MSA Gas Detection Handbook

M S A G a s D e t e c t i o n H a n d b o o k

The MSA Gas Detection Handbook is designed to introduce users to key termsand concepts in gas detection and to serve as a quick reference manual forinformation such as specific gas properties, exposure limits and other data.

The Handbook contains:

• a glossary of essential gas detection terms and abbreviations.

• a summary of key principles in combustible and toxic gas monitoring.

• reference data—including physical properties and exposure limits—for the most commonly monitored gases, in industrial and variousother environments.

• a comparison of the most widely-used gas detection technologies.

• a table indicating the gas hazards common to specific applicationswithin major industries.

• a summary of key gas detection instrumentation approvalsinformation, including hazardous locations classification.

• MSA’s exclusive Sensor Placement Guide, detailing important factors to take into consideration when determining optimum gas sensor placement.

Note to User:

Mine Safety Appliances Company (“MSA”) makes no warranties,understandings or representations, whether expressed, implied or statutoryregarding this gas detection handbook. MSA specifically disclaims anywarranty for merchantability or fitness for a particular purpose. In no eventshall MSA, or anyone else who has been involved in the creation, productionor delivery of this handbook be liable for any direct, indirect, special,incidental or consequential damages arising out of the use of or inability touse this handbook or for any claim by any other party.


Table of Contents

Section 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7Gas Detection Terms & Abbreviations

Section 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15Gas Monitoring CategoriesCombustible AtmospheresToxic Atmospheres Oxygen Deficiency/ Enrichment AtmospheresGas Detection TechnologiesGas Sampling

Section 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49Gas Information Table

Section 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71A Selection of Gases Typically Associated with Various Industries

Section 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103ApprovalsHazardous Locations Classification

CLASS I: Flammable Gases, Vapors or Liquids

CLASS II: Combustible DustsCLASS III: Ignitable Fibers & Flyings

ATEX Explosive AtmospheresA Selection of Recognized Testing LaboratoriesSystem Installation

Section 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .131Sensor Placement Guide

Section 7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .139Calibration

Section 8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .142Resources

Section 1Gas Detection Terms & Abbreviations


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Gas Detection Terms & Abbreviations

ACGIH - American Conference of Governmental Industrial Hygienists.

Alarm Set Point - The selected gas concentration level at which an alarm is activated.

Ambient air - Surrounding air to which the sensing element is normally exposedin its installed position.

Asphyxiant - A substance that impairs normal breathing by displacing oxygen.

Atmosphere - The total gases, vapors, mists and fumes present in a specific location.

Autoignition Temperature [also “spontaneous ignition temperature” (SIT) - Theminimum temperature at which a combustible substance (gas, vapor, liquid or solid) will ignite and sustain combustion under its own heat energy.

Bump Check (Functional Test) - Procedure used to verify the response of aninstrument which does not include actual adjustment. (also known as “Span Check”)

Calibration - Procedure by which the performance of a detector is verified tomaximize the accuracy of its readings. A calibration is performed by: (1)comparing the instrument with a known standard, and (2) adjusting theinstrument reading to match the standard.

Calibration Gas (also “Span Gas”) - A known concentration of gas that is usedto set instrument accuracy.

Ceiling - The maximum gas concentration to which a worker may be exposed.

Combustible Gas* - A gas that is capable of igniting and burning.

Combustion - The rapid oxidation of a substance involving heat and light.

Confined Space - An area that is large enough for an employee to bodily enterand perform work, has limited or restricted areas of entry or exit, and is notdesigned for continuous human occupancy.

* Any material that will burn at any temperature is considered to be“combustible”, so this term covers all such materials, regardless of how easilythey ignite. The term “flammable” specifically refers to those combustible gasesthat ignite easily and burn rapidly.


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Controller - The part of a gas detector that provides centralized processing ofthe gas signal. The controller receives and responds to the electrical signalfrom the sensor to output an indication, alarm or other function.

Cross Sensitivity - The predictable response of a detector to compounds otherthan the target gas.

Dew Point - The temperature at which a gas (air) is saturated with acondensable component.

Diffusion - Process by which particles spread from regions of higherconcentration to regions of lesser concentration as a result of randommolecular movement. Also used to describe the process by which theatmosphere being monitored is transported to the gas-sensing element bynatural random molecular movement.

Electrochemical Sensor - A sensor that uses an electrochemical reaction toprovide an electrical output proportional to the measured gas concentration.

Explosion - Rapid uncontrolled combustion process which generates a hightemperature, a large volume of gas, and a pressure or shock wave.

Explosionproof (XP) - Method of protection in which an explosion in a hazardous location is prevented by containing any combustion within thedevice, and thereby, preventing it from spreading into the atmospheresurrounding the enclosure.

Explosive (or “Flammable”) Limits - Though a flammable liquid can supportcombustion at its flash point temperature, to sustain it requires the vaporconcentration to be between two specific levels, or “flammable limits”, the lower flammable limit and the upper flammable limit. (see below) Any gas or vapor concentration that falls between these two limits is in theflammable range.

• Lower Explosive (or “Flammable”) Limit (LEL) - the minimumconcentration of a vapor (usually expressed as the percentage ofmaterial in air) required to sustain a fire.

• Upper Explosive (or “Flammable”) Limit (UEL) - the maximumconcentration of a vapor (usually expressed as the percentage ofmaterial in air) beyond which a fire cannot be sustained, as theamount of oxygen would be insufficient to continue the fire.


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Explosive (or “Flammable”) Range - The range that encompasses any gas orvapor concentration between the substance’s lower explosive limit and upperexplosive limit, and is therefore capable of sustaining combustion.

Flammable Gas* - This term applies to a special group of combustible gasesthat ignite easily and burn rapidly.

Flash Point - The minimum temperature at which a liquid gives off enough vaporto form an ignitable mixture with air (reaching 100% LEL).

Gas - A state of matter characterized by very low density and viscosity (relativeto liquids and solids), comparatively great expansion and contraction withchanges in pressure and temperature, ability to diffuse readily into other gases,and ability to occupy with almost complete uniformity the whole of anycontainer. (Often used interchangeably with “vapor”.)

Gas Detection Instrument - A device composed of electrical, optical,mechanical or chemical components that senses and responds to the presenceof gas mixtures.

General Purpose (GP) Enclosure - An enclosure intended for indoor use in non-hazardous rated areas, primarily to prevent accidental contact of personnelwith the enclosed equipment in areas where unusual service conditions do not exist.

Hazardous Atmosphere - (As defined by OSHA 29 CFR 1910.146) An atmospherein which workers are exposed to the risk of death, injury, incapacitation orillness.

Humidity - The amount of water vapor present in the atmosphere.

IDLH (Immediately Dangerous to Life and Health)**The maximum concentration level of a substance (gas) from which a workercould escape within 30 minutes without developing immediate, severe orirreversible health effects, or other escape-impairing symptoms. IDLH levels aremeasured in ppm (parts per million).**As defined by NIOSH (National Institute for Occupational Safety and Health).

* Any material that will burn at any temperature is considered to be“combustible”, so this term covers all such materials, regardless of how easily they ignite. The term “flammable” specifically refers to those combustiblegases that ignite easily and burn rapidly.


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Interferent - Any gas other than the target gas that will cause a response from agas sensor.

Intrinsic Safety (IS) - A method of protection in which an explosion is preventedthrough an electrical design using energy storage devices in which thepossibility of ignition is eliminated.

LEL (Lower Explosive Limit) - (see “Explosive Limits”)

Monitor - An instrument used to continuously measure a condition that must bekept within specific limits.

NIOSH - National Institute for Occupational Safety and Health.

OSHA - United States Department of Labor Occupational Safety and HealthAdministration.

Oxygen Deficient Atmosphere - An atmosphere containing less than 19.5%oxygen by volume. (Possesses a risk of insufficient oxygen for breathing.)

Oxygen Enriched Atmosphere - An atmosphere containing more than 20.8%oxygen by volume. (Possesses an increased risk of explosion.)

PEL (Permissible Exposure Limit) - An airborne concentration of contaminantthat most workers can be exposed to repeatedly in a normal 8- hour day, in a 40-hour week, without adverse health effects. PEL levels are measured in ppm(parts per million) and are established by OSHA.

Permanent (or Fixed) Gas Monitor - A gas monitor that is permanently installedin a location.

PPM (Parts Per Million) - The most common unit of measurement for toxicgases. A “10,000 parts per million” gas concentration level equals a 1% byvolume exposure.

Relative Density - The density of a gas as compared to that of another gas(typically air). In gas detection, relative density is used to assist in determiningoptimum sensor placement. If the relative density of the monitored gas is lessthan 1, then it will tend to rise in air; if the relative density is greater than 1 thenit will tend to sink in air and accumulate at ground level.


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Sensor - The part of a gas detector that converts the presence of a gas or vaporinto a measurable signal.

Smart Sensor - Sensor that contains a microprocessor, allowing it to recorddata, communicate with other devices or control devices such as relays.

Span Check - (see “Bump Check”).

STEL - Short-term exposure limit ( See “TLV - STEL”).

TLV® (Threshold Limit Value)* - Refers to the airborne concentration ofsubstances and represents conditions under which it is believed that nearly allworkers may be repeatedly exposed day after day without adverse healtheffects.* As defined by the ACGIH (American Conference of Governmental IndustrialHygienists).

There are three categories of TLVs:

TLV - TWA (Time Weighted Average) - This is the average amount ofgas that a worker can be repeatedly exposed to in a normal 8-hourday, in a 40-hour week, without adverse health effects.

TLV - STEL (Short Term Exposure Limit) -The gas concentration thatmost workers can be continuously exposed to for a 15-minute timeperiod without suffering adverse health affects that would impair self-rescue or worker safety. This limit should not be repeated more than 4 times per day and there should be at least 60 minutes betweenindividual STEL exposure periods.

TLV - C (Ceiling) - The highest gas concentration to which workersmay be exposed. Ceiling TLVs should never be exceeded and theytake precedence over all TWAs and STELs.

Toxic Atmosphere - An atmosphere in which the concentration of gases, dusts,vapors or mists exceeds the permissible exposure limit (PEL).

Toxic Gas or Vapor - Substance that causes illness or death when inhaled orabsorbed by the body in relatively small quantities.


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True Zero - A reading indicating that no amount of target gas is present in thesample. Also known as “baseline”.

TWA - Time-weighted average (see “TLV-TWA”).

UEL (Upper Explosive Limit) - (see “Explosive Limits”).

Vapor - Often used interchangeably with “gas”; vapor is generally used to referto the gaseous phase of a substance that generally exists as a liquid or solid atroom temperature, while “gas” is more commonly used to refer to a substancethat generally exists in the gaseous phase at room temperature.

Vapor Density - the weight of a volume of pure gas or vapor compared to that ofan equal volume of air at the same temperature and pressure. A vapor densityof less than 1 indicates that the gas or vapor is lighter than air and will tend torise. A vapor density of greater than 1 indicates that the vapor is heavier thanair and will tend to accumulate closer to the ground. It may also move asignificant distance at these low levels to a source of ignition and then flashback to the original location once ignited. When using vapor density todetermine optimum sensor placement, other factors such as air flow patternsand temperature gradients should also be considered.

Vapor Pressure - The pressure exerted when a solid or liquid is in equilibriumwith its own vapor. Vapor pressure is directly related to temperature. In gasdetection, this is significant because the higher the vapor pressure of asubstance, the greater the amount of it that will be present in vapor phase at agiven temperature, and thus a greater degree of gas hazard exists.

Zero Check - Check performed to verify that the instrument reads true zero.

Zero Gas - A cylinder of gas that is free of the gas of interest and interferents. It is used to properly zero an instrument’s base line.

Section 2Gas Monitoring CategoriesCombustible AtmospheresToxic AtmospheresOxygen Deficiency Enrichment AtmospheresGas Detection TechnologiesGas Sampling


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The Four Main Types of Gas HazardsThe following table summarizes the four main reasons why gas monitoring is performed:

Type of Monitoring The Purpose The Hazard Possible Source

of Hazard

Personalprotection

Worker safety Toxic gases Leaks, fugitiveemissions,industrial processdefects

Explosive Worker andfacility safety

Explosions Presence ofcombustiblegases/vapors dueto leaks, industrialprocess defects

Environmental Environmentalsafety

Environmentaldegradation

Oil leaks intosewers or lakes,Acid gasemissions

Industrial process Process control Malfunction of the process

Possible fault orother processerror


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Gas Monitoring CategoriesGas Monitoring Categories:

1. Combustible/ Flammable Gas• Explosive hazard.

• To avoid an explosion, atmospheric levels must be maintained belowthe lower explosive limit (LEL) for each gas, or purged of oxygen.

• Generally measured as 0-100% of the lower explosive limit or in partper million range.

• Combustible gas monitors are designed to alarm before a potentialexplosive condition occurs.

2. Toxic/ Irritant Gases• Hazardous to human health; worker exposure must be monitored.

• Typically measured in the part per million (ppm) range.

• Toxic gas monitors are designed to alert workers before the gas level reaches a harmful concentration.

• Some toxic gas monitors can calculate the average exposure overtime, providing short-term exposure limit (STEL) and time-weightedaverage (TWA) readings.

3. Oxygen• Atmospheres containing too little oxygen (less than 19.5% oxygen by

volume) are considered “oxygen deficient” and interfere with normalhuman respiration.

• Atmospheres containing too much oxygen (more than 25% oxygen byvolume) are considered “oxygen enriched” and possess an increasedrisk of explosion.

• Measured in the percent volume range (normal oxygen percentage inair is 20.8% by volume at sea level).

• Oxygen monitors are generally set to alarm if the atmosphere containseither too little or too much oxygen.


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Combustible AtmospheresCombustible AtmospheresIn order for a flame to exist, three conditions must be met. There must be:

• A source of fuel (e.g. methane or gasoline vapors).

• Enough oxygen (greater than 10-15%) to oxidize or burn the fuel.

• A source of heat (ignition) to start the process.

Examples of Heat and Ignition Sources

• Open flames such as those from lighters, burners, matches andwelding torches are the most common sources of ignition.

• Radiation in the form of sunlight or coming from hot surfaces.

• Sparks from various sources such as the switching on or off of electricappliances, removing plugs, static electricity or switching relays.


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Combustible AtmospheresCombustible Atmosphere FactorsVapor vs. GasThough often used interchangeably, the terms “vapor” and “gas” are notidentical. The term “vapor” is used to refer to a substance that, though presentin the gaseous phase, generally exists as a liquid or solid at room temperature.When we say that a liquid or solid substance is burning, it is actually its vaporsthat burn. “Gas” refers to a substance that generally exists in the gaseousphase at room temperature.

Vapor Pressure and Boiling PointVapor pressure is the pressure exerted when a solid or liquid is in equilibriumwith its own vapor. It is directly related to temperature. An example of vaporpressure is the pressure developed by the vapor of a liquid in a partially-filledclosed container. Depending on temperature, the vapor pressure will increaseup to a certain threshold. When this threshold is reached, the space isconsidered to be saturated.

The vapor pressure and boiling point of a chemical determine how much of it is likely to become airborne. Low vapor pressure means there are lessmolecules of the substance to ignite, so there is generally less of a hazardpresent. This also means that there are less molecules to sense, which maymake detection more challenging and require higher-sensitivity instrumentation.With higher vapor pressure and a lower boiling point, there is a greaterlikelihood of evaporation. If containers of chemicals with such properties areleft open, or if they’re allowed to spread over large surfaces, they are likely tocause greater hazards.

FlashpointA flammable material will not give off an amount of gas or vapor sufficient tostart a fire until it is heated to its flashpoint. Flashpoint is defined as the lowesttemperature at which a liquid produces sufficient vapor to produce a flame. Ifthe temperature is below this point, the liquid will not produce enough vapor toignite. If the flashpoint is reached and an external source of ignition such as aspark is provided, the material will catch fire. The National Fire ProtectionAgency’s NFPA’s document NFPA-325M, Fire Hazard Properties of FlammableLiquids, Gases and Volatile Solvents, lists the flashpoints of many commonsubstances. See www.nfpa.org.


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Combustible AtmospheresFlash points are significant because they give an indication of the degree ofhazard presented by a flammable liquid. Generally, the lower the flash point, theeasier it is for flammable fuel-air mixtures to form, and thus the greater hazard.

Autoignition TemperatureIf heated to a certain point—the spontaneous ignition (or “autoignition”)temperature—most flammable chemicals can spontaneously ignite under itsown heat energy, without an external source of ignition.


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Combustible AtmospheresVapor DensityVapor density is the weight ratio of a volume of flammable vapor compared toan equal volume of air. Most flammable vapors are heavier than air so theygravitate toward the ground, settling in low areas. A gas or vapor with a vapordensity greater than 1 may travel at low levels to find a source of ignition (e.g.hexane, which has a 3.0 vapor density); a gas or vapor with a vapor density lessthan 1 will tend to rise (e.g. methane, which has a 0.6 vapor density). Vapordensity is important to consider when determining optimum sensor placementbecause it helps predict where the gas or vapor is most likely to accumulate ina room or area.

Explosive LimitsTo produce a flame, a sufficient amount of gas or vapor must exist. But toomuch gas can displace the oxygen in an area and fail to support combustion.Because of this, there are limits at both low-end and high-end gas concen-trations where combustion can occur. These limits are known as the LowerExplosive Limit (LEL) and the Upper Explosive Limit (UEL). They are also referredto as the Lower Flammability Limit (LFL) and the Upper Flammability Limit (UFL).

To sustain combustion, the atmosphere must contain the correct mix of fuel andoxygen (air). The LEL indicates the lowest quantity of gas which must be presentfor combustion and the UEL indicates the maximum quantity of gas. The actualLEL level for different gases may vary widely and are measured as a percent byvolume in air. Gas LELs and UELs can be found in NFPA 325.

LELs are typically 1.4% to 5% by volume. As temperature increases, less energyis required to ignite a fire and the percent gas by volume required to reach 100%LEL decreases, increasing the hazard. An environment containing enrichedoxygen levels raises the UEL of a gas, as well as its rate and intensity ofpropagation. Since mixtures of multiple gases add complexity, their exact LELmust be determined by testing.

Most combustible gas instruments measure in the LEL range and display gasreadings as a percentage of the LEL. For example: a 50% LEL reading means thesampled gas mixture contains one-half of the amount of gas necessary tosupport combustion.


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Combustible Atmospheres

Any gas or vapor concentration that falls between these two limits is in theflammable (explosive) range. Different substances have different flammablerange widths — some are very wide and some are narrower. Those with awider range are generally more hazardous since a larger amount ofconcentration levels can be ignited.

Atmospheres in which the gas concentration level is below the LEL (insufficientfuel to ignite) are referred to as too “lean” to burn; those in which the gas levelis above the UEL (insufficient oxygen to ignite) are too “rich” to burn.

Gas Type 100% LEL UEL

Methane 5.0% gas by volume 15.0% gas by volume

Hydrogen 4.0% gas by volume 75.0% gas by volume

Propane 2.1% gas by volume 9.5% gas by volume

Acetylene 2.5% gas by volume 100% gas by volume


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Toxic AtmospheresToxic Gas MonitoringA toxic gas is one which is capable of causing damage to living tissue,impairment of the central nervous system, severe illness or—in extremecases—death, when ingested, inhaled or absorbed by the skin or eyes. Theamounts required to produce these results vary widely with the nature of thesubstance and exposure time. “Acute” toxicity refers to exposure of shortduration, such as a single brief exposure. “Chronic” toxicity refers to exposureof long duration, such as repeated or prolonged exposures.

Toxic gas monitoring is important because some substances can’t be seen orsmelled and have no immediate effects. Thus the recognition of a gas hazard viaa worker’s senses often comes too late, after concentrations have reachedharmful levels.

The toxic effects of gases range from generally harmless to highly toxic. Someare life-threatening at even short, low-level exposures, while others arehazardous only upon multiple exposures at higher concentrations. The degreeof hazard that a substance poses to a worker depends upon several factorswhich include the gas concentration level and the duration of exposure.

Exposure LimitsThe American Conference of Governmental Industrial Hygienists (ACGIH)publishes an annually revised list of recommended exposure limits for commonindustrial compounds, titled “TLV“s and BEI“s Based on the Documentation ofthe Threshold Limit Values for Chemical Substances and Physical Agents andBiological Exposure Indices”. (To order a copy, see www.acgih.org). ACGIHdeveloped the concept of Threshold Limit Value“ (TLV), which is defined as theairborne concentration of a contaminant to which it is believed that almost allworkers may be repeatedly exposed, day after day, over a working lifetimewithout developing adverse effects. These values are based on a combinationof industrial experience and human and animal research.

Time Weighted Averages (TWAs)TLVs are generally formulated as 8-hour time-weighted averages. Theaveraging aspect enables excursions above the prescribed limit as long as theyare offset by periods of exposure below the TLV.


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Toxic AtmospheresShort-Term Exposure Limits (STELs)Short-term exposure limits are concentrations above the 8-hour average towhich workers may be exposed for short periods of time without harmfuleffects. (If the concentration is high enough, even a one-time exposure canproduce harmful health effects.) STELs are used to govern situations in which aworker is exposed to a high gas concentration, but only for a short period oftime. They are defined as 15-minute time-weighted averages that are not to beexceeded even if the 8-hour TWA is below the TLV.

Ceiling ConcentrationsFor some toxic gases, a single exposure exceeding the TLV may be hazardousto worker health. In these cases, ceiling concentrations are used to indicatelevels that are never to be exceeded.

Permissible Exposure Limits (PELs)PELs are enforced by the Occupational Safety and Health Administration(OSHA). Part 29 of the Code of Federal Regulations (CFR) Section 1910.1000contains these standards, which are similar to ACGIH TLVs except that they arelegally enforceable rather than simply recommendations. However, the mostaccurate PELs are listed in the associated Material Safety Data Sheets (MSDS).

Immediately Dangerous to Life and Health (IDLH)The National Institute for Occupational Safety and Health (NIOSH) defines anIDLH exposure condition atmosphere as one that poses a threat of exposure toairborne contaminants when that exposure is likely to cause death or immediateor delayed permanent adverse health effects or prevent escape from such anenvironment. Since IDLH values exist to ensure that a worker can escape froma hazardous environment in the event of failure of respiratory protectionequipment, they are primarily used to determine appropriate respiratoryselection in compliance with OSHA standards.


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Toxic AtmospheresWeb resources:

ACGIH: http://www.acgih.org/TLV

OSHA: http://www.osha.gov

NIOSH: http://www.cdc.gov/niosh/homepage.html

Gas detection systems are used to monitor toxic gases in primarily two types ofmonitoring applications:

1. Ambient air monitoring (includes leak monitoring)

• low-level gas detection for worker safety

• to reduce leakage of expensive compounds (e.g., refrigerants)

2. Process monitoring

• to monitor levels of compounds used in chemical synthesis processes (e.g., in the plastics, rubber, leather and food industries)

• from low ppm levels to high % by volume levels

For toxic gas monitoring, electrochemical, metal oxide semiconductor (solidstate), infrared and photoionization are the sensing technologies mostcommonly used.


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Oxygen Deficiency/EnrichmentOxygen DeficiencyNormal ambient air contains an oxygen concentration of 20.8% by volume.When the oxygen level dips below 19.5% of the total atmosphere, the area isconsidered oxygen deficient. In oxygen-deficient atmospheres, life-supportingoxygen may be displaced by other gases, such as carbon dioxide. This results inan atmosphere that can be dangerous or fatal when inhaled. Oxygen deficiencymay also be caused by rust, corrosion, fermentation or other forms of oxidationthat consume oxygen. As materials decompose, oxygen is drawn from theatmosphere to fuel the oxidation process.

The impact of oxygen deficiency can be gradual or sudden, depending on theoverall oxygen concentration and the concentration levels of other gases in theatmosphere. Typically, decreasing levels of atmospheric oxygen cause thefollowing physiological symptoms:

Oxygen EnrichmentWhen the oxygen concentration rises above 20.8% by volume, the atmosphereis considered oxygen-enriched and is prone to becoming unstable. As a resultof the higher oxygen level, the likelihood and severity of a flash fire or explosionis significantly increased.

% Oxygen Physiological Effect

19.5 - 16 No visible effect.

16 - 12 Increased breathing rate. Accelerated heartbeat.Impaired attention, thinking and coordination.

14 – 10Faulty judgment and poor muscular coordination.Muscular exertion causing rapid fatigue.Intermittent respiration.

10 – 6Nausea and vomiting. Inability to perform vigorousmovement, or loss of the ability to move.Unconsciousness, followed by death.

Below 6 Difficulty breathing. Convulsive movements. Death in minutes.


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Gas Detection TechnologiesGas Detection Technologies There are a variety of gas detection technologies in use today. Among the mostcommonly employed are:

• Catalytic Bead

• Metal Oxide Semiconductor (also known as “solid state”)

• Point Infrared Short Path

• Open (Long Path) Infrared

• Photoacoustic Infrared

• Electrochemical for Toxic Gas Detection

• Electrochemical for Oxygen Detection

• Thermal Conductivity

• Photoionization

• NDIR

The tables and diagrams on the following pages summarize the operation of each technology.


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Gas Detection Technologies

Technology Catalytic bead

Gas TypeDetected Combustible gas

Principle ofOperation

Uses a catalytic bead to oxidize combustible gas; aWheatstone Bridge converts the resulting change inresistance into a corresponding sensor signal.

Description -Detailed

A wire coil is coated with a catalyst-coated glass or ceramicmaterial, and is electrically heated to a temperature thatallows it to burn (catalyze) the gas being monitored,releasing heat and increasing the temperature of the wire.As the temperature of the wire increases, so does itselectrical resistance. This resistance is measured by aWheatstone Bridge circuit and the resulting measurement isconverted to an electrical signal used by gas detectors. Asecond sensor, the compensator, is used to compensate fortemperature, pressure and humidity.

Readings % LEL

ProsLong life, less sensitive to temperature, humidity, condensationand pressure changes; high accuracy; fast response; monitorsa wide range of combustible gases and vapors in air.

Cons Subject to sensor poisoning; requires air or oxygen; shortenedlife with frequent or continuous exposure to high LELs.


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Typical Catalytic Bead Sensor Operation


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Technology Metal Oxide Semiconductor

Gas TypeDetected Combustible gas; Toxic gas


Made of a metal oxide that changes resistance in response to the presence of a gas; this change is measured andtranslated into a concentration reading.


A semiconducting material (metal oxide) is applied to a non-conducting substance (substrate) between two electrodes.The substrate is heated to a temperature at which thepresence of the gas can cause a reversible change in theconductivity of the semi-conducting material. When no gas ispresent, oxygen is ionized onto the surface and the sensorbecomes semi-conductive; when molecules of the gas ofinterest are present, they replace the oxygen ions,decreasing the resistance between the electrodes. Thischange is measured electrically and is proportional to theconcentration of the gas being measured.

Readings PPM

Pros High sensitivity (detects low concentrations); wide operatingtemperature range; long life.

Cons Non-specific (cross-sensitive to other compounds); nonlinearoutput; sensitive to changes in humidity: subject to poisoning.


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Typical Metal Oxide Semiconductor (Solid State) Sensor Operation

Silicon Chip

Sensor Film

Heater


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Technology Point Infrared Short Path



[Also referred to as Non-Dispersive Infrared (NDIR)];Absorptive IR uses a gas ability to absorb IR radiation. Two gas samples--the gas of interest, and an inert referencegas--are exposed to infrared light. The amount of lighttransmitted through each sample is compared to determinethe concentration of the gas of interest.


Uses an electrically modulated source of infrared energy andtwo detectors that convert the infrared energy into electricalsignals. Each detector is sensitive to a different range ofwavelengths in the infrared portion of the spectrum. Thesource emission is directed through a window in the mainenclosure into an open volume. A mirror may be used at theend of this volume to direct the energy back through thewindow and onto the detectors.

The presence of a combustible gas will reduce the intensityof the source emission reaching the analytical detector, butnot the intensity of emission reaching the reference detector.The microprocessor monitors the ratio of these two signalsand correlates this to a %LEL reading.

Readings % LEL

Pros

High accuracy and selectivity; large measurement range; low maintenance; highly resistant to chemical poisons; doesnot require oxygen or air; span drift potential virtuallyeliminated (no routine calibration required); fail-to-safe.

Compared to open-path IR, provides exact gas level (but at point of detection only).

Cons Not suitable for hydrogen detection.


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Typical Point Infrared Short Path Operation


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Technology Open Path Infrared



Operates similarly to point infrared detectors, except that theIR source is separated from the detector.


Open-path IR monitors expand the concepts of point IRdetection to a gas sampling path of up to 100 meters. Likepoint IR monitors, they utilize a dual beam concept. The"sample" beam is in the infrared wavelength which absorbshydrocarbons, while the second "reference" beam is outsidethis gas absorbing wavelength. The ratio of the two beams iscontinuously compared. When no gas is present, the signalratio is constant; when a gas cloud crosses the beam, thesample signal is absorbed or reduced in proportion to theamount of gas present while the reference beam is not.System calculates the product of the average gasconcentration and the gas cloud width, and readings aregiven in %LEL/meter.

Readings % LEL per meter

Pros

High accuracy and selectivity; large measurement range; low maintenance; highly resistant to chemical poisons; doesnot require oxygen or air; span drift potential virtuallyeliminated (no routine calibration required); fail-to-safe.

Cons

Not suitable for hydrogen detection.

Compared with point IR detection, is not capable of isolating the leak source.

Requires unobstructed path between source and detector.


35

Gas Detection TechnologiesTypical Open Long Path Infrared Operation


36


Technology Photoacoustic Infrared

Gas TypeDetected Combustible gas; Toxic gas


Uses a gases ability to absorb IR radiation and the resulting change in pressure.


The gas sample is exposed to infrared light; as it absorbslight its molecules generate a pressure pulse. The magnitudeof the pressure pulse indicates the gas concentrationpresent.

Readings % LEL, % by volume, PPM, PPB

Pros High sensitivity; linear output; easy to handle; not subject to poisoning; long-term stability.

Cons Not suitable for hydrogen detection.


37

Gas Detection TechnologiesPumped Photoacoustic Infrared Operation

(Diffusion method also available)

Sample gas enters the measuring cell.

The gas is irradiated with pulsed infrared energy.


38


The gas molecules heat and cool as they absorb the infrared energy. The pressurechanges as a result of the heating and cooling of the molecules measured by thedetector. This pressure change is converted into a gas reading.

The gas is exhausted and a fresh sample enters the cell. This sampling processis continuously repeated.


39


Technology Electrochemical Toxic Gases

Gas TypeDetected Toxic gas


Uses an electrochemical reaction to generate a currentproportional to the gas concentration.


Sensor is a chamber containing a gel or electrolyte and two active electrodes--the measuring (sensing/working)electrode (anode) and the counter electrode (cathode). A third electrode (reference) is used to build up a constantvoltage between the anode and the cathode. The gas sampleenters the casing through a membrane; oxidation occurs atthe anode and reduction takes place at the cathode. Whenthe positive ions flow to the cathode and the negative ionsflow to the anode, a current proportional to the gasconcentration is generated.

Readings PPM readings for toxic gases

Pros High sensitivity; linear output; easy to handle.

Cons Limited shelf life; subject to interferents; sensor lifetimeshortened in very dry and very hot environments.


40


Typical Electrochemical Toxic Sensor


41


Technology Electrochemical Oxygen

Gas TypeDetected Oxygen deficiency/ enrichment


Uses an electrochemical reaction to generate a currentproportional to the gas concentration.


Sensor is a chamber containing a gel or electrolyte and twoelectrodes--the measuring (sensing/working) electrode andthe (usually lead) counter/reference electrode. The gassample enters the casing through a membrane; oxidationoccurs at the anode and reduction takes place at thecathode. When the positive ions flow to the cathode and thenegative ions flow to the anode, a current proportional to thegas concentration is generated.

Readings Percent volume readings for oxygen

Pros High sensitivity; linear output; easy to handle; not subject to poisoning.

ConsLimited shelf life; subject to interferents; sensor life shortened in very dry and very hot environments, or inenriched O2 applications.


42


Typical Electrochemical Oxygen Sensor


43


Technology Thermal Conductivity

Gas TypeDetected Combustible gas; Toxic gases


Measures the gas sample's ability to transmit heat bycomparing it with a reference gas (usually air).


Two sensors (detecting sensor and compensating sensor)are built into a Wheatstone Bridge. The detecting sensor isexposed to the gas of interest; the compensating sensor isenclosed in a sealed compartment filled with clean air.Exposure to the gas sample causes the detecting sensor tocool, changing the electrical resistance. This change isproportional to the gas concentration. The compensatingsensor is used to verify that the temperature change iscaused by the gas of interest and not by ambienttemperature or other factors.

Readings PPM; up to 100% by volume

Pros Wide measuring range.

Cons

Non-specific (cross-sensitive to other compounds); does not work with gases with thermal conductivities (TCs)close to one (that of air, NH3, CO, NO, O2, N2); gases with TCs of less than one are more difficult to measure; outputsignal not always linear.


44


Typical Thermal Conductivity Sensor


45


Technology Photoionization

Gas TypeDetected Toxic (organic compounds)

Principle ofOperation Uses ionization as the basis of detection.


A photoionization detector (PID) uses an ultraviolet lamp to ionize the compound of interest. Ions are collected on a‘getter’, a current is produced and the concentration of the compound is displayed in parts per million on theinstrument meter.

Readings PPM, sub-ppm

Pros Fast response speed, very low level detection, detects a large number of substances.

Cons More expensive, increased maintenance, requires morefrequent calibration, non-specific, sensitive to humidity.


46


Typical Photoionization Sensor Design


47

Gas SamplingGas SamplingThere are three methods of gas sampling:

• Diffusion Sampling

• Pumped Sampling

• Aspirated Sampling

Diffusion SamplingDiffusion is the natural movement of molecules away from an area of highconcentration to an area of lower concentration. The term “diffusion” denotesthe process by which molecules or other particles intermingle as a result oftheir random thermal motion. Ambient conditions such as temperature, aircurrents and other characteristics affect diffusion.

Advantages:• Most effective placement is at desired sampling point.

• Fast response because no sample transport is required.

• No pumps and/or filters to maintain.

Pumped SamplingPumped sampling uses a pump to pull the sample from a remote location into or through the sensor. With pumped sampling, samples can be gatheredsimultaneously from two or more locations.


48

Gas SamplingConditions Favoring Pumped Sampling:

• Sampling point is too hot/cold.

• Sampling point is difficult to access.

• Heavy vapor present that does not diffuse well by natural forces.

• An application can be converted from an explosionproof (XP) rating toa general purpose (GP) rating through pumped operation. (Flashbackarrestors may be necessary between the sample port and the sensor.)

• Confined Spaces

Aspirated SamplingAspirated sampling uses suction to draw the sample from a remote location intoor through the sensor.

Advantages of Aspirated Sampling Versus Pumped:

• Lower cost

• Reduced maintenance because there are no moving parts

Section 3Gas Information Table


50

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Acet

alde

hyde

Acet

ic a

ldeh

yde

C 2H 4

OHe

avie

rX

-38

4.0

60-

25 [C

]20

02,

000

XX

X17

521

750

Acet

ic A

cid

C 2H 4

O 2He

avie

rX

394.

019

.910

1510

50X

XX

X46

311

811

Acet

ical

dehy

deAc

etal

dehy

deC 2

H 4O

Heav

ier

X-3

84.

060

-25

[C]

200

2,00

0X

XX

175

2175

0

Acet

one

C 3H 6

OHe

avie

rX

-20

2.5

12.8

500

750

1,00

02,

500

XX

XX

465

56

Acet

onitr

ileC 2

H 3N

Heav

ier

X6

3.0

1620

-40

500

XX

XX

524

8273

Acet

ylen

eC 2

H 2Li

ghte

rX

Gas

2.5

100

AA

--

XX

XX

305

-83

Acro

leic

aci

dAc

rylic

aci

dC 3

H 4O 2

Heav

ier

X50

2.0

82

--

-X

XX

438

142

3

Acro

lein

Acry

lald

ehyd

eC 3

H 4O

Heav

ier

X-2

62.

831

-0.

1 [C

]0.

12

XX

XX

220

5221

0

Acry

lald

ehyd

eAc

role

inC 3

H 4O

Heav

ier

X-2

62.

831

-0.

1 [C

]0.

12

XX

XX

220

5221

0

Acry

lic a

cid

Acro

leic

aci

dC 3

H 4O 2

Heav

ier

X50

2.0

82

--

-X

XX

438

142

3

Acry

loni

trile

C 2H 3

NHe

avie

rX

03.

017

2-

285

XX

X48

177

83

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor

Thermal Conductivity

Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


51

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Ally

l alc

ohol

2-pr

open

ylC 3

H 6O

Heav

ier

X21

2.5

180.

5-

220

XX

XX

378

9717

Ally

l Chl

orid

eC 3

H 5Cl

Heav

ier

X-3

22.

911

.11

21

250

XX

392

4529

5

Amm

onia

NH 3

Ligh

ter

XGa

s15

.028

2535

5030

0X

XX

X65

1-3

340

0 @

45°

C

Amyl

ace

tate

, n-

C 7H 1

4O2

Heav

ier

X16

1.1

7.5

--

100

1,00

0X

XX

360

149

Arsi

neAs

H 3He

avie

rX

Gas

5.1

780.

05-

0.05

3X

-62

>760

Benz

eneˆ

C 6H 6

Heav

ier

X-1

11.

37.

10.

52.

510

500

XX

XX

498

8075

Benz

ene

chlo

ride

Chlo

robe

nzen

eC 6

H 5Cl

Heav

ier

X29

1.3

9.6

10-

751,

000

XX

XX

638

132

12

Brom

ine

Br2

Heav

ier

n/a

n/a

n/a

0.1

0.2

0.1

3X

5917

5

Brom

ochl

orod

iflu

orom

etha

neHa

lon

1211

CF2C

lBr

Heav

ier

n/a

n/a

n/a

--

--

XX

X-

3.3

778

Brom

omet

hane

Met

hylb

rom

ide

CH3B

rHe

avie

rX

n/a

10.0

161

-20

[C]

250

[Ca]

XX

XX

537

41,

250

Brom

otrifl

uoro

met

hane

Halo

n 13

01CB

rF3

Heav

ier

n/a

n/a

n/a

1,00

0-

1,00

0-

XX

X-

-58

12,1

53 @

25°C

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


52

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Buta

dien

esC 4

H 10

Heav

ier

X-7

62.

011

.52

(-)1

2,00

0X

XX

X42

0-4

Gas

Buta

ne, n

-C 4

H 10

Heav

ier

XGa

s1.

58.

580

0-

--

XX

XX

287

-1

Buta

nol,

n-Bu

tyl a

lcoh

olC 4

H 10O

Heav

ier

X29

1.4

11.2

20-

100

1,40

0X

XX

X34

311

7

Buta

nol,

sec-

Buty

l alc

ohol

C 4H 1

0OHe

avie

rX

241.

79.

810

0-

150

2,00

0X

XX

X40

594

Buta

none

, 2-

Met

hyle

thyl

keto

neC 4

H 8O

Heav

ier

X-9

1.4

11.4

200

300

200

3,00

0X

XX

X40

480

Buty

l ace

tate

, n-

C 6H 1

2O2

Heav

ier

X22

1.3

7.6

150

200

150

1,70

0X

XX

X42

012

7

Buty

l ace

tate

, sec

-C 6

H 12O

2He

avie

rX

171.

79.

820

0-

200

1,70

0X

XX

X-

112

Buty

l ace

tate

, ter

tC 6

H 12O

2He

avie

rX

221.

5-

200

-20

01,

500

XX

XX

-

Buty

l acr

ylat

e, n

-C 6

H 12O

2He

avie

rX

291.

59.

92

--

-X

XX

X26

712

7

Buty

l alc

ohol

, n-

Buta

nol,

n-C 4

H 10

Heav

ier

X29

1.4

11.2

20-

100

1,40

0X

XX

X34

311

7

Buty

l eth

ylen

ehe

xyle

neHe

xene

, 1-

C 6H 1

2He

avie

rX

-26

1.2

6.9

50-

--

XX

X25

363

308

@ 3

8°C

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


53

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Buty

rald

ehyd

eBu

tyla

ldeh

yde:

buta

nal

C 4H 8

OHe

avie

rX

-22

1.9

12.5

--

--

XX

XX

218

76

Carb

on d

ioxi

deCO

2He

avie

rn/

an/

an/

a5,

000

30,0

005,

000

40,0

00X

XX

-

Carb

on d

isul

fide

CS2

Heav

ier

X-3

01.

350

10-

2050

0X

9046

300

Carb

on m

onox

ide

COSl

ight

ly li

ghte

rX

Gas

12.0

7525

-50

1,20

0X

XX

XX

609

-192

>760

Carb

on te

trach

lorid

eTe

trach

loro

met

hane

CCl 4

Heav

ier

n/a

n/a

n/a

510

1020

0X

X-

7791

Carb

onyl

chl

orid

ePh

osge

neCO

Cl2

Heav

ier

n/a

n/a

n/a

0.1

-0

2X

X-

856

8 @

0°C

Chlo

rine

Cl2

Heav

ier

Gas

-n/

a0.

51

1 [C

]10

X-

-34

Gas

Chlo

rine

diox

ide

ClO 2

Heav

ier

n/a

n/a

n/a

0.1

0.3

0.1

5X

-

Chlo

robe

nzen

eBe

nzen

e ch

lorid

eC 6

H 5Cl

Heav

ier

X29

1.3

9.6

10-

751,

000

XX

X63

813

212

Chlo

roet

hane

Ethy

l chl

orid

eC 2

H 5Cl

Heav

ier

X-5

03.

815

.410

0-

1,00

03,

800

XX

X51

912

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


54

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Chlo

rofo

rmTr

ichl

orom

etha

neCH

Cl3

Heav

ier

n/a

n/a

n/a

10-

50 [C

]50

0X

X-

6216

0

Chlo

rom

etha

neM

ethy

l chl

orid

eCH

3Cl

Heav

ier

XGa

s-5

017

.450

100

100

2,00

0X

XX

632

-24

Cum

ene

Isop

ropy

lenz

ene

C 9H 1

2He

avie

rX

330.

96.

550

-50

500

XX

XX

425

152

3.2

Cycl

ohex

ane

C 6H 1

2He

avie

rX

-20

1.3

810

0-

300

1,30

0X

XX

X24

582

Cycl

ohex

anon

eC 6

H 10O

Heav

ier

X43

1.1

9.4

25-

5070

0X

XX

X42

015

6

Cycl

opet

ane

C 5H 1

0He

avie

rX

-37

1.1

8.7

600

--

-X

XX

X36

149

Diac

eton

e al

coho

lDi

acet

one

C 6H 1

2O2

Heav

ier

X58

1.8

6.9

50-

501,

800

XX

XX

603

164

Dibo

rane

Boro

etha

neB 2

H 6Sl

ight

ly h

eavi

erX

-90

0.8

980.

1-

0.1

15X

38-5

2-9

322

4 @

112

°C

Dich

loro

benz

ene,

o-

C 6H 4

Cl2

Heav

ier

X66

2.2

9.2

2550

50 [C

]20

0X

XX

X64

818

01.

2

Dich

loro

etha

ne .

1,1-

Ethy

liden

e di

chlo

ride

C 2H 4

Cl2

Heav

ier

X-1

75.

411

.410

0-

100

3,00

0X

XX

X45

857

-59

Dich

loro

etha

ne .1

,2-

Ethy

len

dich

lorid

eC 2

H 4Cl

2He

avie

rX

136.

215

.910

-50

50 [C

]X

XX

X41

384

100

@ 2

9°C

Diet

hyl e

ther

Ethy

l eth

erC 4

H 10O

Heav

ier

X-4

51.

936

400

500

400

1,90

0X

XX

X16

035

442

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


55

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Diet

hyl k

eton

eDE

KC 5

H 10O

Heav

ier

X12

1.6

6.4

200

300

--

XX

XX

450

103

Diet

hyla

min

eDi

etha

min

eC 4

H 11N

Heav

ier

X-2

81.

810

.15

1525

200

XX

XX

312

5619

4

Diet

hylb

enze

neDo

wth

erm

JC 1

0H14

Heav

ier

X55

--

--

--

XX

380

181

0.75

Diis

opro

pyla

min

eC 6

H 15N

Heav

ier

X-6

0.8

7.1

5-

520

0X

XX

X31

684

60

Diflu

orom

etha

neHF

C-32

CH2F

2He

avie

rX

n/a

12.7

33.4

--

--

XX

X64

7-5

211

,377

@

21°

C

Dim

ethy

l ace

tam

ide

C 4H 9

NO

Heav

ier

X70

1.8

11.5

10-

1030

0X

XX

X49

016

5

Dim

ethy

l eth

erDM

EC 2

H 6O

Heav

ier

XGa

s3.

427

--

--

XX

XX

350

-24

1, 4

Dim

ethy

lam

ine

DMA

C 2H 7

NHe

avie

rX

Gas

2.8

14.4

515

1050

0X

XX

X43

07

1500

@25

°C

Dim

ethy

leth

ylam

ine

C 2H 1

1NHe

avie

rX

-45

0.9

11.2

--

--

XX

X19

036

-

Dim

ethy

lform

amid

eDM

FC 3

H 7N

OHe

avie

rX

572.

215

.210

-10

500

XX

X44

515

3

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


56

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Dim

ethy

lsul

foxi

deC 2

H 6SO

942.

642

--

--

XX

X21

518

9

Diox

ane

Diet

hyle

ne d

ioxi

deC 4

H 8O 2

Heav

ier

X12

2.0

22-

-10

050

0X

XX

X18

010

129

Dow

ther

m J

Diet

hylb

enze

neC 1

0H14

Heav

ier

X55

--

--

--

XX

380

181

0.75

Epic

hlor

ohyd

rinC 3

H 5OC

lHe

avie

rX

313.

821

0.5

-5

75X

XX

X41

111

613

Etha

neC 2

H 6Sl

ight

ly h

eavi

erX

Gas

3.0

12.5

(15.

5)A

A-

AX

XX

X47

2-8

9

Ethe

neEt

hyle

neC 2

H 4Sl

ight

ly li

ghte

rX

Gas

2.7

3.6

AA

--

XX

XX

490

-104

Etho

xyet

hano

l, 2-

Cello

solv

eC 4

H 10O

2He

avie

rX

431.

715

.65

-20

050

0X

XX

X23

513

5

Ethy

l ace

tate

C 4H 8

O 2He

avie

rX

-42.

011

.540

0-

400

2,00

0X

XX

X42

777

Ethy

l acr

ylat

eC 5

H 8O 2

Heav

ier

X9

1.4

145

1525

300

[Ca]

XX

XX

372

100

31

Ethy

l alc

ohol

Etha

nol

C 2H 6

OHe

avie

rX

123.

319

1,00

0-

1,00

03,

300

XX

XX

363

78

Ethy

lben

zene

C 8H 1

0He

avie

rX

211.

06.

710

012

510

080

0X

XX

X43

213

67

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


57

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Ethy

l chl

orid

eCh

loro

etha

neC 2

H 5Cl

Heav

ier

X-5

03.

815

.410

0-

1,00

03,

800

XX

XX

519

12

Ethy

l eth

erDi

ethy

l eth

erC 4

H 10O

Heav

ier

X-4

51.

936

400

500

400

1,90

0X

XX

X16

035

442

Ethy

lene

Ethe

neC 2

H 4Sl

ight

ly li

ghte

rX

Gas

2.7

3.6

AA

--

XX

XX

490

-104

Ethy

lene

dich

lorid

e1,

2di

chlo

roet

hyle

neC 2

H 4Cl

2He

avie

rX

136.

215

.910

-50

50 [C

a]X

XX

X41

384

100

@29

°C

Ethy

lene

gly

col

C 2H 6

O 2He

avie

rX

111

3.2

15.3

-10

0m

g/m

3-

-X

398

197

Ethy

lene

oxi

deEt

OC 2

H 4O

Heav

ier

X-2

03.

010

01

-1

800

[Ca]

XX

XX

429

111,

095

Ethy

liden

edi

chlo

ride

Dich

loro

etha

ne,

1, 1

-C 2

H 3Cl

2He

avie

rX

-17

5.4

11.4

100

-10

03,

000

XX

XX

458

57-5

9

Fluo

rine

F 2He

avie

rn/

an/

an/

a1

20.

125

XX

X42

9-1

88

Furfu

ral

Furfu

rol

C 5H 4

O 2He

avie

rX

602.

119

.32

-5

100

XX

X31

616

22

Gaso

line

Hept

ane,

Hex

ane

-X

-42

1.4

7.6

300

500

-[C

a]X

XX

X

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


58

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Halo

n 12

11Br

omoc

hlor

odi-

fluor

omet

hane

CF2C

lBr

Heav

ier

n/a

n/a

n/a

--

--

XX

X-3

.377

8

Halo

n 13

01Br

omot

rifluo

ro-

met

hane

CBrF

3He

avie

rn/

an/

an/

a1,

000

-1,

000

-X

XX

-58

12,1

53 @

25°C

Hept

ane,

n-

C 7H 1

6He

avie

rX

-41.

16.

740

050

050

075

0X

XX

X20

498

1,29

3

Hexa

fluor

o 1,

3bu

tadi

ene

C 4F 6

Heav

ier

X-

773

--

--

XX

X-

64,

800

Hexa

fluor

opro

pene

Hexa

fluor

o-pr

opyl

ene

C 3F 6

Heav

ier

n/a

n/a

n/a

--

--

XX

X-

-30

4,80

0

Hesa

fluor

opro

pyle

neHe

xaflu

oro-

prop

ene

C 3F 6

Heav

ier

n/a

n/a

n/a

--

--

XX

X-

-30

Hexa

none

, 2-

Met

hyl b

utyl

keto

neC 6

H 12O

Heav

ier

X25

1.2

85

1010

01,

600

XX

X42

312

8

Hexe

ne, 1

-Bu

tyl e

thyl

ene

hexy

lene

C 6H 1

2He

avie

rX

-26

1.2

6.9

50-

--

XX

X25

363

308

@38

°C

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


59

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Hexa

ne, 2

-C 6

H 12

Heav

ier

X<-

7-

--

--

-X

XX

245

6731

0 @

38°C

HFC

- 32

Diflu

orom

etha

neCH

2F2

Xn/

a12

.733

.4-

--

-X

X64

7-5

211

,377

@21

°C

HFE

347E

C 4F 7

OH3

Heav

ier

-n/

an/

a-

--

-X

XX

n/a

3650

0 @

22°C

HFE

7100

Heav

ier

--

--

--

-X

XX

405

6120

2 @

25°C

Hydr

obro

mic

aci

dHy

drog

en b

rom

ide

HBr

Heav

ier

n/a

n/a

n/a

-3

[C]

330

X74

Hydr

ocar

bons

(see

spe

cific

)

Hydr

ogen

H 2Li

ghte

rX

Gas

4.0

75A

A-

-X

XX

X40

0-25

3Ga

s

Hydr

ogen

brom

ide

Hydr

obro

mic

aci

dHB

rHe

avie

rn/

an/

an/

a-

3 [C

]3

30X

s74

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


60

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Hydr

ogen

chl

orid

eHy

droc

hlor

ic a

cid

HCl

Heav

ier

n/a

n/a

n/a

-5

[C]

5 [C

]50

X-

-85

Gas

Hydr

ogen

cya

nide

HCN

Ligh

ter

X-1

85.

640

-4.

7 [C

]10

50X

X54

026

Hydr

ogen

fluo

ride

HFLi

ghte

rn/

an/

an/

a-

3 [C

]3

30-

2076

0

Hydr

ogen

sul

fide

H 2S

Heav

ier

XGa

s4.

346

1015

20 [C

]10

0X

X26

0-6

014

,060

Isoa

myl

alc

ohol

C 5H 1

2OHe

avie

rX

431.

29

50-

100

500

XX

350

132

Isob

utan

eC 4

H 10

Heav

ier

XGa

s1.

88.

4-

--

-X

XX

X46

0-1

2

Isob

utyl

ace

tate

C 6H 1

2O2

Heav

ier

171.

310

.515

0-

150

1,30

0X

XX

X42

111

8

Isop

ar G

Isop

araf

finic

hydr

ocar

bon

Heav

ier

X38

1.2

9.6

XX

X>1

602.

3

Isop

horo

neC 9

H 14O

Heav

ier

X84

0.8

3.8

-5

[C]

2520

0X

XX

X46

021

5<1

Isop

rene

C 5H 8

Heav

ier

X-5

42.

09

--

--

XX

XX

220

3440

0 @

15°C

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


61

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Isop

ropa

nol

Isor

opyl

alc

ohol

C 3H 8

OHe

avie

rX

112.

012

.740

050

040

02,

000

XX

XX

399

83

Isop

ropy

l ace

tate

C 5H 1

0O2

Heav

ier

X2

1.8

825

031

025

01,

800

XX

XX

460

90

Isop

rory

l alc

ohol

Isop

ropa

nol

C 3H 8

OHe

avie

rX

112.

012

.740

050

040

02,

000

XX

XX

399

83

Isop

ropy

lbe

nzen

eCu

men

eC 9

H 12

Heav

ier

X33

0.9

6.5

50-

5090

0X

XX

X42

515

23.

2

Isop

ropy

l eth

erDi

isop

ropy

l eth

erC 6

H 14O

Heav

ier

X-2

81.

47.

925

031

050

01,

400

XX

XX

443

69

Kero

sene

/JP-

1Je

t fue

lFu

el o

il no

. 1He

avie

rX

37-7

20.

75

--

--

XX

X21

015

1-30

1

Met

hane

CH4

Ligh

ter

XGa

s5.

015

AA

-A

XX

XX

X53

7-1

62

Met

hano

lM

ethy

l alc

ohol

CH4O

Heav

ier

X11

6.0

3620

025

020

06,

000

XX

X46

464

Met

hoxy

etha

nol,

2-M

ethy

l cel

loso

lve

C 3H 8

O 2He

avie

rX

391.

814

5-

2520

0X

XX

285

124

Met

hyl a

ceta

teC 3

H 6O 2

Heav

ier

X-1

03.

116

200

250

200

3,10

0X

XX

X45

460

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


62

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Met

hyl a

lcoh

olM

etha

nol

CH4O

Heav

ier

X11

6.0

3620

025

020

06,

000

XX

XX

464

64

Met

hyl b

rom

ide

Brom

omet

hane

CH3B

rHe

avie

rX

n/a

10.0

161

-20

[C]

250

[Ca]

XX

XX

537

4

Met

hyl b

utyl

keto

neHe

xano

ne, 2

-C 6

H 12O

Heav

ier

X25

1.2

85

1010

01,

600

X42

312

8

Met

hyl c

ello

solv

e2- m

etho

xyet

hano

lC 3

H 8O 2

Heav

ier

X39

1.8

145

-25

200

XX

X28

512

4

Met

hyl c

hlor

ide

Chlo

rom

etha

neCH

3Cl

Heav

ier

X-5

08.

117

.450

100

100

2,00

0X

XX

X63

2-2

4

Met

hylc

hlor

ofor

mTr

ichl

oroe

than

e,1,

1,1-

C 2H 3

Cl3

Heav

ier

X7

16.0

350

450

350

700

XX

XX

500

74

Met

hyl e

thyl

keto

ne (M

EK)

Buta

none

, 2C 4

H 8O

Heav

ier

X-9

1.4

11.4

200

300

200

3,00

0X

XX

X40

480

Met

hyl fl

uorid

eCH

3FHe

avie

rX

XX

X-7

828

,577

@21

.1°C

Met

hylfo

rmat

eC 2

H 4O 2

Heav

ier

X-1

95.

023

100

150

100

4,50

0X

XX

X45

632

476

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


63

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Met

hyl i

odid

eCH

3IHe

avie

rn/

an/

an/

a2

-5

100

[Ca]

XX

XX

-

Met

hyl i

soam

ylke

tone

C 7H 1

4OHe

avie

rX

361.

08.

250

-10

0-

XX

XX

191

146

Met

hyl i

sobu

tyl

carb

inol

Met

hyla

myl

alco

hol

C 6H 1

4OHe

avie

rX

481.

05.

525

4025

400

XX

XX

-

Met

hyl i

sobu

tyl

keto

ne (M

IBK)

C 6H 1

2OX

181.

28

5075

100

-X

XX

X44

811

716

Met

hyl

met

hacr

ylat

eC 5

H 8O 2

Heav

ier

X10

1.7

8.2

5010

010

01,

000

XX

XX

435

100

29

Met

hyla

min

eM

onom

ethy

lam

ine

CH5N

Slig

htly

heav

ier

XGa

s4.

920

.75

1510

100

XX

XX

430

-62,

622

@25

°C

Met

hyle

nech

lorid

eDi

chlo

rom

etha

neCH

2Cl 2

Heav

ier

X-

13.0

2350

-25

2300

[Ca]

XX

XX

556

4035

0

Mon

o ch

loro

-be

nzen

e(B

enez

ene

chlo

ride)

C 6H 5

ClHe

avie

rX

291.

39.

610

-75

1,00

0X

XX

X63

813

212

Mon

omet

hlam

ine

Met

hyla

min

eCH

5NSl

ight

lyhe

avie

rX

Gas

4.9

20.7

515

1010

0X

XX

X43

0-6

2,62

2 @

25°C

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


64

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Nap

htha

Coal

Tar

-He

avie

rX

-20.

96

--

100

1,00

0X

XX

X

Nap

thal

ene

C 10H

8He

avie

rX

790.

95.

910

1510

250

XX

XX

526

218

1.0

@ 5

3°C

Nitr

ic o

xide

NO

Sam

en/

an/

an/

a25

-25

100

XX

-52

Nitr

oben

zene

C 6H 5

NO 2

Heav

ier

X87

1.8

-1

-1

200

XX

XX

480

211

1,4

Nitr

ogen

dio

xide

NO 2

Heav

ier

Gas

n/a

35

5 [C

]20

XX

15

Nitr

ogen

trifl

uorid

eN

F 3-

n/a

n/a

10-

101,

000

XX

Nitr

opro

pane

, 1-

C 3H 7

NO 2

Heav

ier

X36

2.2

-25

-25

1,00

0X

XX

X42

112

0-13

213

Nitr

opro

pane

, 2-

C 3H 7

NO 2

Heav

ier

X24

2.2

1110

-25

100

[Ca]

XX

XX

428

120-

132

13

Nitr

ous

oxid

eN

2OHe

avie

rn/

an/

a50

--

-X

X

Octa

fluor

ocyc

lo-

buta

neC 4

F 8He

avie

r-

--

--

--

XX

X-6

2,05

2 @

21.1

°COc

taflu

oroc

yclo

-pr

open

eX

XX

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


65

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Octa

ne, n

-CH

8H18

Heav

ier

X13

1.0

6.5

300

-50

01,

000

XX

X20

612

6

Oxyg

enO 2

Sam

eGa

s-

n/a

n/a

n/a

n/a

n/a

X-1

83

Pent

ane

C 5H 1

2He

avie

rX

<-40

1.5

7.8

600

-1,

000

1,50

0X

XX

X26

036

Perc

hlor

oeth

lyen

eTe

trach

loro

ethy

lene

C 2Cl

4He

avie

rn/

an/

an/

a25

100

100

150

[Ca]

XX

X-

121

13

Perfl

uoro

hexa

ne-

-n/

an/

a-

--

-X

XX

>58

-

Perfl

uoro

met

hyl-

viny

l eth

erPM

VEX

X

Phos

gene

Carb

ony

chlo

ride

COCl

2He

avie

rn/

an/

an/

a0.

1-

02

XX

-8

568

@ 0

°C

Phos

phin

ePH

3He

avie

rX

Gas

1.6

980.

31

050

X38

-88

>760

Prop

ane

C 3H 8

Heav

ier

XGa

s2.

19.

52,

500

-1,

000

2,10

0X

XX

X45

0-4

2

Prop

anol

, 2-

Ally

l alc

ohol

C 3H 6

OHe

avie

rX

212.

518

0.5

-2

20X

XX

X37

897

17

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


66

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Prop

anol

, n-

Prop

yl a

lcoh

ol, n

-C 3

H 8O

Heav

ier

X23

2.2

13.7

200

250

200

800

XX

XX

371

97

Prop

yl a

ceta

te, n

-C 5

H 10O

2He

avie

rX

131.

78

200

250

200

1,70

0X

XX

X45

010

2

Prop

yl a

lcoh

ol, n

-Pr

opan

ol, n

C 3H 8

OHe

avie

rX

232.

213

.720

025

020

080

0X

XX

X37

197

Prop

ylen

eC 3

H 6He

avie

rX

Gas

2.0

11.7

AA

--

XX

XX

455

-47

Prop

ylen

e di

chlo

ride

C 3H 6

Cl2

Heav

ier

X16

3.2

14.5

7511

075

400

[Ca]

XX

XX

557

9640

Prop

ylen

e ox

ide

C 3H 6

OHe

avie

rX

-37

2.1

372

-10

040

0 [C

a]X

XX

465

3444

2

Prop

ylen

egly

col

dim

ethy

l ace

tate

Heav

ier

Sila

neSi

H 4He

avie

rX

-1.

496

--

--

X-

-112

Stod

dard

sol

vent

Heav

ier

X21

0.9

610

0-

500

2,00

0m

g/m

322

914

9-20

4

Styr

ene

C 8H 8

Heav

ier

X31

1.1

720

4010

070

0X

X49

014

55

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


67

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Sulfu

r dio

xide

SO2

Heav

ier

Gas

n/a

n/a

25

510

0X

X-

-10

Sulfu

rhe

xaflu

orid

eSF

6He

avie

rn/

an/

an/

a1,

000

-1,

000

-X

X

Tetra

chlo

roet

hyle

nePe

rchl

oroe

thyl

ene

C 2Cl

4He

avie

rn/

an/

an/

a25

100

100

150

[Ca]

XX

X-

121

13

Tetra

chlo

rom

etha

neCa

rbon

Tetra

chlo

ride

CCl 4

Heav

ier

n/a

n/a

n/a

510

1020

0X

X-

7791

Tetra

fluor

oeth

ylen

eC 2

F 4He

avie

rX

<011

.060

2-

--

XX

X18

8-7

8

Tetra

hydr

ofur

anC 4

H 8O

Heav

ier

X-1

42.

011

.820

025

020

02,

000

XX

X32

166

145

Tolu

ene

C 7H 8

Heav

ier

X4

1/2

7.1

50-

200

500

XX

XX

480

111

22

Tric

hlor

oeth

ane,

1, 1

, 1-

Met

hyl c

hlor

ofor

mC 2

H 3Cl

3He

avie

rX

716

.035

045

035

070

0X

XX

X50

074

100

Tric

hlor

oeth

ane,

1, 2

, 2-

C 2H 3

Cl3

Heav

ier

X4

6.0

15.5

10-

1010

0 [C

a]X

XX

X-

113

19

Tric

hlor

oeth

ylen

eC 2

HCl 3

Heav

ier

X-

8.0

10.5

5010

010

01,

000

[Ca]

XX

XX

420

8758

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


68

Gas

or V

apor

Syno

nym

Chem

ical

Form

ula

Rela

tive

Dens

ity(v

s.Ai

r)+

Flas

hPo

int

(°C)

1 *

LEL

(% b

yvo

l)1

UEL

(% b

yvo

l)1

ACGI

HTLV

-TW

A(P

PM)2

ACGI

HTLV

-STE

L(P

PM)2

OSHA

PEL

(PPM

)3

NIO

SHID

LH(P

PM)4

Auto

-ig

nitio

nTe

mp

(°C)

*

Boil-

ing

Poin

t(°

C)1

Vapo

rPr

essu

re(m

m

Hg a

t20

°C) 1,

4

Tric

hlor

omet

hane

Chlo

rofo

rmCH

Cl3

Heav

ier

n/a

n/a

n/a

10-

50 [C

]50

0X

X-

6216

0

Trie

thyl

amin

eC 6

H 15N

Heav

ier

X-9

1.2

81

325

200

XX

X24

989

54

Turp

entin

eC 1

0H16

-X

350.

8-

100

-10

080

0X

XX

220

149

Viny

l ace

tate

C 4H 6

O 2He

avie

rX

-62.

613

.410

15-

-X

XX

X40

273

88

Viny

l chl

orid

eC 2

H 3Cl

Heav

ier

X-7

83.

633

1-

1Ca

XX

XX

472

-14

2,52

4

Viny

l fluo

ride

C 2H 3

FHe

avie

rX

Gas

2.6

21.7

--

--

XX

X38

5-7

225

.2 a

tm

Viny

liden

e ch

lorid

eC 2

H 2Cl

2He

avie

rX

-18

7.3

165

--

CaX

XX

570

3240

0 @

15°C

Xyle

nes

C 8H 1

0He

avie

rX

27-3

01.

16.

710

015

010

090

0X

XX

X46

3-52

813

7-14

4

Electrochemical

Catalytic

Photoacoustic IR

Absorptive IR

Semiconductor


Combustible

Dete

ctio

n Te

chno

logi

es

Gas

Info

rmat

ion

Tabl

e

Key:

[C] =

Cei

ling

Lim

it (n

ever

exc

eed)

A=

Asph

yxia

ntCa

= Ca

rcin

ogen

-= D

ata

not c

urre

ntly

ava

ilabl

en/

a=

Data

not

app

licab

le


69

GAS INFORMATION TABLE1 Data obtained from the National Fire Protection Association (NFPA) FireProtection Guide to Hazardous Materials, 13th ed., 2002, National Institute forOccupational Safety and Health (NIOSH) Pocket Guide to Chemical Hazards,1995, and material safety data sheets.

2 Data obtained from American Conference of Governmental IndustrialHygienists (ACGIH) 2002 Threshold Limit Values (TLVs) and Biological ExposureIndices (BEIs), and material safety data sheets.

3 The PELs are the maximum 8-hour time weighted average concentrations towhich a worker may be exposed, per 29 CFR 1910.1000 Table Z-1; [C] denotes aceiling limit, the maximum concentration to which a worker may be exposed.They are to be determined from breathing-zone air samples. Data obtained fromNational Institute for Occupational Safety and Health (NIOSH) Documentationfor Immediately Dangerous to Life or Health Concentrations, 1995, and materialsafety data sheets.

4 Data obtained from U.S. Department of Labor Occupational Safety and HealthAdministration (OSHA) 29 CFR 1910.1000 Table Z-1 Limits for Air Contaminants,and material safety data sheets.

^ See 29 CFR 1910.1028 for specific circumstantial exceptions.

+ Density of gas at 1 atmosphere.

* ‘ Gas’ indicates substance is a gas at normal ambient temperature.

Section 4A Selection of GasesTypically Associatedwith Various Industries


72

A Selection of Gases Typically Associated with Various Industries

Industry

Aerospace/Defense

Combustible Gases X X X X

Ammonia X

Carbon dioxide X X

Carbon monoxide X X

Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide

Nitric oxide X

Nitrogen dioxide

O2deficiency/enrichment X X X X

Phosphine

Refrigerants X X X

Toluene X

VOC’s

Test

cam

bers

/labs

Plan

tfac

ilitie

s

Heat

treat

ing

Laun

chpa

ds


73


Industry

Agriculture

Combustible Gases X X X

Ammonia X X X X X

Carbon dioxide X X X X X X

Carbon monoxide X X X

Chlorine

Chlorine dioxide

Ethylene X X X

Ethylene oxide X

Hydrogen chloride

Hydrogen cyanide X

Hydrogen sulfide X

Nitric oxide X X

Nitrogen dioxide X X

O2deficiency/enrichment X X X

Phosphine X X

Refrigerants X X

Sulfar Dioxide X X

VOC’s X

Chill

ers

Frui

tsto

rage

area

s

Gree

nhou

ses,

silo

s&

stor

age

area

s

Fork

lifto

pera

tion

Confi

ned

spac

es(s

ilos)

Grai

nst

orag

e&

proc

essi

ng

Poul

tryho

uses

Fum

igat

ion

Live

stoc

k,oi

lex

tract

ion

proc

ess

Soil

ferti

lizat

ion


74


Industry

Automotive


Ammonia

Carbon dioxide X X X


Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide X

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide

Nitric oxide X X



Phosphine

Refrigerants X X X

Sulfur dioxide X

VOC’s X

Rese

arch

&de

velo

pmen

tlab

s

Engi

nete

stin

g

Envi

ronm

enta

lch

ambe

rs


75


Industry

Aviation


Ammonia

Carbon dioxide X

Carbon monoxide X X

Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide X X

Hydrogen sulfide

Nitric oxide X


O2deficiency/enrichment X X

Phosphine

Refrigerants

Sulfur dioxide

VOC’s X X X X

Body

&en

gine

repa

ir&

mai

nten

ance

Confi

ned

spac

e(w

ing)

tank

mai

nten

ance

Airc

raft

parts

mfg

.

Jetf

uelv

apor

s,so

lven

ts

Airc

raft

hang

erfa

cilit

ies,

fuel

&hy

drau

lic fl

uid

stor

age

and

pum

ping

faci

litie

s


76


Industry

Chemical

Combustible Gases X X X X X X

Ammonia X X X X X X

Carbon dioxide X X

Carbon monoxide X X X X X X

Chlorine X X X X X

Chlorine dioxide X X X X

Ethylene X X X X X X

Ethylene oxide X X X X X

Hydrogen chloride X X

Hydrogen cyanide X X X X X

Hydrogen sulfide X X X X

Nitric oxide X X X X

Nitrogen dioxide X X X X


Phosphine X X X

Refrigerants X

Sulfur dioxide X X

VOC’s X X X X X

Gene

ral l

eak

dete

ctio

npr

oces

s m

anuf

actu

ring

Confi

ned

spac

e (li

quid

nitro

gen

carr

iers

/sto

rage

tank

mai

nten

ance

, rea

ctor

wor

k, tu

nnel

s)

Labs

, fine

che

mic

alm

anuf

actu

ring

Man

ufac

turin

g,po

lym

ers/

plas

tics,

pro

cess

man

ufac

turin

g fo

r lea

ks

Orga

nic

synt

hesi

sop

erat

ions

, liq

uid-

solid

sepa

ratio

n, c

lean

ing

agen

ts

Gene

ral l

eak

dete

ctio

n,or

gani

c sy

nthe

sis

Text

iles


77


Industry

Chemical


Ammonia X X X

Carbon dioxide X X

Carbon monoxide X X

Chlorine X X

Chlorine dioxide X X

Ethylene X X

Ethylene oxide X

Hydrogen chloride X

Hydrogen cyanide X X

Hydrogen sulfide X X

Nitric oxide X

Nitrogen dioxide X


Phosphine X

Refrigerants X

Sulfar Dioxide X

VOC’s X X X X

Rubb

er

Stor

age

war

ehou

ses

Solv

entr

ecov

ery

Hold

ing

tank

s,tra

nsfe

rar

eas,

load

ing

&un

load

ing

area

s


78


Industry

Coatings & Printing Adhesives

Combustible Gases X X

Ammonia

Carbon dioxide

Carbon monoxide

Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide

Nitric oxide

Nitrogen dioxide


Phosphine

Refrigerants

Sulfar Dioxide

VOC’s X X

Man

ufac

turin

gflo

or,o

utsi

deof

pres

s

Pres

spr

oces

ses


79


Industry

Food & Beverage


Ammonia X X X X



Chlorine

Chlorine dioxide

Ethylene X X

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide

Nitric oxide X

Nitrogen dioxide X


Phosphine

Refrigerants X X X X

Sulfur dioxide X X X

VOC’s

Refri

gera

tion

faci

litie

s &

cold

sto

rage

Frui

t sto

rage

are

as

Grai

n pr

oces

sing

Edib

le o

il pr

oces

sing

Brew

erie

s &

win

erie

s,be

vera

ge b

ottli

ng,

ferm

enta

tion

tank

s,re

frige

ratio

n fa

cilit

ies,

mea

tpa

ckin

g, fo

od p

roce

ssin

g

Heat

ers

& b

oile

rs, g

asol

ine-

pow

ered

equ

ipm

ent,

vehi

cles

& fo

rklif

ts b

akin

gfa

cilit

ies

Cool

ers,

con

fined

spa

ces


80


Industry

Food & Beverage


Ammonia X

Carbon dioxide X X

Carbon monoxide X X

Chlorine X X

Chlorine dioxide X X

Ethylene X

Ethylene oxide X X

Hydrogen chloride

Hydrogen cyanide


Nitric oxide

Nitrogen dioxide


Phosphine

Refrigerants

Sulfur dioxide X X

VOC’s X X

Was

tew

ater

tank

s,dr

aina

ge &

sew

age

area

s

Drai

nage

& s

ewag

ear

eas,

boi

lers

&he

ater

s, fo

od p

acka

ging

Ferm

enta

tion

proc

ess,

pack

agin

g or

gas

sing

food

s, c

onfin

ed s

pace

Fum

igat

ion

of y

east

&

mol

d sp

ores

,st

erili

zatio

n

Disi

nfec

ting

equi

pmen

t &

ute

nsils


81


Industry

Food & Beverage

Combustible Gases X

Ammonia X

Carbon dioxide X X

Carbon monoxide X

Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide

Nitric oxide

Nitrogen dioxide


Phosphine

Refrigerants X

Sulfur dioxide X

VOC’s X

Cold

sto

rage

&tra

nspo

rt fa

cilit

ies,

mea

t pac

king

pla

nts,

supe

rmar

kets

,re

frige

rato

r & s

tora

gelo

catio

ns, f

ood

stor

age

syst

ems

mon

itorin

g

Food

pac

kagi

ng(s

olve

nt v

apor

pro

cess

mon

itorin

g)


82


Industry

Foundries Fuel cell Manufacturing

Combustible Gases X X X X X

Ammonia


Carbon monoxide X X X X X

Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide X

Hydrogen sulfide X X X

Nitric oxide X

Nitrogen dioxide X


Phosphine

Refrigerants

Sulfur dioxide X

VOC’s

Furn

ace

oper

atio

n,co

rem

akin

g, m

etal

prep

arat

ion

& p

ourin

g

Met

al-m

inin

g,

finis

hing

wor

k

Core

mak

ing

Heat

-trea

ting

proc

esse

s

Confi

ned

spac

e

Man

ufac

turin

g flo

or,

fuel

cel

ls


83


Industry

HAZMAT


Ammonia X

Carbon dioxide X X

Carbon monoxide X X X X

Chlorine X

Chlorine dioxide X

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide X

Nitric oxide

Nitrogen dioxide


Phosphine X

Refrigerants

Sulfur dioxide X

VOC’s X X X X

HazM

at

appl

icat

ions

Flam

mab

le li

quid

/ga

s st

orag

e &

pum

ping

faci

litie

s

Confi

ned

spac

e

Unde

rgro

und

cons

truci

ton

Stor

age,

tran

sfer

and

treat

men

t


84


Industry

Heavy Manufacturing


Ammonia X

Carbon dioxide X X


Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride X

Hydrogen cyanide X

Hydrogen sulfide X

Nitric oxide X X

Nitrogen dioxide X X X X

O2deficiency/enrichment

Phosphine

Refrigerants X X

Sulfur dioxide X X

VOC’s X X X X

Vehi

cle

man

ufac

turin

gpl

ants

Heat

-tran

sfer

fluid

s

Vehi

cle

emis

sion

s

Met

al-p

latin

g

Man

ufac

turin

gpr

oces

sem

issi

ons

Fork

lift &

cra

neop

erat

ions


85


Industry

Heavy Manufacturing


Ammonia X X

Carbon dioxide

Carbon monoxide X

Chlorine X

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide

Nitric oxide

Nitrogen dioxide


Phosphine

Refrigerants X

Sulfur dioxide

VOC’s X X X

Chem

ical

load

ing/

off-l

oadi

ng

Pain

t boo

ths

Degr

ease

rs

Mec

hani

cal

equi

pmen

t roo

ms


86


Industry

HVAC


Ammonia X X X X X

Carbon dioxide X X X X


Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide X X

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide

Nitric oxide

Nitrogen dioxide X X X


Phosphine


Sulfur dioxide

VOC’s X X

Heat

ing

boile

rs o

r duc

ting,

gene

ral o

ffice

app

licat

ions

Park

ing

gara

ges,

war

ehou

ses

Occu

pied

bui

ldin

gs, o

ffice

build

ings

, res

earc

h la

bs

Park

ing

gara

ges,

tunn

els,

furn

ace

room

s,m

aint

enan

ce g

arag

es

Vent

ilatio

n du

cts

Cold

sto

rage

& tr

ansp

ort

faci

litie

s, m

eat p

acki

ngpl

ants

, sup

erm

arke

ts,

refri

gera

tor s

tora

gelo

catio

ns, f

ood

stor

age

syst

em m

onito

ring

Mec

hani

cal r

oom

s


87


Industry

Indoor air quality


Ammonia

Carbon dioxide X X

Carbon monoxide X X

Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide

Nitric oxide

Nitrogen dioxide X


Phosphine

Refrigerants X X

Sulfur dioxide

VOC’s X

Occu

pied

bui

ldin

gs(in

dust

rial,

com

mer

cial

,re

side

ntia

l),

offic

e bu

ildin

gs,

rese

arch

labs

Park

ing

gara

ges,

tunn

els,

furn

ace

room

s,m

aint

enan

cega

rage

s, c

raw

lsp

aces


88


Industry

Iron & Steel


Ammonia X X X

Carbon dioxide X X


Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide


Nitric oxide X



Phosphine

Refrigerants X

Sulfur dioxide X X

VOC’s X X

Blas

t fur

nanc

e op

erat

ion

& m

aint

enan

ce, c

onve

rter

oper

atio

n, fu

rnac

e &

gas

pipe

line

leak

s

Met

al-m

inin

g, fi

nish

ing

wor

k, fu

el s

tora

ge

Coki

ng o

pera

tions

Wel

ding

Confi

ned

spac

e

Mai

nten

ance

room

s(c

hille

rs)

Mot

or m

aint

enan

ce &

clea

ning

, cok

e ov

enem

issi

ons


89


Industry

Medical

Combustible Gases X

Ammonia X

Carbon dioxide X X

Carbon monoxide X X

Chlorine

Chlorine dioxide

Ethylene X X

Ethylene oxide X X X

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide

Nitric oxide

Nitrogen dioxide


Phosphine

Refrigerants X

Sulfur dioxide

VOC’s X X X

Oper

atin

g ro

oms,

occu

pied

are

as

Alco

hol’s

, “si

ck b

uild

ing

synd

rom

e”

Cent

ral s

uppl

y,

ster

iliza

tion

area

s

MRI

Park

ing

gara

ges

Deco

ntam

inat

ion

area

s

Mec

hani

cal e

quip

men

tro

oms


90


Industry

Mining


Ammonia X


Carbon monoxide X X X X X

Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide X


Nitric oxide X X



Phosphine

Refrigerants X

Sulfur dioxide

VOC’s

Confi

ned

spac

e

Mec

hani

zed

coal

cut

ting

Min

ing

proc

ess

Resu

lt of

com

bust

ion

(fire

),di

esel

-pow

ered

mac

hine

ryex

haus

t, co

nfine

d sp

ace

blas

ting

Met

al m

inin

g

Dies

el e

xhau

st

Dies

el-p

ower

ed m

achi

nery

,bl

astin

g


91


Industry

Oil & Gas


Ammonia X X

Carbon dioxide

Carbon monoxide X X

Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride X X X

Hydrogen cyanide

Hydrogen sulfide X X X X X

Nitric oxide

Nitrogen dioxide X

O2deficiency/enrichment X

Phosphine

Refrigerants


VOC’s X X X X

Petro

leum

refin

ing

Pipe

line

com

pres

sor

stat

ions

& p

umpi

ng s

tatio

ns

Refin

erie

s

Refin

erie

s, p

etro

chem

ical

faci

litie

s, p

erim

eter

mon

itorin

g

Inco

mpl

ete

com

bust

ion,

conv

ersi

on, c

okin

g, g

ener

alpr

oces

sing

, lea

k de

tect

ion

Conv

ersi

on p

roce

sses

,is

omer

izatio

n, c

atal

ytic

refo

rmin

g, tr

eatm

ent

proc

esse

s, le

ak d

etec

tion,

stor

age

vess

els,

per

imet

erm

onito

ring


92


Industry

Oil & Gas

Combustible Gases X X X X X X X

Ammonia

Carbon dioxide X X

Carbon monoxide

Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide X X X X

Nitric oxide

Nitrogen dioxide


Phosphine

Refrigerants X

Sulfur dioxide X X

VOC’s X X X

Refin

ing

proc

ess,

gen

eral

leak

det

ectio

n, tr

eatm

ent

proc

esse

s, c

rude

sepa

ratio

n, d

rillin

g rig

s

Confi

ned

spac

e (ta

nkcl

eani

ng o

pera

tions

,en

clos

ed b

ldgs

or s

truct

ures

)

Nat

ural

gas

line

s

Offs

hore

dril

ling

plat

form

s-st

orag

e &

pro

cess

ing

area

s,co

ntro

l roo

ms,

livin

g sp

aces

,po

wer

gen

erat

ion

room

s

Refin

ing

proc

ess,

pro

cess

stre

am s

ampl

e co

llect

ion,

gene

ral p

lant

ope

ratio

ns

Mec

hani

cal e

quip

men

tro

oms

Ther

mal

oxi

dize

rs


93


Industry

Paper & Pulp


Ammonia X X

Carbon dioxide

Carbon monoxide

Chlorine X X

Chlorine dioxide X

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide


Nitric oxide



Phosphine

Refrigerants X X

Sulfur dioxide X X

VOC’s X

Pape

r pro

duct

ion

(ble

achi

ng)

Chem

ical

pul

ping

,Kr

aft p

ulpi

ng

Confi

ned

spac

es(ta

nks,

pits

, su

mps

, vat

s)

Pape

r pro

duct

ion

(coa

ting

& d

ying

)

Mec

hani

cal

equi

pmen

t roo

ms


94


Industry

Pharmaceutical


Ammonia X X X X X

Carbon dioxide X X

Carbon monoxide X

Chlorine X X X

Chlorine dioxide X

Ethylene X

Ethylene oxide X X X X

Hydrogen chloride

Hydrogen cyanide X X X X

Hydrogen sulfide

Nitric oxide

Nitrogen dioxide


Phosphine

Refrigerants X

Sulfur dioxide X

VOC’s X X X

Man

ufac

turin

g,

gas

leak

s

Solv

ent v

apor

proc

ess

mon

itorin

g

Chem

ical

syn

thes

isop

erat

ions

Labs

, fine

che

mic

alm

anuf

actu

ring

Labs

, org

anic

synt

hesi

s, li

quid

-so

lid s

epar

atio

n,co

mpo

undi

ng,

gran

ulat

ing

&ta

blet

-coa

ting

oper

atio

ns, d

ryin

g&

pac

kagi

ng, fi

nech

emic

alm

anuf

actu

ring


95


Industry

Pharmaceutical

Combustible Gases X

Ammonia

Carbon dioxide X


Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide

Nitric oxide

Nitrogen dioxide


Phosphine

Refrigerants X

Sulfur dioxide

VOC’s

Nitr

ogen

blan

ketin

g of

stor

age

vess

els,

reac

tors

and

cent

rifug

es

Com

pres

sed

brea

thin

g ai

r

Utili

ties


96


Industry

Power generation


Ammonia X X X


Carbon monoxide X X X X X X

Chlorine X

Chlorine dioxide

Ethylene

Ethylene oxide


Hydrogen cyanide

Hydrogen sulfide

Nitric oxide X



Phosphine

Refrigerants


Sulfur hexafluoride X

VOC’s X X

Hom

e fu

rnac

e le

aks

Tran

sfor

mer

insu

latio

n

Pow

er g

ener

atio

n pl

ants

Fuel

sto

rage

Fuel

tran

spor

tL lo

adin

g &

unl

oadi

ng

Foss

il fu

el p

ower

pla

nts

Confi

ned

spac

e

Coal

& fu

el o

il ox

idiza

tion

in c

ombu

stio

n pr

oces

s(e

mis

sion

s)


97


Industry

Semiconductor fabs


Ammonia X

Arsine X

Bromine X

Carbon monoxide X X

Chlorine X

Chlorine dioxide X

Diborane X

Germane X


Hydrogen cyanide

Nitric oxide X

Nitrogen dioxide X


Phosphine X

Refrigerants X X

Silane X

VOC’s X X

Man

ufac

turin

g, p

roce

ssin

g

As d

opin

g ag

ent i

nm

anuf

actu

ring,

diff

usio

n an

dio

n im

plem

enta

tion,

chec

mca

l vap

or d

epos

ition

Clea

ning

age

nts,

fluor

inat

ed c

ompo

unds

Lith

ogra

phy,

etch

ing,

oxid

atio

n, m

etal

izatio

n,as

sem

bly

& te

stin

g

Chill

er p

lant

Com

pres

sed

brea

thin

g ai

r


98


Industry

Shipyard/marine

Combustible Gases X X X X X X X X

Ammonia X X X X

Carbon dioxide X


Chlorine

Chlorine dioxide X

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide


Nitric oxide

Nitrogen dioxide


Phosphine


Sulfur dioxide

VOC’s X X

Confi

ned

spac

e (s

tora

ge h

olds

)

Fuel

sto

rage

&

pum

ping

faci

litie

s

Engi

ne ro

om

Was

te tr

eatm

ent

Chill

ers

LNG

trans

port

Oil t

anke

r pum

ps

U.S.

Nav

y sh

ips

Ferr

y bo

ats


99


Industry

Water & Wastewater

Combustible Gases X X X X X X X X X

Ammonia X


Carbon monoxide X X

Chlorine X X X

Chlorine dioxide X X X

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide X X X X X X X

Nitric oxide

Nitrogen dioxide


Phosphine

Refrigerants

Sulfur dioxide X

VOC’s X X

Proc

essi

ng; s

tora

ge ta

nks,

room

s &

pip

es

Dige

ster

s, d

iges

ter

gas

stor

age

Stag

nant

gas

, inc

iner

ator

s

Plan

t pum

ps, p

lant

sew

age

basi

n m

onito

ring

for s

olve

ntle

aks

or d

umpi

ng

Gene

ral p

roce

sses

Sew

er w

ork

Confi

ned

spac

e

Dech

lorin

izatio

n,

stor

age

tank

s

Wet

wel

l infl

uent

Pum

p st

atio

ns


100


Industry

Welding


Ammonia X

Carbon dioxide X

Carbon monoxide X X

Chlorine

Chlorine dioxide

Ethylene X

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide

Nitric oxide

Nitrogen dioxide


Phosphine

Refrigerants

Sulfur dioxide

VOC’s

Confi

ned

spac

e, a

rcai

r cut

ting,

flux

-sh

ield

ed &

gas

shie

lded

arc

wel

ding

,m

etal

cut

ting

& fl

ame

goug

ing,

gas

pres

sure

wel

ding

Gene

ral o

pera

tions

Ther

mite

and

stu

dw

eldi

ng, l

aser

wel

ding

& c

hilli

ng, a

rc a

ircu

tting

, arc

wel

ding

,el

ectri

c re

sist

ance

&ga

s pr

essu

re w

eldi

ng,

met

al c

uttin

g &

flam

ego

ugin

g, b

razin

g


101


Industry

Welding


Ammonia

Carbon dioxide

Carbon monoxide X

Chlorine

Chlorine dioxide

Ethylene

Ethylene oxide

Hydrogen chloride

Hydrogen cyanide

Hydrogen sulfide

Nitric oxide

Nitrogen dioxide X


Phosphine

Refrigerants

Sulfur dioxide

VOC’s

Arc

wel

ding

&cu

tting

, stu

d w

eldi

ng,

arc

+ ai

r cut

ting,

gas

pres

sure

wel

ding

,m

etal

cut

ting

&

flam

e go

ugin

g

Confi

ned

spac

ew

eldi

ng, e

lect

ron

beam

wel

ding

Section 5Hazardous Locations Classification

Class I: Flammable Gasses, Vapors or LiquidsClass II: Combustible DustsClass III Ignitable Fibers & Flyings

ATEX - Explosive AtmospheresA Selection of Recognized Testing LaboratoriesSystem Installation


104

Hazardous Locations ClassificationThe hazardous location classification system was designed to promote the safeuse of electrical equipment in environments defined as “hazardous areas”. Ahazardous area is a location in which the potential presence of a flammablegas/ air mixture requires special precautions to reduce the possibility of anyelectronics in the hazardous area becoming a source of ignition.

In the gas detection applications, hazardous areas are generally defined by twofactors: the type of gas that may be present, and the degree of probability that itwill be present at any given instant. Hazardous areas are defined slightlydifferently in various countries, but essentially the same result is achieved.

Areas are classified according to the likelihood that they will produce acombustion hazard for the electronic device. In a hazardous area eachapparatus must possess the appropriate approvals for safe operation in thatarea (i.e., to ensure that it does not become a source of ignition). Variousmethods of protection are used to meet this need.

Area Classification

Each area is classified according to the likelihood that the hazard will be present at any given instant. There are two major hazardous locationclassifications:

• Classification 1: Used in North American installations (US NationalElectric Code“ and Canadian Electric Code). Areas are subdivided into“Classes” and “Divisions”.

• Classification 2: Used in European (CENEL EC) and InternationalElectrotechnical Committee- (IEC) aligned countries such as Australia;also used in some North American installations. Areas are categorizedinto “Zones”.

Gas Groups

Gases are grouped according to their ignition energies which are producedfrom spark sources (from most easily ignited to least easily ignited).


105

Hazardous Locations ClassificationTemperature Class

Gases are also grouped according to their ignition temperature. This is themaximum surface temperature that can be attained by an apparatus orcomponent at maximum-rated ambient temperature. Six basic temperatureclasses are used to categorize this factor (T1 through T6). The higher thetemperature class, the lower the maximum surface temperature and thus thewider the range of gases for which the apparatus is suitable.

Protection Methods

Various forms of ignition protection are used, such as intrinsic safety,explosionproof, flameproof, purging/ pressurization, hermetic sealing and non-sparking design.

Environmental Protection

Environmental protection refers to design methods used to minimize equipment exposure to invasive environmental conditions such as water, ice, dust andcorrosion. As with Hazardous Area Classifications, equipment environmentalprotection ratings vary somewhat within and outside of North America. As seenin the following two tables, National Electrical Manufacturers Association(NEMA) and Ingress Protection (IP) Codes provide similar information regardinginstrument protection against various environmental conditions.

Attaining one rating does not imply that the other ratings have also been met.


106

Hazardous Locations Classification

INGRESS PROTECTION (IP) CODES(IEC/EN 60529)

FIRST NUMERAL SECOND NUMERALProtection against solid bodies Protection against

liquids

No Protection No Protection

Objects Greater Than 50mm

Vertically Dripping Water

Objects Greater Than 12mm

Angled DrippingWater - 75° to 90°

Objects Greater Than 2.5mm Sprayed Water

Objects Greater Than 1.0mm Splashed Water

Dust-Protected Water Jets

Dust-Tight Heavy Seas

Effects of Immersion

Indefinite Immersion

0 0

1 1

2 2

3 3

4 4

5 5

6 6

7

8

Example: IP65 equipment isdust-tight and protectedagainst water jets


107


Enclosure Ratings

NEMA, UL, & CSA Type Rating

ApproximateIEC/IPclassification

Abbreviated protection description

1 IP30 Indoor, from contact with contents

2 IP31 Indoor, limited, from dirt & water

3 IP64 Outdoor, from rain, sleet, windblown dust & ice damage

3R IP32 Outdoor, from rain, sleet & ice damage

4 IP66Indoor & outdoor, from windblown dust, rain, splashing & hose directed water & ice damage

4X IP66Indoor & outdoor, from corrosion,windblown dust, rain, splashing & hosedirected water & ice damage

6 IP67Indoor & outdoor, from hose-directedwater, water entry during submersion &ice damage

12 IP55 Indoor, from dust, falling dirt & dripping non-corrosive liquids

13 IP65 Indoor, from dust, spraying water, oil & non-corrosive liquids


108


Class I: Flammable Gases, Vapors or LiquidsClass I Area ClassificationDivision 1:

Where ignitable concentrations of flammable gases, vapors or liquids can existall of the time or some of the time under normal operating conditions.

Division 2:

Where ignitable concentrations of flammable gases, vapors or liquids are notlikely to exist under normal operating conditions.

Zone 0:

Where ignitable concentrations of flammable gases, vapors or liquids are presentcontinuously or for long periods of time under normal operating conditions.

Zone 1:

Where ignitable concentrations of flammable gases, vapors or liquids are likelyto exist under normal operating conditions.

Zone 2:

Where ignitable concentrations of flammable gases, vapors or liquids are notlikely to exist under normal operating conditions.

Class I GroupsDivision 1 and 2A acetylene

B hydrogen, fuel and combustible process gases containing more than 30%hydrogen by volume, or gases or vapors of equivalent hazard such asbutadiene, ethylene oxide, propylene oxide and acrolein

C cyclopropane, ethyl ether, ethylene, or gases or vapors of equivalent hazard

D acetone, ammonia, benzene, butane, ethanol, gasoline, hexane, methane,natural gas, naptha, propane, or gases or vapors of equivalent hazard

Zone 0, 1 and 2

IIC acetylene and hydrogen, fuel and combustible process gases containingmore than 30% hydrogen by volume, or gases or vapors of equivalent hazardsuch as butadiene, ethylene oxide, propylene oxide and acrolein

IIB cyclopropane, ethyl ether, ethylene, or gases or vapors of equivalent hazard

IIA acetone, ammonia, benzene, butane, ethanol, gasoline, hexane, methane,natural gas, naptha, propane, or gases or vapors of equivalent hazard


109


Class I: Flammable Gases, Vapors or LiquidsClass I Temperature Codes(Maximum surface temperature of apparatus)

Division 1 and 2

T1 (≤450°C)

T2 (≤300°C)

T2A, T2B,T2C,T2D(≤280°C, ≤260°C, ≤230°C, ≤215°C)

T3 (≤200°C)

T3A, T3B, T3C(≤180°C, ≤165°C, ≤160°C)

T4 (≤135°C)

T4A (≤120°C)

T5 (≤100°C)

T6 (≤85°C)

Zone 0, 1, and 2

T1 (≤450°C)

T2 (≤300°C)

-

T3 (≤200°C)

-

T4 (≤135°C)

T5 (≤100°C)

T6 (≤85°C)


110


Class I: Flammable Gases, Vapors or Liquids

Class I, Division 1 and 2 Protection Methods

Applicable Certification Documents

Area Protection Methods USA Canada

Div. 1

• Explosionproof

• Intrinsic safety (2 fault)

• Purged/pressurized (Type X or Y)

UL 1203

UL 913

NFPA 496

CSA-30

CSA-157

NFPA 496

Div. 2

• Hermetically sealed

• Nonincendive

• Non-Sparking

• Purged/Pressurized (Type Z)

• Any Class I, Div. 1 method

• Any Class I, Zone 0, 1 or 2 method

UL 1604

UL 1604

UL 1604

NFPA 496

—

UL 2279

CSA-213

CSA-213

CSA-213

NFPA 496

—

CSA-E79Series


111


Class I: Flammable Gases, Vapors or Liquids

Class I, Zone 0, 1 and 2 Protection Methods


Area Protection Methods USA Canada IECExScheme† Europe

• Intrinsic safety, 'ia' (2 fault)

• Special requirements

UL 60079-11

Pending

E60079-11

No

IEC 60079-11

IEC 60079-26

EN 60079-11

EN 60079-26

• Encapsulation, ‘m’

• Flameproof, ‘d’

• Increased safety, ‘e’

• Intrinsic safety, ‘ib’ (1 fault)

• Oil immersion, ‘o’

• Powder filling, ‘q’

• Pressurization, ‘px’ or ‘py’

• Any Class I, Zone 0

• Any Class I, Div. 1

UL 60079-18

UL 60079-1

UL 60079-7

UL 60079-11UL 60079-6

UL 60079-5

ISA 12.04.01

Yes

Yes

CSA-E79-18

E60079-1

E60079-7

E60079-11

E60079-6

E60079-5

E60079-2

Yes

Yes

IEC 60079-18

IEC 60079-1

IEC 60079-7

IEC 60079-11

IEC 60079-6

IEC 60079-5

IEC 60079-2

Yes

No

EN 60079-18

EN 60079-1

EN 60079-7

EN 60079-11

EN 50015

EN 50017

EN 60079-2

Yes

No

• Non-sparking, 'nA'

• Enclosed break, 'nC'

• Energy limited, 'nL'

• Restricted breathing, 'nR'

• Pressurization, 'pz'

• Any Class I, Zone 0 or 1 method

• Any Class I, Div. 1 or 2 method

UL 60079-15

UL 60079-15

UL 60079-15

UL 60079-15

ISA 12.04.01*

Yes

Yes

E60079-15

E60079-15

E60079-15

E60079-15

E60079-2

Yes

Yes

IEC 60079-15

IEC 60079-15

IEC 60079-15

IEC 60079-15

IEC 60079-2

Yes

No

EN 60079-15

EN 60079-15

EN 60079-15

EN 60079-15

EN 60079-2

Yes

No

Zone

0Zo

ne1

Zone

2

Note: 60079-0 General requirements used in conjunction with 60079-xx. UL 60079-xx equivalents are availableas ANSI/ISA 60079-xx.

Note 2: UL 60079-xx equivalents are available as ANSI/ISA 60079-xx.

Note 3: Requirements subject to change without notice. Check your local authorithy having jurisdiction forcurrent requirements.

* See NFPA 496 for Type X, Y, and Z.


112


Class II: Combustible DustsClass II Area Classification

Division 1:

Where ignitable concentrations of combustible dusts can exist all of the time orsome of the time under normal operating conditions.

Division 2:

Where ignitable concentrations of combustible dusts are not likely to existunder normal operating conditions.

Class II GroupsDivision 1 and 2

E (metals – Div. 1 only)

F (coal)

G (grain)

Class II Temperature Codes

Division 1 and 2

T1 (≤450°C)

T2 (≤300°C)

T2A, T2B,T2C,T2D(≤280°C, ≤260°C, ≤230°C, ≤215°C)

T3 (≤200°C)

T3A, T3B, T3C(≤180°C, ≤165°C, ≤160°C)

T4 (≤135°C)

T4A (≤120°C)

T5 (≤100°C)

T6 (≤85°C)


113


Class II: Combustible Dusts

Class II, Division 1 and 2 Protection Methods



Div. 1

• Dust-ignitionproof

• Intrinsic safety

• Pressurized

UL 1203

UL 913

NFPA 496

CSA-25 or CSA-E1241-1-1

CSA-157

NFPA 496

Div. 2

• Dusttight


• Nonincendive

• Pressurized

• Any class II, Div. 1 method

UL 1604

UL 1604

UL 1604

NFPA 496

—

CSA-157 or CSA-E1241-1-1

—

—

NFPA 496

—


114


Hazardous Locations Markings

Class I, II & III, Division 1 & 2 (USA & Canada) – This marking would include:Class(es), Division(s), Gas/Dust Group(s), Temperature CodeExample: Class I, Division 1, Group C & D, T4A

Class I, Zone 0, 1 & 2 (USA) – This marking would include:For Zone Listings based on 60079-xx Class, Zone, AEx,Protection Method(s), Gas Group, Temperature CodeExample: Class I, Zone 1, AEx de IIB T4

Class I, Zone 0, 1 & 2 (Canada) – This marking would include:For Zone Listings based on Canadian Zone Certification Documents Class, Zone, Ex, Protection Method(s), Gas Group, Temperature CodeExample:Class I, Zone 1, Ex de IIB T4

Zone 0, 1 & 2 (IECEx Scheme) – This marking would include:Ex, Protection Method(s), Gas Group, Temperature CodeExample: Ex de IIB T4

Zone 0, 1 & 2 (Europe) – This marking would include:EEx, Protection Method(s), Gas Group, Temperature CodeExample: Ex de IIB T4

ATEX Directive (Europe) – In addition to the European Ex marking string noted above, this marking would include:

Non-mining: CE, Notified Body (NB) Identifier, , Equipment Group & Category, G (gas)/D (dust)Example: (for DEMKO): 0539 II 2

Mining: CE, Notified Body (NB) Identifier, , Equipment Group & CategoryExample: (for DEMKO): 0539 I 2


115


Class III: Ignitable Fibers & FlyingsClass III Area ClassificationDivision 1:

Where easily ignitable fibers or materials producing combustible flyings are handled, manufactured or used.

Division 2:

Where easily ignitable fibers are stored or handled.

Class III GroupsDivision 1 and 2

None

Class III Temperature Codes

Division 1 and 2

NoneNote: Article 503 of the NEC limits the maximumtemperature for Class III equipment to 165ºC forequipment not subject to overloading and to120ºC for equipment that may be overloaded.


116


Class III: Ignitable Fibers & Flyings

Class III, Division 1 and 2 Protection Methods



Div. 1• Dusttight


• Intrinsic safety

UL 1604UL 1604UL 913

CSA--157—

CSA-157

Div. 2• Nonincendive

• Any Class III, Div. 1 method

UL 1604 ——


117


UL’s Hazardous Locations Standards

UL 515 Electrical Resistance Heat Tracing for Commercial and Industrial Applications

ANSI/UL 583 Electric-Battery-Powered Industrial Trucks

ANSI/UL 674 Electric Motors and Generators for Use in Division 1 Hazardous (Classified) Locations

ANSI/UL 698 Industrial Control Equipment for Use in Hazardous (Classified) Locations

ANSI/UL 698A Industrial Control Panels Relating to Hazardous (Classified) Locations

ANSI/UL 781 Portable Electric Lighting Units for Use in Hazardous(Classified) Locations

ANSI/UL 783 Electric Flashlights and Lanterns for Use in Hazardous(Classified) Locations

ANSI/UL 823 Electric Heaters for Use in Hazardous (Classified) Locations

ANSI/UL 844 Electric Lighting Fixtures for Use in Hazardous (Classified) Locations

ANSI/UL 877 Circuit Breakers and Circuit-Breaker Enclosures for Use in Hazardous (Classified) Locations

ANSI/UL 886 Outlet Boxes and Fittings for Use in Hazardous (Classified) Locations

ANSI/UL 894 Switches for Use in Hazardous (Classified) Locations

ANSI/UL 913 Intrinsically Safe Apparatus and Associated Apparatus for Use in Class I, II, and III, Division I, Hazardous(Classified) Locations


118


UL’s Hazardous Locations Standards

ANSI/UL 1002 Electrically Operated Valves for Use in Hazardous (Classified) Locations

ANSI/UL 1010 Receptacle-Plug Combinations for Use in Hazardous (Classified) Locations

ANSI/UL 1067 Electrically Conductive Equipment and Materials for Use inFlammable Anesthetizing Locations

ANSI/UL 1203 Explosionproof and Dust-Ignition-Proof Electrical Equipment for Use in Hazardous (Classified) Locations

ANSI/UL 1207 Sewage Pumps for Use in Hazardous (Classified) Locations

UL 1604 Electrical Equipment for Use in Class I and II, Division 2, and Class III Hazardous (Classified) Locations

ANSI/UL 2208 Solvent Distillation Units

UL 2225 Metal-Clad Cables and Cable-Sealing Fittings for Use in Hazardous (Classified) Locations

ANSI/UL 2279 Electrical Equipment for Use in Class I, Zone 0, 1 and 2 Hazardous (Classified) Locations


119

CE ApprovalCE is a labeling system required by some European countries to identify thoseproducts which are permitted to be sold in EU (European Union) member states.CE approval is used to verify compliance with certain European health andsafety rules known as “Directives”. The Directives relevant to permanent gasdetection instrumentation are the Electromagnetic Compatibility (EMC)Directive, Low Voltage Directive and ATEX Directive.

EMC DirectiveThe Electromagnetic Compatibility Directive 89/336/EEC is designed to limit the effects that one piece of equipment may have on another piece ofequipment due to the electrical interference it produces. The effects of suchinterference can be severe enough to cause a device to shut down whenanother one is switched on. Electrical signals called EMI (ElectromagneticInterference) are the main cause of these effects. Most of the interference is inthe form of radio waves (electromagnetic radiation, also called “emissions”)that are produced inside electrical equipment as a result of high speedcommunications involving the switching of high speed currents. The EMCDirective requires that equipment emissions be minimized and that the devicebe rendered immune to the emissions of other equipment. This is accomplishedby designing the unit to meet the requirements set forth in European standardEN 50270, which sets limits on the amount of emissions permitted andsusceptibility levels (immunity) for equipment. Electrostatic Discharge (ESD),another form of electrical interference that can disrupt equipment functions, is also addressed in EN 50270.

Low Voltage DirectiveThe Low Voltage Directive (LVD) is a European personal safety Directive that iscomparable to a US/Canadian fire/shock and safety approval. It applies to ACline powered devices and high voltage DC equipment. Specifically, the Directiveapplies to any equipment powered from a 50 VAC or 75 VDC or higher powersource. The standard used for designing to compliance is EN/IEC 61010.


120

ATEX – Explosive AtmospheresATEX is the term used for the European Union’s Directive 94/9/EC whichconcerns equipment and protective systems intended for use in potentiallyexplosive atmospheres. The purpose of the directive is to facilitate trade withinthe EU by aligning the laws of the Member States in Europe regarding safetyrequirements for hazardous area products.

ATEX approval requires that the following issues be met:

1. Safety requirementsThe product must meet the applicable hazardous location requirements.

2. Performance requirementsIf the product is designed to monitor combustible gas and/or oxygen, then itmust meet certain performance criteria in fields such as response time,accuracy and linearity.

3. Quality management certificationThe manufacturer must have an approved quality management system.


121

ATEX Explosive Atmospheres

EXPLOSION SAFETY HIERARCHY(European Standard EN 1127-1)

Avoid the hazard• Use non-flammable materials, or

• Contain the flammable materials in order to avoid the formation of an explosive atmosphere

Control the riskIf an explosive atmosphere cannot be avoided, even under abnormal conditions:

• Prevent ignition of the explosive atmosphere, or

• Control the effects of explosions to avoid damage to people and property

� �

�

CONTROLLINGEXPLOSIONS

Use a protective system to:

• Contain• Isolate

• Suppress –actively

• Suppress –passively

• Relieve (vent) the explosion

PREVENT IGNITION

Identify potential ignition sources• Electric arcs • Compression ignition• Electric sparks • Static Electricity• Flames • Electromagnetic

radiation• Hot surfaces • Ionizing radiation• Mechanical impact • Chemical reactions• Friction • Acoustic energy

�A B


122

��A B

�C �D

PROTECTIVE SYSTEMS

Explosion suppression systems

Explosionproof equipment

Flame arresters

Explosion venting devices

Inerting

Limitation of concentration of combustibles

Dust explosion venting systems

Gas explosion venting systems

Explosion suppression devices

Active explosion extinguishingbarriers

Explosion barriers for mines

Mechanical explosion barriers

PROTECT IGNITION SOURCES

Category of protection(EU Directive 94/9/EC – ATEX)

Mining equipment – Group I Category M1Very high level of protection.Equipment can be operated inpresence of explosive atmosphere

Category M2High level of protection. Equipment tobe de-energized in presence ofexplosive atmosphere

Non-mining equipment – Group II

Category 1Very high level of protection. Usedwhere explosive atmosphere ispresent continuously or for longperiods of time (Zone 0, 20)*

Category 2High level of protection. Used whereexplosive atmosphere is likely tooccur in normal service (Zone 1, 21)*

Category 3Normal level of protection. Usedwhere explosive atmosphere isunlikely to occur and would beinfrequent and for short time (Zone 2,22)*

* EN 1127-1:1997. Clause 6.3


123

ATEX Explosive Atmospheres

Methods Of Protection: Standards

Electrical equipment for ses, vapors and mists (G) Category

Code Cenelec EN IEC M1 M2 1 2 3

General requirements 50014 79-0

Oil immersion o 50015 79-6 +

Pressurized p 50016 79-2 +

Powder filled q 50017 79-5 +

Flameproof enclosure d 50018 79-1 + +

Increased safety e 50019 79-7 + +

Intrinsic safety ia 50020 79-11 + +

Intrinsic safety ib 50020 79-11 + +

Encapsulated m 50028 79-18 +

Type of protection ‘n’ n 50021 79-15 +

Category I G 50284* - +

Category MI 50303* - +

Electrical equipment for flammable dusts (D)

Construction andtesting 50281-1-1 + + +

Non-electrical equipment CEN EN

General requirements xxxx Pt 1*Restrictive breathingenclosure xxxx Pt 2*

Flameproof enclosure xxxx Pt 3*

Inherent safety xxxx Pt 4*

Constructional safety xxxx Pt 5*

Control of ignitionsources xxxx Pt 6*

�C

�E*Standards in preparation


124

Note for reference only, ATEX now supercedes CenelecATEX Explosive Atmospheres

Equi

pmen

t Mar

king

CEN

ELEC

/IEC

EEx

dIIB

T6Ta

mb

= -4

0°C

to 5

0°C

(EU

Dir

ectiv

e 94

/9/E

C)CE

III

G

Conf

orm

ityw

ith E

urop

ean

Stan

dard

. IEC

mar

king

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Expl

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nPr

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sym

bol

Type

of

Prot

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de s

eeta

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abov

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Gas

Gro

upI

Met

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(fire

dam

p) M

inin

g On

lyIIA

Prop

ane

Typi

cal g

ases

IIB

Ethy

lene

clas

sifie

d ac

cord

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IICHy

drog

ento

igni

tabi

lity

ofII

No

igni

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gas/

air m

ixtu

recl

assi

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Tem

pera

ture

Cla

ss(G

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Refe

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to a

mbi

ent o

f –20

°C to

+40

°C u

nles

sin

dica

ted

as a

bove

TM

axim

umCl

ass

surfa

cete

mpe

ratu

reT1

450°

CT2

300°

CT3

200°

CT4

135°

CT5

100°

CT6

85°C

Equi

pmen

tG

roup

Equi

pmen

tCa

tego

ry

G

Gas

vapo

rm

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D Dus

t

Zone

Zone

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d*M

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de-e

nerg

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* In

pre

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ex

plos

ive

atm

osph

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2 no

n-m

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g1

– ve

ry h

igh

020

prot

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n2

– hi

gh p

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213

– no

rmal

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ion

222

CE M

arki

ng

EU Expl

osiv

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mos

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mbo

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Type

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expl

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�D�E


125

A Selection of Recognized Testing Laboratories

North America

CSA Canadian Standards Association

ENT Entela, Inc.

ETL ETL SEMKO, Intertek Testing Service

FMGT FM Global Technologies LLC

MET MET Laboratories, Inc.

MSHA Mine Safety and Health Administration

UL Underwriters Laboratories Inc.

Australia

TestSafe TestSafe Australia Safety Engineering, Testing and Certification Services

Brazil

CEPEL Centro De Pesquisas De Enrgia Electrica

France

INERIS Institut National De L'Environnemant Industriel Et Des

Germany

DMT Deutsche Montan Technologie GmbH

TUV TUV Product Services GmbH

KEMA KEMA Registered Quality, Inc.

Russia

GOSSTAND ART Gosstandart of Russia


126

ApprovalsSystem InstallationPermanent gas detection systems can be used in both hazardous and non-hazardous rated locations. In North America, if a monitoring system is located ina hazardous area then it must carry the appropriate approvals for that area,(Class, Division and Group). (See “Hazardous Location Classification” earlier inthis section for descriptions of hazardous area classifications.) Most hazardousarea monitoring applications require Class 1, Division 1 approval, which meansthat ignitable atmospheres are likely to be present, and thus protection fromignition sources is required to reduce the possibility of an explosion. The threeprotection methods approved for electrical equipment in this type of area areexplosionproof, intrinsically safe and purged/pressurized.

I. ExplosionproofThe device prevents an explosion in a hazardous location by containing anycombustion within the device, and thereby preventing it from spreading into theatmosphere surrounding the enclosure. (Note: wires connected toexplosionproof classified devices must be contained in an explosionproofclassified conduit.)


127

ApprovalsInstead of having both the sensor and the controller rated explosionproof (XP),explosionproof sensor housings are sometimes used with general purpose (GP)controllers that are located in non-hazardous locations.

• Widely used in US

• More costly to install and maintain

• Requires conduit and seals

• Non-intrusive calibration enhances installation

• If atmosphere ignites, it remains inside enclosure

II. Intrinsically SafeThe device prevents explosions in hazardous locations through an electricaldesign in which the possibility of ignition is eliminated. To achieve this,protective components are often added in series with energy storage devices.The protective components eliminate the risk of ignition from sparks or anincreased component surface temperature.

In this situation, an intrinsically safe sensor assembly is located in thehazardous area and an intrinsically safe barrier is installed in the non-hazardous area to reduce the chance of an electrical spark reaching thehazardous area. If multiple sensors are required, then multiple barriers are used.


128

Approvals• Eliminates explosion proof conduit for electrical safety

• Requires electrical barriers to limit energy to sensor

• Both heat and electrical energy are kept below ignition thresholds

III. Purged/ PressurizedPurged/ pressurized equipment cabinets containing spark-producing devicesexclude flammable atmospheres. This is done by using compressed air or aninert gas such as nitrogen to pressurize the cabinet’s interior. The unit is alsodesigned to turn off the spark-producing device and trigger an alarm in theevent of a pressurization failure. NFPA-496 contains specific designrequirements for purged/ pressurized equipment.

There are three types of purging:

• Type X purging – reduces the classification within an enclosure from Division 1 to nonhazardous

• Type Y purging – reduces the classification within an enclosure from Division 1 to Division 2

• Type Z purging – reduces the classification within an enclosure from Division 2 to nonhazardous

When a purged/pressurized system is used, the unit is located in the hazardousarea. Purging/ pressurization works in one of two ways: by either preventingoutside atmospheres from entering the enclosed unit, or by removing flammablegases from the enclosure by flushing it with inert gas and maintaining internalpressure on the unit.


129

ApprovalsIV. FlameproofWith the flameproof method of protection, the sample is pumped from thehazardous area to the GP sensor, which is located in the non-hazardous area.Flashback arrestors are installed at the hazardous area barrier to reduce thechance of an ignition source entering the hazardous area.

For each of the preceding circumstances, the detection system componentsshould have a label similar to those shown below, indicating that they havereceived the approvals appropriate to the environment in which they are to beinstalled.

NOTE: When installing a gas detection system, always follow National ElectricCode (NEC) installation requirements and check the manufacturer’s guidelinesfor calibration.


130

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Section 6Sensor Placement Guide


134

Quantity and Placement of SensorsMSA gas detection systems monitor the concentration of specifiedgases at the immediate location of the sensor. The installationinstructions and other information from MSA provide only basicguidance on the properties of the gas in question as well as the effectsof certain environmental conditions on the function of the sensor. Whilethis information may be used to help determine the number of sensorsneeded and the optimum sensor placement, do not rely on thisinformation alone to determine the appropriate quantity and placementof the sensors for any particular site or area to be monitored. It isrecommended that the user consult with appropriate industrial hygiene,environmental, and/or health professionals when determining thequantity and placement of sensors to adequately monitor the specificarea in question.

WARNINGMSA gas detection systems monitor the gas concentration only at theimmediate location of the sensor. The user must perform an appropriateenvironmental analysis on the specific installation site to determine thepreferred quantity of sensors and optimum sensor placement. Improperinstallation can cause a gas release to be undetected and result in seriouspersonal injury or loss of life.


135

Sensor Placement GuideMSA Guide to Gas Sensor Selection and Placement

STEP 1: To determine where to place sensors, perform an analysis of thepotential gas hazards in your facility

STEP 2: Create drawings indicating all potential leak sites, as well as theseverity of each site’s hazard potential

There are two main categories of hazardous locations:

A. Potential gas discharge points. These are places where hazardousgases may be released, such as valve stem seals, gaskets,compression fittings and expansion joints.

B. Potential contact areas. These are places where hazardous gasesmay endanger workers or damage equipment or property. Examplesinclude populated areas, confined spaces, pits, stairwells, crawlspaces, shelters, and residential, business and industrialenvironments located nearby.

STEP 3: Since gases do not always behave in the same way, take air flowconditions, as well as potential gas pockets, into consideration before placingsensors. MSA smoke tubes (P/N 458481) can be useful in measuring thedirection and rate of air flow to determine areas where gases may accumulate.


136

Sensor Placement GuideIn general, when placing sensors the following principles should be considered:

• Place sensors in areas where the air currents are likely to produce thehighest gas concentration, including areas where gas buildup is likely,such as corners or stopping points of moving devices that release gas.

• If you are attempting to take a representative room sample, do notplace sensors near entrances or fresh air vents (because sampleconcentration will be diluted by incoming air) unless there is a need tosample that specific area of the room.

• Place sensors close to the possible gas/leak source.

• Place combustible gas sensors between the potential leak and the ignition source.

• Place toxic (and oxygen deficiency) sensors between the potentialleak and the populated area, and in the workers’ breathing zone.

• Consider ease of access to the sensor for maintenance requirements,such as periodic calibration. Use a remote sensor for high orinaccessible locations.

• Avoid mounting sensors near radio transmitters or other RFI-producing sources (e.g., welding activity and induction heaters), to reducepossible RFI interference.

• Avoid locations where airborne particles may coat or contaminate thesensor, such as paint booths.

• Install in a position that prevents water or dust accumulation on the sensor head (which may impede the diffusion of gas into thesensor). Preferred position is facing downward; horizontal placementis also acceptable.

• Facility air intakes are generally good locations for sensors.

• Ensure that the entire area in question is sufficiently monitored,including little-used areas such as closets, warehouses and otherstorage areas.

• Factor in the vapor density of the monitored gases, when compared to air.


137

Sensor Placement Guide

Combustible Gas Sensors• Hydrogen and methane are lighter than air, so place sensors near the

ceiling, and in ceiling corners where pockets of air may collect.

• For electric motor monitoring, place sensors near the ignition source.

• Gasoline is heavier than air, so place sensors near—but not directly on—the floor.

• When monitoring multiple combustible gases, calibrate the instrumentfor the least sensitive gas.

Toxic & Oxygen Gas Sensors• Place carbon monoxide and carbon dioxide sensors for indoor air

quality monitoring near air intake ducts.

• In general, in occupied areas (e.g., confined spaces), monitor foroxygen and toxic gases in the workers’ breathing zone (4-6 feet). Thiswill vary, depending on whether the density of the gas is heavier, thesame as, or lighter than, air or oxygen.

Toxic & Combustible Sensors• Place sensors near the potential release source for process

monitoring applications (e.g., pipelines, valves).

• Gas cylinder storage areas: If they are ventilated, place sensor nearthe return air vent.

• Acid/ solvent drum storage areas: These gases are heavier than air(e.g., heavy hydrocarbons) so place sensors close to the ground and incorners where air may collect in pockets.

• If the hazard is outside, place sensors near the air intake for bothcombustible and toxic gas monitoring; if the hazard is inside, placesensors near the exhaust.

Gases Gas Density Sensor Placement

carbon dioxide,heavyhydrocarbons

greater than air closer to the ground

hydrogen,methane

less than air near the ceiling

carbon monoxide,nitrogen

similar to air according to air current path, at or near breathing level (usually 4 to 6ft. from floor)


138

Sensor Placement Guide• Some gases may collect in pockets in room corners, at both floor and

ceiling levels. Place sensors in these areas if necessary.

Referigerant Monitor Placement• ASHRAE 15 states that a refrigerant monitor capable of detecting the

TLV for a refrigerant gas must be installed in a mechanical equipmentroom.

• Place the end of the sample line in the location most likely to develop arefrigerant gas leak or spill. Such areas include valves, fittings and thechiller itself. Also, monitor any refrigerant storage location. It is goodpractice to keep all sampling lines as short as possible when anaspirated or pumped sampling system is used.

• Since most refrigerant gases are heavier than air, monitor these gasesclose to the floor. Any pits, stairwells or trenches are likely to fill withrefrigerant gas before the main area. It may be necessary to monitorthese locations for refrigerant gas.

• If ventilation exists in the chiller room, MSA smoke tubes (P/N 458481)will help to determine the most appropriate gas monitoring locations.

• Monitor displays can be placed just outside the doorway of themonitored area. Personnel can check the status of the instrumentbefore entering the area.

• ASHRAE Standard 147P states the following;4.8 Refrigerant Monitor. On Large refrigerating systems for which arefrigerant monitor is required per ASHRAE 15, a refrigerant monitorcapable of detecting refrigerant concentrations of 1 ppm by volume orless shall be used to provide early warning of leaks.

Guideline for Sensor PlacementWhen monitoring multiple combustible gases, calibrate the instrument for theleast sensitive gas.

Note: This is for informational purposes only and is intended for use as ageneral guide to important considerations in sensor placement. It is notintended to serve as an exhaustive review of all considerations. Due to the large number of variables present, each site should be considered individuallyby a trained professional. The services of a Certified Industrial Hygienist (CIH) or Certified Safety Professional (CSP) should be considered if an onsitesurvey is required.

Section 7Calibration

CalibrationInstrument CalibrationWhether an instrument warns and/ or alarms at the proper time depends on itsability to translate the quantity of gas it detects into an accurate reading.“Calibration” refers to an instrument’s measurement accuracy relative to aknown concentration of gas. Gas detectors perform relative measurements:rather than independently assessing the quantity of gas present, they measurethe concentration of the air sample and then compare it to the knownconcentration of the gas that the instrument is configured to sample. This“known concentration” serves as the instrument’s measurement scale, orreference point.

If the instrument’s reference point has moved, then its reading will also move.This is called “calibration drift” and it happens to most instruments over time.(Common causes of calibration drift include the normal degradation of sensors,exposure of the sensor to poisons, and harsh operating conditions.) When aninstrument experiences calibration drift it can still measure the quantity of gaspresent, but it cannot convert it into an accurate numerical reading. Regularcalibration with a certified standard gas concentration updates the instrument’sreference point, re-enabling it to produce accurate readings.

There are two methods of verifying instrument calibration: through a functionalor “bump” test (or span check) or by performing a full calibration. Each isappropriate under certain conditions.

Bump (or Span) CheckA bump check is a means of verifying calibration by exposing the instrument to a known concentration of test gas. The instrument reading is then comparedto the actual quantity of gas present (as indicated on the cylinder). If theinstrument’s response is within an acceptable range of the actual concen-tration, then its calibration is verified. When performing a bump test, the testgas concentration should be high enough to trigger the instrument alarm. If thebump test results are not within the acceptable range, then a full calibrationmust be performed.

140



141

CalibrationFull CalibrationA full calibration is the adjustment of the instrument’s reading to coincide withknown concentrations (generally a certified standard) of zero and span gases,to compensate for calibration drift. In most cases, a full calibration is onlynecessary when an instrument does not pass the bump test (or after it has beenserviced).

Zero CheckA zero check is performed to verify that the instrument reads true zero (alsoreferred to as the “baseline”) in an environment in which no amount of targetgas is present. Common situations in which a zero check is performed include:

• after exposure of the sensor to a sensor contaminant

• after the sensor has been exposed to a very high concentration of the target gas

• as the sensor ages, since it may gradually drift

• after the unit has operated in varying background conditions(e.g. humidity levels)

• after exposure to extreme conditions (e.g. high temperature orhumidity)

If the instrument fails the zero check, then a zero adjustment should beperformed, where the instrument is adjusted to true zero.

Frequency of CalibrationThe frequency of calibration depends on the sensor’s operating time, conditionsof use (including chemical exposure) and user experience with the instrument.New sensors should be calibrated more often until the calibration records provesensor stability. The calibration frequency can then be reduced to the scheduleset by the safety officer or plant manager. Before calibrating the sensors, it isgood practice to apply power to the unit to allow the sensor to adapt to the newenvironment. Sensors should be powered at least one full hour before anycalibration attempt is made.

Section 8Resources


144

Resources:Code of Federal Regulations (CFR) Title 29 Part 1910, U.S. Department of Labor(DOL), Occupational Safety and Health Administration (OSHA), Washington, D.C.Available online at: www.osha.gov/comp-links.html andwww.access.gpo.gov/nara/cfr/waisidx_01/29cfr1910_01.html

NIOSH Pocket Guide to Chemical Hazards, Department of Health and HumanServices (DHHS), National Institute of Occupational Safety and Health (NIOSH),85-114. Available online at: www.cdc.gov/niosh/npg/npg.html

Occupational Health Guidelines for Chemical Hazards, DHHS, DOL, Washington,D.C., January 1981, DHHS (NIOSH) No. 81-123. Available online at:www.cdc.gov/niosh/81-123.html

Fire Protection Guide to Hazardous Materials, 13th edition, National FireProtection Association (NFPA) One Battery Park, Quincy, MA 02269 (2002).Available online at: www.nfpa.org

2002 TLVs® and BEIs®, American Conference of Governmental IndustrialHygienists (ACGIH), Cincinnati, OH 45240. Available online at: www.acgih.org

Many governmental agencies and other safety organizations with health andsafety expertise maintain web sites on the Internet.

GOVERNMENT AGENCIES:Agency for Toxic Substances and Disease Registry (ATSDR) www.atsdr.cdc.govBureau of Labor Statistics (BLS) www.bls.govCenter for Disease Control and Prevention (CDC) www.cdc.govCode of Federal Regulations (CFR) www.access.gpo.gov/nara/cfr/cfr-table-search.htmlDepartment of Transportation (DOT) Office of Hazardous Materials Safetywww.hazmat.dot.govFederal Mine Safety and Health Review Commission www.fmshrc.govNational Institute of Environmental Health Sciences www.niehs.nih.govNational Institute for Occupational Safety and Health (NIOSH)www.cdc.gov/niosh/homepage.htmlNational Institute of Health (NIH) www.nih.govNational Safety Council (NSC) www.nsc.orgNuclear Regulatory Commission (NRC) www.nrc.govOccupational Safety and Health Administration (OSHA) www.osha.govOffice for Mine Safety and Health Research www.cdc.gov/niosh/miningU.S. Department of Health and Human Services (US DHHS) www.os.dhhs.govU.S. Department of Labor, Mine Safety and Health Administration (MSHA)www.msha.govU.S. Environmental Protection Agency (EPA), Washington, D.C. www.epa.gov


145

Resources:PROFESSIONAL & TRADE ASSOCIATIONS:Air and Waste Management Association www.awma.org

American Board of Industrial Hygiene www.abih.org

American Conference of Governmental Industrial Hygienists (ACGIH)www.acgih.org

American Industrial Hygiene Association (AIHA) www.aiha.org

American Society of Heating, Refrigerating and Air Conditioning Engineerswww.ashrae.org

American Society of Safety Engineers (ASSE) www.asse.org

Building Officials and Code Administrators (BOCA) International www.bocai.org

Center for Chemical Process Safety, American Institute of Chemical Engineerswww.aiche.org/ccps/index.htm

Chemical Manufacturers Association www.cmahq.com

Compressed Gas Association www.cganet.com

International Society for Measurement and Control (ISA) www.isa.org

National Fire Protection Association (NFPA) www.nfpa.org

National Safety Council (NSC) www.nsc.org

Water Environment Federation® (WEF) www.wef.org

World Health Organization (WHO) www.who.int

World Safety Organization www.worldsafety.org

APPROVALS & STANDARDS ORGANIZATIONS:

American National Standards Institute (ANSI) www.ansi.org

Canadian Standards Association (CSA) International www.csa-international.org

European Committee for Electrotechnical Standardization (CENELEC)www.cenelec.org

National Electrical Manufacturers Association (NEMA) www.nema.org

Underwriters Laboratories, Inc. (UL) www.ul.com

International Electrotechnical Commission (IEC) www.iec.ch

GAS DETECTION INSTRUMENTATION SUPPLIER:

Mine Safety Appliances Company (MSA)

www.msagasdetection.com

MSA Instrument DivisionP.O. Box 427Pittsburgh, PA 15230

Phone: 1.800.MSA.INSTFax: 1.724.776.3280

www.msagasdetection.com

ID 5555-312-MC / Aug 2007© MSA 2007 Printed in U.S.A.

MSA Gas Detection Handbook

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