
1.Checkstothearea
2.Workprocedure
3.Generalworkarea
4.Checkingforpresenceofrefrigerant
5.Presenceoffireextinguisher
6.Noignitionsources
7.Ventilatedarea
8.Checkstotherefrigerationequipment
Priortobeginningworkonsystemscontainingflammablerefrigerants,safetychecksare
necessarytoensurethattheriskofignitionisminimised.Forrepairtotherefrigerating
system,thefollowingprecautionsshallbecompliedwithpriortoconductingworkonthe
system.
Workshallbeundertakenunderacontrolledproceduresoastominimisetheriskofa
flammablegasorvapourbeingpresentwhiletheworkisbeingperformed.
Allmaintenancestaffandothersworkinginthelocalareashallbeinstructedonthenature
ofworkbeingcarriedout.Workinconfinedspacesshallbeavoided.Theareaaroundthe
workspaceshallbesectionedoff.Ensurethattheconditionswithintheareahavebeen
madesafebycontrolofflammablematerial.
Theareashallbecheckedwithanappropriaterefrigerantdetectorpriortoandduringwork,
toensurethetechnicianisawareofpotentiallyflammableatmospheres.Ensurethatthe
leakdetectionequipmentbeingusedissuitableforusewithflammablerefrigerants,i.e.no
sparking,adequatelysealedorintrinsicallysafe.
Ifanyhotworkistobeconductedontherefrigerationequipmentoranyassociatedparts,
appropriatefireextinguishingequipmentshallbeavailabletohand.Haveadrypowderor
CO2fireextinguisheradjacenttothechargingarea.
Nopersoncarryingoutworkinrelationtoarefrigerationsystemwhichinvolvesexposing
anypipeworkthatcontainsorhascontainedflammablerefrigerantshalluseanysourcesof
ignitioninsuchamannerthatitmayleadtotheriskoffireorexplosion.Allpossibleignition
sources,includingcigarettesmoking,shouldbekeptsufficientlyfarawayfromthesiteof
installation,repairing,removinganddisposal,duringwhichflammablerefrigerantcan
possiblybereleasedtothesurroundingspace.Priortoworktakingplace,theareaaround
theequipmentistobesurveyedtomakesurethattherearenoflammablehazardsorignition
risks.NOSMOKINGsignsshallbedisplayed.
Ensurethattheareaisintheopenorthatitisadequatelyventilatedbeforebreakingintothe
systemorconductinganyhotwork.Adegreeofventilationshallcontinueduringtheperiod
thattheworkiscarriedout.Theventilationshouldsafelydisperseanyreleasedrefrigerant
andpreferablyexpelitexternallyintotheatmosphere.
Whereelectricalcomponentsarebeingchanged,theyshallbefitforthepurposeandtothe
correctspecification.Atalltimesthemanufacturer'smaintenanceandserviceguidelines
shallbefollowed.Ifindoubtconsultthemanufacturer'stechnicaldepartmentforassistance.
Thefollowingchecksshallbeappliedtoinstallationsusingflammablerefrigerants:
thechargesizeisinaccordancewiththeroomsizewithinwhichtherefrigerantcontaining
partsareinstalled;
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theventilationmachineryandoutletsareoperatingadequatelyandarenotobstructed;
ifanindirectrefrigeratingcircuitisbeingused,thesecondarycircuitshallbechecked
forthepresenceofrefrigerant;markingtotheequipmentcontinuestobevisibleand
legible.
markingsandsignsthatareillegibleshallbecorrected;
refrigerationpipeorcomponentsareinstalledinapositionwheretheyareunlikelytobe
exposedtoanysubstancewhichmaycorroderefrigerantcontainingcomponents,unless
thecomponentsareconstructedofmaterialswhichareinherentlyresistanttobeing
corrodedoraresuitablyprotectedagainstbeingsocorroded.
Repairandmaintenancetoelectricalcomponentsshallincludeinitialsafetychecksand
componentinspectionprocedures.Ifafaultexiststhatcouldcompromisesafety,thenno
electricalsupplyshallbeconnectedtothecircuituntilitissatisfactorilydealtwith.Ifthefault
cannotbecorrectedimmediatelybutitisnecessarytocontinueoperation,anadequate
temporarysolutionshallbeused.Thisshallbereportedtotheowneroftheequipmentsoall
partiesareadvised.
Initialsafetychecksshallinclude:
thatcapacitorsaredischarged:thisshallbedoneinasafemannertoavoidpossibilityof
sparking;
thattherenoliveelectricalcomponentsandwiringareexposedwhilecharging,
recoveringorpurgingthesystem;
thatthereiscontinuityofearthbonding.
10.1Duringrepairstosealedcomponents,allelectricalsuppliesshallbedisconnectedfrom
theequipmentbeingworkeduponpriortoanyremovalofsealedcovers,etc.Ifitis
absolutelynecessarytohaveanelectricalsupplytoequipmentduringservicing,thena
permanentlyoperatingformofleakdetectionshallbelocatedatthemostcriticalpoint
towarnofapotentiallyhazardoussituation.
10.2Particularattentionshallbepaidtothefollowingtoensurethatbyworkingonelectrical
components,thecasingisnotalteredinsuchawaythatthelevelofprotectionis
affected.Thisshallincludedamagetocables,excessivenumberofconnections,
terminalsnotmadetooriginalspecification,damagetoseals,incorrectfittingofglands,
etc.
Ensurethatapparatusismountedsecurely.
Ensurethatsealsorsealingmaterialshavenotdegradedsuchthattheynolonger
servethepurposeofpreventingtheingressofflammableatmospheres.Replacement
partsshallbeinaccordancewiththemanufacturer'sspecifications.
Theuseofsiliconsealantmayinhibittheeffectivenessofsometypesofleak
detectionequipment.Intrinsicallysafecomponentsdonothavetobeisolatedpriorto
workingonthem.
Donotapplyanypermanentinductiveorcapacitanceloadstothecircuitwithoutensuring
thatthiswillnotexceedthepermissiblevoltageandcurrentpermittedfortheequipmentin
use.Intrinsicallysafecomponentsaretheonlytypesthatcanbeworkedonwhileliveinthe
presenceofaflammableatmosphere.Thetestapparatusshallbeatthecorrectrating.
Replacecomponentsonlywithpartsspecifiedbythemanufacturer.Otherpartsmayresult
intheignitionofrefrigerantintheatmospherefromaleak.
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9.Checkstoelectricaldevices
10.Repairstosealedcomponents
11.Repairtointrinsicallysafecomponents
NOTE: