仪表防爆及接地系统施工方案设计中英

仪表防爆与接地系统施工方案ConstructionSchemeforInstrumentExplosionproofandEarthingSystem1编制说明：在现代工业生产装置中，许多易燃、易爆、易挥发的工艺介质出现在生产流程中，防爆施工对装置的安全运行非常重要；各种工艺参数的检测、显示和控制都实现了自动化、集中化、智能化，特别是集散控制系统〔DCS〕的广泛应用，对仪表接地系统的要求越来越高。正确完成仪表接地系统，对保证设备与人身安全，保证装置安全运行意义重大。为了高速优质地完成装置防爆与接地施工任务，特编制本方案。2编制依据:2.1设计施工图与其它设计文件。2.2现行《自动化仪表工程施工与验收规X》。2.3现行的《电气装置安装工程施工与验收规X》。2.4现行《自动化仪表工程质量检验评定标准》。2.5厂商提供的产品安装使用说明书等技术文件。2.6公司《质量保证手册》、《质量体系子程序》与其支撑性文件。3.工程概况工程概况应包括：工程名称、地点、规模、特点、X围、主要技术参数、主要实物工程量、工期要求与投资等。4.防爆施工：Explosion-proofConstruction:4.1一般规定：GeneralRegulations:Thestyleofexplosion-proofandwiringforelectricequipmentandinstrumentequipment,whichusedinexplosionandfiredangerousareas,mustaccordwiththedesignrequirementandcontentwithexplosionproofclassstipulation.Concerningelectricandinstrumentalequipmentandmaterialthatisinstalledinexplosionandfiredangerousarea,theirexplosion-proofqualitytechniqueappraisaldocumentandexplosion-proofmanufacturecertificatemustbepliancewiththenewstandardrequirementofcountryorvocation.Therearen’tdamageandcrackinappearanceofdeviceandmaterial.Fortheexplosion-proofelectricandinstrumentalequipmentthatisusedinexplosionandfiredangerousarea,thenameplateandexplosion-proofmarkshouldappearontheequipment,thenumberofexplosion-proofcertificateissuedbythedepartmentofnationalaccreditationshouldbeprovidedonnameplate.“电源未切断不得打开〞的标志。Thepluspressureventilationinstrumentpanel(box),junctionbox,electricequipmentandinstrumentequipmentinstalledinexplosiveandfiredangerousarea,excepttheintrinsicallysafetype,itshouldhas“Donotopenwhenenergized〞notice.Fortrench,cabletray,protectionpipeusedforinstrumentelectriccircuitandinstrumentconnectionpiping,iftheycrosstheseparatedroomindifferentexplosion-proofclassexplosionandfirearea,fillingandsealingshouldbedoneoutsidetheseparatedroom.4.2设备安装ErectingEquipment:Fortheexplosion-proofinstrumentpanel(box),junctionboxwithpluspressureventilation,aftertheyareinstalled,thepressureinboxshouldbeensurednolowerthanthedesignpressure.theinterlockandalarmunitshouldactcorrectlyandreliablywhenthepressureislow.Theexplosion-proofinstrumentpanel(box),junctionboxadoptingpluspressureairiness,itspluspressureairinesspipingmustremainaccessibleandshouldnotmountshuttingoffvalue.Fortheinstrumentbox,junctionbox,wiringbox，explosion-proofinstrumentandelectricequipmentwhichinstalledinexplosionandfiredangerousareas,theentranceofcableshouldbesealedwithexplosion-proofsealfilling.Whenoneconduitcontainsmultiplecable,theentrancecanmountsealingboxwithproprietyfilling.Doexplosion-proofsealingtospareholesinshell.或隔防密封面连接螺栓应均匀严密，并应有弹簧垫。Coversshouldhavespringsealingwasherforexplosion-proofinstrumentbox,junctionbox,andconnectionbox.Andconnectionboltsandnutsofseparatingandpreventingfaceshallbetightequablyandhavespringwasher.Theexplosion-proofelectricandinstrumentdevicesshallbeinstalledfirmly.Insidewiringmustbecorrectandfirmwithlooseness-proofandshedding-proofunit.3电气线路安装ErectingElectricalcableline:Sealingwayfortrenchthatcrossesseparatedwallsbelongingtodifferentclassofexplosionandfiredangerousareas:a.电缆沟内充砂密封，可敷设一层电缆，充填一层砂，砂层厚约100mm。电缆全部敷设完后，充砂填满电缆沟。Methodoffillingfinesandintotrench:fillingone-layersandabout100mmdepthafterinstallonelayercable.Thetrenchshallbefullofsandafterallcablelayout.b.在分界处两侧安装隔板，隔板之间充砂，长度不少于1m。Theseparatedboardsshouldbefixedatbothsidesofinterface,zonebetweenboardsshallbefilledwithsand,andthelengthisnolessthan1m.c.在分界处用阻火密封填料充填。Sealingwithfire-resistantfillingattheinterfaces.取的密封措施：Takingairproofmeasureswherecabletraypassesthroughtheinterfaceofdifferentclassexplosionandfiredangerousareas:a.在分界处作气密砂封。Carryoutsealwithsandattheinterface.b.在分界处用阻火密封填料充填，形成密封阻挡层。Sealwithfire-resistantsealfillingattheinterfaceandformsealingandresistantlayer.Choosethick-wallgalvanizedconduitascableprotectiveconduitlaidinexplosionandfiredangerousareas.Selectedpipepiecesshouldadoptproperexplosion-proofstructureandtypeaccordingtorequirementsofthedangerousareasclass.缠麻涂铅油、缠绝缘胶带或涂其它油漆。Adoptcylindricalgasthreadtoconnectconduitanddevicesorpipe-pieces.Makesurethateffectiveengagementismorethansixpitchesandlocktightlyequipmentswithlocknut.Thethreadshallbepaintedwithelectricpoly-greaseorconductiveantirustgrease.Notwringhempropes,notwringinsulatedtapeandnotpaintleadoilorotherpainting.Instrumentelectricalcircuitshallnothavemiddlejointinexplosion-proofarea.Ifitisobligatory,jointshallbeintheexplosionjunctionbox,keepconnectionhardandtight,haveallrightelectricalconductivitywithlooseness-proofandshedding-proofunit.Whenlaylinealongtheprocesspipestanchion,layoutlocationshouldbeatthesidethatpossibilityofexplosionandfireislittle.当工艺管线内爆炸和火灾危险介质的密度大于空气时，应在工艺管道的上方，反之，应在其下方。Whendensityofexplosionandfiredangerousmediumintheprocesspipeisheavierthanthatofair,itslayoutlocationshouldbeabovetheprocesspipe;onthecontrary,itslayoutlocationshallbebelow.Whenconnectprotectionpipewithinstrumentequipmentatsite,theexplosion-proofandairtightpipeconnectorsshallbeinstalled,filledandsealed.Makesurethatthedistancebetweenairproofpipeconnectorsandinstrumentequipmentisnomorethan0.45m.Theflexiblepipecanbeusedtoconnectairtightpiecesandinstrumentandmountaccordingtoexplosion-proofinstructionbook.Atmeantime,flexiblematerialshallagreewithapplicationcondition.4.4本安系统施工：ConstructionofIntrinsicallySafeSystem:Theintrinsicallysafelineandaccessoriesshallbemarkedwithbluewearmark.Addshieldnettoseparatetheintrinsicallysafecircuitfromthenon-intrinsicallysafecircuitandkeepsomedistancebetweenthem.Safebars,separatorsandotherrelatedequipmentsintheintrinsicallysafelineshallbeerectedatthesideofsafelocationorintoexplosion-proofdeviceshellthataccordswithconditions.Equipmentsneededearthingshallbereliablygrounded.Forrelateddevicesofvariousseriesintrinsicallysafeinstrumentsandlines,theirmanufacture’slicenseandexplosionproofcertificate,approvedbynationalauthoritydepartment,mustbeprovided.Ifwanttoreplacethem,theirspecificationsandtypesmustbeapprovedbyprimarydesignunitinformoffiles.5.接地系统施工：ConstructionforEarthingSystem:5.1一般规定：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保护接地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信号回路接地：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本安系统接地：EarthingforIntrinsicallySafeSystem:Intrinsicallysafecircuititselfdoesnotground.Ifinstrumentfunctionrequiresittoground,carryoutearthingaccordingtoerectionandoperationinstructionanddesignrequirements.Astosystemearthingf