儀表防爆與接地系統(tǒng)施工方案ConstructionSchemeforInstrumentExplosionproofandEarthingSystem1編制說明：在現(xiàn)代工業(yè)生產(chǎn)裝置中，許多易燃、易爆、易揮發(fā)的工藝介質(zhì)出現(xiàn)在生產(chǎn)流程中，防爆施工對(duì)裝置的安全運(yùn)行非常重要；各種工藝參數(shù)的檢測(cè)、顯示和控制都實(shí)現(xiàn)了自動(dòng)化、集中化、智能化，特別是集散控制系統(tǒng)〔DCS〕的廣泛應(yīng)用，對(duì)儀表接地系統(tǒng)的要求越來越高。正確完成儀表接地系統(tǒng)，對(duì)保證設(shè)備與人身安全，保證裝置安全運(yùn)行意義重大。為了高速優(yōu)質(zhì)地完成裝置防爆與接地施工任務(wù)，特編制本方案。2編制依據(jù):2.1設(shè)計(jì)施工圖與其它設(shè)計(jì)文件。2.2現(xiàn)行《自動(dòng)化儀表工程施工與驗(yàn)收規(guī)X》。2.3現(xiàn)行的《電氣裝置安裝工程施工與驗(yàn)收規(guī)X》。2.4現(xiàn)行《自動(dòng)化儀表工程質(zhì)量檢驗(yàn)評(píng)定標(biāo)準(zhǔn)》。2.5廠商提供的產(chǎn)品安裝使用說明書等技術(shù)文件。2.6公司《質(zhì)量保證手冊(cè)》、《質(zhì)量體系子程序》與其支撐性文件。3.工程概況工程概況應(yīng)包括：工程名稱、地點(diǎn)、規(guī)模、特點(diǎn)、X圍、主要技術(shù)參數(shù)、主要實(shí)物工程量、工期要求與投資等。4.防爆施工：Explosion-proofConstruction:4.1一般規(guī)定：GeneralRegulations:Thestyleofexplosion-proofandwiringforelectricequipmentandinstrumentequipment,whichusedinexplosionandfiredangerousareas,mustaccordwiththedesignrequirementandcontentwithexplosionproofclassstipulation.Concerningelectricandinstrumentalequipmentandmaterialthatisinstalledinexplosionandfiredangerousarea,theirexplosion-proofqualitytechniqueappraisaldocumentandexplosion-proofmanufacturecertificatemustbepliancewiththenewstandardrequirementofcountryorvocation.Therearen’tdamageandcrackinappearanceofdeviceandmaterial.Fortheexplosion-proofelectricandinstrumentalequipmentthatisusedinexplosionandfiredangerousarea,thenameplateandexplosion-proofmarkshouldappearontheequipment,thenumberofexplosion-proofcertificateissuedbythedepartmentofnationalaccreditationshouldbeprovidedonnameplate.“電源未切斷不得打開〞的標(biāo)志。Thepluspressureventilationinstrumentpanel(box),junctionbox,electricequipmentandinstrumentequipmentinstalledinexplosiveandfiredangerousarea,excepttheintrinsicallysafetype,itshouldhas“Donotopenwhenenergized〞notice.Fortrench,cabletray,protectionpipeusedforinstrumentelectriccircuitandinstrumentconnectionpiping,iftheycrosstheseparatedroomindifferentexplosion-proofclassexplosionandfirearea,fillingandsealingshouldbedoneoutsidetheseparatedroom.4.2設(shè)備安裝ErectingEquipment:Fortheexplosion-proofinstrumentpanel(box),junctionboxwithpluspressureventilation,aftertheyareinstalled,thepressureinboxshouldbeensurednolowerthanthedesignpressure.theinterlockandalarmunitshouldactcorrectlyandreliablywhenthepressureislow.Theexplosion-proofinstrumentpanel(box),junctionboxadoptingpluspressureairiness,itspluspressureairinesspipingmustremainaccessibleandshouldnotmountshuttingoffvalue.Fortheinstrumentbox,junctionbox,wiringbox，explosion-proofinstrumentandelectricequipmentwhichinstalledinexplosionandfiredangerousareas,theentranceofcableshouldbesealedwithexplosion-proofsealfilling.Whenoneconduitcontainsmultiplecable,theentrancecanmountsealingboxwithproprietyfilling.Doexplosion-proofsealingtospareholesinshell.或隔防密封面連接螺栓應(yīng)均勻嚴(yán)密，并應(yīng)有彈簧墊。Coversshouldhavespringsealingwasherforexplosion-proofinstrumentbox,junctionbox,andconnectionbox.Andconnectionboltsandnutsofseparatingandpreventingfaceshallbetightequablyandhavespringwasher.Theexplosion-proofelectricandinstrumentdevicesshallbeinstalledfirmly.Insidewiringmustbecorrectandfirmwithlooseness-proofandshedding-proofunit.3電氣線路安裝ErectingElectricalcableline:Sealingwayfortrenchthatcrossesseparatedwallsbelongingtodifferentclassofexplosionandfiredangerousareas:a.電纜溝內(nèi)充砂密封，可敷設(shè)一層電纜，充填一層砂，砂層厚約100mm。電纜全部敷設(shè)完后，充砂填滿電纜溝。Methodoffillingfinesandintotrench:fillingone-layersandabout100mmdepthafterinstallonelayercable.Thetrenchshallbefullofsandafterallcablelayout.b.在分界處兩側(cè)安裝隔板，隔板之間充砂，長(zhǎng)度不少于1m。Theseparatedboardsshouldbefixedatbothsidesofinterface,zonebetweenboardsshallbefilledwithsand,andthelengthisnolessthan1m.c.在分界處用阻火密封填料充填。Sealingwithfire-resistantfillingattheinterfaces.取的密封措施：Takingairproofmeasureswherecabletraypassesthroughtheinterfaceofdifferentclassexplosionandfiredangerousareas:a.在分界處作氣密砂封。Carryoutsealwithsandattheinterface.b.在分界處用阻火密封填料充填，形成密封阻擋層。Sealwithfire-resistantsealfillingattheinterfaceandformsealingandresistantlayer.Choosethick-wallgalvanizedconduitascableprotectiveconduitlaidinexplosionandfiredangerousareas.Selectedpipepiecesshouldadoptproperexplosion-proofstructureandtypeaccordingtorequirementsofthedangerousareasclass.纏麻涂鉛油、纏絕緣膠帶或涂其它油漆。Adoptcylindricalgasthreadtoconnectconduitanddevicesorpipe-pieces.Makesurethateffectiveengagementismorethansixpitchesandlocktightlyequipmentswithlocknut.Thethreadshallbepaintedwithelectricpoly-greaseorconductiveantirustgrease.Notwringhempropes,notwringinsulatedtapeandnotpaintleadoilorotherpainting.Instrumentelectricalcircuitshallnothavemiddlejointinexplosion-proofarea.Ifitisobligatory,jointshallbeintheexplosionjunctionbox,keepconnectionhardandtight,haveallrightelectricalconductivitywithlooseness-proofandshedding-proofunit.Whenlaylinealongtheprocesspipestanchion,layoutlocationshouldbeatthesidethatpossibilityofexplosionandfireislittle.當(dāng)工藝管線內(nèi)爆炸和火災(zāi)危險(xiǎn)介質(zhì)的密度大于空氣時(shí)，應(yīng)在工藝管道的上方，反之，應(yīng)在其下方。Whendensityofexplosionandfiredangerousmediumintheprocesspipeisheavierthanthatofair,itslayoutlocationshouldbeabovetheprocesspipe;onthecontrary,itslayoutlocationshallbebelow.Whenconnectprotectionpipewithinstrumentequipmentatsite,theexplosion-proofandairtightpipeconnectorsshallbeinstalled,filledandsealed.Makesurethatthedistancebetweenairproofpipeconnectorsandinstrumentequipmentisnomorethan0.45m.Theflexiblepipecanbeusedtoconnectairtightpiecesandinstrumentandmountaccordingtoexplosion-proofinstructionbook.Atmeantime,flexiblematerialshallagreewithapplicationcondition.4.4本安系統(tǒng)施工：ConstructionofIntrinsicallySafeSystem:Theintrinsicallysafelineandaccessoriesshallbemarkedwithbluewearmark.Addshieldnettoseparatetheintrinsicallysafecircuitfromthenon-intrinsicallysafecircuitandkeepsomedistancebetweenthem.Safebars,separatorsandotherrelatedequipmentsintheintrinsicallysafelineshallbeerectedatthesideofsafelocationorintoexplosion-proofdeviceshellthataccordswithconditions.Equipmentsneededearthingshallbereliablygrounded.Forrelateddevicesofvariousseriesintrinsicallysafeinstrumentsandlines,theirmanufacture’slicenseandexplosionproofcertificate,approvedbynationalauthoritydepartment,mustbeprovided.Ifwanttoreplacethem,theirspecificationsandtypesmustbeapprovedbyprimarydesignunitinformoffiles.5.接地系統(tǒng)施工：ConstructionforEarthingSystem:5.1一般規(guī)定：GeneralRegulations:Instrumentearthingsystemgenerallyprisesoffourtypes:safeguardearthing,signalloopearthing,shieldearthingandintrinsicallysafeearthingAllearthlingsofinstrumentsystemshouldhaveitsownsystem,everyearthlingsystemshallseparateandconnecttoitsownearthingbus.Busandbranch-lineshouldbeinsulatedeachother.Earthingresistanceofinstrumentearthingsystemshouldbepliancewithrequirementsofmanufacture’stechnicalfilesordesignfilesforrespectiveinstrumentsystem.Whenitisneededtopreventdisturbance,sparecoresofmulti-corecableshouldbegroundedatonepoint.Sparecoresofshieldedcableanditsshieldshouldbegroundedatthesameside.Colorofearthingwireshouldconformtodesignregulationsandsetyellow-greensign.Connectionlineforearthingsystemshouldapplywithcopper-coreinsulatedcableorwireandfastenoncopperboltandnut.Earthingbusbarinsideinstrumentpanel(box)orcabinetshallbemadeofcopperandbefixedbyinsulatedsupport.Applyweldingbetweenearthingmainlineandearthingpole.Whenfabricateearthingbusbarbyourselves,connectboltwithbusbarbytappingthread.5.2保護(hù)接地SafeguardEarthing:Allnotelectriferousmetallicpartsinnormalcondition,suchasshellofusage-powerinstruments,instrumentpanel,cabinet,box,caseandcabletray,conduit,supportfoundationetc.,shouldbeperformedsafeguardearthingiftheirinsulationlayershavebeendamagedandmayhavedangerousvoltage.Whendesigndoesnotrequire,safeguardearthingforlocalinstrument,switch,etc.,whosesupplypowerisnomorethan24V,canbeignored.Alllowvoltageelectricaldevicesinsmallsize,suchaspushbutton,signallight,relayetc.,fixedonmetalpanelandboardinnon-explosionarea,iftheirconnectionwithgroundedmetallicpanelorboardisingoodcondition,theirsafeguardearthingcanbeignored.Safeguardearthingsystemcanconnecttosafeguardearthingnetforelectricengineeringlowvoltageplantsandensureconnectionreliableandhard.However,forbidexecutingserialearthing.Forcableductandprotectivepipeerectedontobuilding,ifdesignfilesdonotrequireonlyone-pointearthing,multi-pointearthingisavailable.5.3信號(hào)回路接地：SignalLoopEarthing:Signalloopearthingshouldbeperformedatthesideofdisplayinstrument.Ifusingwell-groundedthermocoupleormeasuringelementsofinstrumenthavebeenearthed,earthingatthesideofdisplayisunnecessary.Everyinstrumentsignalloopandsystemshouldhaveonlyone-pointearthingingeneral,exceptthatusingseparatortosegregateDCsignalloopbetweentwoearthingpoints.Forinstrumentssuchassolenoidflowmeter,turbineflowmeterandanalyzingelements,carryoutearthingaccordingtoinstallationoroperationinstructionandmanufacture’stechniquefiles.Signalloopearthingandshieldearthingcanshareasingleearthingsystem.4屏蔽接地：ShieldEarthing:Performshieldearthingforshieldedcableatsideofdisplayinstrument.Forthesameconduit,ensureshieldhasreliableelectriccontinuityandearthatone-point.Whenperformingconnectioninsideofinstrumentpanelorjunctionbox,shieldshouldbeprotectedwithinsulatedsheathtopreventittouchpanelorbox.Whilemakingcableterminal,ifitisunnecessarytofetchouttheshield,cutoffshieldlayerfromcablesheath.Ifnecessarytofetchoutshield,fornet-shapedshield,housinginsulatedtubeandwrappingitsendintocableterminal;forpapyraceousshield,weldingwireisrequired.Wirecross-sectionareaforshieldearthingshallbenolessthan1.5mm2.Whenmanyshieldedcablesarebandedtogetherandallneedearthing,connectthemequallytojointpositionofbusbar.5.5本安系統(tǒng)接地：EarthingforIntrinsicallySafeSystem:Intrinsicallysafecircuititselfdoesnotground.Ifinstrumentfunctionrequiresittoground,carryoutearthingaccordingtoerectionandoperationinstructionanddesignrequirements.Astosystemearthingf