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Mechanicalandelectricalsystems

--fromBuildingAdditionsDesignThedesignofthemechanicalandelectricalsystemsforabuildingadditionrequires,inmostinstances,thesameapproachasthedesignofanewbuilding.Ineffect,thedesignerinbothinstancesisrespondingtothesamerequirementsofprovidingsatisfactoryenvironmentalconditionsofcomfortandconvenienceforthebuilding'soccupantsandadequateutilitiesforthebuilding'soperation.Itisthepurposeofthisarticletodescribenotthestandardelementsofthemechanicalandelectricaldesign,butthosefactorswhichdistinguishthedesignofadditionsfromthoseofnewstructures.SincethesefactorsoftenapplytoboththeMechanicalandelectricalengineeringdesignoftheneextension,wewillreviewtheseaspectsinacombinedsenseandpointoutwheretheremaybeaspecialimpactonaspecificengineeringdiscipline.ADEQUACYOFUTILITIESInadditiontodeterminingtheabilityofthepresentsystemtosatisfytheneedsoftheextendedbuilding,theincomingutilitiesmustbeofadequatesizetothenewrequirements.Acarefulreviewoftheseutilitiesshouldbemadebysomeoneknowledgeableinthespecificengineeringfields.

Attheearliestpossibletime,assessmentsmustbemadeofthepresentandfutureloadingonthevariousutilityserviceswhichsupplythemechanicalandelectricalsystems.Thesemustincludetherequirementsforwater(includingbothdomesticandfireprotectionrequirements),gas,electricity,stormdrainage,andsanitarysewers.Basedupontheseanalyses,anynecessaryrequirementsforextracapacityintheutilitiesmustbereflectedinthedesignofthenewextension.

Localcodesandutilitycompaniesusuallyrequirethatonlyoneserviceconnectionbeallowedtoabuilding.Therefore,whenadditionalutility-serivcecapacityisnecessary,theoldutilityservicewilleitherhavetobeenlargedorabandonedandreplaced.

Carefulnoteshouldbetakenofanyexistingorpendingmoratoriaorrestrictionswhichmaybeineffectatthetimethatextensionwillhavetobeoccupiedorbuilt.Inmanycommunities,becauseofashortageofsanitarywastedisposalfacilitiesorlackofadequategassupplyorwatercapacity,moratoriahavebeenestablishedwhichwouldpreventtheconstructionofneworextendedbuildingswhichwouldfurtherstrainthesesystems.Thiswouldpreventtheconstructionandoccupancyofthenewextension.Itisimportanttoknowabouttheserestrictionsbeforeanysubstantialeffortismadetodesignandbuildtheaddition.

Wheretheutilitiesarefoundtobeinadequate,additionalservicewillhavetoberequestedfromthelocalutilitycompany.Itisimportant,beforeanymajorexpenditureismadeintheproject,aletterbeobtainedfromtheutilitycompanytotheeffectthattherequesthasbeenreceivedandthatadditionalservicewillbeprovidedatnecessarytime.

Whenadditionalsewer,gas,orelectriclinesarenecessary,becarefultodeterminetheoriginofthesepipesandtheportionofthecostofinstallationtheownerwillhavetobearToooftenownershavediscoveredthatwhilecapacitywasavailable,itwaseconomicallyunfeasibletopayforthelonglengthofpipeorwirenecessarytoachievetheinstallation.IMPACTONEXISTINGSYSTEMSThedesignofthesystemsforthenewextensionshouldbeapproachedwiththeunderstandingthat,inthiscase,thedesignerhasanadvantage.Theexistingbuildingcanbemeasured,analyzed,andobserved.Thereforethereshouldbenosurprisestothedesignerabouttheconditionoftheexistingsystemsandtheirimpactonthenewsystemsandviceversa.Oneofthemajorimpactswhichtheextensionmayhaveontheexistingequipmentisthefactthatsomelocalcodesrequiremodificationofexistingsystemstomeetthepresentcoderequirements,ifthesystemsdonotalreadyconform.Oftenthisrequirementistiredtothesizeoftheaddition.Oneofthefirstinvestigationsthedesignteamshouldmakeincontemplatingtheadditionistoexaminethelocalcodestoseewhatimpacttheymayhaveonboththeexistingandnewsystems.Theattachmentofanynewequipmenttoanexistingsystemisboundtocreatechallengesandproblemswhichshouldbeanticipatedinordertoavoidtrouble.Forinstance,whenanewpumpisplacedonlinewithanexistingpipingsystem,oftenanumberofleakssuddenlyappearwhichwerepreviouslynotknownabout.Soitiswithanewextension.Anearlyfactorinthedesignistodeterminethelifeexpectancyofthepresentequipmentandsystems,forwhiletheremaybesparecapacityinthesystem,portionsorallofitmaybesooldthatitisnotworthwhileorfeasibletoextendthesystemtothenewaddition.Thisexistingsystemsurveywilldeterminehowmuchoftheexistingsystemwillhavetobereplacedwithnewparts,equipment,orevenentiresystems.Anotherquestionwhichmustbeansweredearlyintheanalysisiswhetherornotthenewlyenlargedstructurewilloperateasonesystem.Ofcourseitisusuallybettertohaveonesystemthroughouttheenlargedbuilding.Notonlyareoperationandmaintenanceeasier,butthisisalsousuallythemostcosteffectiveapproachMechanicalandelectricalsystemmustbeevaluatedindependently,sincetheconditionofeachonemayvaryconsiderably,andaseparatedeterminationmustbemadeastothedesirabilityofretaining,modifying,orreplacingeachsystem,inwholeorinpart.LOCATIONANDDISTRIBUTIONOften,whiletheremaybeadequatesparecapacityintheexistingutilitiesandsystems,aproblemarisesfromthelocationoftheseelementsinrelationtothelocationoftheextensionForinstance,aboilerwithplentyofsparecapacitymaybesofarthearcaitissupposedtoheatthatitcannotdoaneconomicalandefficientjob.Thebestsolution,therefore,maybetorelocatethemechanicalroomofanextendedbuildingtoamorecentrallocationinthenewcomplex.Thedecisionofwhetherornottorelocatetheexistingequipmentflowsfromtherequirementsofthespecificproject.Notonlyisthehorizontallocationimportanttoconsiderbutalsotheverticaldistance.Forinstance,anair-conditioningsystemmaybewelllocatedforthepresentbuildingbutmaybedoomedtofailureifextendedtohigherlevels,andmorefancapacityorgreaterductsizemayberequired.Howthepresentpiping,duct,andelectricaldistributionsystemsarearrangedareimportantelementswhichmustbeinvestigatedinordertohaveaclearpictureofthenewextension'simpact.Letusexaminesomeoftheseelements.Theverynatureofapipingsystemdependsuponsizes,length,andslopeifagravitysystemisutilized,andsizeandlengthifapressurizedsystemisutilized.Attemptingtoextendpipingtoofarcancreateproblemsindistributiontothenewareas.Theseproblemsarisefrominadequateslopeinthecaseofgravitysystem,suchassewers,andtoomuchfrictionduetolengthinothercases.Itisimportant,therefore,tomakesurethatthenewdistributionlayoutofthepipesiswithintheacceptedstandardsofsize,distance,andslope.Withregardtoductworkforheating,ventilating,andairconditioning,thesamerulesapply,sincefrictionisaproductofthesizeandlengthoftheductwork.Inaddition,inbothpipesandducts,quiteabitofenergylosscanresultfromtoomuchdistancefromthesourcetothedestination.Adequateinsulationwillbenecessaryinthesecases.Locationsofpipeandductrisersarealsoofsignificance,sincetheydeterminepatternsinmultistorybuilding.Especiallyinverticaladditionstheymustbecarefullyplacedsoasnottoaffectadverselytheexistingbuildingoperations.Thelessontobelearnedwhenevaluatingabuildingistheimportanceofnotonlythesparecapacityoftheexistingsystems,butalsothenewlocationanddistancestowhichtheymustbeextended.ENERGYCONSIDERATIONSThedesignofanadditiontoanexistingbuildingprovidesanopportunitytoimprovetheenergyuseoftheentirebuilding.Thedesignofequipmentandsystemsfortheadditionshouldnotonlylooktothenewextensiontoachieveenergy-savinggoals,butalsoshould,whereverpossible,seektoachievethesesavingsintheexistingbuildingaswell.Thesameenergy-conservationconsiderationswhichareapplicabletonewconstructionareofimportanceinthedesignoftheextension.Thebuildingofanextensiongivestheownera"secondchance"toachieveenergysavingswhichwerepossiblynotavailableatthetimeoftheoriginaldesignandconstruction.Whileinnowayattemptingtobeallinclusive,somepftheentirebuildingarelistedbelow:·Designtheorientation,siting,andlandscapingofthenewextensionformaximumpassivesolareffect.·Takctheopportunitytofullyinsulatenotonlythenewwork,butalsoanyequipment,piping,andductworkexisting.Thismayalsobeagoodtimetoremoveasbestosinsulation.·Designtheenvelopeoftheadditionbyusingshadingcontrols,multipleglazing,andextrainsulation.·DesignacombinedHVACsystem,heatrecovery,andthermalstoragesystems,whereitisfeasible.·Makesurethattheequipmentissizedfortheloadswhichwillbeimposed.·Considerinthedesigntheinstallationoftheloadsheatingelements,bothpassiveandactive,aswellasanyotherrenewableenergysource.·Carefullyreviewtheelectricallightingsystemforefficientperformance,andinstalladequateswitchinginordertoisolateareasoflightingaswellasequipmentwhicharenotinuse.·Considertheinstallationofanenergymanagementcontrolsystemtoassistintheenergy-efficientoperationofbuilding.·Whereverpossible,considernaturalcoolingthroughventilation,nightflushing,evaporation,radiation,ordehumidification.·Considermaximumuseofnaturallightinginthedesign.·DividetheHVACsystemsintoproperzonesinordertorespondmostefficientlytolocalconditions.·Makeprovisionsforpossiblefutureenergy-conservingmeasures.Withtheseandothermethodswhichtheindividualbuildingsituationmightsuggest,itispossiblethattheadditioncanhelpdevelopafargreaterenergyconservationprogramthantheextensionalonemaysuggest.CONDITIONOFEXISTINGEQUIPMENTAsbeenexplainedinseveraloftheforegoingsections,theconditionoftheexistingequipmentandsystemaccessoriescanquiteoftenbethedeter-miningfactorinevaluatinganewsystemshouldbeinstalledorwhetheranattemptshouldbemadetoutilizeandpossiblyextendtheexistingequipment.Toarriveattheproperdecisioninthesecasesrequirestheinputofexpertswhoknowtheequipmentandsystems,Withtheenormousvariationsinthetypeofadditions,aswellasthetypeofexistingequipment,itisalmostimpossibletogeneralizetosuggestafewsimpleideas:·Inanyadditionproject,theprimereasonforkeepingexistingequipmentinservice-determinedonlyaftercarefulanalysis-isthatpotentialremainingusablelifewillmakeitsretentioncosteffective.·Existingequipment,althoughpresentlyoperatingingoodcondition,maybeadverselyaffectedbytheadditionofnewloads,andtheimpactofthisincreasedstressshouldbecarefullyconsidered.·Thedesiretoretainexistingpieceofmechanicalorelectucalequipmentshouldnot,byitselfpreventtheinstallationofamoreefficient,costeffectivesystemfortheentirebuilding.·Takeintoconsiderationtheenergyconservation,operation,andmain-tenanceaspectsinmakingthedecisiontoreuseorreplaceequipment.·Whereequipmentisstillingoodandusablecondition,butwhereitdoesnottotallyfitinwiththelong-rangeplans,considerationshouldbegiventoaphasedreplacementoftheequipment,sothatallgoalsareeventuallymetwhiletheexistingequipmentisutilizedtothemaximum.·Insomesituations,considerthepotentialsalvagevalueoftheoldequipmentinmakingyoureconomiccomparison.·Becausenewerequipmentisusuallysmallerinsizeandmoreefficient,considerwhetherornotthereplacementofalarge,olderpieceofequipmentmightallowextraroomintheexistingmechanicalspacetoprovideforthegreaterloadsoftheextendedbuilding.OPERATIONANDMAINTENANCEInthedesignofthesystemsforthebuildingthedesignerwillhavetobesensitivetotheoperationalaspectsofthebuilding,sinceitisinthisareathatthelargesthiddencostsmayoccur.Thisisespeciallytruewithanad-ditionsincethedesignerisdealingwithbothnewandexistingequipmentand,therefore,theproblemsmaybecomeenlarged.Forexample,wherenewandoldequipmentisinvolved,thestorageofsparepartsbecomesaproblembecausetheownerwillhavetodealwithdissimilarequipment,usuallyofdifferentgenerations.Tobestprovideforthis,thecontractorwhoinstallsthenewequipmentandhooksitontotheoldequipmentshouldputtogetheracomplete,comprehensiveoperationandmaintenancemanualwhichcoversalltheequipment.Thisshouldinclude,wheneverpossible,whenever,possible,literatureforeachmajorpieceofequipment,aswellaslubricationschedules,valvetagschedules,testingandbalancingreports,andalistofallnecessaryaccessoriessuchasfiltersandfanbelts.Theimportantfactoristhattheentireinstallationshouldbeviewedasonesystemandnotasindividualsystems,sincethatishowtheownerwillhavetolivewithitduringthelifeofthebuilding.Atthetimetheadditionisdesigned,seriousconsiderationshouldbegiventotheinstallationofacentralizedcontrolsystem,whichwillmonitortheimportantoperationalandmaintenancecontrols,aswellasanenergymanagementcontrolsystem.Inthisway,inonecentrallocation,theim-portantaspectsoftheextendedbuildingmaybemonitored.MAINTAININGTHEEXISTINGBUILDINGINOPERATIONAfactorwhichoftendistinguishestheadditionfromnewconstructionistherequirementtomaintaintheexistingbuildinginfullorpartialoperationduringtheinstallationofthenewaddition.Thiscanbeverydifficultperiodfromthepointofviewofreducedemployeecomfort,productivity,andprofit.Andsoitisamattertobeconsideredveryseriously.Thereisonlyoneanswertothequestionofhowtobestprovideforthisdifficultperiod.Thatoneanswerisplanning!Themoretimespentinanalyzingandforecastingtheoperationalaspectsoftheexistingbuildingduringtheinstallationoftheaddition,thegreatertheopportunityforasmoothtransitionduringtheconstructionperiod.Animportantaspectwhichmustbeconsideredistheprotectionandsafetyofthebuildingoccupantsduringtheconstruction.Carefulthoughtmustgointoseparatingthevariouscirculations:thebuilderwithneedsforaccessandstorageofmaterials;theemployeeswithneedsforaccessandcirculationthroughoutthebuilding;andtheoperationalrequirementsthatmustcontinueduringtheconstruction.Whilethecontractorwillbegiventheresponsibilityformaintainingsafetyonthesite,theownermustdoproperplanninginadvancetoseethatallaspectsoftheoperationsareconsideredandprovidedfor.Thearchitectmustincludeinthecontractdocumentsallnecessarylanguagetoalertthecontractortothepotentialproblemsandsiterestrictionsandtodefinethecontractor'sresponsibilitytomaintainasafeoperationandpremises.

Majordifficultiesarisefromthechangeoversinservicethatareoftennecessarywhennewsystemsareeitheraddedto,orsubstitutedfor,existingsystems.Theseeventsshouldbeplanned,wheneverpossible,forweekends,holidays,orvacationperiodstolimitthelossofproductivityandtheinconveniencetothebuilding'soccupants.Insomeinstancesitmaybenecessarytoinvolvetemporaryservicesinordertoavoidthesehardships.Anticipatingtheseeventsandplanningfortheiroccurrenceisamajorfactorinthesuccessoftheadditionproject.Itmustnotbeoverlooked,becauseitcanbeextremelycostlyinmoneyandpersonneldissatisfactionwhennotproperlyaccommodated.HISTORICBUILDINGSWhenaddingtobuildingsofhistoricorarchitecturalsignificancetherearecertainspecialchallengesinthedesignandinstallationofthemechanicalandelectricalsystems.Thesechallengesposebothproblemsandopportunities,andshouldbeapproachedwithasopenamindaspossibleinordertofindthebestsolutionsfortheparticularproject.Indecidingwhichmechanicalandelectricalsystemsshouldbeinstalledinthebuilding,oneofthemainconsiderationswillbetheopportunitiesavailabletodesignertoplanthenecessarypipingandductworkdistri-bution.Thiscanbethedecisivefactorintheselectionofthosesystems,sinceitisusuallythedistributiveelementsofthesystems,andnotthemainequipment,whichposetheproblemsinthesetypesofbuildings.Thespecialnatureofthehistoricbuildingusuallyrequiresthatthebuildingbealteredaslittleaspossibleduringtheinstallationoftheneworalteredsystems.Manyofthedevicesthatthedesignerusestolocateandconcealthepipesandductsinanewbuildingarenotavailableinthehistoricinterior.Hungceilings,pipechases,andwetcolumnsareusuallynotavailableinthistypeofbuidling,exceptiftheyaredesignedwithgreatsensitivity,Toachievethenecessarydistributionofsystemsinthesebuildings,variousdeviceshavebeenused.Forinstance,designershavefoundmasonryshaftsintheheavyinteriorandexteriorwallsofolderbuildingswhichmightoncehavebeenusedforventilationsystemsandwhichnowcanbeusedasverticalchasestoconcealpipingandductwork.Horizontaldistributionisoftenthemostdifficulttoachievewell.Avarietyofmethodsareavailabletothedesigner,dependinguponthespecificcircumstances.Thesemayrangeallthewayfromfullyexposingthepipes,ducts,andconduitsasfreestandingelementsandpaintingthembrightcolors,tokeepingallthedistributioninverticalshafts,diffusingtheairthroughwallgrilles,andplacingallelectricalreceptaclesonthewalls,Otherinter-estingdevicesforconcealinghorizontaldistributionincludetheuseoffiat-wiredistributionsystemsbelowthecarpetandtheuseofa"cloud"ceiling,onewhichfloatsfreeofallwallsandthereforedoesnotengageanyverticalsurface.Inthatwayitconcealsthepipingandductworkaboveitwithoutappearingaspartofthehistoricinterior.Ductsandpipeswhichmustextendoutfromthewallstoabovethe"cloud"arepaintedinsuchawaytobenoticedaslittleaspossible.Existingmouldingssometimesprovideuniqueopportunitiestoconcealpipingandconduit.Becauseoftherelativelyhighceilingsusuallyfoundinolderbuildings,thesemouldingswilloftenbeaboveeyelevelandthereforeofferagoodchanceatconcealment.Wherethemouldingmaynotbeofasizesufficienttoprovideadequatecover,itissometimespossibletobuildupawidermouldinginordertodojob.Thechoiceoflighting,plumbing,andotherfixturesandaccessorieswhichappearonthesurfacesofthehistoricbuildingshavetoberesearchedandcarefullyselectedinordertofitwithinthehistoricinterior.Oldpicturesofthebuildingorofthoseofthesameerawillsometimesgivecluesastowhatisacceptable.Theuseofarchitecturalhistorianstoassistinthisresearchcanbeveryhelpful.Oftenexistingfixturesmayberefurbishedandalteredasnecessarytoworkwellinthenewbuildingaddition.

Insummary,whilethehistoricbuildingpresentsanumberofdifferentchallengestothemechanicalandelectricaldesigner,italsopresentsanamaz-ingassortmentofopportunitiesforcreativesolutionswhichnotonlyprovidetheproperconditionstothebuilding'soccupants,butalsopreserveanim-portantsenseofhistory.

VERTICALTRANSPORTATIONIndesigningthenewaddition,thearchitectandengineermusttakeintoaccounttheinstallation,whenrequired,ofnewverticaltransportationsys-tems,suchaselevators,escalators,andmateriallifts.Alsocomingintothiscategoryarethesystemsforthetransportingofmaterialsthroughoutthebuildingsuchaspneumatictubesystemsandconveyors.Inthecaseofthesetypesofinstallations,thedesignermusttakespecialcarethatthenewsystemswillfitwithintheexistingbuilding.Structuralproblemsoftenoccurbecauseoftheconflictbetweenthenewsystemsandtheexistingbeams,girders,columns,andslabs.Whennewopeningsarerequiredtoaccommodatethenewsystems,theyshouldalwaysbedesignedbyastructuralengineertoassurethatthestructuralsystemoftheexistingbuildingwillnotbecom-promised.Otherproblemsresultfromconflictsbetweenthenewsystemsandex-istingpipesandducts.Thedesignforthenewsystemsshouldbedonecarefullywiththesepotentialobstructionsmeasuredandlaidouttoscaleondrawings,inordertomakesurethattheproperclearancesareavailable.Asineverythingelsedescribedinthischapter,thereisnosubstituteforcarefulinvestigation,planning,anddesign.CONCLUSIONSThedesignofthemechanicalandelectricalsystemsoftheadditioncannotbedoneinavacuum.Theyareprimarilydependentuponanunderstandingofthesystemsintheexistingbuilding.Acarefulanalysisbycompetentprofessionalsisessentialinthedecision-makingprocessconcerningthetypeofsystemstobeinstalled.Thesedecisionsshouldbebasednotonlyonthetechnicalfactorsinvolved,butalsooncost,efficiencyofoperation,mainte-nance,andappearance.Surveyingtheexistingbuildingtomakesurethattheactualexistingconditionshavebeentakenintoaccountisextremelyimportant.Inaddition,theprotectionandsafetyofthebuildingoccupantsduringtheconstructionperiodmustbeplannedcarefully.機械和電氣系統(tǒng)——摘自《建筑物擴建設計》大多數(shù)情況下,為滿足建筑擴建要求而作的機械、電氣系統(tǒng)設計，和一座新建筑的設計是有相同的著眼點的。實際上，這兩個方面的設計人員要對以下要求做出回應：為建筑的使用者提供舒適、方便的令人滿意的環(huán)境條件，以及為使用建筑提供合適的設備。這篇文章的目的不是描述構成機械、電氣系統(tǒng)設計的標準要素，而是介紹以下有別于新建結構的擴建設計所需考慮的因素。這些因素包括：對已建系統(tǒng)的新要求產(chǎn)生的影響；為支持擴建的結構而新引入的設備的適用性；各種將被擴展的部分的位置與分布形式；已建設施和附屬部分的情況；已建建筑和各系統(tǒng)的供能特點；混合系統(tǒng)的維護和操作；在新的擴建部分施工的同時，原有建筑能正常使用的要求；歷史古跡擴建的特殊挑戰(zhàn)。因為這些因素通常作用于新擴建結構的機械、電氣工程設計，所以我們將以綜合的理念來回顧這些方面，并指出何處在特殊工程控制上可能出現(xiàn)特殊的影響地點和布置通常，當已有設備和系統(tǒng)具備充足甚至空余的供應能力時，一個關于擴建部分位置的問題就應運而生了。例如，一臺擁有大量空余能力的供暖鍋爐可能迄今仍無法經(jīng)濟而高效的運轉。因此，最好的解決途徑可能是將擴建建筑的機電房重新安裝到各接近中心的位置。是否重新安裝已有設備的決定應來自于特定項目的需要。不僅水平位置重要，垂直距離也應好好考慮。比如，一個空調系統(tǒng)在原有建筑中可能位置較好，但隨著擴建更高的層數(shù)，當要求更強的運輸能力和更巨大的導管尺寸時，這個空調系統(tǒng)可能就面臨失去作用的命運。為了解原有系統(tǒng)對新擴建部分的影響，必須調查現(xiàn)有管道、導管、電力分配系統(tǒng)是如何安排的。這些是重要的因素，讓我們細致檢查這些因素吧。管道系統(tǒng)自然要依賴其尺寸、長度，如果是重力系統(tǒng)就需利用傾斜度，如果是壓力系統(tǒng)則需利用尺寸和長度。為了分布到新區(qū)域而企圖將管道延伸得很長，這會引起新問題的。例如給水管道這樣的重力系統(tǒng)中問題出在不夠充分的傾斜度上。而其他關于長度的情況則出在太多摩擦上。因此，確保新管道分布的鋪設的尺寸、距離和傾斜度在可接受的標準內，這是很重要的。以上的規(guī)則也同樣適用于供暖、通風、空調的管網(wǎng)，因為這些管網(wǎng)的尺寸和長度亦產(chǎn)生磨擦損耗。此外，無論管道還是導管，從供應源到目的地的過長距離皆可導致相當一部分能量的損失。在這種情況下，充足的絕緣隔離措施是必須的。管道和導管擋板的位置也同樣重要，因為他們會影響有悠久歷史的建筑的樣式。尤其是在垂直方向的擴建部分，應仔細布置，以免災難般影響已建建筑的使用。從這一節(jié)中了解到，在估計建筑的重要性時，不僅考慮已建系統(tǒng)的空余能力，也要考慮擴建部分的位置和新舊部分之間的距離。設備的適用性除了考慮現(xiàn)有系統(tǒng)滿足擴建建筑需要的能力，新引入的設備也必須有足夠尺寸來滿足新要求。一些在特定工程領域有豐富知識的技術人員應對這些設備進行一次仔細評議。在盡可能早的時候，就必須對已在和即將承擔為機械和電氣系統(tǒng)提供支持的各種公共設施作出評估。這些評估對象必須包括對水（包括正常使用和用于救火的要求）、氣、電、排水、以及凈化管道。根據(jù)這些分析，任何對設備額外能力的必須要求肯定會影響新擴部分的設計。地方法規(guī)和設備供應商通常要求一座建筑只允許有一個服務關系。因此，當附加的公共設施的效能被確定后，舊的服務設施或者將不得不擴大，或者將被遺棄和取而代之。應該對任何可能影響擴建部分施工的已存在或未定的延緩或限制予以重視。在許多社區(qū)，因為缺乏處理廢棄物的設施或充足的氣供應和供水能力的不足，拖延了新建或將進一步影響整體系統(tǒng)的擴建建筑的建設。這也影響了新擴建部分的施工和使用。因此，在設計出最終成果并建造出附屬部分之前，清楚這些限制是很重要的。原有設備被發(fā)現(xiàn)不能滿足需要時，附加部分的服務將不得不求助于當?shù)卦O備供應商。在編制項目主要經(jīng)費前，收到設備供應商回應對附加部分服務的求助，并得到其關于在必要時后能向附加部分設施供貨的保證是很重要的。當需要擴建給水、氣或電管道時，注意保證這些管道的來源以及安裝它們的費用是業(yè)主所能承受的。業(yè)主經(jīng)常發(fā)現(xiàn)，雖然供應能力是有效的，但在經(jīng)濟上卻不可能為成功安裝長管道或電纜而償付必需的費用。對已建系統(tǒng)的影響新擴部分的各系統(tǒng)的設計應基本明白設計人員有一個優(yōu)勢。已建建筑是可以被測量、分析和觀察的。因此，設計者不應驚奇于已建系統(tǒng)的狀況和他們在新系統(tǒng)中的影響。擴建結構對原有設施的主要影響之一，是一些當?shù)胤ㄒ?guī)規(guī)定：如果原有系統(tǒng)