HC Cabinet Code - Final V1 Jan2012

8/2/2019 HC Cabinet Code - Final V1 Jan2012

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CodeofPracticeDesign

and

Manufacture

of

Refrigerated

CabinetsRunningonHydrocarbon

Refrigerants

FinalDraftV1forBRA,February2012


2/30

BRACodeofPractice,HCCabinetsFinalV1,January2012 Page|1

CodeofPracticefortheDesignandManufactureofRefrigeratedCabinetsRunningonHydrocarbonRefrigerants

Inordertosupporttheincreasinguseofhydrocarbonrefrigerantsinintegralcommercial

refrigeratedcabinetstheBritishRefrigerationAssociationCabinetandColdStoreSectionhas

commissionedthisCodeofPractice. Itclarifiestheregulations,standardsandpractices

whichapplytotheleaksimulationtestingandsubsequentdesignofsystemswhichuse

hydrocarbonrefrigerants. Thiswillprovidethebasisforaconsistentapproachtobe

adoptedbyallmanufacturers,endusersandspecifierswhenusingtheserefrigerants.

IanGarvey

ChairmanofBRACabinet&ColdstoreSectionHydrocarbonworkinggroup

Disclaimer FederationofEnvironmentalTradeAssociationsLtd 2012

Allrightsreserved. Apartfromanyfairdealingforthepurposesofprivatestudyorresearch

allowedunderapplicablecopyrightlegislation,nopartofthepublicationmaybe

reproduced,storedinaretrievalsystem,ortransmittedinanyformbyanymeans,

electronic,mechanical,photocopying,recordingorotherwise,withoutthepriorpermission

oftheFederationofEnvironmentalTradeAssociations,2WalthamCourt,MilleyLane,Hare

Hatch,Reading,BerkshireRG109TH.

FETAuses

its

best

efforts

to

promulgate

Standards

and

Guidelines

for

the

benefit

of

the

publicinthelightofavailableinformationandacceptedindustrypracticesbutdonotintend

suchStandardsandGuidelinestorepresenttheonlymethodsorproceduresappropriatefor

thesituationdiscussed. FETAdoesnotguarantee,certifyorassurethesafetyor

performanceofanyproducts,components,orsystemstested,installedoroperatedin

accordancewithFETA'sStandardsorGuidelinesorthatanytestsconductedunderits

StandardsorGuidelineswillbenonhazardousorfreefromrisk.

FETA,andtheindividualcontributors,disclaimsallliabilitytoanypersonforanythingorfor

theconsequencesofanythingdoneoromittedtobedonewhollyorpartlyinrelianceupon

thewholeoranypartofthecontentsofthisbooklet.


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CodeofPracticefortheDesignandManufactureofRefrigeratedCabinetsRunningonHydrocarbonRefrigerants

September2011

ThisCodeofPracticehasbeenpreparedbyCoolConcernsLtdattherequestoftheCouncil

oftheBritishRefrigerationAssociation(BRA)becauseoftheincreaseindemandfor

refrigeratedcabinetsrunningonhydrocarbon(HC)refrigerants. Cabinetsthataredesigned

andmanufacturedinaccordancewiththisCodemeetbasicsafetyprincipleswithregardto

theapplicationofaflammable(A3)refrigerant.

ThisCodeshouldbereadinconjunctionwiththestandardssummarisedinAppendix2.

ScopeThisCodedefinesstandardsinthedesignandmanufactureofintegral(pluginandhard

wired)andclosecoupledremotetypecabinetsforfooddisplay,serviceandstorage(stand

aloneandmultiplexed). Itisaimedatcabinetswithachargesizegreaterthan150g. Itis

alsoapplicabletocabinetswithlessthan150g,butforthesecabinetsotherstandards,

including60335224:2010and60335289:2010,alsoapply. Thesestandardsarealsooften

usedforLowVoltageDirective(LVD)andElectromagneticCompatibility(EMC)directive

compliance.

ATEX

ATEXisthenamecommonlygiventothelegalrequirementsforcontrollingexplosive

atmospheresandthesuitabilityofequipmentandprotectivesystemsusedinthem. Itis

unclearwhetherHCrefrigerationsystems,whicharedesignedtocontainarelativelysmall

andfiniteamountofflammablegas,arecoveredbythisdirective,andifsotowhatdegree

theyshouldcomply.

Discussionsare

currently

on

going

between

the

RAC

industry

and

the

Health

and

Safety

ExecutivetoclarifythesituationregardingATEXandHCsystems. ThisCodeprovides

guidancewhichfollowstheprinciplesofATEXwithregardtoareaclassificationand

avoidanceofsourcesofignition.



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TableofContents1.Introduction...........................................................................................................................4

2.Flammability

..........................................................................................................................

6

2.1HCsystemclassification..................................................................................................6

2.2Chargesizerestrictions....................................................................................................7

3.IntroductiontotheDesignProcess.......................................................................................8

3.1Reducingleakpotential...................................................................................................9

4.SimulatedLeakTesting........................................................................................................10

4.1Releaseratecalculation.................................................................................................11

4.2Thetestwork.................................................................................................................12

4.3Adjacent

equipment

......................................................................................................

13

4.4Reporting.......................................................................................................................13

5.ElectricalDevicesTypesandEnclosures...........................................................................14

5.1Electricaldevicesforuseinpotentiallyflammableatmospheres.................................15

5.2Cabinetswithdoorsandwells.......................................................................................16

5.3Enclosures......................................................................................................................17

5.4Connection/disconnection..........................................................................................17

5.5Wiring............................................................................................................................17

6.Air

flow

................................................................................................................................

18

7.LabellingandDocumentation.............................................................................................20

8.Manufacture........................................................................................................................21

9. EndUserPostInstallationChecks......................................................................................23

10.ServiceandRepair.............................................................................................................24

10.1Personalleakdetection...............................................................................................24

10.2Toolsandequipment...................................................................................................24

10.3Procedures...................................................................................................................25

11.Training

..............................................................................................................................

26

Appendix1,SourcesofFurtherInformation...........................................................................27

Appendix2,StandardsandRegulations..................................................................................28



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1.IntroductionThissectionprovidesbasicinformationabouthydrocarbonrefrigerants.

Endusers

are

increasingly

specifying

hydrocarbon

(HC)

refrigerants

in

cabinets,

mainly

due

totheirlowglobalwarmingpotentialandgoodenergyefficiency. TherangeofHCs

availableisshownbelow. Thehydrocarbonspredominantlyusedincommercial

refrigerationsystemsareR290andR1270. R600aisusedinsomesmallcommercial

systems,butismostlyusedindomesticsystems.

Refrigerantnumber TradenamePropane R290 Care40Propene(propylene) R1270 Care45IsoButane R600a Care10

Thechart(right)showsan

approximatecoolingcapacity

comparisonbetweenHCsand

HFCs. Theactualcomparison

dependsonoperatingconditions

andcompressortechnology.

Generallytheenergyefficiencyis

upto20%betterthanforHFCs.

Thelatent

heat

of

HCs

is

up

to

2.5

timeshigherandtheheattransfer

upto1.5timeshigherthanfor

HFCs. Thedensityis

approximately45%thatofHFCs.

Thegraphbelowshowstherelationshipbetweenpressureandsaturationtemperature.

AccuratedatacanbeobtainedfromsoftwaresuchasCoolpack1.

1Coolpackcanbeobtainedfromhttp://www.et.web.mek.dtu.dk/coolpack/uk/download.html
http://www.et.web.mek.dtu.dk/coolpack/uk/download.htmlhttp://www.et.web.mek.dtu.dk/coolpack/uk/download.html


6/30


-1

4

9

14

19

24

29

-40 -20 0 20 40 60

temp, C

pressure,

barg R404A

R1270

R290

R134a

R600a


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2.FlammabilityThissectionprovidesinformationabouttheflammabilityofHCs,sourcesofignitionand

chargesizelimits.

Flammabilityinformation

is

shown

in

the

table

below

2.

PEDfluid

group

Practicallimit

(kg/m3)3

Lower

flammability

limit(LFL,

kg/m3)

Lower

flammability

limit(LFL,%,

byvolumeof

air)

Autoignition

temperature,OC

R600a 1 0.008 0.043 1.8 460

R290 1 0.008 0.038 2.1 470

R1270 1 0.008 0.040 2.0 455

IftheconcentrationofHCinairisbetweentheLFLandtheUFL(upperflammabilitylevel,

approximately10%)therefrigerantcanbeignited. Sourcesofignitionincludeunsealed

(sparking)electricalswitchesandnakedflames. Moreinformationaboutelectricalsources

ofignitionisinsection5.

2.1HCsystemclassificationUnderATEXareasareclassifiedaccordingtothehazardassociatedwiththeflammablegas.

Accountistakenofthelikelihoodofanexplosiveatmosphereoccurringanditspersistenceif

itdoes.

The

following

classifications

typically

apply

to

refrigerated

cabinets.

Zone2areainwhichanexplosivegasatmosphereisnotlikelytooccurinnormaloperationbut,ifitdoesoccur,willpersistforashorttimeonly

4.

Secondarygradeofreleasereleasewhichisnotexpectedtooccurinnormaloperationand,isitdoesislikelytodosoonlyinfrequentlyandforshortperiods

5.

Equipmentcategory3Gequipmentsuitableforzone2. ElectricalequipmentofgroupIIisintendedforuseinplaceswithanexplosivegas

atmosphereotherthanminessusceptibletofiredamp(flammablegasessuchas

methane). GroupIIissubdivided;groupIIAincludesgasessuchaspropane6.

UnderEN3781:2008,HCrefrigerantsareclassifiedinSafetyClassA3theyhavehigher

flammabilityandlowertoxicity.

2EN3781:2008,AnnexE3EN3781:2008,AnnexE4

EN60079

10

1:2008,

3.8

5EN60079101:2008,3.106EN600790,4.2


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2.2ChargesizerestrictionsFlammabilityrestrictsHCchargesizes maximumchargesizesandthepracticallimitare

specifiedinEN3781:2008. ThepracticallimitisusediftheHCrefrigerantcouldleakintoan

occupiedspace,forexampleasupermarketshopfloororpreparationarea,orintoacold

room(see

example,

below).

In

addition

there

are

maximum

charge

sizes

dependent

on

the

occupancycategory. Whicheveristhelowestchargeapplies.

ExampleofpracticallimitInapreparationroom3mby5mby2.5mhigheachHCsystemcannothavemorethan

0.3kgcharge.

Maxcharge=5mx3mx2.5mx0.008kg/m3=0.3kg

ThefollowingisanextractfromEN3781:2008TableC.1whichprovidesmaximumcharge

sizesfor

arange

of

occupancies

and

equipment

types.

The

information

below

would

encompassmostintegralrefrigeratedcabinetsfortheretailsector.

Refrigerationsystemlocation MaximumchargepersystemRefrigerationsystemlocatedinahuman

occupiedspace(occupancyclassAgeneral

occupancy),whichisnotamachineryroom

OnlysealedsystemswithMaxcharge=

practicallimitxroomvolumeandnot

exceeding1kgbelowgroundfloorleveland1.5kgabovegroundfloorlevel

Refrigerationsystemlocatedinahuman

occupiedspace(occupancyclassB

supervisedoccupancy),

which

is

not

amachineryroom

OnlysealedsystemswithMaxcharge=

practicallimitxroomvolumeandnot

exceeding1kg

below

ground

floor

level

and

2.5kgabovegroundfloorlevel

TheinformationinitalicshasbeenaddedbytheauthorsasitisnotincludedinEN378in

errorandwillbecorrectedinrevisionsgoingforward

OccupancyclassAiswherethenumberofpeoplepresentisnotcontrolledortowhichany

personhasaccesswithoutbeingnecessarilyacquaintedwiththegeneralsafetyprecautions.

Anexampleisasupermarketshopfloor.

OccupancyclassBisrooms,partsofbuildingorbuildingswhereonlyalimitednumberof

peoplemay

be

assembled,

some

of

them

being

necessarily

acquainted

with

the

general

safetyprecautions.MostdesignersassumeanoccupancyclassAbecausethedefinitionof

occupancyclassBisdifficulttocontrolinreality.

RefertoEN3781:2008TableC1forfullinformation,includinglimitsforindirectsystems,

andforsystemsorpartsofsystemlocatedinmachineryroomsoroutsideetc.



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3.IntroductiontotheDesignProcessThissectionoutlinestheprocessnecessarytoensureHCsystemsaresafe. Moredetailed

informationisprovidedinsubsequentsections.

AleakofHCrefrigerantcanpotentiallyresultinaflammablezonearoundthesystem.

Sourcesofignitionwithinthepotentiallyflammablezonewillpresentahazardintheevent

ofaleak. Anessentialpartofthedesignprocessistoensuretherearenosourcesofignition

insidepotentiallyflammablezones. Thiscanbeachievedbyensuringleaksdonotresultina

flammablezoneorbyremovingsourcesofignitionfromtheflammablezone.

TheprocessforensuringHCsystemsaresafeissummarisedbelowforanysystemwhich

containssourcesofignition,regardlessofthechargesize.

Step1Carry

out

flammable

zone

testing

(area

classification)

to

determine

the

extent

of

thepotentiallyflammablezoneintheeventofaleak.

Seesection4.

Step2Identifysourcesofignitionwithinthepotentiallyflammablezone.

Seesection5.

Step3

Option1

or

Option2

or

Option3

or

Option4

Movethesourceofignitionoutsidethepotentiallyflammable

zone. EN6007914requiresthat,whereverpossible,electrical

equipmentshouldbelocatedinnonhazardousareas7.

Replacethesourceofignitionwithasuitabledevice. Seesection5.Increasetheairflowand/ormaintainapermanentairflowto

reducethepotentiallyflammablezone. Seesection6.Locate

the

source

of

ignition

in

asuitable

enclosure

(this

is

usually

costprohibitiveforsmallsystemsanddifficulttoachieve). Seesection5.

Moredetailedinformationoneachoftheaboveisshowninsubsequentsectionsas

indicated.

7EN6007914:2008,4.1


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3.1ReducingleakpotentialThepotentialforleakageshouldbereducedasmuchasispractical. Considerationshould

begivento:

Minimisingthenumberofjoints; Qualityofbrazingandbrazingprocedures; Competenceandqualificationofbrazers; Methodofaccesstothesystemforservice:

o CappedSchradervalvesonboththehighandlowsidesofthesystemshouldbeused;

Qualityofpipebending; Vibrationelimination; Minimisingthepotentialforchafing; Minimisingpotentialforexposuretodamage; Protectingpipeworkfromcorrosion,e.g.dischargepipeworkwhichevaporates

defrostcondensate;

PressuretestingforstrengthandleaktightnessbeforecharginginaccordancewithEN378.



11/30

4.SimulatedLeakTestingThissectioncoversthesimulatedleaktestingrequiredtodeterminetheextentofa

potentiallyflammablezoneintheeventofaleak.

Simulatedleaktestingiscarriedouttodeterminetheextentofapotentiallyflammablezone

intheeventofaleak. ThetestworkshouldcomplywithEN66079101. Theprocedure

belowsummarisestheprocess,andfurtherdetailisprovidedwithinthissection,but

referenceshouldbemadetothestandardforfullinformation.

Step1Identifypotentialleaklocation(s)(seesectiononTestWorkforfurther

information).

Step2

CalculatethereleaseratefromEN60079101,AnnexAforeachlocation. The

followingneedstobedetermined:

Theholesizeoftheleak; Whetherthereleasewillbeliquidorgas; Themaximumpressureandtemperatureoftherefrigerantatthepoint

ofleakage.

Step3

Decidewhethertherewillbeairflow. Iffansrunpermanentlythentheycan

runduringthetest. Iffansswitchoffwhentherefrigerationsystemisoff(on

temperatureforexample)theyshouldnotberunduringthetest,i.e.testing

shouldbecarriedoutatworstcasescenarioconditions.

Step4

Carryouttheleaksimulationtest,measuringtheHCconcentrationwherethere

aresourcesofignitionandaroundthesystemtofindtheextentofthe

potentiallyflammable

zone

(area

classification).

Step5 Recordthetestworkinatechnicalfile.



12/30


4.1ReleaseratecalculationReleaseratecalculationsaregiveninEN60079101forleaksofbothliquidandgas. These

modelsdonotaccountforvolatilefluids. Therequirementforamodelforvolatilefluidsis

thesubjectofongoingdiscussionsbetweenindustryandtheHSE. Theliquidrelease

calculationgives

an

overly

onerous

release

rate

and

is

not

usually

used

in

refrigeration

systemsbecauseattheactualpointofleakage,forexampleinaliquidline,therefrigerant

willeitherbetwophaseorgasveryshortlyaftertheleakstarts. Thecalculationisincluded

inthisCodeforcompleteness.

Catastrophicleaksdonotneedtobeconsidered8.

Thegasreleaserateforgasisgiveninthestandardforbothchokedandnonchokedgas

velocity. Thenonchokedgasvelocitycalculationisusedbecausethedischargeofleaking

refrigerantisbelowthespeedofsoundfortheHC. Theequationisasfollows9:

dG/dt releaserateofgas(kg/s)

p pressureinsidethesystem(Pa)

p0 pressureoutsidethesystem(Pa)

S crosssectionoftheopening(hole)throughwhichthegasisreleased(m2)

M molecularmassofthegas(kg/kmol)

=44.096forR290

=42.06forR1270

T

absolutetemperature

inside

the

system

(K)

polytropicindexofadiabaticexpansion

=1.134forR290

=1.156forR1270

R theuniversalgasconstant

=8314J/kmolK.

Thereleaserateforliquidiscalculatedasfollows10:

dG/dt releaserateofgas(kg/s)

S crosssectionoftheopening(hole)throughwhichthegasisreleased(m2)

liquiddensity(kg/m3)

=500forR290

=515forR1270

p pressuredifferenceacrosstheopeningthatleaks(Pa)

8

EN60079

10

1:2008

1

note

d

and

note

5

9EN60079101,A3.2.210EN60079101,A3.1


13/30


Theholesizetypicallyusedis0.6mmdiameter(S=0.282mm2=0.000000282m

2). Itis

likelythatthiswillbeincludedforsealedsystemsintherevisionofEN378currentlybeing

carriedout.Thisholesizecouldrepresentalargeleakandcanresultinoverclassifyingthe

dimensionsofazone,soifajustificationcanbegiventouseasmallerholesizethisshould

bedocumentedinthetechnicalfile.

Thetablebelowshowsthemaximumpressuresandtemperaturesthatshouldbeused:

Maxpressure(p),barg11 Maxtemperature(T),OCLowside Highside Lowside Highside

R290 10.3 18.1 32 55R1270 12.7 21.8 32 55R600a 3.3 6.8 32 55

4.2ThetestworkTheleaksimulationtestingshouldbecarriedoutinanenvironmentsimilartothatwhere

thesystemwillbelocated.Naturalairflowratesinthetestingenvironmentshouldbe

limitedtobelow0.2m/sec12

soasnottoadverselyinfluencethedispersionofHC

refrigerant.Considerationshouldbegiventoroomsizeandadjacentequipmentwith

regardstoignitionsourcesduringthetesting.

Potentialleakpointstypicallyincludejoints,abendofmorethan90O,pipeandcomponents

whichareexposedtodamageandanyotherweakpointinthesystem.

TheHCreleaseistypicallyfromacylinderviaatubetotheleaklocationonthesystem. The

leakcaneitherbe:

ThroughaholeofsizeSwiththerefrigerantatthemaximumsystem

pressure,connectedtothecylinders

liquidorgasofftakeasrequired. The

refrigerantpressureshouldbeas

specifiedinthetableabove. Itis

recommendedthattheleakrateis

recorded.The

photo

shows

assemblies

usedforsimulatedleaktestingwith

holesizesof 0.35mmand1.1mmdiameter;

or

Throughanadjustablemeteringvalveattheratecalculatedbyoneoftheequationsabove. The

photoshowsaneedlevalveusedforleaksimulation

11Basedon32

OCand55

OCinaccordancewithEN3781:2008

12InlinewithperformancetestingstandardISOEN239535.3.1.2


14/30


testing,capableofmeteringthereleaseattherequiredrate.

Careshouldbetakentoensurethattheinstallationoftheleak,thepositioningofthe

refrigerationsystem

and

the

refrigerant

sampling

equipment

do

not

notably

influence

the

testresults. Theequipmentformeasuringtherefrigerant

concentrationshouldhavesufficientlyrapidresponseto

changesinconcentration,typically2to3seconds. Ifthe

measuringmethodisonethatremovesgassamples,thenit

shalldosoataratelessthan4mlperminute13. The

concentrationcanbemeasuredusingametersuchasthat

showninthephoto(BWTechnologiesGasAlertMicro5).

Anylocationwheretheconcentrationisabove50%ofthe

LFLforanypartofthetestisdeemedtobepotentially

flammable

14

.The

factor

of

0.5

is

used

because

an

HC

refrigerant

leak

is

defined

as

asecondaryrelease.

Section5showshowtodealwithsourcesofignitionwithinpotentiallyflammableareas.

4.3AdjacentequipmentThesimulatedleaktestingalsoidentifiestheareaaroundasystemwhichmustbefreefrom

sourcesofignition. IfapotentiallyflammablezonecanoccurbeyondthefootprintoftheHC

equipmentitisimportantthatotherequipmentlocatedwithinthisareaissuitableforusein

apotentiallyflammableenvironment.

ForcabinetswithdoorswhereHCcouldleakinsidethecabinet,testingshouldbecarriedout

todeterminetheextentofapotentiallyflammablezonewhenthedoor(s)areopenedafter

aleakintothecabinet.

4.4ReportingRecordingtheresultsofthesimulatedleaktestingprovidesevidenceofcompliancewiththe

principlesofATEXanddemonstratestoendusersthatleaksimulationtestinghasbeen

carriedouttotherelevantstandard. Thefollowinginformationshouldbeincluded:

Refrigeration/airconditioningsystem(makeandmodel)tested; Leakrateandleakpositions; Standardsusedtodeterminethereleaserateandmaximumallowable

concentration;

Explanationoftestmethodology; Equipmentusedandrelevantcalibrationinformation; Refrigerantinformation; Assumptionsmadesuchasmaximumpressureandtemperaturewhererelevant; Airflowrateduringthetestassociatedwiththeequipmentandexternal;

13InstituteofRefrigerationCodeforA2andA3refrigerants.

14EN60079101:2009B.5.2.1,2


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Testresults concentrationmeasuredateachlocationthroughouttest. Itisrecommendedthatthisispresentedasagraphofthe%LFLagainsttimeforeach

leaklocation,withphotosshowingthelocationoftheleakandsensor.

5.ElectricalDevicesTypesandEnclosuresThissectionsummarisestherequirementsforelectricaldevices,enclosuresandconnections

usedinpotentiallyflammableatmospheres. Itisnotpossibletoincludefullanddetailed

informationinthisCode. Therelevantstandardsareincludedandmustbereferredtofor

specificinformation.

Thesimulatedleaktestingwillidentifysourcesofignitionwhicharewithinthepotentially

flammablezone. Electricaldeviceswithinthepotentiallyflammablezonemustnot:

Produceanoperationalarcorspark(unlessthatarcorsparkispreventedfromcausingignitioninaccordancewithIECEN6007915,clauses16to20); Developamaximumsurfacetemperatureinexcessofthemaximumappropriateto

thetemperatureclassoftheapparatus(unlessthetemperatureispreventedfrom

causingignitioninaccordancewithIECEN6007915,clauses16to20).

Sourcesofignitionassociatedwithrefrigeratedcabinetstypicallyinclude:

On/offswitchesorcontactors; Relays(e.g.oncontrolsandsinglephasecompressors); Pressureswitches; Thermaloverloads; Fanmotors; Thermostats; Condensatepumps; Miniaturecircuitbreakers(MCBs); Defrostheatersifthesurfacetemperaturecanexceed360OC(maximumheater

surfacetemperatureshouldbedemonstratedbytestingintheoperating

environmentmaximumambient,assumingdefrostterminationhasfailed).

Thisisnotanexhaustivelist,butincludesthemostcommonelectricaldeviceswhichneedto

beconsidered.

Thefollowingitemsaregenerallynotsourcesofignition:

Cabinetlighting(theswitch,starterandterminationsmustbeconsideredevenforlowvoltagelighting),

Capacitors(itisrecommendedthatbleedresistorsarefittedtominimisethehazardcausedbydischargeduringservice);

Solenoidvalvecoils; Wiringconnections(accidentaldisconnection,forexampleduringservice,can

produceaspark. Tominimisethisriskwithpushcrimpterminals,tagged

terminationsthat

cannot

be

accidentally

disconnected

are

recommended);



16/30


Fuses(deemednonsparkingdevicesiftheyarenonrewirable,nonindicatingcartridgetypesorindicatingcartridgetypes,accordingtoIEC602693,operating

withintheirrating15).

Therearevariousoptionsfordealingwithsourcesofignitionwithinapotentiallyflammable

zone.In

order

of

simplicity

and

effectiveness

they

are:

1. Movethesourceofignitionoutsidethepotentiallyflammablezone.Or

2. Replacethesourceofignitionwithasuitabledevice.Or

3. Increasetheairflowand/ormaintainapermanentairflowtoreducethepotentially

flammable

zone.

Or

4. LocatethesourceofignitioninasuitableenclosurewhichmeetstherequirementsofEN6007915:2010(thisisusuallycostprohibitiveforsmallsystems).

Airflowiscoveredinthenextsection. Theremainderofthissectioncoverssafeelectrical

devicesandenclosures.

5.1ElectricaldevicesforuseinpotentiallyflammableatmospheresIECEN6007915definestypenprotectionasthatwhich,innormaloperationandin

certainspecifiedabnormalconditions,isnotcapableofignitingasurroundingexplosivegas

atmosphere. Switchingelectricaldeviceswhicharelocatedinapotentiallyflammable

atmosphereshouldthereforebetypeninaccordancewithIECEN6007915,which

includesdifferenttypesofprotectionasfollows:

nAnonsparking(deviceconstructedtominimisetheriskoroccurrenceofarcsorsparkscapableofcreatinganignitionhazardduringconditionsofnormal

operation16).

nCenclosedbreak(deviceincorporatingelectricalcontactsthataremadeandbrokenandthatwillwithstandaninternalexplosionoftheflammablegasorvapour

whichmayenteritwithoutsufferingdamageandwithoutcommunicatingthe

internalexplosiontotheexternalflammablegasorvapour17).

nChermeticallysealeddevice(devicewhichissoconstructedthattheexternalatmospherecannotgainaccesstotheinteriorandinwhichthesealismadeby

fusion,forexamplebysoldering,brazing,weldingorthefusionofglasstometal18).

15EN6007915:2010,9.1

16

EN60079

15:2010,

3.7.1

17EN6007915:2010,3.7.2.1

18EN6007915:2010,3.7.2.2


17/30


nCnonincendivecomponent(componentshavingcontactsformakingorbreakingaspecifiedignitioncapablecircuitbutinwhichthecontactingmechanism

isdesignedandconstructedsothatthecomponentsisnotcapableofcausing

ignitionofthespecifiedexplosivegasatmosphere19).

nCsealeddevice(devicewhichissoconstructedthatitcannotbeopenedduringnormalserviceandissealedeffectivelytoprevententryofanexternalatmosphere20).

nRrestrictedbreathing(enclosurethatisdesignedtorestricttheentryofgases,vapoursandmists

21).

SomeelectricaldevicesusedinrefrigerationsystemsmeettherequirementsofIECEN60079

typenprotection,buthavenotbeentestedtoconfirmthis. Deviceswhicharetypen

mustbetestedbyanapprovednotifiedbodyandcorrectlydocumented.

5.2CabinetswithdoorsandwellsIntheeventofaleakintoacabinetwithdoorstherefrigerantcannotdisperseifthedoors

remainclosed,e.g.outoftradinghours. ThepersistencetimeabovetheLFListherefore

greaterthanwithopencabinets. Thisaffectstheareaclassificationtheinsideofthe

cabinetshouldbetreatedasazone2area. FanmotorsshouldcomplywithEN6007915or

beExrated. Othersourcesofignitionshouldberemovedfromtheinsideofthecabinet

suchasdoorswitchesandheaterklixonsorreplacedwithsuitableelectricstestedto

EN6007915.

The

above

might

also

apply

to

well

type

cabinets.

Testing

should

be

carried

out

to

check

the

concentrationinthewellintheeventofaleak. Ifitisgreaterthan50%LFLtheabovewill

apply.

Considerationshouldbegiventotheareainfrontofcabinetwithdoorswhichcouldalsobe

azone2areawhenthedoorsareopenedduring/afterarefrigerantleak. Measurements

shouldbecarriedoutinfrontofthecabinettodeterminetheextentofthezone.

Testingcarriedoutoncabinetswithdoorsorwellsshouldrecordthedurationthat50%LFL

wasexceeded(i.e.thepersistencetime).

Arefrigerantleakdetectorcouldbefittedintotheenclosedspacetoisolateallelectrical

circuitsasanultimateprotection.Thedetectorshouldactivateatthepracticallimit

(0.008kg/m3orapproximately4000ppm).Duetothenatureoftheoperatingenvironment

andlongtermmaintenancethedetectorwouldbedeemedasfalliblesocannotactasa

primaryprotectionmethod.

19

EN60079

15:2010,

3.7.2.3

20EN6007915:2010,3.7.2.4

21EN6007915:2010,3.7.3.ThespecifictestingcanbefoundinEN6007915,22.6.


18/30


5.3EnclosuresSparkingelectricaldevicescanbelocatedinasealedenclosurewithinthepotentially

flammablezone. TheenclosuremustmeettherequirementsofIECEN6007915:2010. Any

enclosurewillbedesignatedrestrictedbreathingduetoitsIPrating. Thetestingforthisis

onerousand

difficult

to

apply

physically

and

is

usually

cost

prohibitive.

5.4Connection/disconnectionElectricalconnectionswithinapotentiallyflammablezonearehazardousifdisconnected

whileenergised.

Plugsandsockets,iftheyareallocatedandconnectedtoonlyonepartoftheequipment,

shallbesecuredmechanicallytopreventunintentionalseparationorhaveaminimum

separationforceof15Nm. Theequipmentshallbemarkedasfollows22:

WARNINGdonotseparatewhenenergised.

Fuseenclosuresshallbeinterlockedsothatthefusescanonlyberemovedorreplacedwith

thesupplydisconnectedortheenclosureshallcarrythefollowingwarninglabel23:

WARNINGdonotremoveorreplacefusewhenenergised.

Thephotoshowsanexampleofalabelonadisplaycabinet.

5.5WiringNonsheathedsinglecoresshallnotbeusedforliveconductors,unlesstheyareinstalled

insideswitchboards,enclosuresorconduitsystems24.

22

EN60079

15:2010,

10.1

and

24.3.1

23EN6007915:2010,9.4

24EN6007914:2008,9.3.5


19/30


6.AirflowThissectioncoverstheuseofairflowtoreducetheextentofthepotentiallyflammable

zoneintheeventofaleakandtheapplicationoftheoreticalVzcalculations.

Zone2ofNE(NegligibleExtent)Ifitcanbedemonstratedthatatheoreticalflammablevolume(Vz)isbelow0.1m

3theZone

canbeclassedasaZone2ofNE(NegligibleExtent).ThecalculationforZone2NEcanbe

foundinEN60079101,AnnexBwhichprovidesinformationandformulastoallowthe

flammablezonetobecalculatedfromtherefrigerantleakrate,airflow,LFL,temperature

andenclosurevolume.Iftheresultantpotentiallyflammablevolume(Vz)isequaltoorless

than0.1m3itisconsideredtobeaZone2ofnegligibleextent.

Theairflowassociatedwitharefrigerationsystemscondenserfan/sisusuallysufficientto

reducethe

potentially

flammable

area

to

azone

of

negligible

extent25.

Leak

simulation

testingshouldbecarriedouttoprovetheresultsofanycalculationsasgeometryandactual

airflowsachievedwillinfluencedispersionofHCrefrigerant.Anymeasurementexceeding

50%LFLindicatesthattheareacouldbepotentiallyflammableintheeventofaleakand

thatairflowonitsownisnotsufficienttoprotectsourcesofignition.Seriousconsideration

shouldalsobegiventofouledcondensersorfailedfanmotorswhichwouldreduce

availableairflowsignificantly.

VentilationDegreeisHighwhenanevaluationoftheriskshowsthattheextentofpotential

damageduetothesuddenincreaseintemperatureasaresultofignitionofanexplosivegas

atmosphereofvolume=Vz,isnegligible. ThisisnormallywhenVzislessthan0.1m3. Air

flowassociatedwithcondenserfansisgenerallyhigh.

AvailabilityisGoodwhenventilationispresentvirtuallycontinuously.

AvailabilityisFairifventilationisexpectedtobepresentduringnormaloperation.

Discontinuitiesarepermittedprovidedtheyoccurinfrequentlyandforshortperiods.

25EN60079101:2009,B.7


20/30

Toavoidtheneedforchangestoelectricaldevicesorenclosureseither:

Condenserfanscanberunconstantly(i.e.notswitchedoffwhenthesystemisdowntotemperature). Thiswillincreasethepowerconsumptionofthesystem;

or

Asupplementaryfancanbeswitchedonwhenthecondenserfanisoff. Sufficientairflowisusuallyprovidedbyasmallerfanthanthatusedforcondensercooling,so

thepowerrequirementassociatedwiththisoptionisusuallylessthanconstantly

runningacondenserfan.Theairflowofthesupplementaryfanmustbetestedwith

leaksimulationtoensuretheairflowissufficienttodispersetheHCrefrigerant.

Note:Seriousconsiderationshouldbegiventofouledcondensersorfailedfanmotorsboth

reducingavailableairflowsignificantly,especiallyiftheyaretheprimaryprotectionmethod

forsourcesofignition.



21/30

7.LabellingandDocumentationThissectioncoversthelabellingofsystemschargedwithHCrefrigerant.

Systemsshould

be

clearly

labelled,

with

the

ISO

label

(right),

to

show

therefrigeranttypeandthatitisflammable.

Itisrecommendedthatanadditionallabelisfixedtothesystemtoprovidebasicsafety

informationtoserviceengineers. AnexamplelabelforanR290systemisshownbelow.

RefrigerantR290(Care40,Propane)ThisunitmustnotbelocatedinanroomorareawithavolumelessthanXXXm3.Note:Onlyengineerswhohavebeentrainedinthesafehandlinganduseofhydrocarbon(HC)refrigerantsshouldworkonthissystem. Workonthissysteminawellventilatedareaoroutside.

Usealocalleakdetectortoindicateifthereishydrocarbonintheairaroundthesystembeforeand

duringworkonthesystem(placeitatlowlevel HCs

areheavierthanair).

Ensuretherearenosourcesofignition(flamesorsparkingelectricalcomponents)within3m(10feet)

ofyourworkarea.

Ifreplacingcomponents,uselikeforlikereplacements.

TakegreatcarewhenbrazingtoensureallHChasbeenremovedfromthesystem.Userefrigerantgradepropane(R290orCARE40).

Theminimumroomvolumeiscalculatedusingthepracticallimit(0.008kg/m3).



22/30

8.ManufactureThissectionprovidesoutlineinformationabouttheaspectsofmanufacturerelatedtothe

useofHCrefrigerants.

Systemsshouldbeprocessedtoensurejointsaresafeandleaktightinaccordancewith

EN378:

Strengthtestedto1.1xPS; Leaktightnesstestedto1xPS,measuredusingasystemwithasensitivityof

3g/year;

wherePSisthesystempressureasdefinedinEN3781:2008.

Thesystemshouldthenbeevacuatedto375microns(0.375Torr,0.5mbar)beforecharging.

Thepressuretestingforstrengthandleaktightness,thevacuumachievedandperformance

checksshouldberecorded.

ConsiderationshouldbegiventothefollowingpointswhendesigningtheHCcharging

facility:

Accuracyofchargeforcriticallychargedsystems. Becauseofthelowerchargeweight

comparedtoHFCs,thetolerancecanbeaslowas5gincommercialcabinets.

Location. TheHCchargingareamustnotbebelowgroundlevel. Theremustbenobelow

groundareas

adjacent

to

the

charging

areas

where

leaking

HC

could

collect.

Ventilation. Usuallytwolevelsofventilationareusedlowlevelfornormaloperation

switchingtoahighlevelforemergencyoperation(e.g.intheeventofanHCleak). The

ventilationshouldextractairatlowlevelfromthechargingareaanddischargeittoanarea

outsidewhereHCwillbesafelydispersed. Fansandmotorsshouldberatedforuseina

potentiallyflammableatmosphere.

Sourcesofignition. Anareaaroundthechargingequipmentshouldbefreefromsourcesofignition. Typicallythiswillbeanarea3mfromtheequipment,buttheactualzonewill

dependonventilation,factorylayout,leakdetectionetc.

HCgasdetection. ThetypeusedshouldaccuratelysensetheHC(s)beingused,andnotbeaffectedbyotherairbornesubstances. Aninfraredsystemwillbethemostreliable. The

systemshouldbeproperlycommissionedandregularlychecked. Sufficientsensorsshould

beusedtoensurealeakofHCrefrigerantisdetected. Inthiseventthecontrolsystem

shouldswitchonthehighlevelventilationandactivateanalarm. Thedetectionsystem

shouldbesettoactivateat20%LFL.

StorageofHCrefrigerant. TheminimumquantityofHCshouldbeinsidethechargingarea.AllotherHCcylindersshouldbestoredoutsideinasafearea.

Operatortraining. OperatorschargingHCrefrigerantandtheirsupervisorsshouldbetrainedinthesafehandlingofHCs(seesection10formoreinformation).



23/30

Access. AccesstotheHCchargingareashouldberestrictedtopersonnelwhohave

receivedsafehandlingtraining. Theareashouldbeclearlymarkedwithwarningsigns. The

chargingareashouldbeeasilyaccessibleintheeventofanemergency.

HCsupply. AnypipeworkassociatedwithHCchargingshouldbeprotectedfromaccidentaldamage.

The

HC

cylinder

or

vessel

should

be

fitted

with

an

excess

flow

valve.

Fireextinguishers. Fireextinguishersshouldbelocatedinthechargingarea(drypowderorCO2types).

Afterchargingthefinaljoint(s)mustbeleaktested.



24/30

9. EndUserPostInstallationChecksEndusersusuallydrivethemovetoHCrefrigerants,butwherethisisnotthecasethey

shouldbemadeawarethatsystemsarechargedwithHCs. Whereapplicableinformation

aboutthe

minimum

room

size

the

equipment

can

be

located

in

and

the

flammable

zone

aroundthecabinetshouldbeprovided.

ItisrecommendedthattheapplicationandinstallationofHCcabinetsarechecked,for

examplebyanindependentexpert. Thisshouldincludeconfirmationthat:

Thecabinethasbeenproducedtospecification; ItslocationisinaccordancewithEN3781:2008; SourcesofignitionarenotlocatedinapotentiallyflammablezonearoundHC

cabinets;

Appropriatelytrainedandqualifiedengineersworkonthecabinets.



25/30


10.ServiceandRepairThissectionprovidesanoutlineoftheserviceandmaintenanceofHCsystems,where

proceduresandequipmentdifferfromserviceofHFCsystems.

10.1PersonalleakdetectionAnHCgasdetectorshouldbeusedtomonitortheairinthe

Thedetectorshouldnothaveazerobackground

alarmatamaximumof20%LFL.Theengineerwouldneed

todeterminethemostappropriateplacetolocatethe

sensordependentontheworkingenvironment. Thephot

showsuitabledetectors.

workarea.

facility andshould

os

ththefollowing

10.2ToolsandequipmentStandard(HFC)equipmentcanbeusedforservicingHCsystemswi

exceptions:

Electronicleakdetectors. MostHFCleakdetectorsarenotsafeforusewithHCsandarenotsensitivetoHCs. ElectronicHC(combustiblegas)leakdetectorsare

availablefromanumberofsuppliers.

Recoverymachines. HFCrecoverymachinesarenotsafeforusewithHCssoonespecially

designed

for

use

with

HCs

must

be

used.

Scales. MoreaccuratescalesarenecessarywhenchargingHCsystemswithasmall,criticalcharge. Anaccuracyof5gisoftennecessarymostscalesusedforservice

arenotthisaccurate.

Additionalsafetyequipmentisalsorequired:

AdrypowderorCO2fireextinguisher. Asuitableventilationfanshouldbeusedwhenworking

inside

ifthere

is

insufficient

natural

ventilation. Anexampleisshowninthephoto

whichhasanExratedfanmotoranda5m

extensionleadsothefancanbeswitched

outsidethe3mworkarea.


26/30

10.3ProceduresIngeneral,goodrefrigerationpracticeshouldbefollowedwhenservicingHCequipment.

Differencesareoutlinedbelow.

Theworkareamustbewellventilatedwithnosourceofignitionwithin3m(typically)oftheHCsystemandequipmentsuchasavacuumpumpandrecovery

machine.

Thevacuumpumpshouldbecontrolledbyaswitchoutsidethe3mzone(thevacuumpumpsswitchshouldnotbeusedasitisasourceofignition). Careshould

betakentoensurethatthevacuumpumphasnomotorstarterssuchasrelaysor

centrifugalswitches.ThevacuumpumpcoulddischargeresidualHCssoshouldbe

locatedinawellventilatedarea.

IftheHCchargeislessthan150gitcanbeventedratherthanrecovered,providingit

can

be

vented

to

outside

abuilding

and

safely

dispersed.

PriortounbrazingjointstheHCmustberemovedfromthesystem,andthesystemfilledwithnitrogen. Forsystemwithmorethan150gchargetheprocedureis:

1. RecovertheHCfromthesystem.2. Runtherecoverymachineforaslongaspossiblesothesystemisundervacuum

andasmuchoftheHCchargeisremovedfromthesystemaspossible. Note

themachinecommonlyusedforHCrecovery(theCaresaver)canonlyberunfor

5minuteswiththelowpressureswitchbypassed,butthisshouldbesufficient.

3. Fillthesystemwithdrynitrogentoaslightpositivepressure.4. Releasethepressureandleavethesystemconnectedtotheventlineandopen.5. Unbrazeconnectionsasquicklyaspossiblewearglovesandgoggles.NotewhenrecoveringHCfromlargesystemstheprocesscanbespeededupby

recoveringintoevacuated,chilledrecoverycylinders.

Faultyelectricaldevicesandcompressorsmustbereplacedwithlikeforlikecomponents.



27/30


11.TrainingThissectionoutlinesthetopicstobeincludedintrainingofserviceengineersand

manufacturingpersonnel.

EN378specifiesthatanyoneworkingonHCsystemsshouldbetrainedtoincludethe

following26:

Knowledgeoflegislation,regulationandstandardsrelatingtoflammablerefrigerants;

Detailedknowledgeofandskillinhandlingflammablerefrigerants,personalprotectiveequipment,refrigerantleakageprevention,handlingofcylinders,

charging,leakdetection,recoveryanddisposal.

BOCspecifies

that

anyone

purchasing

CARE

(HC)

refrigerant

from

them

or

HRP

attend

their

awarenesstrainingsession. TheyregistertrainedengineersandissuephotoIDcards. The

BOCsessioncoversthetopicslistedabove.

CityandGuildsiscurrentlydevelopingahydrocarbonrefrigerantCPDmodulewhichalso

coversthetopicslistedabove. ItwillbeanoptionalpartofC&G2079andshouldbe

availableearly2012.

26EN3784:2008,E4


28/30


Appendix1,SourcesofFurtherInformationThistablebelowprovidesdetailsoforganisationsandpublicationsformoreinformation

aboutvariousaspectsofHCrefrigerants.

Item WebsiteCompanieswhoprovideproductsand

servicesrelatedtoHCrefrigerantswww.hydrocarbons21.com

InstituteofRefrigeration SafetyCodeof

PracticeforsystemsutilisingA2andA3

refrigerants

www.ior.org.uk

StandardsreferencedinthisCode http://shop.bsigroup.com/

CityandGuilds www.cityandguilds.com
http://www.hydrocarbons21.com/http://www.ior.org.uk/http://shop.bsigroup.com/http://www.cityandguilds.com/http://www.cityandguilds.com/http://shop.bsigroup.com/http://www.ior.org.uk/http://www.hydrocarbons21.com/


29/30

Appendix2,StandardsandRegulationsATEXisthenamecommonlygiventothelegalrequirementsforcontrollingexplosive

atmospheresandthesuitabilityofequipmentandprotectivesystemsusedinthem. Itis

unclearwhether

HC

refrigeration

systems

which

are

designed

to

contain

small

amounts

of

flammablegasarecoveredbythisdirective,andifsotowhatdegreetheyshouldcomply.

ATEX95(94/9/EC)coversthedesignofequipmentandprotectivesystemsintendedforuse

inpotentiallyexplosiveatmospheres.

ATEX137(99/92/EC)coverstheminimumrequirementsforimprovingthesafetyandhealth

protectionofworkerspotentiallyatriskfromexplosiveatmospheres. Itapplies,for

example,toserviceengineersworkingonHCsystems. DSEAR(DangerousSubstancesand

ExplosiveAtmosphereRegulations)istheUKimplementationofATEX137. Italsocovers,

forexample,oxyacetylenebrazingintheworkplace.

EN378isnotharmonisedwiththeATEXdirectiveanditdoesnotspecifythatATEXapplies,

butitdoesreferenceotherATEXharmonisedstandardssuchasEN60079.

DiscussionsarecurrentlyongoingbetweentheRACindustryandtheHealthandSafety

ExecutivetoclarifythesituationregardingATEXandHCsystems. ThisCodeprovides

guidancewhichfollowstheprinciplesofATEXwithregardtoflammablezonetestingand

avoidanceofsourcesofignition. Manufacturersshouldfollowtheseprinciplesand

documentallsimulatedleaktesting,assumptionsonleakrates,methodsofreducingleakage

potentialanddecisionsregardingsourcesofignition.

Thefollowing

standards

include

guidance

on

HC

systems.

Standard Title Guidance(relevanttorefrigeratedcabinetsusingHCrefrigerants)

EN3781:2008

Refrigeratingsystemsandheat

pumpsSafetyandenvironmental

requirements,Basicrequirements,

definitions,classificationand

selectioncriteria

Practicallimit

Maximumchargesizes

EN3782:2008



requirements,Design,

construction,testing,markingand

documentation

Highpressureprotection

Ventilatedenclosures

EN3783:2008



requirements,Installationsiteand

personalprotection

Machineryrooms

HCdetectors

EN3784:2008



requirements,Operation,

maintenance,repairandrecovery

RepairstoHCsystems

Competenceofpersonnelworkingon

HCsystems



30/30

EN60079

0:2009

Explosiveatmospheres

Equipmentgeneralrequirements

Categorisationofflammablegases

Classificationofequipment

Zones

EN6007910

1:2009


Classificationofareasexplosive

gasatmospheres

Zonesandclassificationofequipment

Leaksimulationtesting

Vz(volume

of

flammable

zone)

Airflowrequirements

EN60079

14:2008

ExplosiveatmospheresElectrical

installationsdesign,selectionand

erection

Locationofsourcesofignition

Wiring

EN60079

15:2010


Equipmentprotectionbytypeof

protectionn

Electricalequipmentandenclosures

foruseinpotentiallyflammable

areas

Labellingofelectricalequipment

EN603352

24:2010

Household&similarelectrical

appliancesSafety

Part224:

Particular

requirements

forrefrigeratingappliances,ice

creamappliances&icemakers

Systemswithlessthan150gHC

charge.

EN603352

89:2010

Household&similarelectrical

appliancesSafety

Part289:Particularrequirements

forcommercial

refrigeratingapplianceswithan

incorporatedor

remoterefrigerantcondensingunit

orcompressor

Systemswithlessthan150gHC

charge,leaksimulationtestingfor

areaclassification.

Instituteof

Refrigeration

SafetyCode

of

Practice

for

RefrigeratingSystemsutilisingA2

andA3refrigerants

Generalguidance

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