照明系统外文翻译文档格式.docx

照明系统外文翻译文档格式.docx

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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