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guide togas Cabinet safety

and Code Conformance

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Gas Cabinet safety and Code ConformanCe

Table of Contents

IntroductionandClassificationofGases ...........................................................................................3ControlAreasandThresholdQuantities ............................................................................................5CodeConformanceExamples ...........................................................................................................6TypicalSafetyFeaturesofGasCabinets ...........................................................................................7GasCabinetDescriptions ..................................................................................................................8Laboratory1000SeriesFlammableGasCabinets ...........................................................................9Laboratory2000SeriesToxic&CorrosiveGasCabinets ...............................................................10Laboratory3000SeriesHighlyToxic&PyrophoricGasCabinets ..................................................11FrequentlyAskedQuestions(FAQs) ................................................................................................12Glossary of Terms .............................................................................................................................14InternationalCodes:AdoptionbyState ...........................................................................................15

TheGuidetoGasCabinetSafetyandCodeConformance(”Guide”)isprovidedbyAirgas,Inc.(“Airgas”)forinformationalpurposes only. The codes referenced in the Guide are based on informationfromNFPA55-2010Editionand2009versionsoftheInternationalCodes.ThisGuideisnotareplacementforcompleteengineeringdesignbyaqualifiedengineerincompliancewithallapplicablecodes.Customermustconsultcurrentfederal,state and local building codes and ordinances for complete code compliance.Installationsmayrequireothersitespecificdesignrequirements. Be advised that codes are subject to change. Any gascylinder(s)installationandtheenduseofthegaseswarrantsreviewforlocalconditionsorBuildingandFireCoderequirements.

This Guide is compiled from various reference sources and is designed to provide current information on the subject matter covered. This Guide is provided with the understanding that Airgas and Airgas’ personnel are not engaged in rendering, legal, regulatory or other professional services. Airgas believes the information provided to be correct but assumes no liability for any damages attendant to the use of this Guide.

Airgas shall not be held liable for any improper or incorrect use of the information described and/or contained in the Guide or any related training and assumes no responsibility for any user’s use of such information and/or training. In no event shall Airgas or Airgas personnel be liable for any direct, indirect, incidental, special,exemplary,orconsequentialdamageshowevercausedand on any theory of liability, whether in contract, strict liability, ortort(includingnegligenceorotherwise)arisinginanywayoutof the use of these materials and information. This disclaimer of liability applies to any damages or injury, including but not limited to those caused by any failure of performance, error, omission, completeness, or use of materials.

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IntroductionThe handling and storage of hazardous gases is covered extensivelythroughoutseveralNationalCodes.Thecodes applygeneralrulestodifferentclassesofgassuchasflammable,toxic,corrosive,highlytoxicandpyrophoric.Theintentofthisguide is to:•Inform its users of the principal code requirements•Assist in selecting and obtaining the proper equipment•Helpachieveacode-compliantgascylindersystem This guide will outline some of the requirements given in the following editions of the national codes and standards:•NationalFireProtectionAssociation2010Edition(“NFPA”)•InternationalFireCode2009Edition(“IFC”)•InternationalBuildingCode2009(“IBC”)•InternationalMechanicalCode2009(“IMC”)

Duetothecomplexityofthecodes,thisguideisnotareplacementforaprojectspecific,completeengineeringdesignandreviewbyaqualifiedengineerknowledgeableintheapplicationofcodes and standards for their construction and use. Also, the usershouldrecognizethatCodesandStandardsareperiodicallyupdatedandthatanyspecificcitationcontainedorreferencedhereinwillneedtobeverifiedwiththelatestcurrenteditionthatapplies. Further, it is important to remember that the local authority havingjurisdiction,suchasabuildinginspectororfiremarshal,can go above and beyond the requirements of the written codes.

TheIFChasbeenadoptedin43states;theIBChasbeenadoptedin50states;andtheIMChasbeenadoptedin46states.Astateadoption table is shown at the end of this document. For the most recentlistings,aswellasspecificjurisdictionswithinastate,goto:http://www.iccsafe.org/gr/Documents/stateadoptions.pdf

Flammable Gas: A material that is a gas at 68° F or less at an absolutepressureof14.7psi,thatisignitableatanabsolutepressureof14.7psiwheninamixtureof13percentorlessbyvolumewithair,orthathasaflammablerangeatanabsolutepressureof14.7psiwithairofatleast12percent,regardless of the lower limit.

AflammablegasisgenerallyaU.S.Departmentof Transportation(“DOT”)Class2.1FlammablewithaNFPAflammabilityratingof4.

Corrosive Gas: A gas that causes visible destruction of or irreversible alterations in living tissue by chemical action at the site of contact.

AcorrosivegasisgenerallyaDOTClass2.3Poisonwitha NFPAhealthratingof3or4.

Pyrophoric Gases: With an autoignition temperature in air at orbelow130°F.

ApyrophoricgasisgenerallyaDOTClass2.1FlammablewithaNFPAreactivityratingof3.

Oxidizing Gas: A gas that can support and accelerate combustion of other materials more than air does.

AnoxidizinggasisgenerallyaDOTClass2.2Oxidizer.

Rather than dealing with individual gases, the national codes addressspecifichazardtypes.Forexample,thecodesmaynotoffer guidelines for storage and handling of chlorine but would provideinformationontoxicgasesasawhole.

In order for us to understand how to interpret the codes, we mustfirsthaveaclearideaofthedefinitionofeachgashazardtype.Therearefivehazardtypesthataretypicallystoredingascabinets. Below is a listing of these classes complete with their definitionsasusedinNFPA:

Classification of Gases

Thedefinitionofatoxicandhighlytoxicgasisrelatedtothelethalconcentrationwhere50%ofasamplepopulationofalbinoratsdieafterexposure.ThisvalueisreferredtoastheLC50,withthelevelsdefinedasfollows:

Toxic Gas:Agaswithamedianlethalconcentration(LC50) inairofmorethan200partspermillion(ppm)butnotmorethan2,000ppmbyvolumeofgasorvapor.Examplesoftoxicgasarechlorine,hydrogensulfide(H2S)andhydrogenfluoride(HF).

Highly Toxic Gas: A chemical that has a median lethal concentration(LC50)inairof200ppmorlessbyvolumeofgasorvapor.Examplesofhighlytoxicgasarearsine,phospine(PH3),andnitricoxide(NO).

Atoxic/highlytoxicgasisgenerallyaDOTClass2.3PoisonwithaNFPAhealthratingof3or4.

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Forfurtherinformationongashazardtype,Table1providesapartiallistofcommonlyusedgasesandtheirclassifications.

Table 1. Partial List of Gases and Their ClassificationsGas Chemical Name Liquefied or

Non-Liquefied Gas?

Flammable (see p. 9 for equipment offering)

Toxic (see p. 10 for equipment offering)

Corrosive (see p. 10 for equipment offering)

Pyrophoric (see p. 11 for equipment offering)

Highly Toxic (see p. 11 for equipment offering)

Ammonia Liquefied * √

Arsine Liquefied √

CarbonMonoxide Non-liquefied √ **

Chlorine Liquefied √

Disilane Liquefied √ √

Ethane Liquefied √

EthylChloride Liquefied √

Ethylene Liquefied √

Fluorine Non-liquefied √

Hydrogen Non-liquefied √

HydrogenChloride(HCl) Liquefied √

HydrogenFluoride(HF) Liquefied √ ***

HydrogenSulfide(H2S) Liquefied √ √

Methane Non-liquefied √

NitricOxide Non-liquefied √

NitrogenDioxide Liquefied √

Phosgene Liquefied √

Phosphine Liquefied √ √

Silane Non-liquefied √

Silicon Tetrachloride Liquefied √ ***

SiliconTetrafluoride Non-liquefied √

SulfurDioxide Liquefied √

Trimethylamine Liquefied √ √TungstenHexafluoride Liquefied √ ***

*Ammonia is classified as a corrosive, but does have flammability hazards. Ammonia will ignite and burn although its flammable range is too narrow to fit the definition of a flammable gas. While it doesn’t meet the definition of a flammable gas, it is classified as a Group D flammable according to the National Electrical Code.**Carbon Monoxide is classified as a flammable but should be used with a toxic gas cabinet.***Hydrogen fluoride, silicon tetrachloride and tungsten hexafluoride are classified as toxics, but are recommended to be used with a highly toxic gas cabinet.

ItshouldbenotedthatNFPA557.1.10.1.1referencestheseparationofcompressedgascylindersbasedontheirhazardclasstype(alsoseeNFPA55Table7.1.10.2forseparationdistances).Thisisanimportantconcepttokeepinmind,asitdictatesthatwecannotstoreincompatiblegashazardclassesinthesamegascabinet.Forexample,wecannotstorebothethane(flammable)andsulfurdioxide(toxic)inthesamecabinetastheyaretwodifferenthazardclassifications.

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Control Areas and Threshold QuantitiesChapter4oftheIBCdefinesacontrolareaasaspacewithinabuildingwherequantitiesofhazardousmaterialnotexceedingthemaximumallowablequantities(MAQ)arestored,dispensed,used

or handled. It is advantageous to utilize the control area concept to prevent having the entire room or building of a facility meet BuildingandFireCoderequirementsforhigh-hazardoccupancy.

Table 2. Maximum Allowable Quantity (MAQ) of Gas per Control Area

Gas Hazard Type Phase

Unsprinklered Area Sprinklered AreaNo gas cabinet, gas roomorexhausted

enclosure

Gas cabinet, gas roomorexhausted

enclosure

No gas cabinet, gas roomorexhausted

enclosure

Gas cabinet, gas roomorexhausted

enclosureFlammable Liquefied

Non-liquefied150lbs.1,000ft3

300lbs.2,000ft3

300lbs.2,000ft3

600lbs.4,000ft3

Toxic LiquefiedNon-liquefied

150lbs.810ft3

300lbs.1,620ft3

300lbs.1,620ft3

600lbs.3,240ft3

Corrosive LiquefiedNon-liquefied

150lbs.810ft3

300lbs.1,620ft3

300lbs.1,620ft3

600lbs.3,240ft3

Pyrophoric LiquefiedNon-liquefied

0lbs.0ft3

0lbs.0ft3

4lbs.50ft3

8 lbs.100ft3

HighlyToxic LiquefiedNon-liquefied

0lbs.0ft3

4lbs.20ft3

0lbs.0ft3

8 lbs.40ft3

Oxidizers LiquefiedNon-liquefied

150lbs.1,500ft3

300lbs.3,000ft3

300lbs.3,000ft3

600lbs.6,000ft3

Source: NFPA 55 Table 6.3.1.1

Inordertomeettheclassificationofacontrolareaandavoidclassificationashigh-hazardoccupancy,thequantityinuse/storage must be reduced, or multiple control areas must be created.Table3showsthemaximumnumberofcontrolareas

allowed per building. The source of this table is the International BuildingCodeSection414(2009edition).Stateandlocalbuildingandfirecodesmustalsobereviewed.

Table 3. Maximum Number of Control Areas Allowed per Building

FloorLevel PercentageoftheMAQperControlArea

MaximumNumberofControlAreasperFloor

Fire Resistance Rating for FireBarriers(inhours)

Above Grade

1234567-9

Higher than 9

100755012.512.512.5

55

43222221

11122222

Below Grade12

Lowerthan2

7550

Not Applicable

32

Not Applicable

11

Not ApplicableSource: IBC Section 414

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Code Conformance ExamplesExample 1: Customer Using Flammable Gas A customer is using methane for one of their plant processes. Thisnon-liquefiedflammablegasis(perTable1ofthisguide) both stored and used in an area that was unsprinklered and withoutagascabinet,gasroomorexhaustedenclosure.Thequantities on hand are as follows:

•3cylindersofmethanex360ft3/cylinder=1,080ft3 of methane on hand

Inthisscenario,thecustomerdoesnotconformwithNFPA,IFCandIBCsincetheyareabovetheMAQof1,000ft3(perTable2 ofthisguide)foranareawithoutasprinkleredgascabinet,roomorexhaustedenclosure.

InordertocomplywithNFPA,IFCandIBCrequirementsforthreshold quantities, a gas cabinet would need to be used. By placingtheseflammablegascylindersintoacabinettheywouldbeallowedtokeepupto2,000ft3ofnon-liquefiedflammablegases in this particular area. This entire area could now be classifiedasacontrolarea.PertheInternationalBuildingCodethis customer could have up to three additional control areas on thisfirstflooroftheirfacility(perTable3ofthisguide).

Example 2: Customer Using Toxic GasesAcustomerisusingthefollowingliquefiedtoxicgases(perTable1ofthisGuide)inoneareaoftheirplantwithoutanysprinkler,cabinet,gasroomorexhaustedenclosure:

•1cylinderofhydrogensulfidex60lbs./cylinder=60lbs.•2cylindersofchlorinex90lbs./cylinder=180lbs.•Totaltoxic(liquefied)gasesinarea=240lbs.

The240lbs.oftoxicgasesareabovethe150lbs.MAQforuseinanunsprinkleredareawithnogascabinet,gasroomorexhaustedenclosure(seeTable2ofthisguide).

InordertoconformtoNFPA,IFCandIBC,onecabinetcouldbeusedforallthreecylinders.Sincethesetwogasesarebothtoxics,they are compatible hazardous materials and can be placed together in one cabinet. If they were incompatible gases (e.g.,toxicandcorrosive)separatecabinetswouldberequired. Inacabinet,thecustomercannowstoreupto300lbs.ofliquefiedtoxicgases.ThisentireareacouldnowbeclassifiedasacontrolareaperIBCandthiscustomercouldhaveuptothreeadditionalcontrolareasonthisfirstflooroftheirfacility(perTable3of thisguide).

Example 3: Customer Using Flammable and Corrosive GasesAclienthasbothmethane(non-liquefiedflammablegas)andsulfurdioxide(liquefiedcorrosivegas)inoneroomoftheirfacilitywhich is unsprinklered and without a gas cabinet, gas room or exhaustedenclosure.Thequantitiesonhandareasfollows:

•3cylindersofmethanex360ft3/cylinder=1,080ft3 of methane on hand

•2cylindersofsulfurdioxidex150lbs./cylinder=300lbs.ofsulfurdioxideonhand

Sincethisareahasnosprinkleredgascabinet,roomorexhaustedenclosure,thecustomerdoesnotconformwithNFPA,IFCandIBCsincetheyareabovetheMAQof1,000ft3fornon-liquefiedflammablegasesandabovetheMAQof150lbs.foraliquefiedcorrosivegas(perTable2ofthisguide).

InordertocomplywiththeNFPA,IFCandIBCgascabinetswould need to be used. However, in this scenario, it is important torememberthatperNFPA55,weneedtoseparatedifferenthazard classes. Thus, the customer cannot have one cabinet with bothmethaneandsulfurdioxideinside.Instead,theymusthaveone cabinet for methane and another separate cabinet for sulfur dioxidetocomplywithNFPA.

By placing the three methane cylinders in one cabinet and the two cylindersofsulfurdioxideinanothercabinetthecustomerwouldbebelowtheNFPA,IFCandIBCMAQsasstatedinTable2.

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A gas cabinet itself is designed to isolate gas cylinders from the surrounding environment. In doing so, it protects end users from thehazardsassociatedwiththedifferentgastypes.PerNFPA556.16,cabinetsmusthavethefollowingdesignfeatures:

•Notlessthan12-gaugesteelconstruction•Access to controls via self closing doors and windows•Ventilationrequirementsof200ft./minutefacevelocityat

access openings•Internally sprinklered•No more than three tanks per cabinet, which must be compatible

Inadditiontothegascabinet,extrasafetyfeaturesareoftenbuiltinto the overall system. Such components are considered based onthegashazardtype(e.g.,flammable,toxic,pyrophoric,orhighlytoxic);incorporatingthesecomponentsintothecabinetwillserve as additional methods of protection for individuals working withandaroundhazardousgases.Table4listssomeofthesefeaturesandtheirsafetybenefits.

Typical Safety Features of Gas Cabinets

Table 4. Common Safety Components of Airgas Gas Cabinet SystemsFeature BenefitEmergencyShut-OffValve Quicklystopsflowofgasesintheeventofleakdownstreamandcanbeactivatedautomaticallybygas

detection system or manually by emergency stop buttonExcessFlowControl Haltsflowofgaswhenabnormal(high)gasflowlevelsoccur,whicharetypicallyindicativeofaleak

in the pipingExhaustAlarm Alertsenduserswhennegativepressureorexhaustflowtocabinetislost;alsoshutsdowngasflowto

ensureoperatorsaren’texposedtopotentialleaksthatmayoccurduringlossofnegativepressureGasDetectionSystem Providesnotificationofflammable,toxic,highlytoxicorpyrophoricgasconcentrationsinatmosphere;

alarmsactivatedbeforedangerouslevelsarereached(i.e.LFL,PEL)PurgeSystem Usedtoflushresidueofprocessgasouttovent,helpstoensurethatoperatorisnotexposedto

hazardous gas during cylinder changeoutVacuumDrive Usedinconjunctionwithpurgesystemasameansofextractinghazardousgasesfrom

delivery equipmentSource: Airgas Engineering Solutions

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Laboratory 1000 Series Flammable Gas Cabinet: The1000SeriesFlammableGasCabinetisdesignedwithaprocess panel containing either an individual pressure regulator or automatic changeover manifold to regulate the source gas pressure. The system also includes a gas detector to determine the%lowerexplosivelimit(LEL)ofthegasinthecabinet.Ifaleak is detected, a controller tied into the gas detector closes the emergencyshut-offvalveonthepanel,stoppingtheflowofgas.Foraddedsafety,thecabinetcontainsaflashbackarrestorandexcessflowcontrolonthepaneloutlet.TheflammablegascabinetsystemalsoincludesashutoffvalveandCGAconnectionwithintegratedchecknippleontheflexhose(s),sonopurgesystemorvacuumdriveisrequired.Figure1showsastandardflammableprocesspanelwiththeindividualregulatorconfiguration.

Laboratory 2000 Series Toxic and Corrosive Gas Cabinet: The2000SeriesToxicandCorrosiveGasCabinetisdesignedwith a process panel containing either an individual pressure regulator or automatic changeover manifold to regulate the source gas pressure. The panel will include a purge system with vacuum drive to protect operator safety during a cylinder change as well as prolong the life of the equipment. The purge process is semi-automated,allowingtheoperatortoopenandcloseaseriesof valves during the cylinder change out. The cabinet system includesagasdetectortodeterminethepartspermillion(ppm)concentration of the gas in the cabinet. If a leak is detected, a controllertiedintothegasdetectorclosestheemergencyshut-offvalveonthepanel,stoppingtheflowofgas.Figure2showsastandardtoxicandcorrosiveprocesspanelwiththeindividualpressureregulatorconfiguration.

Laboratory 3000 Series Highly Toxic and Pyrophoric Gas Cabinet:The3000SeriesHighlyToxicandPyrophoricGasCabinetisdesignedwithaprocesspanelcontaininganindividualpressure regulator. The panel will include a purge system with vacuum drive to protect operator safety during a cylinder change as well as prolong the life of the equipment. The purge process is fully-automated,allowingtheoperatortocontrolthepurgecyclesfromanonboardPLC.Thecabinetsystemincludesagasdetectorto determine the ppm concentration of the gas in the cabinet. If a leak is detected, a controller tied into the gas detector closes the emergencyshut-offvalveonthepanel,stoppingtheflowofgas.Foradditionalsafety,exhaustalarmsareutilizedwiththislineofcabinets.Figure3showsastandardhighlytoxicandpyrophoricprocesspanelwiththeindividualpressureregulatorconfiguration.

Gas Cabinet Descriptions To Process

RegulatorManual

Valve

Check ValveNipple

PneumaticEmergency Shut-off

ValveFlashback Arrestor

FlammableGas Cylinder

Excess Flow Valve

Figure 1: Flammable gas panel with individual pressure regulator

Figure 2: Toxic & corrosive gas panel with individual pressure regulator

Nitrogen Motive


Valve

To Process

NitrogenInlet

Toxic orCorrosive

Gas Cylinder

To Vent

To Process

Nitrogen Motive


Valve

NitrogenInlet

To Vent

Highly Toxicor PyrophoricGas Cylinder

Figure 3: Highly toxic & pyrophoric gas panel with individual pressure regulator

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Laboratory 1000 Series Flammable Gas Cabinets TheLaboratory1000Seriesgascabinetsaredesignedtomeetthesafestoragerequirementsforflammablegaseswhileconformingtotheguidelinesprovidedintheapplicablenationalcodes,suchastheInternationalFireCode(IFC),InternationalBuildingCode(IBC),InternationalMechanicalCode(IMC)andtheNationalFireProtectionAgency(NFPA).

Theflammablegascabinetincludeseitheraregulatororautomaticchangeovermanifold, gasdetector,automaticflowshutoffvalve,anexcessflowvalveandaflashbackarrestor.

Acontrolboxisprovidedasastandardwiththecabinettoprovidepowertothegasdetector as well as offer an emergency stop button and commands to the automatic shutoff valve.

Additionaloptionssuchaspressureandflowmonitoring,remoteE-stop,andremotegas monitoringareavailabletomeetyourspecificprocessrequirements.AirgasalsoprovidestheNanoSemilineofgascabinetswhichfeatureVCRconstructionandcleanroomassembly.

Standard ConfigurationsLaboratory 1000 Series Flammable Gas Cabinet with Individual Process Panel

Part # V89 ES1452

24”widesteelcylindercabinetwithindividualbrasspressureregulatortohouseoneprocesscylinderandonesparecylinder.Cabinetalsocontainsanexcessflowvalveandflashbackarrestormounteddownstreamoftheregulator.Agasdetectorandcontrolboxmountedtothetopofthecabinetprovidesameansofshuttingdownthesystemintheeventofaleak.Constructedwith NPTconnections.

Laboratory 1000 Series Flammable Gas Cabinet with Automatic Changeover Manifold

Part # V89 ES1450

24”widecylindersteelcabinetwithbrassautomaticchangeovermanifoldtohousetwoprocesscylinders.Thepanelallowsforautomaticswitchingtosecondcylinderupondepletionofthefirstcylinder.Cabinetalsocontainsanexcessflowvalveandflashbackarrestormounteddownstreamofthemanifold.Agasdetectorandcontrolboxmountedtothetopofthecabinetprovidesameansofshuttingdownthesystemintheeventofaleak.ConstructedwithNPTconnections.

Design FeaturesDesigned for code conformance 11-gaugesteelcabinetconstructionwithself-closingdoorsandwindowsandinternal

sprinkler head Protects personnel Safelyexhaustshazardousgases

Gas detection with cabinet mounted display View gas levels from outside the cabinet, automatic shutdown at alarm levels

Automatic shutdown Normally closed shutoff valve actuated by emergency stop button or high gas concentration

Facilities RequirementsPower 110VAC N/A

Pneumatic Supply (N2 or clean, dry air) adjustableto90psig 1slmmax.

Sprinkler 30psig 31gpm

Exhaust >0.15”H20 300scfm(2cylinder)

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Laboratory 2000 Series Toxic and Corrosive Gas Cabinets

TheLaboratory2000Seriesgascabinetsaredesignedtomeetthesafestoragerequirementsfortoxicandcorrosivegaseswhileconformingtotheguidelinesprovidedintheapplicablenationalcodes,suchastheInternationalFireCode(IFC),InternationalBuildingCode(IBC),InternationalMechanicalCode(IMC)andtheNationalFireProtectionAgency(NFPA).

Thetoxicandcorrosivegascabinetincludeseitheraregulatororautomaticchangeovermanifoldwithpurgecontrolsutilizingavacuumventuri,gasdetectorandautomaticflowshutoffvalve.

Acontrolboxisprovidedasastandardwiththecabinettoprovidepowertothegasdetectoraswell as offer an emergency stop button and commands to the automatic shutoff valve.

Additionaloptionssuchaspressureandflowmonitoring,remoteE-stop,andremotegas monitoringareavailabletomeetyourspecificprocessrequirements.AirgasalsoprovidestheNanoSemilineofgascabinetswhichfeatureVCRconstructionandcleanroomassembly.

Standard ConfigurationsLaboratory 2000 Series Toxic and Corrosive Gas Cabinet with Individual Process Panel

Part # V89 ES1453

24”widesteelcylindercabinetwithindividualstainlesssteelpressureregulatortohouseoneprocesscylinderandapurgegascylindermountedinsidethecabinet.Cabinetalsocontainsapurgegasregulatorforvacuummotivesupply.Agasdetectorandcontrolboxmountedtothetopofthecabinetprovidesameansofshuttingdownthesystemintheeventofaleak.ConstructedwithNPTconnections.

Laboratory 2000 Series Toxic and Corrosive Gas Cabinet with Automatic Changeover Manifold

Part # V89 ES1451

36”widesteelcylindercabinetwithstainlesssteelchangeovermanifoldtohousetwoprocessgascylindersandapurgegascylindermountedinsidethecabinet.Cabinetalsocontainsapurgegasregulatorforvacuummotivesupply.Agasdetectorandcontrolboxmountedtothetopofthecabinetprovidesameansofshuttingdownthesystemintheeventofaleak.Constructedwith NPTconnections.




Automatic shutdown Normally closed shutoff valve actuated by emergency stop button or high gas concentration

Facilities RequirementsPower 110VAC N/A

Pneumatic Supply (N2 or clean, dry air) adjustableto90psig 1slmmax.

Process Purge (N2 cylinder) adjustableto80psig 30slm

Vacuum Drive (N2 from cylinder or house line) adjustable to 85 psig 85slmmax



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Laboratory 3000 Series Highly Toxic and Pyrophoric Gas Cabinets

TheLaboratory3000Seriesgascabinetsaredesignedtomeetthesafestoragerequirementsforhighlytoxicandpyrophoricgaseswhileconformingtotheguidelinesprovidedintheapplicablenationalcodes,suchastheInternationalFireCode(IFC),InternationalBuildingCode(IBC),InternationalMechanicalCode(IMC)andtheNationalFireProtectionAgency(NFPA).

Thehighlytoxicandpyrophoricfullyautomaticgroupofcabinetsincludesaprocesspanelwithpurgecontrolsutilizingavacuumventuri,gasdetectorandautomaticflowshutoffvalve.

Atouch-screenPLCisprovidedasastandardwiththecabinettoprovideautomatedcontrolofallcriticalfunctionssuchaspurgesequence,emergencyshutoff,alarmoutputsandexhaustpressure monitor. Additional options such as automatic switchover, integrated scales, purgeable splitters,restrictivefloworifices,filtrationandpurificationareavailabletomeetyourspecificprocess requirements.

Standard ConfigurationLaboratory 3000 Series Highly Toxic and Pyrophoric Gas Cabinet

24”widesteelcylindercabinetwithindividualprocesspanel to house one process cylinder and a purge gas cylindermountedinsidethecabinet.Cabinetalsocontains a purge gas regulator for vacuum motive supply,gasdetectorandautomaticflowshutoffvalve.Atouch-screenPLCmountedtothetopofthecabinetprovidesautomatedcontrolofcriticalfunctions.CleanroomassemblywithVCRconnections.




PLC Controls Colortouchscreeninterface,auto-sequencedroutingsofoperationandmaintenance

Facilities RequirementsPower 115V/3A N/A

Pneumatic Supply (N2 or clean, dry air) adjustableto90psig 1slmmax

Process Purge (N2 cylinder) adjustableto80psig 30slm

Vacuum Drive (N2 from cylinder or house line) adjustable to 85 psig 85slmmax

Process Vent >1.0”WC 100slm



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1) Why do I need a gas cabinet?The main reason for a gas cabinet is to protect individuals and ensurecompliancewithrelevantcodesandregulations.Usingagascabinetallowsthemaximumstoragequantityforflammableandtoxicgases.Italsoprovidesafirebarrierbetweentwoincompatible materials.

2) How much flammable or toxic gas can I store on site?TheMaximumAllowableQuantity(MAQ)offlammableandtoxicgasesthatcanbestoredonsiteundertheNFPAisshownin Table2ofthisguideaswellasTable6.3.1ofNFPA55.

Forflammablegases,theNFPAMAQislimitedto30gallonsofaliquefiedgasand1,000ft3ofanon-liquefiedgas.Thisquantitycanbedoubledifplacedintoagascabinetorexhaustedenclosure(2,000ft3).Thequantitycanbedoubledagainifthegascabinetorexhaustedenclosureisasprinkleredarea(4,000ft3).

FortoxicandcorrosivegasestheNFPAMAQis150pounds foraliquefiedgasand810ft3 foranon-liquefiedgas. Again the quantities can be doubled if placed into a gas cabinet(300pounds/1,620ft3)anddoubledagainifthegascabinetorexhaustedenclosureisinasprinkleredarea(600pounds/3,240ft3).

3) What if I exceed the threshold quantity for a given gas?ThethresholdquantitieslistedperNFPAinTable2givethemaximumamountofgasthatcanbestoredpercontrolarea.Ifthesequantitiesareexceeded,theareacannolongerbeconsideredacontrolarea,butratherhigh-hazardoccupancy (H2forflammablegases,H4fortoxicgases)andwouldneedtomeet the additional requirements as listed in the International Fire Code(IFC)andInternationalBuildingCode(IBC).

Suchitemsasexplosioncontrol,standbyemergencypower,fireseparation, supervised central alarm system, and higher level of sprinkler protection may be required and should be considered.

It is permissible to have multiple control areas in a building in order to spread out the quantity of stored gas within a facility. Table 3showsthemaximumnumberofcontrolareasforeachfloorofabuildingasoutlinedinIBCSection414.Alwayschecklegalrequirements as well.

4) What if my bottle isn’t connected? Does it still count toward my threshold quantity?Yes!Acontrolareaisdefinedasaspacewithinabuildingwherequantities of hazardous materials are stored, dispensed, used or handled.

5) What is a control area and how many can I have in my facility?AccordingtoChapter4oftheIBC,acontrolareaisdefinedasaspace within a building where quantities of hazardous material not exceedingthemaximumallowablequantitiespercontrolareaarestored, dispensed, used or handled.

Table414.2.2oftheIBC(alsoshownonTable3ofthisguide)shows the number of control areas and the percentage of allowablequantitiesthatareallowedperfloorlevel.

6) What is the difference between a toxic and highly toxic gas?Thedifferenceisbaseduponthelethalconcentrationwhere50%ofasamplepopulationofanimals(typicallyalbinorats)diesafterexposure.ThisisreferredtoastheLC50.

AtoxicgasisdefinedbyNFPAasachemicalthathasanLC50between200ppmand2000ppm.AhighlytoxicgasisdefinedasachemicalthathasanLC50between0and200ppm.

SeeTable1ofthisguideforsomeofthemostcommonlyusedgasesandtheirclassifications

7) Do I need gas detection if I’m below the Threshold Quantity?AccordingtoNFPAifagashasphysiologicalpropertiesbelowthe threshold quantities gas detection is not required. However, in general,gasdetectorsshouldbeusedtodetecttoxicgasesatorbelowtheirPermissibleExposureLimits(PEL),andat25%oftheLowerFlammableLimit(LFL)forflammablegases.Further,thegas detection system should be tied to automatic controls that shut offthesupplyofgasintheeventofaleak.RefertoIBCChapter9andIFCSection2703forfurtherreview.

8) Do I need excess flow control? Yes,perIFC,excessflowprotectioncanbeprovidedinoneoftwoways. A gas detector tied into an emergency shutoff as described in the previous point is one way. The second method is to use an excessflowvalve.

9) Does the exhaust fan need to run all the time? Yes,accordingtotheInternationalMechanicalCode(IMC) Chapter5,gascabinetshavethefollowingrequirements:

•Mustbeconnectedtoanexhaustsystem•Provideafacevelocityof200feetperminute(FPM)atgas

cabinet access ports and windows•Maynotbeusedasthesolemeansofexhaustforanyroom

or area

Frequently Asked Questions (FAQs)

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Frequently Asked Questions (FAQs) continued....10) How much airflow do I need for my gas cabinet?Theairflowrequirementsaregiventoinsurethegascabinetoperates at a negative pressure relative to the surrounding area, as well as to sweep air across access ports.

Allaccessports,(typicallythewindows),haveafacevelocityrequirement. The typical gas cabinet requires a ventilation rate of approximately300cubicfeetperminute(CFM)inordertomeetthis requirement. 11) What are the design requirements of my gas cabinet?•Notlessthan12gaugesteelconstruction•Accesstocontrolsviaself-closingdoorsandwindows•Ventilationrequirementsof200ft/minfacevelocityat

access openings•Internally sprinklered•No more than three tanks per gas cabinet, which must

be compatible

SeeNFPA55Chapter6forcompletereference.

12) Do I need to have an exhaust alarm on my gas cabinet?Gascabinetsstoringflammablegasesdorequireanautomaticshutdownofthesourcegasesiftheexhaustflowislost.(ReferenceIBCSection908.)

13) Do I need a scrubber or abatement system for my gas cabinet?AccordingtoNFPA55Chapter7,atreatmentsystemisnotrequiredfortoxicgassystemsthathavethefollowingtwoitems in place:

•Agasdetectionsystemwithasensingintervalnotexceeding 5 minutes

•Thegasdetectionsystemshallmonitortheexhaustsystemat the point of discharge from the gas cabinet.

However,underNFPA,ahighlytoxicgasrequiresthatthecabinetbe ventilated through a treatment system. The user must also check local laws including applicable environmental regulations.

14) What maintenance do I need to do on an ongoing basis?The gas detection system, alarms and automatic emergency shutoff valves need to be tested at one of the following intervals:

•Not less than annually• In accordance with the manufacturer’s requirements• In accordance with approved recognized industry standards• In accordance with an approved schedule

SeeIFCChapter27forcompletereference.

15) What type of manifold system should I have in my gas cabinet?Seepages9–11inthisdocumentfortypicalgascabinetswithindividual regulators as well as changeover manifolds. Items such as process downtime should be considered to determine if a changeover manifold is required. Other options such as low pressure alarm, cylinder scales, and multiple outlets are available tofityourprocess.

16) What if I am using hazardous gases at volumes below the threshold quantities?IncaseswhereafacilitymaybebelowtheNFPAMAQthresholdquantity for a particular gas, a cabinet may not be required by code.However,NFPA55,IFCandIBCallhaverequirementsforgasdeliverysystems.MostnotablyIFC2703.2.2.1:

“WheregasesorliquidshavingahazardrankingofhealthhazardClass3or4,FlammabilityClass4,orReactivityClass3or4inaccordancewithNFPA704thatarecarriedinpressurizedpipingabove15psig,anapprovedmeansofleakdetectionandemergencyshutofforexcessflowcontrolshallbeprovided…” It is important to note that this IFC requirement applies to gases that are below the threshold quantity of the control area. In other words,acabinetmaynotbeneededbutspecificsafetyfeatures of a gas delivery system are still necessary to comply with applicablecodessuchasNFPA,IFCandIBC.

Even though you may be below the threshold quantities, it is often easier and considered best practice to utilize a gas cabinet and related gas delivery equipment with the appropriate safety features.

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Glossary of TermsAbatement System: An assembly of equipment capable of processing a hazardous gas and reducing the gas concentration to a predetermined level at the point of discharge from the system totheatmosphere(alsoreferredtoasascrubber).

Control Area: A space within a building where quantities of hazardousmaterialnotexceedingtheMaximumAllowableQuantities(MAQ)arestored,dispensed,usedorhandledperIBC.

Corrosive Gas: A gas that has the ability to attack and produce irreversible damage to human tissues or the ability to attack and eat away rubber, metal and other substances. Emergency Shutoff Valve: A designated valve designed to shut offtheflowofgasesorliquids.

Excess Flow Control:Afail-safesystemorapprovedmeansdesignedtoshutoffflowduetoaruptureinpressurizedpipingsystems.

Exhaust Alarm: An alarm that is triggered by low negative pressure orlostexhaustflowinagascabinet.Typicallythealarmistiedtoameansofshuttingdowngasflowwhenthealarmlevelisreached.

Exhausted Enclosure: A noncombustible enclosure consisting of twosides,atop,backthatprovidesameansforlocalexhaust.

Face Velocity: Average measured air speed at the face of gas cabinet access ports and windows.

Fire Resistance Rating: The amount of time in minutes or hours that afireprotectionsystemhaswithstoodastandardfireresistancetest.

Flammable Gas: A material that is a gas at 68° F or less at an absolutepressureof14.7psi,thatisignitableatanabsolutepressureof14.7psiwheninamixtureof13percentorlessbyvolumewithair,orthathasaflammablerangeatanabsolutepressureof14.7psiwithairofatleast12percent,regardlessofthelowerlimitperNFPA.

Gas Cabinet: A fully enclosed, noncombustible enclosure used to provide an isolated environment for compressed gas cylinders in storage or use.

Gas Room: A separately ventilated, enclosed room, isolated from other parts of a building in which compressed gases are used and/or stored.

High-Hazard Occupancy:ClassificationofanareathatcontainsquantitiesofsubstancesthatexceedthepublishedMAQ. High-hazardoccupanciescannotbeclassifiedascontrolareasandrequireadditionalsafeguardstomeetrequirementsforexplosioncontrol, emergency power, alarm systems, sprinkler protection, detachedbuildings,etc.perIFCandIBC.

Highly Toxic Gas: A chemical that has a median lethal concentration(LC50)inairof200ppmbyvolumeorlessofgasorvapor,or2mg/Lorlessofmist,fumeordust,whenadministeredbycontinuousinhalationfor1hour(orlessifdeathoccurswithin 1hour)toalbinoratsweighingbetween0.44lband0.66lbeach.

International Building Code (IBC): A set of model codes publishedbytheInternationalCodeCouncil(ICC)thatservesasguidelines for the construction and design of new buildings as wellasalterationstoexistingbuildings.TheIBCisdesignedtoestablish minimum safety levels against hazards associated with building construction or occupancy.

International Fire Code (IFC): A set of model codes published by theInternationalCodeCouncil(ICC)thataredesignedtoprotectlifeandpropertyfromfiresandexplosionhazards.

International Mechanical Code (IMC): A set of model codes publishedbytheInternationalCodeCouncil(ICC)thatregulatethedesignandinstallationofmechanicalsystems.TheIMCservestoestablish minimum safety levels to protect life and property from the dangers of operation/installation of mechanical systems.

Liquefied Gas: A gas which, under the charged pressure, ispartiallyliquidatatemperatureof70ºF(21.1ºC)perNFPAGlossary of Terms.

Lower Flammable Limit (LFL): The minimum percent by volume ofagaswhich,whenmixedwithairatnormaltemperatureandpressure,willformaflammablemixture.TheLFLisalsoreferredtoastheLowerExplosiveLimit(LEL).

Maximum Allowable Quantity (MAQ): A threshold quantity of hazardousmaterialinaspecifichazardclassthat,onceexceeded,requires the application of additional administrative procedures, constructionfeaturesorengineeringcontrolsperNFPA.

Median Lethal Concentration (LC50): The concentration of a substancethat,whenadministeredtoagroupofexperimentalanimals,willresultinthedeathof50%ofthesamplepopulationoveraspecifiedtime.

National Fire Protection Association (NFPA): An international organizationthatpublishesfireandbuildingsafetycodes.

Non-Liquefied Gas: Gases, other than those in solution, that are contained in a packaging under the charged pressure and areentirelygaseousatatemperatureof68°F(20°C)perNFPAGlossary of Terms.

Permissible Exposure Limits (PEL):Thelegallimitsofexposureofanemployeetoachemicalsubstanceorphysicalagent.PELsareestablishedbyOSHAandtypicallyexpressedbysubstance.

Purge Gas:Inertgasusedtoflushgasdeliveryequipmenttoremove contamination or residue.

Pyrophoric Gas: A gas with an autoignition temperature in air at orbelow130°F.

Threshold Quantity: Amounts of a hazardous material, established as a means of safety and code conformance. In this case, the threshold quantity of a substance is set as a trigger for its MaximumAllowableQuantity(MAQ)perNFPA.

Toxic Gas: A chemical that has a median lethal concentration (LC50)inairofmorethan200ppmbutnotmorethan2000ppmbyvolumeofgasorvaporperNFPA.

Vacuum Drive:Agas,typicallynitrogen,setatadefinedpressurewhich is used to create a vacuum for purging gas delivery components such as regulators or manifolds.

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International Codes: Adoption by StateTheInternationalCodeCouncil(ICC)makeseveryefforttoprovidecurrent,accuratecodeadoptioninformation.NotalljurisdictionsnotifyICCofcodeadoptions.Toobtainmoredetailedinformationonamendmentsandchangestoadoptedcodes,pleasecontactthejurisdiction. To submit code adoption information: www.iccsafe.org/adoption

State International Fire Code International Building Code International Mechanical CodeAlabama S09,L S09,L S09,LAlaska X09 X09 X09Arizona S06,L S09,L S09,LArkansas X12 X12 X09California X12 X12Colorado S12,L S12,L S12,LConnecticut X03 X03 X03Delaware L12 L12 L12DistrictofColumbia X12 X12 X12Florida X09 X09Georgia X12 X12 X12Hawaii X06Idaho X12 X12 X12Illinois S09,L S09,L S09,LIndiana X12 X12 X12Iowa X09 S09,L S09,LKansas S06,L L LKentucky X12 X12 X12Louisiana L X12 X12Maine L X09Maryland X15 X15Massachusetts X09 X09Michigan L X12 X12Minnesota X06 X06 X00Mississippi S12,L S12,L S12,LMissouri L S12,L S12,LMontana L X12 X12Nebraska L S09,L LNevada S12,L S12,L LNew Hampshire L X09 X09New Jersey X06 X09 X09NewMexico X03 X09 LNew York X06 X06 X06NorthCarolina X09 X09 X09NorthDakota L S12,L S12,LOhio X09 X09 X09Oklahoma S09,X S09,X S09,XOregon X12 X12 X12Pennsylvania X09 X09 X09Rhode Island X12 X12SouthCarolina X12 X12 X12SouthDakota S09,L S12,L S09,LTennessee S06,L S06,L LTexas L06 X06 L06Utah X12 X12 X12Vermont X12Virginia X12 X12 X12Washington X12,L X12 X12West Virginia X12 X12Wisconsin L X09 X09Wyoming X12,L X12,L X12,L

Source: International Code Council (February 2015)

X = Effective Statewide S = Statewide adoptions with limitations L=AdoptedbyLocalGovernments

15=2015Edition09=2009Edition 03=2003Edition

12=2012Edition06=2006Edition00=2000Edition

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The Airgas Engineering Solutions Group is a team of engineers specializing in the design, construction and installation of gas delivery equipment. Based in Oakwood Village, OH, the group can provide the right solution for items such as:

• Gas cabinets • Gasdetectionsystems • Gasblenders • Laboratoryequipmentandpipinginstallations • Processchemicaldeliverysystems • Customgasdeliveryequipmentdesign and fabrication

Our team works directly with customers to develop equipment solutions that focus on safety, reliability and performance. For more information or to speak with an engineer, please dial toll free 1-800-282-1524.

ENGINEERINGSOLUTIONS GROUP

Engineering Solutions GroupOakwood Village, OH

Airgas, Inc. — Engineering Solutions Group21610 Alexander Rd. Oakwood Village, OH 44146Airgas.com

For more information call

1-800-282-1524 Or visit Airgas.com

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