消防系统运行可靠性的估计毕业设计中英文对照.docx
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消防系统运行可靠性的估计毕业设计中英文对照.docx
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消防系统运行可靠性的估计毕业设计中英文对照
0
本科毕业设计
外文文献及译文
文献、资料题目:
EstimatesoftheOperationalReliability
ofFireProtectionSystems
文献、资料来源:
网络
文献、资料发表(出版)日期:
2008.6
院(部):
市政和环境工程学院
专业:
给水排水工程
班级:
姓名:
学号:
指导教师:
翻译日期:
2008.6
外文文献:
EstimatesoftheOperationalReliabilityofFireProtectionSystems
Forthepastthreeyears,theNationalInstituteofStandardsandTechnology(NIST)hasbeenworkingtodevelopanewencryptionstandardtokeepgovernmentinformationsecure.Theorganizationisinthefinalstagesofanopenprocessofselectingoneormorealgorithms,ordata-scramblingformulas,forthenewAdvancedEncryptionStandard(AES)andplanstomakeadecisionbylatesummerorearlyfall.Thestandardisslatedtogointoeffectnextyear.
RichardW.Bukowski,P.E.
SeniorEngineer
MSTBuildingandFireResearchLaboratory
Gaithersburg,MD20899-8642USA
EdwardK.Budnick,P.E.,andChristopherF.Scheme1
VicePresidentChemicalEngineer
HughesAssociates,IncHughesAssociates,Inc.
Baltimore,MD21227-1652USABaltimore,MD21227-1652USA
INTRODUCTION
Background
Fireprotectionstrategiesaredesignedandinstalledtoperformspecificfunctions.Forexample,afiresprinklersystemisexpectedtocontrolorextinguishfires:
Toaccomplishthis,thesystem
sprinklersmustopen,andtherequiredamountofwatertoachievecontrolorextinguishment
mustbedeliveredtothefirelocation.Afiredetectionsystemisintendedtoprovidesufficient
earlywarningofafiretopermitoccupantnotificationandescape,fireservicenotification,andin
somecasesactivationofotherfireprotectionfeatures(e.g.,specialextinguishingsystems,smoke
managementsystems).Bothsystemactivation(detection)andnotification(alarm)mustoccurtoachieveearlywarning.Constructioncompartmentationisgenerallydesignedtolimittheextent
offirespreadaswellastomaintainthebuilding’sstructuralintegrityaswellastenabilityalong
escaperoutesforsomespecifiedperiodoftime.Inordertoaccomplishthis,theconstruction
featuresmustbefire“rated”(basedonstandardtests)andtheintegrityofthefeatures
maintained.
Thereliabilityofindividualfireprotectionstrategiessuchasdetection,automaticsuppression,
andconstructioncompartmentationisimportantinputtodetailedengineeringanalysesassociated
withperformancebaseddesign.Inthecontextofsafetysystems,thereareseveralelementsof
reliability,includingbothoperationalandperfornzancereliability.Operationalreliability
providesameasureoftheprobabilitythatafireprotectionsystemwilloperateasintendedwhen
needed.Performancereliabilityisameasureoftheadequacyofthefeaturetosuccessfully
performitsintendedhnctionunderspecificfireexposureconditions.Theformerisameasure
ofcomponentorsystemoperabilitywhilethelatterisameasureoftheadequacyofthesystem
design.
Thescopeofthisstudywaslimitedtoevaluationofoperationalreliabilitydueprimarilytothe
formofthereporteddataintheliterature.Inadditiontothisdistinctionbetweenoperationaland
performancereliability,thescopefocusedonunconditionalestimatesofreliabilityandfailure
estimatesintermsoffail-dangerousoutcomes.Adiscussionofthesetermsisprovidedlaterinthepaper.
Scop
Thispaperprovidesareviewofreportedoperationalreliabilityandperformanceestimatesfor
(1)
firedetection,
(2)automaticsuppression,andtoalimitedextent(3)construction
compartmentation.Ingeneral,thereportedestimatesforfiredetectionarelargelyforsmoke
detectiodfirealarmsystems;automaticsprinklerscomprisemostofthedataforautomatic
suppression,andcompartmentationincludescompartmentfireresistanceandenclosureintegrity.
Itshouldbenotedthatinsomecasestheliteraturedidnotdelineatebeyondthegeneral
categoriesof“firedetection”or“automaticsuppression,”requiringassumptionsregardingthe
specifictypeoffireprotectionsystem.
Severalstudiesreportedestimatesofreliabilityforbothfiredetectionandautomaticsprinkler
systemstrategies.However,verylittleinformationwasfounddetailingreliabilityestimatesfor
passivefireprotectionstrategiessuchascompartmentation.Alimitedstatisticalbasedanalysis
wasperformedtoprovidegeneralizedinformationontherangesofsuchestimatesandrelated
uncertainties.Thislattereffortwaslimitedtoevaluationofreporteddataondetectionand
suppression.Insufficientdatawereidentifiedoncompartmentationreliabilitytobeincluded.
Thispaperaddresseselementsofreliabilityastheyrelatetofiresafetysystems.Theliterature
searchthatwasperformedforthisanalysisisreviewedandimportantfindingsanddata
summarized.Thedatafoundintheliteraturethatwereapplicabletosprinklerandsmoke
detectionsystemsreliabilitywereanalyzed,withdescriptiveestimatesofthemeanvaluesand95
percentconfidenceintervalsfortheoperationalreliabilityoftheseinsitusystemsreported.
ELEMENTSOFRELIABILITYANALYSIS
ThereisconsiderabIevariationinreliabilitydataandassociatedanaIysesreportedinthe
literature.Basically,reliabilityisanestimateoftheprobabilitythatasystemorcomponentwill
operateasdesignedoversometimeperiod.Duringtheusefulorexpectedlifeofacomponent,
thistimeperiodis“reset”eachtimeacomponentistestedandfoundtobeinworkingorder.
Therefore,themoreoftensystemsandcomponentsaretestedandmaintained,themorereliable
theyare.Thisformofreliabilityisreferredtoasunconditional.
Unconditionalreliabilityisanestimateoftheprobabilitythatasystemwilloperate“on
demand.”Aconditionalreliabilityisanestimatethattwoeventsofconcern,i.e.,afireand
successfuloperationofafiresafetysystemoccuratthesametime.Reliabilityestimatesthatdo
notconsiderafireeventprobabilityareunconditionalestimates.
Twootherimportantconceptsappliedtooperationalreliabilityarefuiled-safeandfailed-
dangerous.whenafiresafetysystemfailssafe,itoperateswhennofireeventhasoccurred.A
commonexampleisthefalsealarmingofasmokedetector.Afiresafetysystemfailsdangerous
whenitdoesnotfunctionduringafireevent.Inthisstudy,thefailed-dangerouseventdefines
theOperationalprobabilityoffailure(1-reliabilityestimate).Asprinklersystemnotoperating
duringafireeventoranoperatingsystemthatdoesnotcontrolorextinguishafireareexamples
ofthistypeoffailure.
Theoverallreliabilityofasystemdependsonthereliabilityofindividualcomponentsandtheir
correspondingfailurerates,theinterdependenciesoftheindividualcomponentsthatcomposethe
system,andthemaintenanceandtestingofcomponentsandsystemsonceinstalledtoveri@
operability.Allofthesefactorsareofconcerninestimatingoperationazreliability.
Firesafetysystemperformanceisalsoofconcernwhendealingwiththeoverallconceptof
reliability.Systemperformanceisdefinedastheabilityofaparticularsystemtoaccomplishthe
taskforwhichitwasdesignedandinstalled.Forexample,theperformanceofafirerated
separationisbasedontheconstructioncomponent’sabilitytoremainintactandprovidefire
separationduringafire.Thedegreetowhichthesecomponentspreventfirespreadacrosstheir
intendedboundariesdefinessystemperformance.
Performancereliabilityestimatesrequiredataonhowwellsystemsaccomplishtheirdesigntask
underactualfireeventsorfullscaletests.Informationonperformancereliabilitycouldnotbe
discerneddirectlyfrommanyofthedatasourcesreviewedaspartofthiseffortduetotheform
ofthepresenteddata,andtherefore,itisnotaddressedasaseparateeffect.
Thecauseoffailureforanytypeofsystemistypicallyclassifiedintoseveralgeneralcategories:
installationerrors,designmistakes,manufacturing/equipmentdefects,lackofmaintenance,
exceedingdesignlimits,andenvironmentalfactors.Thereareseveralapproachesthatcanbe
utilizedtominimizetheprobabilityoffailure.Suchmethodsinclude
(1)designredundancy,
(2)
activemonitoringforfaults,(3)providingthesimplestsystem(i.e.,theleastnumberof
components)toaddressthehazard,and(4)awelldesignedinspection,testing,andmaintenance
program.
Thesereliabilityengineeringconceptsareimportantwhenevaluatingreliabilityestimates
reportedintheliterature.Dependingonthedatausedinagivenanalysis,thereliabilityestimate
mayrelatetooneormoreoftheconceptspresentedabove.Theliteraturereviewconducted
underthescopeofthiseffortaddressestheseconceptswhereappropriate.Mostofthe
informationthatwasobtainedfromtheliteratureinsupportofthispaperwerereportedinterms
ofunconditionaloperationaZreliability,i.e.,intermsoftheprobabilitythatafireprotection
strategywillnotfaiZdangerous.
LITERATUREREVIEW
Aliteraturesearchwasconductedtogatherreliabilitydataofalltypesforfiresafetysystems
relevanttotheprotectionstrategiesconsidered:
automaticsuppression,automaticdetection,and
compartmentation.Theobjectiveoftheliteraturesearchwastoobtainsystem-specificreliability
estimatesfortheperformanceofeachtypeoffiresafetysystemasafunctionofgeneric
occupancytype(e.g.,residential,commercial,andinstitutional).
Sourcesofinformationincludednationalfireincidentdatabasereports,USDepartmentof
Defensesafetyrecords,industryandoccupancyspecificstudies,insuranceindustryhistorical
recordsandinspectionreportsdocumente
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- 关 键 词:
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