消防系统运行可靠性的估计毕业设计中英文对照.docx

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