, pressure and relative humidity).

➤ Sensor replacement procedures (on site versus manufacturer replacement).

➤ Warranty period.


• Sensor Issues– Sensor Drift (CAT)– Zeroing– Saturation– Environmental Exposure– Battery Life


• Maintenance– As part of good operating practices, gas monitors

should be bump tested every day before use. A bump test is defined as a qualitative function check where a challenge gas is passed over the sensor(s) at a concentration and exposure time sufficient to activate all alarm indicators to present at least their lower alarm setting.


• Docking Stations• Data Log Capabilities & Benefits


• Atmospheric Monitoring Best Practices– Spot Checks vs Continuous Monitoring– Pump vs natural aspirated monitors– Flow rate through hose on pump models– Calibration & Bump Testing

Lightning Safety

• Postpone outdoor activities if thunderstorms are imminent. Lightning can travel 5-10 miles away from the thunderstorm and strike the ground with blue sky overhead. The storm doesn’t have to be overhead in order for you to be struck. 15 miles is SWN’s weather action plan shut down

• Move to a sturdy shelter or vehicle. Do not take shelter in a small shed, under isolated trees, or in a convertible-top vehicle. Stay away from tall objects such as trees or towers or poles.

• If in your vehicle when lightning strikes – don’t touch a metal surface. You are safer in a vehicle than being outdoors.

Date post:	14-Apr-2017
Category:	Environment
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