照明系统外文翻译.docx
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照明系统外文翻译
英文翻译
原文:
ABSTRACT
Thispaperdiscussestheimplementationofsemi-permanent,high-mastpole-mountedlightingfornighttimeroadworkconstructionandmaintenancebasedonaninstallationalongInterstate90inAlbany,NewYork.Thehigh-mastlightingsystemmetstatelightingperformancespecifications.Therewerenorecordedaccidentsatthesiteduringtheconstructionperiod.Althoughthisislargelyattributabletoroadwayclosuresallowedduringpartoftheproject,theconsensusofthecontractorandtransportationagencyisthatthelightingcontributedatleastinparttoanincreaseinsafety.Thecostofthehigh-mastlightingsystemwasapproximately16%higherthantheestimatedcostoftheportablelighttowers.Despitethehigherestimatedcostofthehigh-mastlightingsystem,theeconomicandsocietalbenefitsappearconsiderableinthisparticularlocation,namelyanurban,heavilytraveledthroughway.Inparticular,thislightingapproachprobablyallowedthedurationoftheconstructionperiodtobeshortened,leadingtoareductioninworkeranddriverriskexposuresandtoareductionintrafficdelaysformotorists.Anapproachtoidentifyingprojectswherethislightingtechniquemightbewarrantedispresented.
INTRODUCTION
Semi-permanent,high-mast(70ft.)pole-mountedfixtureswereusedbyaconstructioncontractorhiredbytheNewYorkStateDepartmentofTransportation(NYSDOT)toilluminatenighttimeroadworkconstructionandmaintenancealongathree-milestretchofInterstate90(I-90)inAlbany,N.Y.,asanalternativetothemorecommonportablelighttowers
(1).Thehigh-mastlightingwasinstalledpriortoconstructionworkandremovedaftertheconstructionprojectwascompleted,aboutsevenmonthslater.Freyssinieretal.
(2)documentedthehigh-mastlightingsystemanditsperformanceintermsofphotometricperformance,visibilityandglare.Thehigh-mastlightingsystemwasfoundtohaveperformedwellandasintended.Theinstallationprovidedalevelofilluminationsufficientforperformingthemaintenanceandconstructionactivitiesatthesite(3),withlesspronouncedshadowsandrelativelylowglare.Thepurposeofthepresentpaperistodiscussapproachestoidentifyingifandwhenthislightingapproachcanbeappropriateforahighwayconstructionproject.Issuesregardingsafety,economicsandenvironmentalimpactsarediscussed,andanapproachtowarrantingsemi-permanent,high-mastnighttimeconstructionlightingisoffered.
Todecideifandwhensemi-permanenthigh-mastlightingisfeasibleforhighwayconstructionwork,onemustconsidersafety,economicsandenvironmentalimpacts.Theseissuesarediscussed,inturn,inthefollowingsections.
SAFETY
CrashRiskFactor
WhenthecontractorhiredbyNYSDOTtoperformroadworkalongI-90proposedusingsemi-permanent,high-maslightingfornighttimeconstructionwork,safetyengineersanalyzedtheproposalagainsttheconcernthatmost(aboutwo-thirds)oftheproposedhighmastswouldbelocatedwithinthe30ftclearzonedesiredforthishighway.Theclearzoneisdefined(4)astheareaoutsidethepavedroadwayareawhereavehiclecouldsafelytravelifitlefttheroad.Acknowledgingthatportablelightingfornighttimeroadwayconstructionworkisnearlyalwayslocatedwithintheclearzoneandinfactoftenclosertodrivers,NYSDOTengineersconcludedthathigh-mastlightingprobablyhadalowerriskfactorthanportablelighttowers,andauthorizedthecontractortoproceedwiththeinstallationandroadwork,basedonthefollowingreasons:
Whileinuse,portablelightplantsarealmostalwayslocatedinsidetheclearzone.
Aboutonethirdofthe108high-mastpolesproposedcouldbelocatedoutsidetheclearzonewithoutcompromisinglightingquality.Thelowernumberofpolesintheclearzone,comparedtothenumberofconventional,portableunitsneededtoilluminateaportionofthehighway,wasthoughttoweighagainsttheaddedriskofdrivers!
ˉconstantexposuretosemi-permanentpolesduringbothdaytimeandnighttime.Howeveradditionalsafetyfeatureswererecommended,suchastrafficbarriers,guardsandcrashcushions.
High-mastpolesavoidthehigh-riskexposureofworkerseverynightduringsetupandremovaloftheconventionalportablelightunits.IntheI-90project,itwasestimatedthatatleast8250worker-hoursofhigh-exposurewouldbeeliminated.Timesavingsinthemobilizationofportablelightsmeantnightconstructioncouldbecompletedin222daysratherthan275,reducingtheworktooneconstructionseason.NYSDOT!
ˉsauthorizationwasconditionedontremovalofthehigh-mastpolesbywintershutdown,regardlessofthecontractor!
ˉsworkaccomplishments.
WorkerSafetyImplications
Whiletheconventionallighttowersareextremelyusefulbecauseoftheirportablenature,thereareanumberofknownissuesregardingthedifficultyoftheirinstallation,operation,andmaintenance.First,therearealargenumberofwarningsassociatedwithmostproducts(duringsetup,operation,maintenance,stowing,andtransportation).Second,thetwomainrisksassociatedwiththeuseofportablelighttowersaretheinteractionofworkerswithtrafficduringsetupandremovalwhenbothconditionsrepresentahighriskofcollisionbetweenworkersanddrivers,andthesetupoflighttowersnearpowerlines.Althoughtherearenopublishedstatistics,itisreasonabletobelievethatcrewsareatincreasedriskofinjuryorfatalitywhenraisingamastnearpowerlines.Itfollowsthatbyhavingasemi-permanentlightinginstallation,muchoftheriskmentionedwouldnotbepresent.
TABLE1EstimatedOperationalCostofPortableLightTowerInstallation
Estimatednumberofportablelighttowersrequired120*
Dailysetupandremovalcost
Numberofcrewmembersinchargeofsetupandremoval10
Estimatednumberofhourstosetupandremovelighttowers,pernight3
Totalworkerhourspernight30
Estimatedcostperhour(baserate+benefits+overhead&profit)$40
Totalsetupandremovalcostpernight$1,200
Dailyoperationalcost
Hourlyoperationalcostperlighttower(fuel,oil,regularmaintenance,etc.)$3.60
Estimateddailycostperlighttower(@6hourspernight)$21.60
Dailyrentalcost(@$990permonthrent)$33
Totaloperationalcostpernight(assumingcontractorowns100towersandrents20)$3,252
Totalcostpernight(setup,removal,andoperation)$4,452
Estimateddurationofprojectindays275**
Totalcosttoprovidelightingwith120portablelighttowers$1,224,300
120towersisestimatedtoberequiredtoilluminateasufficientportionoftheworkzoneatonetime.
Thedurationwasestimatedtobe40daysshorterusingthehigh-mastsystem.
Anotherpotentialsafetybenefitofhigh-mastlightingthatcouldnotbequantifiedpreciselywasthefactthatwarningsigns,signals,andothermaterialsforguidingtrafficthroughtheworkzonecouldbesetupeachnightunderlightedconditions.Incomparison,suchwarningsaretypicallysetupbyworkersinadvanceofhavingtheconventionallighttowersoperational.
TheEnvironmentalProtectionAgencyrecommendsamaximumnoiselevelof75dBAinworkenvironmentsforhearingconservation(5).Thoughthegeneratorsthatpowermostofthecommerciallighttowerstypicallyhaveanoiselevelratingof71dBA,thelargenumberoflighttowers(eachwithitsowngenerator)andtheirrelativelyclosespacing(typicallyabout100ftbetweenunits)cancausenoisetoadduptolevelsthatcouldbemorethanthemaximumrecommended.Duringthisproject,fivelargegeneratorspoweredtheentirehigh-mastlightinginstallation;eachgeneratorwaslocatedasfarfromtheworkareaaspossible.Eachofthesegeneratorswasratedat71dBA,dramaticallyreducingnoiselevelsthroughoutthesite.Workersofthisprojectcommentedthatthenoisereductionenabledthemtohearvehiclesapproaching,againgreatlydecreasingtheirriskofinjurybyamovingvehicleormachine.
Finally,byusinghigh-mastlightingwithremotelylocatedgenerators,workerswerenotasexposedtothefumesandharmfulpollutantsthatresultfromthegeneratorsadjacenttoeachportablelighttowerandthatmightcauseheadaches,fatigue,andpotentialheartproblems(6).
ECONOMICANALYSIS
Tables1and2summarizetheeconomicsofalightingsystemusingtheportabletowersandthehigh-mastsystem.Despitethehigherestimatedcost(approximately16%higher)ofthehigh-mastsystemasoutlinedinthesetwotables,therewereseveralpositiveeconomicimplicationsthatresultedfromtheuseofhigh-mastlighting.Onesignificantbenefitwasthetimesavedeverydayfromnothavingtosetupandremovetheportablelighttowers.Thistimecouldbeusedperformingthecontractedconstructionworkratherthansettinguplightingequipment,probablycontributingtotheaheadofschedulecompletionoftheproject.Inthisproject,theestimatedcostofsetupandremovalofportablelighttoweraddedupto$330,000(30worker-hourspernightat$40perhour,for275days).Forlargerjobsthiscostwouldincreaseconsiderably.
TABLE2EstimatedOperationalCostofSemi-PermanentHigh-MastLightingInstallation
Numberofhigh-mastpolesinstalled108
Numberof250-kWgeneratorsinstalled5
Installationcosts
Estimatedinstallationcostperpole$2,844
EstimatedinstallationcostperkWofgeneratorcapacity$24.50
Totalestimatedinstallationcosts(polesandgenerators)$337,777
Lightingequipmentrental
Estimatedrentalcostperpolewithfourluminaires$5,500
Totallightingequipmentrental(forthedurationoftheproject)$594,000
Generationcosts
EstimatedpurchasecostperkWofgeneratorcapacity$200
Estimatedtotalgeneratorspurchas