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FREQUENTLY ASKED QUESTIONSABOUT
Portable Oxy-Fuel Gas EquipmentVersion 1 March 2007
ThisdocumenthasbeencompiledfromthemostcommonaskedquestionstoWorkSafeonportableoxy-fuelgascuttingandweldingequipment.IthasbeenpublishedtoassistindustrybyclarifyingandexplainingWorkSafespositiononthesecommonquestions.Oxy-fuelgases,includeoxygen,acetyleneandliquefiedpetroleumgas(LPGas).
Typical oxy-fuel gas equipment
Contents
Page
1.TRANSPORTINGGASCYLINDERSINVEHICLES...................................22.STORINGGASCYLINDERSONCONSTRUCTIONSITES.......................33.USE,CAREANDHANDLINGOFGASCYLINDERS..................................64.FLASHBACKARRESTORS........................................................................ 75.FIREPROTECTIONEQUIPMENT..............................................................86.MAINTENANCEOFOXY-FUELGASEQUIPMENT...................................87.PERSONALPROTECTIVEEQUIPMENT.................................................108.ATTACHMENTONE.................................................................................119.FURTHERINFORMATION........................................................................12
Frequently Asked Questions:
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1. TRANSPORTING GAS CYLINDERS IN VEHICLES
1.1 How should I transport gas cylinders in my work ute, tray truck ortrailer?
Whentransportinggascylindersonutilities,openvehicles,ortrailers:
Removeregulatorsbeforeloadingontovehicleandtransporting.
Ensurecylindervalvesremainclosedandusevalveprotectionguardsorcaps,where
possible.
Securecylindersinanuprightposition,topreventthemtippingorfallingover.
Avoidcarelesshandling,donotdroporallowheavyobjectstofallonthem.
Removeorsecureloosetoolsandmaterialsthatcandamageandrupturecylinders.
Carryfirefightingequipmentonyourvehicle.
Parkvehicleintheshade,wherepossible.
DONOTsmoke,usenakedflameornonflameproofelectricsanywherenearavehiclecarryingfuelgases.
DONOTtransportfuelgascylindersinaseparateenclosedcargocompartment(suchasutilitieswithcanopies),unlessthecompartmentispermanentlyventedtooutside.
DONOTcoverutilities,openvehicles,ortrailerswithatarpaulinwhentransportingfuelgascylinders.
DONOTleavecylindersunattendedinvehicleswheretheyareaccessibletounauthorisedpersons.
1.2 Is it OK to transport gas cylinders in my work van?Yesprovidedadditionalsafetyprecautionsaretaken.Where the cargo compartment is open to the passenger compartment and/or engine
compartment (as in most typesof vans) then youmust house the fuel gas cylinders in aseparate airtight compartment, which must be permanently vented to the outside of thevehicle. The number of cylinders carried will be dependant on the size of the fuel gascompartment.Ensure cylinder valves are closed and checked for leaks, (e.g. with soapy water) beforeloadingintovan.
DO NOTuse cylinderswhilst theyare still in your van. Always remove them to open airbeforeuse.
Note: Wheneverpossible,gascylindersshouldbetransportedonopenvehicles,ortrailers.
Frequently Asked Questions:
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2. STORING GAS CYLINDERS ON CONSTRUCTION SITES
Storagerequirementsvarydependingonthequantityofgasbeingstoredandwhetherthestoreisclassifiedasaminorstorage.Forthisreasonitisessentialtodeterminethequantityofgascylinderson-site,sothatcylindersarestoredinanappropriatemannerandin
accordancewithdangerousgoodslegislation.
Note:Quantitiesofgasinuse,asstand-byorempty,shouldbeminimisedasfaraspossible.
2.1 What quanti ty of gas is classif ied as a minor storage?
Refer to the tables below and the following work example to determine if the quantity of gason-site is classified as a minor storage.
TABLE 2.1
MAXIMUM QUANTITIES OF GASES PERMISSABLE FOR
CLASSIFICATION AS MINOR STORAGE
AS 4332 2004 Section 2.3
Division Class) of Gas Maximum Aggregate Water CapacityDivision(Class)2.1
Flammablegas(LPG,Acetylene)
500litres
Division(Class)2.2Nonflammablegas(Nitrogen,Argon)
2000litres
Division(Class)2.2withClass5.1subsidiaryrisk(Oxygen)
1000litres
MixedGaseswithnoindividualclasstoexceedits
subclassintable2.1
2000litres
AGGREGATE WATER CAPACITY OF CYLINDERS
AS 4332 2004 Appendix C
Type of Gas Cylinder size
G E D
Oxygen 48litres 24litres 10litresAcetylene 48litres 24litres 10litres
Cylinder Size
45 kg 15 kg 9 kgLPG 108litres 44litres 23litres
For an example see Attachment 1 - WORK EXAMPLE: Determining minor quantities.
Frequently Asked Questions:
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2.2 How should gas cylinders be stored?
Cylinderstorageareasshouldbewellventilatedandpreferablyoutdoors.Protectionfromweatherisdesirable,butnotattheexpenseofventilation.Withinthestorageareaoxygencylindersshouldbestoredatleast3metresfromfuelgascylinders,unlessseparatedbyafirewall(minimum4hourfirerating).
STORAGE OF FUEL GASES EXAMPLES
EITHERUseascreenwall(DiagramA)toachievethesegregationdistance,ORMaintain3metresegregation(DiagramB).
Diagram A Diagram B
Allcylindersshouldbetreatedasfull,regardlessoftheircontentandthefollowingsafetyprecautionsobserved:
Securecylindersinanuprightposition,inawellventilatedarea.
Keepcylindersawayfromignitionorartificialheatsources(eg.weldingleads,flames,heatersetc.)andotherflammablematerials.
Storefullandemptycylindersseparately.
Protectionfromdirectsunlightisrecommended.
DisplayDanger:NoSmoking,NoIgnitionSourcesandRestrictedArea,AuthorisedPersonnelOnlysignageinthecylinderstoragearea.
DONOTrepaintcylindersorobscurecylinderlabels,evenifthecylinderisrusty,dirtyordamaged.
DONOTusecylindersthatcannotbeclearlyidentified.
Note:Cylindersshouldnotbeaccessibletounauthorisedpersons.
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2.3 What if the quanti ty of gases in cylinders is greater than those givenfor minor storage?
Cylindersshouldbekeptinapurpose-designedstoreorstoragearea:
Storetobeatgroundlevel,thebaseorfloorshallbelevelandconstructedofnon-
combustiblematerials.
Storetobeconstructedofnoncombustiblematerials.
Storetobeseparatedfromotherbuildingsorhavea4hourratedfirewallandtheroof
ofthestoreshallbe3hourfireratedifanotherbuildingisontop.
Storeandcylinderstobeprotectedfromimpactbyvehicles,forkliftsetc.andfenced
andsecuredagainstunauthorisedaccess.
ElectricalequipmentinflammablegasstoresshallcomplywithAS/NZS3000andthe
storageareashallhaveNOIGNITIONsources.
Cylinderstoredoorsshallopenoutwards.
Storetobeventilatedeitherbymechanicalornaturalmeans.
StoretobefittedwithappropriatefireprotectionsystemrefertoAS4332table7.2.
FurtherinformationonthestorageofgascylindersexceedingthemaximumquantitiesclassifiedasaminorstoragecanbefoundinAS4332,Section4,Table2.1.
2.4 Can I store gas cylinders in unmodif ied shipping (freight)
containers?No.Unmodifiedshippingcontainersshouldnotbeusedasanalternativetoapurposebuiltcylinderstoreorstillage.AS4332-Thestorageandhandlingofgasesincylinders,Section4providesguidanceontheconstruction,locationandventilationofstoresandshouldbereferencedpriortostoringcylindersinmodifiedshippingcontainers.
2.5 What signage (placarding) do I need on a gas cylinder store orstillage?
Gasstoresandstillages(classifiedasaminorstorage)shouldhavethefollowingsignsattached:
Awarningsigntoprohibitsmokingandtoexcludeothersourcesofignition,e.g.
DANGER:NOSMOKING,NOIGNITIONSOURCES.
Awarningsigntorestrictentrye.g.RESTRICTEDAREA,AUTHORISED
PERSONNELONLY.
DangerousgoodsplacardsandHAZCHEMouterwarningplacardsshallbedisplayedatpremisesifthequantityofdangerousgoodsexceedsminorstoragequantities(RefertoTable2.1whendeterminingstoragequantities).Theseplacardswarntheemergencyservicesof
thechemicalhazardspresentandprovidestheinformationnecessaryforthemtodealsafelywithanemergencyatthepremises.
Frequently Asked Questions:
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3. USE, CARE AND HANDLING OF GAS CYLINDERS
3.1 What do I need to consider before manually lift ing and carryingcylinders?Gascylinderscanbeawkwardtomoveduetotheirsize,shapeandweight.Liftingand
carryingofcylindersisahighriskactivity,thereforepropercontrolmeasuresshouldbeputinplacewhenmovingcylinders.Employersneedtoconsidertheuseofappropriateliftingortransportequipmenttominimisemanualhandlingrisksassociatedwithmovingfullandemptycylinders.
Whereitisnotpracticaltousemechanicalliftingaids,andcylindersaremanuallyliftedandcarried,thesmallestsizedcylindersuitableforthejobshouldbeused.Do Not rollcylindersalongthegroundinahorizontalposition,asthiscanopenordamagethecylindervalve.Note: Cylinder valves should not be used as a lifting anchor point at any time.Also, care should be taken whenmanually lifting and carrying cylinders up stairs and between floor levels and should be avoided where possible.
3.2 Can I use gas cylinders that are lying in a horizontal posi tion?
No.Gascylindersshouldonlybeusedwhilsttheyareinanuprightpositionandsecuredagainstfalling.
Thetransportationorstorageofacetylenecylindershorizontallyshouldbeavoided.
Whereacetylenecylindershavebeentransportedorstoredhorizontally,thecylindershould
beallowedtostanduprightforaminimumof12hourspriortouse.Thiswillallowtheacetone
toevenlyre-distributewithinthecylinderandpreventacetonebeingcarriedintotheflame.
Note:An indication that acetone is being carried to the flame can be the discoloration of the flame.
3.3 Can I use oxy fuel gas equipment in poor ly ventilated areas?
Yes.Wherepracticable,forcedventilationshouldbeprovidedtothearea.Cylindersshouldbelocatedoutsidepoorlyventilatedareasandequipmentshouldbeleaktestedatworkingpressurepriortobeingused.
3.3 Can adjustable worm drive clips (jubilee clips) be used to clamp gas
hoses?
No.Theuseofjubileeclipscouldcausegasleaksduetounder-tightened(loosened
connections)orover-tightened(cutinhose)conditions.
Frequently Asked Questions:
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4. FLASHBACK ARRESTORS
4.1 What are some of the common causes of flashback?
Aflashbackistheburning-backoftheflameintotheblowpipeortheignitionofanexplosivemixtureinoneofthegaslines.Frequently,theonlysignofflashbackisacloudofcarbonsmokeissuingfromtheweldingtipwhentheblowpipevalvesareopen.Theleastamountof
damagecausedbyaflashbackistheburningoftheinsideofthehoseliningwhich,ifrepeatedoveraperiodoftimewillresultindisintegrationofthehose.Commoncausesofflashbacksare:
Incorrectoperatingpressures
Blockageintheweldingtip
Faultyequipment,suchaswornormalfunctioningtorchvalves
Backfeeding,whichoccurswhenhigherpressuregasfeedsbackupalowerpressure
gasline
Flowrateofacetyleneexceedswithdrawalrate
o Withdrawalrate,referstotherateatwhichacetylenegasisabletowithdrawfrom
acetoneliquid
o Flowrate,referstotheamountofgaspassingthroughtheregulator
Therefore,theflowrateshouldbelessthanthewithdrawalrate.Whereitexceedsthewithdrawalrate,acetoneliquidwillbewithdrawnwithacetylenegasfromthecylinder.
Acetoneliquidbeingwithdrawnfromthecylinderisoneofthemajorcausesofflashbackwithacetyleneequipmentandischaracterisedbytheflametakingonayelloworgreentinge.
Forfurtherinformationregardingflowratesandwithdrawalrates,contactyourlocalgasequipmentsupplier.
GuidancecanbefoundinAS4267Pressureregulatorsforusewithindustrialcompressedgascylinders.
Note:Acetylene regulators should be designed in such a way that it shall not be possible to adjust them to anoutlet pressure exceeding 150 kPa in the flowing condition.
4.2 Do I need to use flashback arrestors?
Yes.Suppliersofallcommonfuelgassystemsrecommendtheuseofflashbackarresters(compliantwithAS4603)topreventflamestravellingbackintothecylinders.Itisrecommendedthatflashbackarrestorswithadequate(high)flowcapacitiesbeused.
Thefitmentofincorrectflashbackarresterscanresultinreducedflowcapacity,whichmaybebelowtheminimumrequiredbytheheatingorcuttingdevice.Thishasthepotentialtocauseanincreaseinflameinstabilityatwhichpointtheinstalledsafetydevices(flashbackarrestors)mayincreaseratherthandecreasetheriskofflashback.
Forhighflowapplications,especiallyheating,theoperatorneedstoensurehigherflowflashbackarrestorsareused.Consultmanufacturersorsuppliersspecificationsforfurtherinformation.
Frequently Asked Questions:
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4.3 Where should flashback arrestors be fit ted?
Suppliersadviceshouldbefollowedtoensurethecorrectplacementandfittingoftheflashbackarrestors.WorkSaferecommends:
forhoses3metresorless,flashbackarrestorsfittedtoeachgaslineattheregulator
outletissufficient
forhoseslongerthan3metres,twoflashbackarrestorsshouldbefittedtoeachgas
line;oneattheblowpipeconnectionandoneattheregulatoroutlet
Theregulatorendofthegashoseshouldincorporateaflamearrester,nonreturnvalveandatemperatureactuatedcutoffvalve.
Thetorchendofthegashoseshouldincorporateaflamearresterandnon-returnvalve.
5. FIRE PROTECTION EQUIPMENT
5.1 Do I need to have access to a fire extinguisher?
Yes.Anappropriatefireextinguisherneedstobereadilyaccessibleincaseofafire.Typically,asuitablefireextinguisher(DryChemicalorCO2)shouldbeeitherattachedtothe
cylindertrolleyorbeintheimmediateareawherefuelgasesarebeingused.Incertainapplications,firehosereels,gardenhosesandfireblanketscanalsobeusedtoextinguishfires.
Note:The most common incidents to occur are ignitions of leakages of fuel gas from hose connectionsor defective hose. An appropriate emergency plan needs to be in place in case of a fire and/or explosionand should form part of the safe work procedure.
6. MAINTENANCE OF OXY-FUEL GAS EQUIPMENT
6.1 Who should carry out maintenance work on oxy-fuel gasequipment?
Itisexpectedthatmaintenanceworkiscarriedoutbyatechnicallycompetentpersonwhohassoundknowledgeandexperienceofoxy-fuelgasequipmentandunderstandstheimportanceofintegrityandsafetyintheuseofoxy-fuelgasequipment.
Frequently Asked Questions:
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6.2 What inspection and maintenance regime should I have in place formy oxy-fuel gas equipment?Aswithalltypesofplantandequipment,regularinspectionandperiodicmaintenanceshouldbecarriedoutonoxy-fuelgascomponentsincluding:
Regulators(includingtheirintegralprotectivedevices)
Flashbackarrestors
Hoseassemblies
Blowpipes,mixersandattachments
Asuitableinspectionandperiodicmaintenanceregimeincludes:Daily inspection: apre-operationvisualcheckshouldbecarriedoutwhenconnecting
equipmenttocylinders.Damagedequipmentmustbewithdrawnfromservice.
Weekly inspection:visuallyexamineandcheckequipmentforitssuitabilityforcontinueduse.Allthreadsandsealingsurfacestobecheckedfordamage,oil or greasecontaminationandleaktestedwheredeemedappropriate.Six month inspection:equipmenttobefunctiontestedtoensurecorrectoperationofinternalcomponents.Hoseassembliestobecheckedforcracksandothersignsofwearandtear.Refurbishment and replacement program:Faultycomponentsshouldberefurbishedandreplacedinaccordancewiththemanufacturersorsuppliersrecommendations.Allrepaired
componentsshouldbefunctionandleaktestedbeforeuse.Recordsofinspectionandmaintenanceshouldbekeptbythepersonwhoownstheoxy-fuelgasequipment.Onemeansofcompliancemaybetotagorattachstickerstooxyfuelgasequipmentthathasbeeninspectedandtested.Note:If fuel gas and oxygen components are subjected to harsh working conditions or rough treatment, itmay be necessary to inspect them on a more regular basis.
6.3 Who can inspect and test flashback arrestors?
Inspectionandtestingofflashbackarrestorscanbecarriedoutbythemanufacturerorsupplieroftheflashbackarrestorsoratechnicalcompetentperson.Thetestingmustbedoneevery12monthsonmachinerypurposebuiltforthetaskandapprovedbythemanufactureroftheflashbackarrestor.Testingwillincludecheckson:
Throughflow
Non-return
Leaktightness
Frequently Asked Questions:
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7. PERSONAL PROTECTIVE EQUIPMENT
7.1 Why cant I use sunglasses as eye protection when carrying out hot
work processes?
OnlyeyeprotectionthatcomplieswithAS1336shouldbewornwhencarryingouthotworkandusingoxy-fuelgassystems.Ingasweldingorcutting,andresistanceweldingorbrazing,suitableeyeprotectionshallbeprovidedtoguardagainstinvisibleradiationandtoreducethevisibleradiationtoacomfortablelevel.Forsuchprocesses,sufficientprotectionwillusuallybegivenbygogglesandglasseswithfiltersofShadeNumbers3to7,inclusive.
GuidancecanbefoundinAustralianStandardAS1336Recommendedpracticesforoccupationaleyeprotection,Section5,Eyeprotectionagainstultravioletandinfraredradiation.
7.2 What clothing should I wear during hot work?Clothingshouldbewellfitting,yeteasytoremoveandfreefromoilorgreaseandmadefrom
heavycottonorwool.Leatherworkbootsshouldbeworntoprotectthefeetfromsparkshotslagandotherobjects.Leatherglovesshouldbeworntoprotectthehandsandsafetyglassesshouldbewornwhenworkingwithgasunderpressure.Syntheticorotherflammableclothing,includingsometypesofhighvisibilityvestsandnylon,flyingjackets,shouldnotbewornbyworkersinvolvedingascuttingorwelding.GuidancecanbefoundinAustralianStandardAS4839,Thesafeuseofportableandmobileoxy-fuelgassystemsforwelding,cutting,heatingandalliedprocesses,Section10,SafetyInstructions.
Frequently Asked Questions:
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Attachment 1:
WORK EXAMPLE: Determining minor quantities.
Whendeterminingminorstorages,thetotalcapacityallowedforanyparticularsituationshallincludecylindersinuse,sparecylindersnotinuseandcylindersawaitingremoval.Step1-Conductastocktakeofallgascylinderson-siteincludingempties,checkingsizeofcylinderandquantity.Stocktakerevealsthefollowinglistofcylindersison-site;6OxygensizeG,6AcetylenesizeG,4OxygensizeEand4AcetylenesizeE.Step2-Multiplythenumberofcylindersbythewatercapacityofeachcylinder.
6OxygensizeG (6x48L) = 288litres
6AcetylenesizeG (6x48L) = 288litres
4OxygensizeE (4x24L) = 96litres
4AcetylenesizeE (4x24L) = 96litres
= 768litresNote:eachindividualdivision(class)ofgasislessthanthemaximumaggregatewatercapacity;Acetylene384litres(500LMax),Oxygen384litres(1000LMax)andthecombinedmixedgascapacityarelessthan2000litres.ThereforetheabovestoreofgascylindersisclassifiedasaMINORSTORAGE.
Frequently Asked Questions:
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FURTHER INFORMATION
Alerts and G uidance Notes
WorkSafeGuidanceNoteElevatingworkplatformsandtheplacementofgascylindersforcuttingorwelding.
WorkSafe Victoria
GototheWorkSafehomepage,www.worksafe.vic.gov.auchooseanindustryorpublicationcategory
Contacttheadvisoryserviceon1800136089ORemailinfo@worksafe.vic.gov.au
Standards Australia
AS4332:2004Thestorageandhandlingofgasesincylinders
AS4839:2001Thesafeuseofportableandmobileoxy-fuelgassystemsforwelding,cutting,heatingandallied
processes
AS4603:1999-FlashbackarrestersSafetydevicesforusewithfuelgassesandoxygenorcompressedair.
AS1336:1997-Recommendedpracticesforoccupationaleyeprotection.
AS1674.1:1997-Safetyinweldingandalliedprocesses
CopiesofstandardscanbeobtainedbycontactingStandardsAustraliaon1300654646orbyvisitingthewebsiteatwww.standards.com.au
Note:
ThisguidancematerialhasbeenpreparedusingthebestinformationavailabletoWorkSafeVictoria.Anyinformationaboutlegislativeobligationsorresponsibilitiesincludedinthismaterialisonlyapplicabletothecircumstancesdescribedinthematerial.Youshouldalwayscheckthelegislationreferredtointhismaterialandmakeyourownjudgementaboutwhatactionyoumayneedtotaketoensureyouhavecompliedwiththelaw.Accordingly,theVictorianWorkCoverAuthorityextendsnowarrantiesastothesuitabilityoftheinformationfor
yourspecificcircumstances.
Frequently Asked Questions:
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http://www.worksafe.vic.gov.au/mailto:[email protected]:[email protected]://www.worksafe.vic.gov.au/