商业建筑外文文献翻译).doc

商业建筑外文文献翻译).doc

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CommercialBuildings

Abstract:

Aguideandgeneralreferenceonelectricaldesignforcommercialbuildingsisprovided.Itcoversloadcharacteristics;voltageconsiderations;powersourcesanddistributionapparatus;controllers;services,vaults,andelectricalequipmentrooms;wiringsystems;systemsprotectionandcoordination;lighting;electricspaceconditioning;transportation;communicationsystemsplanning;facilityautomation;expansion,modernization,andrehabilitation;specialrequirementsbyoccupancy;andelectricalenergymanagement.Althoughdirectedtothepowerorientedengineerwithlimitedcommercialbuildingexperience,itcanbeanaidtoallengineersresponsiblefortheelectricaldesignofcommercialbuildings.Thisrecommendedpracticeisnotintendedtobeacompletehandbook;however,itcandirecttheengineertotexts,periodicals,andreferencesforcommercialbuildingsandactasaguidethroughthemyriadofcodes,standards,andpracticespublishedbytheIEEE,otherprofessionalassociations,andgovernmentalbodies.

Keywords:

Commercialbuildings,electricpowersystems,loadcharacteristics

1.Introduction

1.1Scope

Thisrecommendedpracticewillprobablybeofgreatestvaluetothepowerorientedengineerwithlimitedcommercialbuildingexperience.Itcanalsobeanaidtoallengineersresponsiblefortheelectricaldesignofcommercialbuildings.

However,itisnotintendedasareplacementforthemanyexcellentengineeringtextsandhandbookscommonlyinuse,norisitdetailedenoughtobeadesignmanual.Itshouldbeconsideredaguideandgeneralreferenceonelectricaldesignforcommercialbuildings.

1.2CommercialBuildings

Theterm“commercial,residential,andinstitutionalbuildings”asusedinthischapter,encompassesallbuildingsotherthanindustrialbuildingsandprivatedwellings.Itincludesofficeandapartmentbuildings,hotels,schools,andchurches,marine,air,railway,andbusterminals,departmentstores,retailshops,governmentalbuildings,hospitals,nursinghomes,mentalandcorrectionalinstitutions,theaters,sportsarenas,andotherbuildingsservingthepublicdirectly.Buildings,orpartsofbuildings,withinindustrialcomplexes,whichareusedasofficesormedicalfacilitiesorforsimilarnonindustrialpurposes,fallwithinthescopeofthisrecommendedpractice.

Today’scommercialbuildings,becauseoftheirincreasingsizeandcomplexity,havebecomemoreandmoredependentuponadequateandreliableelectricsystems.Onecanbetterunderstandthecomplexnatureofmoderncommercialbuildingsbyexaminingthesystems,equipment,andfacilitieslistedin1.2.1.

1.2.2ElectricalDesignElements

Inspiteofthewidevarietyofcommercial,residential,andinstitutionalbuildings,someelectricaldesignelementsarecommontoall.Theseelements,listedbelow,willbediscussedgenerallyinthissectionandindetailintheremainingsectionsofthisrecommendedpractice.Theprincipaldesignelementsconsideredinthedesignofthepower,lighting,andauxiliarysystemsinclude:

1）Magnitudes,quality,characteristics,demand,andcoincidenceordiversityofloadsandloadfactors

2）Service,distribution,andutilizationvoltagesandvoltageregulation

3）Flexibilityandprovisionsforexpansion

4）Reliabilityandcontinuity

5）Safetyofpersonnelandproperty

6）Initialandmaintainedcost

7）Operationandmaintenance

8）Faultcurrentandsystemcoordination

9）Powersources

10）Distributionsystems

11）Legallyrequiredandoptionalstandby/emergencypowersystems

12）Energyconservation,demand,andcontrol

13）Conformancewithregulatoryrequirements

14）Specialrequirementsofthesiterelatedto:

seismicrequirements,altitude,soundlevels,security,exposuretophysicalelements,firehazards,hazardouslocations,andpowerconditioninganduninterruptiblepowersupply（UPS）systems

1.10Safety

Safetyoflifeandpreservationofpropertyaretwoofthemostimportantfactorsinthedesignoftheelectricsystem.

Thisisespeciallytrueincommercialbuildingsbecauseofpublicoccupancy,thoroughfare,andhighoccupancydensity.Inmanycommercialbuildings,thesystemsoperatingstaffhaveverylimitedtechnicalcapabilitiesandmaynothaveanyspecificelectricaltraining.

Variouscodesproviderulesandregulationsasminimumsafeguardsoflifeandproperty.Theelectricaldesignengineermayoftenprovidegreatersafeguardsthanoutlinedinthecodesaccordingtohisorherbestjudgment,whilealsogivingconsiderationtoutilizationandeconomics.

Personnelsafetymaybedividedintotwocategories:

1）Safetyformaintenanceandoperatingpersonnel

2）Safetyforthegeneralpublic

Safetyformaintenanceandoperatingpersonnelisachievedthroughtheproperdesignandselectionofequipmentwithregardtoenclosures,key-interlocking,circuitbreakerandfuse-interruptingcapacity,theuseofhigh-speedfaultdetectionandcircuit-openingdevices,clearances,groundingmethods,andidentificationofequipment.

Safetyforthegeneralpublicrequiresthatallcircuit-makingandcircuit-breakingequipment,aswellasotherelectricalapparatus,beisolatedfromcasualcontact.Thisisachievedbyusingdead-frontequipment,lockedroomsandenclosures,propergrounding,limitingoffaultlevels,installationofbarriersandotherisolation（includingspecialventilatinggrills）,properclearances,adequateinsulation,andsimilarprovisionsoutlinedinthisrecommendedpractice.

Circuitprotectionisafundamentalsafetyrequirementofallelectricsystems.Adequateinterruptingcapacitiesarerequiredinservices,feeders,andbranchcircuits.Selective,automaticisolationoffaultedcircuitsrepresentsgoodengineeringpractice.Faultprotection,whichiscoveredinChapter9,shouldbedesignedandcoordinatedthroughoutthesystem.Physicalprotectionofequipmentfromdamageortampering,andexposureofunprotectedequipmenttoelectrical,chemical,andmechanicaldamageisnecessary.

1.12DesignConsiderations

Electricalequipmentusuallyoccupiesarelativelysmallpercentageoftotalbuildingspace,and,indesign,itmaybeeasiertorelocateelectricalserviceareasthanmechanicalareasorstructuralelements.Allocationofspaceforelectricalareasisoftengivensecondaryconsiderationbyarchitecturalandrelatedspecialties.Inthecompetingsearchforspace,theelectricalengineerisresponsibleforfulfillingtherequirementsforaproperelectricalinstallationwhileatthesametimerecognizingtheflexibilityofelectricsystemsintermsoflayoutandplacement.

Architecturalconsiderationsandappearancesareofparamountimportanceindeterminingthemarketabilityofabuilding.Aestheticconsiderationsmayplayanimportantroleintheselectionofequipment,especiallylightingequipment.Providedthatthedictatesofgoodpractice,coderequirements,andenvironmentalconsiderationsarenotviolated,theelectricalengineermayhavetonegotiatedesigncriteriatoaccommodatethedesiresofothermembersofthedesignteam.

1.12.1CoordinationofDesign

Theelectricalengineerisconcernedwithprofessionalassociatessuchasthearchitect,themechanicalengineer,thestructuralengineer,and,whereundergroundservicesareinvolved,thecivilengineer.Theymustalsobeconcernedwiththebuilderandthebuildingowneroroperatorwho,asclients,maytakeanactiveinterestinthedesign.Moreoften,theelectricalengineerwillworkdirectlywiththecoordinatorofoveralldesignactivities,usuallythearchitect,ortheprojectmanager;andmustcooperatewiththesafetyengineer,fireprotectionengineer,perhapstheenvironmentalenginner,andahostofotherconcernedpeople,suchasspaceplannersandinteriordecorators,allofwhomhaveasayintheultimatedesign.Theelectricaldesignermustbecomefamiliarwithlocalrulesandknowtheauthoritieshavingjurisdictionoverthedesignandconstruction.Itcanbeinconvenientandembarrassingtohaveanelectricalprojectheldupatthelastmomentbecauseproperpermitshavenotbeenobtained,forexample,apermitforastreetclosingtoallowinstallationofutilitiestothesiteoranenvironmentalpermitforanon-sitegenerator.

Localcontractorsareusuallyfamiliarwithlocalordinancesandunionworkrulesandcanbeofgreathelpinavoidingpitfalls.Inperformingelectricaldesign,itisessential,attheoutset,toprepareachecklistofallthedesignstagesthathavetobeconsidered.Majoritemsincludetemporarypower,accesstothesite,andreviewbyothers.Certainelectricalworkmayappearinnonelectricalsectionsofthespecifications.Forexample,thefurnishingandconnectingofelectricmotorsandmotorcontrollersmaybecoveredinthemechanicalsectionofthespecifications.Foradministrativecontrolpurposes,theelectricalworkmaybedividedintoanumberofcontracts,someofwhichmaybeunderthecontrolofageneralcontractorandsomeofwhichmaybeawardedtoelectricalcontractors.Amongitemswithwhichthedesignerwillbeconcernedare:

preliminarycostestimates,finalcostestimates,plansordrawings,technicalspecifications（whicharethewrittenpresentationofthework）,materials,manuals,factoryinspections,laboratorytests,andtemporarypower.Thedesignermayalsobeinvolvedinprovidinginformationonelectricalconsiderationsthataffectfinancialjustificationoftheprojectintermsofowningandoperatingcosts,amortization,returnoninvestment,andrelateditems.

Manyelectricaldesignsfollowtheconceptofcompetitivenessinthecommercialsense.Here,costisaprimaryconsideration,andsuchdesignstendtowardminimumcoderequirements.Thereisgreatpressureonthedesignertoconsidercostabovemaintainabi