Year of Issue : 2010
1. Preface 04
2. Scope 05
3. Definitions 063.1 ConfinedSpace 063.2 CharacteristicsofConfinedSpace 063.3 ResponsiblePerson 063.4 AuthorisedManager 063.5 CompetentPerson 073.6 ConfinedSpaceSafetyAssessor 073.7 ConfinedSpaceAttendant 073.8 Entrant 073.9 ConfinedSpaceEntryPermit 073.10 Entry 073.11 HazardousAtmosphere 07
4. Introduction 084.1 Background 084.1.1 WhyWorkinginConfinedSpacesisHazardous 084.1.2 WhyEntryintoaConfinedSpaceisNeeded 084.2 RequirementsforWorkingSafelyinConfinedSpaces 084.3 TypesofInjury 09
5. Risk Management Approach to Confined Spaces 105.1 KeyElementsofRiskAssessmentforConfinedSpaces 105.1.1 AssessNeedforEntryintoaConfinedSpace 105.1.2 IdentificationandEvaluationofConfinedSpaces 105.1.3 ControlofConfinedSpaceHazards 115.2 Communication 115.3 PeriodicRiskAssessment 125.4 Documentation 12
6. Types Of Hazards in Confined Spaces 136.1 SuffocationHazards—ByOxygenDeficiency 136.2 Fire/ExplosionHazards—ByFlammableGasesandVapours 146.3 Poisoning—ByToxicGases,VapoursorFumes 156.4 OtherConfinedSpaceHazards 16
7. Working Safely in Confined Spaces 197.1 ConfinedSpaceEntryPermit 197.2 InformationRequiredontheEntryPermit 197.3 RiskAssessment 207.4 IssuanceofEntryPermit 20
Contents
1
9. TrainingforPersonnelInvolvedinConfinedSpaceEntryandWork 599.1 PersonneltobeTrained 599.2 PlanninganEffectiveTrainingProgramme 609.3 ElementsofTrainingandTrainingCourses 609.3.1 KeyElementsofTraining 619.3.2 TrainingCourses 649.4 CriteriaforTraining,RefresherorSupplementaryTraining 649.5 CompetencyofTrainers 649.6 AssessmentofTraining 65
10. Annexes 6610.1 Annex1:GuidelinesforWeldinginConfinedSpaces 6610.1.1 LocalExhaustVentilationSystem 6610.1.2 DilutionorForcedVentilation 6610.2 Annex2:GuidelinesforPaintinginConfinedSpaces 6610.2.1 SprayPainting 6610.2.2 BrushandRollerPainting 6610.3 Annex3:SampleofConfinedSpaceEntryPermit 6710.4 Annex4:SampleFlowchartofPermitApplication 6910.5 Annex5:SampleofRiskAssessment 7010.6 Annex6:EnergyIsolationandLockoutMethods 7410.6.1 LockoutDevices 7410.6.2 MethodsofIsolationfromContaminants 7510.6.3 MethodsofIsolationfromMovingParts 7610.6.4 RemovalofMeansofIsolation 7610.7 Annex7:ConfinedSpacePlanChecklist 77
11. CaseStudies 8011.1 Case1:ExplosionfromChemicalStorageTank 8011.2 Case2:ExposuretoPhosgeneGasduringGasTesting 8111.3 Case3:ToxicPoisoninginFoodReactor 8211.4 Case4:DeathbySuffocation 83
12. Acknowledgements 85
13. References 86
14. ListofFigures 88
15. ListofTables 90
7.4.1 STAGE1—ApplicationofEntryPermitbySupervisor 217.4.2 STAGE2—EvaluationbyConfinedSpaceSafetyAssessor 217.4.3 STAGE3—IssuancebyAuthorisedManager 217.4.4 STAGE4—PostingofEntryPermit 217.5 DisplayofEntryPermit 227.6 ReviewandEndorsementofEntryPermit 227.7 RevocationofEntryPermit 227.8 Re-certificationofConfinedSpaces 227.9 RecordKeeping 237.10 ControlofHazardousEnergy 237.10.1 EnergyIsolationandLockout 237.10.2 FormsofHazardousEnergy 247.11 GeneralRequirements 247.11.1 OpeningsofConfinedSpaces 247.11.2 Barricade 247.11.3 Communication/WarningSigns 247.11.4 ConfinedSpaceAttendant(CSA) 257.11.5 AccessandEgress 257.11.6 DisplayofNameandIdentificationBadge 257.11.7 Communication 267.11.8 LightingandElectricalEquipment 267.11.9 RespiratoryProtectiveEquipment 277.11.10 GasTestingandMonitoringoftheConfinedSpaceAtmosphere 317.11.11 WhattoTestandWhataretheAcceptableLimits 327.11.12 TypesofTestingMethods/Equipment 327.11.13 TestingProceduresandConsiderations 337.11.14 ContinuousMonitoringandFrequencyofTests 367.11.15 MaintenanceofEquipment(General) 367.12 PurgingandVentilation 427.12.1 Purging 427.12.2 Ventilation 43
8. EmergencyandRescueProcedures 518.1 EstablishmentofRescueOperationPlans 518.2 RescueArrangements 518.3 RescueConsiderations 528.3.1 CharacteristicswhenDecidingtheAppropriateRescuePlan 528.3.2 ConductingofDrills 538.4 RescueLogistics 538.5 TrainingofRescuePersonnel 558.6 ProvisionofRescueEquipment 558.6.1 SuppliedAir-breathingApparatus 568.6.2 FullBodyHarnesswithLifeline 568.6.3 Hoist/RetrievalSystem 568.6.4 ResuscitatingEquipment 568.6.5 PersonalProtectiveEquipment 578.6.6 AvailabilityandMaintenance 578.7 ProvisionofSafetyDataSheet 58
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2. Scope
ThisTechnicalAdvisory(TA)aimstoprovidedetailedinformationonwhatneedstobedonetomeet therequirementsof relevant legislationandCode(s)ofPractice inallworkplaceswhereentryintoorworkinconfinedspacesisrequired.Italsoaimstoprovidepracticalguidanceonthenecessarymeasuresforsafeentryintoandworkinconfinedspaces.
Confinedspacescanbedeadly.
ManypeoplearekilledorseriouslyinjuredinconfinedspaceseachyearinSingapore.Accordingto the Workplace Safety and Health Council1, 10% of workplace fatalities were due to work-relatedaccidentsinconfinedspaces.
These fatal accidents happened across a range of industries; from complex plants to simplestoragevessels.Thosekilledwerenotonlypeoplewhoworkedintheconfinedspacesbutalsothosewhotriedtorescuethem.Therefore, it is important to implement good safety practices to ensure a safe workingenvironmentforeveryone.
1. Preface
1WorkplaceSafetyandHealthCouncil.2008.Workspace Safety & Health, 2008: National Statistics.Singapore:Author
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3.1 ConfinedSpaceA“confinedspace”isanychamber,tank,manhole,vat,silo,pit,pipe,flueoranyotherenclosedspace,inwhich:
• dangerousgases,vapoursorfumesareliabletobepresenttosuchanextentastoinvolveriskoffireorexplosion,orpersonsbeingovercomethereby;
• thesupply of air is inadequate, or is likely to be reduced to be inadequate, for sustaininglife;or
• thereisariskofengulfmentbymaterial.
3.2 CharacteristicsofConfinedSpaceAconfinedspaceisanyenclosedorpartiallyenclosedareathat:
• isnotprimarilydesignedorintendedforhumanoccupancy;
• hasarestrictedentranceorexitbywayoflocation,sizeormeans;
• maycontainahazardousatmosphere;
• containsmaterialthatcouldtraporburyanentrant;
• hassuchashapethatanentrantcouldbecometrappedorasphyxiated;or
• canpresentarisktothehealthandsafetyofanyonewhoenters,duetooneormoreofthefollowingfactors:
i. itsdesign,construction,locationoratmosphere;
ii. thematerialsorsubstancesinit;
iii. workactivitiesbeingcarriedoutinit;or
iv. themechanical,electrical,processandsafetyhazardspresent.
3.3 ResponsiblePerson A‘‘responsibleperson’’,inrelationtoapersonenteringorworkinginaconfinedspace,is:
• hisemployer;or
• theprincipalunderwhosedirectionheentersorworksintheconfinedspace.
3.4 AuthorisedManagerAn“authorisedmanager”isapersonappointedunderregulation9oftheWorkplaceSafetyandHealth(WSH)(ConfinedSpaces)Regulationsandincludesanyotherpersonappointedtoperformthedutiesofanauthorisedmanagerbytheresponsibleperson.
3.Definitions 3.5 CompetentPersonA“competentperson”referstoapersonwhohassufficientexperienceandtrainingtoperformtheworkrequiredtobecarriedout.
3.6 ConfinedSpaceSafetyAssessorA“confinedspacesafetyassessor”isasafetyassessorappointedunderregulation9(b)oftheWSH(ConfinedSpaces)Regulations.
3.7 ConfinedSpaceAttendantA”confinedspaceattendant”isanattendantappointedunderregulation22oftheWSH(ConfinedSpaces)Regulations.
3.8 EntrantApersonrequiredtoenterconfinedspacestocarryoutinspectionsorwork.
3.9 ConfinedSpaceEntryPermit“Confinedspaceentrypermit”meansapermitissuedunderregulation13oftheWSH(ConfinedSpaces)Regulations.
3.10Entry“Entry” refers to ingress by persons into a confined space.This occurs when a person’s headpassesthroughanopeningintotheconfinedspace.
3.11HazardousAtmosphere“Hazardousatmosphere”meansanatmospherewhere:
• thelevelofoxygenintheatmosphereislessthan19.5%ormorethan23.5%byvolume;
• thelevelofflammablegasesorvapours intheatmosphere is10%ormorethanitsLowerExplosiveLimit(LEL);or
• the levels of toxic substances in the atmosphere exceed the Permissible Exposure Levels(PEL)asspecifiedintheFirstScheduleoftheWSH(GeneralProvisions)Regulations.
6 7
2008 2007
Total 67 63
Fallsfromheight 19 23
Struckbyfallingobjects • Duetocollapseorfailureofstructureandequipment • Fromheights
1486
1257
Struckbymovingobjects • Byprimemovers/trailers/roll-onbintruck
125
52
Firesandexplosions • Occuringinconfinedspaces
53
73
Caughtinbetweenobjects 4 5
Electrocution 4 2
Collapseoftowercrane 3 0
Slipsandtrips 2 2
Otherincidenttypes(e.g.,drowning,exposuretoheat) 0 5
4.1 Background4.1.1 WhyWorkinginConfinedSpacesisHazardousWorkinginconfinedspacesismorehazardousthanworkinginotherworkplacesbecause:
• Theentrances/exitsofconfinedspacesmightnotallowtheentranttoevacuateeffectivelyifthereisafloodorcollapseoffree-flowingmaterial;
• Self-rescuebyentrantismoredifficult;
• Rescueof thevictim ismoredifficult.The interiorconfigurationofaconfinedspaceoftenrestrictsthemovementofpeopleorequipmentwithinit;
• Naturalventilationaloneisoftennotsufficienttomaintainbreathablequalityairbecausetheinteriorconfigurationofsomeconfinedspacesdoesnotallowairmovementtocirculate;
• Conditionscanchangeveryquickly;
• The space outside the confined space can impact on the conditions inside the confinedspaceandviceversa;or
• Workactivitiesmayintroducehazardsnotpresentinitially.
4.1.2 WhyEntryintoaConfinedSpaceisNeededPeopleenteraconfinedspacefor:
• Cleaning;
• Inspection;
• Maintenanceandrepair;
• Construction;or
• Rescue,etc.
4.2 RequirementsforWorkingSafelyinConfinedSpacesWhen any person enters or carries out any work in a confined space, the Employer and/orPrincipalshallcomplywiththeregulationsstrictly.Underthelegislation,theresponsiblepersonhastoensuresafeentry/workinginconfinedspaces.Theseinclude:
• Identification/Record/WarningSigns/Informationofallconfinedspacesattheworkplace;
• Evaluationoftheneedforentryintotheconfinedspace;
• Safemeansofaccesstoandegressfromtheconfinedspace;
• Safepracticesforopeningtheentranceofaconfinedspace;
• Sufficientandsuitablelightingforentryintoorworkinaconfinedspace;
• Adequateventilationofthespacetosustainlifebeforeentryandduringworkinaconfinedspace;
• Proceduresandcontrolofentryintoaconfinedspaceincludinggastesting;
4.Introduction • Safetyandhealthtrainingonworkinginconfinedspacesforworkersandsupervisors;
• Emergencyrescueoperationsinconfinedspaceswhichincludetheestablishmentofarescueplanandprovisionofrescueequipmentforconfinedspace;
• Appointmentofaconfinedspaceattendant;and
• Theworkerisfittoworkinconfinedspaces.
4.3 TypesofInjuryAccording to Workplace Safety & Health, 2008: National Statistics, about 10% of workplacefatalitiesin2008wererelatedtoaccidentsinconfinedspaces.
Figure 1: Number of workplace fatalities by type of incident, 2007 and 2008 (Workplace Safety & Health, 2008: National Statistics).
Thetypesofinjuriesrelevanttoconfinedspaceaccidentsinclude:
• Injuriesarisingfromfireandexplosion;
• Loss of consciousness or asphyxiation arising from harmful gases, vapours or fumes, freeflowingsolidsorlackofoxygen;
• Drowningarisingfromanincreaseinlevelofliquid;
• Heat-relateddisorders;
• Electrocution;
• Physicalcontactwithmovingorrotatingparts;and
• Fallsfromheight.
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InlinewithWSH(RiskManagement)Regulations2006,riskassessmentsmustbeconductedtoidentifysafetyandhealthhazardsassociatedwithpersonnelenteringandworkinginconfinedspaces,andtoimplementreasonablepracticablemeasurestoeliminateormitigatetherisks.
5.1 KeyElementsofRiskAssessmentforConfinedSpacesConducting risk assessments is the key to reducing risks related to entering and working inconfinedspaces.Everyone,fromemployertoworker,mustworktogethertoensurethattheriskassessmentprocessidentifiesanyexpectedriskandadoptallreasonablypracticablemeasurestomaketheconfinedspacesafetoenterandworkin.Itisimportantthattheriskassessmentinconfinedspaceworkisconductedbyknowledgeableandexperiencedpersonnel.
5.1.1 AssessNeedforEntryintoaConfinedSpaceBeforeattemptingtoenterorworkinaconfinedspace,itisimportanttoconsiderthepossibilityofusingalternativesandothermethodstodothejobwithoutenteringtheconfinedspace.Entryintoorworkinaconfinedspaceshouldonlybealastresort.
5.1.2 IdentificationandEvaluationofConfinedSpacesAll confined spaces shall be clearly identified, documented and labelled. It includes anyequipmentthatconstitutesaconfinedspace intheworkplace.Thedocumentshouldcontaintheparticularsofthetypesofconfinedspacesandtheirservices.Fortheequipmentrecord,itisimportanttoalsoincludeitstypeandidentificationnumber.Itiscriticaltoidentifyandevaluateeachconfinedspacetodeterminewhetherithaschemicalorphysicalhazards.Itisadvisablenottoassumethataconfinedspaceishazard-free.Differentchemicalandphysicalhazardsmaybeintroducedthroughvariousworkactivitiesinsidetheconfinedspace.
Chemical Hazards include conditions such as fumes and dust which affect the air in theconfinedspaceandcanbeflammable,toxic,corrosive,orasphyxiating.Theonlywaytoidentifyanatmospherichazardistoconductgastestingfromtheoutsideoftheconfinedspace.
PhysicalHazardsincludeconditionssuchasmechanisedequipment,loosematerials,excessivenoise,extremetemperatures,humidity,lowillumination,andaccessdifficulty.
Itisalsonecessarytodisplaywarningsignsatorneareveryaccesspointtoaconfinedspacetowarnpersonsofthepotentialhazards.
RefertoAnnex5forexamplesonconductingriskassessments.
5.RiskManagementApproachtoConfinedSpaces
5.1.3 ControlofConfinedSpaceHazardsItisimportanttofollowthestepsinthehierarchyofcontrolmeasurestomanagetheidentifiedrisks:
EliminationEliminateallhazardsinthespaceorcontrolthehazardssothattheentrantscanaccomplishtheirtasksandexitthespacesafely.Forexample,disconnect,Lockout&Tagout(LOTO)allelectricalenergysourcesofequipmentintheconfinedspacetoeliminatethehazards;removeremnantsofsludgeandremoveanypotentialtrappedproductsorgasesthroughcontinualcleaning.
SubstitutionInsteadofenteringaconfinedspace tocarryoutanactivity,consider thepossibilityofusingalternativemethodstodothejobwithoutentering.Forexample,usingavacuummachineandanextendedhosetosuckoutthesludgeinsteadofhavingworkersentertheconfinedspacetomanuallyremoveit.
EngineeringControlEngineeringcontrolsarephysicalmeansthatlimitthehazards.Theseincludeusingcontinuousforced ventilation with continuous monitoring of the atmosphere to ensure the ventilation isadequateintheconfinedspace.Thesewillhelptomaintainasafeatmosphericandcomfortableworkenvironment.
AdministrativeControli. EstablishEntryProceduresBefore any worker enters a confined space, it is necessary to establish safe work procedurescovering all phases of the entry process. It is crucial that the entry permit is duly completedandtheconfinedspaceissafeforworkerstoenter.“Entry”occurswhenaperson’sheadpassesthroughanopeningintotheconfinedspace.ii. TheEntryPermitItisnecessaryfortheentrypermitdocumentstoreflectacceptableentryconditionsandindicatethattheconfinedspaceissafeforworkerstoenter.Itisimportanttodisplaytheentrypermitattheentranceoftheconfinedspace.
PersonalProtectiveEquipmentIfreasonablypracticablecontrolmeasuresarenotavailabletomitigatetherisksofworkinginaconfinedspace,theuseofPersonalProtectiveEquipment(PPE)maybeconsideredasthelastlineofdefence.Forexample,whenenteringasewersystemthathasdeepstandingwaterandsludgewithpocketsofmethaneandhydrogensulfide.Thesehazardscannotbeeliminatedbyventilationalone.Ifentryisdeemedessential,freshairsupply,respiratoryprotectionandothercontrolmeasuresareabsolutelynecessary.
5.2 CommunicationItisimportanttocommunicatethefinaloutcomeoftheriskassessmenttoallworkerswhomaybeexposedtotherisksduringconfinedspaceentry.Itisnecessaryformanagers/supervisorstoinformtheworkersof:• Theconfinedspaceworkactivitiestobecarriedout;• Associatedsafetyandhealthhazardsaffectingthemandnatureoftherisksinvolved;• Typesofcontrolmeasuresimplementedtoprotectthem;
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• Theirresponsibilitiesandexpectationstocomplywithallworkrequirementsincluding:i. Obeyinggeneralsafetyrulesandregulations;ii. Theuseofpersonalandrespiratoryprotectiveequipment;iii. Complyingwithsafeworkprocedures;andiv. InstructionsasrequiredunderthePermittoWorksystem.
• Anychangestotheworkconditionsandriskscontrolmeasures.
5.3 PeriodicRiskAssessmentItisessentialtorevieworrevisetheconfinedspaceriskassessmentatleastonceevery3years.Itisalsonecessarytoreviewtheriskassessmentwhenthefollowingeventshappen:• Whenthereissignificantchangetoworkpracticesorproceduresincludingimplementation
ofadditionalriskcontrolmeasures;or
• Afteranincidentarisingfromworkinconfinedspaces.
5.4 DocumentationItisimportanttomaintaindulyapprovedrecordsandcurrentriskassessments.Itisessentialfortherecordtoinclude:• Theresultsorfindingsrecordedintheriskassessments;• Riskcontrolmeasurestakenortobetakenwithinanagreedtimeframe;and
• Anysafeworkprocedures.
Communication
1Preparation
2Hazard
Identification
3Risk
Evaluation
6Implementation
and Review
4Risk
Control
5Record
Keeping
> FormRATeam
> Gatherrelevantinformation
>Identifyhazards
>Identifypotentialaccidents/incidents
> Estimaterisklevelsbasedonidentifiedhazards
> Prioritisethehazardstobecontrolled
> Keepriskassessmentreportsforatleast3years
> Reviewriskassessments:• Onceevery3
years;
• WhenevernewinformationonWSHriskssurfaces;
• Whentherearechangestoworkprocessesand/or;
• Afterany accident/incident.
> FormulatecontrolmeasuresaccordingtotheHierarchyofControls:
• Elimination
• Substitution
• Engineeringcontrols
• Administrativecontrols
• Personalprotectiveequipment
> Analyseandevaluateresidualrisk
Risk Assessment (RA)Hazard
IdentificationRisk
EvaluationRisk
Control1 2 3
Figure 2: Example of the risk management approach.
Manyhazardscanexistinconfinedspaces.Ingeneral,hazardsthatcanoccurinnon-confinedspacescanalsooccurinconfinedspaces.Itisimportanttonotethispoint.Thecharacteristicsofaconfinedspaceusuallyaggravateorintensifymanyofthesehazards.
Themostdangeroushazardsinconfinedspaces(seeSection4.3TypesofInjury)areassociatedwiththeatmospherecontainedwithinthem.Theatmosphereinsidedifferentconfinedspacesvariesdependingonthetypeofspace,theworkbeingdoneinside,andwhatwaspreviouslycontainedorstoredinthem.However,themostcommonatmospherichazardsfoundinconfinedspacescanbebroadlyclassifiedinto:
• Suffocation(orasphyxiation)hazards—duetooxygendeficiency;
• Fire/Explosionhazards—duetopresenceofflammablegasesandvapours;and
• Poisoning—duetopresenceoftoxicgases,vapoursorfumes.
6.1 SuffocationHazards—ByOxygenDeficiencyTheairinournaturalenvironmentcontains20.9%oxygen.
Anenvironmentisconsideredoxygendeficientwhentheconcentrationofoxygenislessthan19.5%byvolume.Theeffectsandsymptomsofdifferentlevelsofoxygendeficiencyonhumansaredescribedbelow.
6.TypesofHazardsinConfinedSpaces
Oxygenconcentration,volume% Effectsandsymptoms
19.5 Minimumsafeentrylevel
16–19 Poorcoordination,fatigue
12–16 Rapidpulse,difficultyinbreathing
10–12 Veryfastanddeepbreathing,lipsbegintoturnblue,headache
8–10 Fainting,unconsciousness,nausea,vomiting
6–8 Fatalin8minutes;50%fatalin6minutes
<6 Comain1minute,convulsions,respiratoryandcardiacarrest,death
Table 1: The effects and symptoms of different levels of oxygen deficiency on humans.
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SubstanceLEL
(%Vol.)UEL
(%Vol.)
AutoIgnition
Temp(°C)
FlashPoint(°C)
PEL(PPM)
Benzene 1.2 7.1 498 -11.1 5
CarbonMonoxide 12.5 74 607 NA 25
HydrogenSulfide 4.3 44 260 NA 10
Ethanol 3.5 19 365 13 1000
Styrene 1.1 6.1 490 31 50
IsopropylAlcohol 2 12.0 399 11.7 400
<6 1.8 8.4 287 -60 800
Thelowoxygenlevelinaconfinedspacecanbecausedbyoxidation,rusting,bacterialgrowth,worksuchaswelding,cuttingordisplacementbyothergasessuchasnitrogenorcarbondioxide.
Insewers,forexample,thenaturaloxidationprocessofrottingmaterialswithinanenclosedspacewilldepletetheoxygeninthisatmosphere,thusresultinginanoxygendeficientenvironment.
Reducedoxygenlevelscouldalsoariseinpoorlyventilatedenclosedspacessuchasshipholds,processplantvessels,silos,andsoon.
6.2 Fire/ExplosionHazards—ByFlammableGasesandVapoursTheriskoffireorexplosioninanenclosedspaceisextremelyhighwheneverthereisabuildupofanyflammablegasandvapours.Ifthegasorvapoursarecolourlessandodourless,thebuild-upcannotbedetectedunlessagasdetectioninstrumentisused.
Forthesegasesandvapourstoigniteandresultinafireorexplosion,thefollowingconditionsmustbemet:
• ASOURCEOFIGNITIONispresent,thetemperatureofwhichisequaltoorhigherthantheIGNITIONTEMPERATURE oftheflammablesubstanceinquestion.Therearemanyprocesseswhichcanbesourcesofignition.Someexamplesinclude:
i. hotworklikeweldingorgascutting;
ii. pyrophoricmaterials(e.g.,ironsulphide);
iii. sparks from internal combustion engines, (e.g., compressor, drilling and non-flamecutting);or
iv. flowsofcertainmaterials likenon-conductiveliquidsandcombustiblepowderswhichcangeneratestaticchargesthusprovidingasourceofignitionoftheflammableliquidorcombustiblepowderitself.
• The concentration of the flammable substance is in the range between the LOWEREXPLOSIVELIMIT(LEL)andtheUPPEREXPLOSIVELIMIT(UEL).Inthecaseofaflammableliquid, a flammable vapour/air mixture can only be generated if the temperature of thesurroundingsisequalorhigherthantheFLASHPOINT oftheliquid.ExamplesofLELandUELvaluesforafewflammablesubstancesaregiveninTable2.
• Asufficientamountofoxygenispresent.
SubstanceLEL
(%Vol.)UEL
(%Vol.)
AutoIgnition
Temp(°C)
FlashPoint(°C)
PEL(PPM)
Benzene 1.2 7.1 498 -11.1 5
CarbonMonoxide 12.5 74 607 NA 25
HydrogenSulfide 4.3 44 260 NA 10
Ethanol 3.5 19 365 13 1000
Styrene 1.1 6.1 490 31 50
IsopropylAlcohol 2 12.0 399 11.7 400
Butane 1.8 8.4 287 -60 800
Table 2: LEL and UEL values for flammable substances.
6.3 Poisoning—ByToxicGases,VapoursorFumesDifferenttoxicsubstancesmaybepresentatthesametimefordifferenttypesofconfinedspaces.Exposure to toxic substances such as hydrogen sulphide and carbon monoxide can result indeathorirreversiblehealtheffects.Theeffectsofexposuretotoxicsubstancesinclude:
Fuel IgnitionSource
Oxygen
Figure 3: The Fire Triangle.
Different toxic substances produce different health effects at different concentrations. It isthereforeessentialtoknowandfindoutwhattoxicsubstancescouldbepresentintheconfinedspacesothatthecorrectgastestingequipmentandtheircorrespondingalarmconcentrationsonthisequipmentcanbepresettoprovideawarninginresponsetoadangerouslevel.Suchlevels are Permissible Exposure Levels (PEL). The PEL is defined as the maximum airborneconcentrationofatoxicsubstancethataworkermaybeexposedtofor8hoursaday,5daysaweekwithoutexperiencingadversehealtheffects.PELs for toxicsubstancesareestablishedbytheMinistryOfManpowerintheFirstScheduleoftheWorkplaceSafetyandHealth(GeneralProvisions)Regulations.
WherethePELforaparticulartoxicsubstanceisnotavailable,otherinternationallyestablishedsourcesofoccupationalexposurelimitsmaybereferredto.Forexample,ThresholdLimitValues(TLV)whichwereestablishedbytheAmericanConferenceofGovernmentIndustrialHygienists(ACGIH),andPELsestablishedbytheNationalInstituteOfSafetyandHealth(NIOSH).
PELvaluesforafewtoxicsubstancesaregiveninTable2.
• Chemicalasphyxiation,aresultofoxygendeficiencyinourbodycausedbyinhalationofgasesorvapours.Anexampleofachemicalasphyxiantiscarbonmonoxidewhich is released during combustion processes asa result of incomplete combustion. For example,hotworkandinternalcombustionengines;
• Narcotic effects like headache, dizziness, nausea. Forexample,hydrocarbonvapoursfromspraypaintingorsludgeremoval;
• Cancer. For example, benzene and vinyl chloridemonomerfromcargotanks;or
• Systemic poisoning. For example, lead from weldingfumes,mercuryfromcrudeoilcoatedontocargotankwallsandreleasedduringcutting.
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6.4 OtherConfinedSpaceHazardsWhilethemostlikelyhazardsinconfinedspacesareexplainedinsections6.1to6.3,manyotherhazardscanoccur.Otherthanoxygendeficiency,flammablesubstancesandtoxicsubstances,many of these other hazards have the potential to cause death or serious injury/illness. It isimportant to give careful consideration to these other hazards when carrying out the riskassessmentforworkinginsideconfinedspaces.Examplesoftheseotherhazards,thesituationswheretheycanoccurandtheirharmfuleffectsaregiveninTable3.
Hazard Howitcanhappen Whatthedangeris
Oxygenenrichment Leakingoxygenfromgascuttingequipment,e.g.,cuttingtorch
Flammablematerialscatchesfiremoreeasily
Combustibleparticulates
• Flourmills→airborneflourdust
• Pharmaceuticalpowders,e.g.,duringtransfer
Fire/explosion
Skincontactwithchemicals/absorption
Painting,cleaning→solvent/acidexposure
• Skinirritation,dryness,swelling
• Skinburns• Systemiceffects,e.g.,liver
poisoning,blooddisorders,ifabsorbedthroughskinintobloodstream
Heat • Poormechanicalventilation• Crowdedspace• Hotwork• Heatgeneratingmachinery• Thick/heavyprotective
clothing/equipment• Strenuousactivity
Heatcramps,heatexhaustion,heatstroke
Noise
• Jackhammering• Cutting• Ventilationfans• Hydro-jetting• Grit/shotblasting
• Shorttermorlongtermhearingloss(noise-induced-deafness)
• Poorcommunication →accidents
Ergonomichazards
• Limitedspace• Awkwardworkingposition,
e.g.,manualhandling/lifting
• Musculoskeletaleffects,e.g.,backache,musclecramps/strains
Poorlighting • Insufficientartificiallighting
• Slips,trips,falls
Roadtraffic • Roadmanholeworkwithoutpropercordoningortrafficdiversion
• Injury,death
Engulfment • Collapsinglooselypackedparticles,e.g.,flour,catalyst
• Steppingonlooselypackedparticles
• Inadvertentopeningoffeedlinestoconfinedspace
• Trappedinsidematerial→ breathingdifficulty→suffocation
Entrapment • Taperingorinwardlyslopingandsmoothwalls,e.g.,cyclones
• Trappedatbottomend,breathingdifficulty → asphyxiation
Mechanicalhazards • Movingorrotatingparts,e.g.,belts,gears
• Injury,death
Electricalhazards • Improperelectricalwiring• Poorhousekeepingof
electricalcables• Noprovisionofgrounding• Wetspaces• Humidenvironment
→ decreasedelectricalresistance
• Electrocution→burns,death
Fallingfromheight • Improperlybarricadedopenings,e.g.,towertrays
• Scaffoldingwithoutproperguardrails
• Workingatheightwithoutproperuseofsafetyharness
• Severeinjury,drowning,death
Fallingobjects • Limitedstorageandworkingspace
• Poorhousekeepingpractices
• Inadequatesecuringoftools,structuralmaterials
• Injury,death
Radiation • UltravioletandInfraredradiationfromwelding
• Non-destructivetesting(Xray)
• Maintenanceoflevelinstrumentationusingradioactiveisotopes
• Skinburns,cataract,arceye,geneticchanges,cancer
Asbestos • Removalofpartitionwallsinships
• Asbestosis,mesothelioma,lungcancer
Drowning • Inadvertentopeningofliquidsupplylines
• Fallingfromheighttobottom
• Death
Biologicalhazards • Viruses,bacteriaindecomposingwasteorwater
• Insects,rodents,snakes
• Gastrointestinaldisease,hepatitisAandpoisoning
Hazard Howitcanhappen Whatthedangeris
Oxygenenrichment • Leakingoxygenfromgascuttingequipment,e.g.,cuttingtorch
• Flammablematerialscatchesfiremoreeasily
Combustibleparticulates • Flourmills→airborneflourdust
• Pharmaceuticalpowders,e.g.,duringtransfer
• Fire/explosion
Skincontactwithchemicals/absorption
• Painting,cleaning→solvent/acidexposure
• Skinirritation,dryness,swelling
• Skinburns• Systemiceffects,e.g.,
liverpoisoning,blooddisorders,ifabsorbedthroughskinintobloodstream
Heat • Poormechanicalventilation
• Crowdedspace• Hotwork• Heatgenerating
machinery• Thick/heavyprotective
clothing/equipment• Strenuousactivity
• Heatcramps,heatexhaustion,heatstroke
Noise
• Jackhammering• Cutting• Ventilationfans• Hydro-jetting• Grit/shotblasting
• Shorttermorlongtermhearingloss(noise-induced-deafness)
• Poorcommunication →accidents
Ergonomichazards
• Limitedspace• Awkwardworking
position,e.g.,manualhandling/lifting
• Musculoskeletaleffects,e.g.,backache,musclecramps/strains
Poorlighting Insufficientartificiallighting Slips,trips,falls
Roadtraffic Roadmanholeworkwithoutpropercordoningortrafficdiversion
Injury,death
Engulfment • Collapsinglooselypackedparticles,e.g.,flour,catalyst
• Steppingonlooselypackedparticles
• Inadvertentopeningoffeedlinestoconfinedspace
Trappedinsidematerial→ breathingdifficulty→suffocation
Entrapment Taperingorinwardlyslopingandsmoothwalls,e.g.,cyclones
Trappedatbottomend,breathingdifficulty → asphyxiation
Mechanicalhazards Movingorrotatingparts,e.g.,belts,gears
Injury,death
Electricalhazards • Improperelectricalwiring• Poorhousekeepingof
electricalcables• Noprovisionofgrounding• Wetspaces• Humidenvironment→
decreasedelectricalresistance
Electrocution→burns,death
Fallingfromheight • Improperlybarricadedopenings,e.g.,towertrays
• Scaffoldingwithoutproperguardrails
• Workingatheightwithoutproperuseofsafetyharness
Severeinjury,drowning,death
Fallingobjects • Limitedstorageandworkingspace
• Poorhousekeepingpractices
• Inadequatesecuringoftools,structuralmaterials
Injury,death
Radiation • UltravioletandInfraredradiationfromwelding
• Non-destructivetesting(Xray)• Maintenanceoflevel
instrumentationusingradioactiveisotopes
• Skinburns,cataract,arceye,geneticchanges,cancer
Asbestos • Removalofpartitionwallsinships
• Asbestosis,mesothelioma,lungcancer
Drowning • Inadvertentopeningofliquidsupplylines
• Fallingfromheighttobottom
• Death
Biologicalhazards • Viruses,bacteriaindecomposingwasteorwater
• Insects,rodents,snakes
• Gastrointestinaldisease,hepatitisAandpoisoning
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Hazard Howitcanhappen Whatthedangeris
Oxygenenrichment • Leakingoxygenfromgascuttingequipment,e.g.,cuttingtorch
• Flammablematerialscatchesfiremoreeasily
Combustibleparticulates • Flourmills→airborneflourdust
• Pharmaceuticalpowders,e.g.,duringtransfer
• Fire/explosion
Skincontactwithchemicals/absorption
• Painting,cleaning→solvent/acidexposure
• Skinirritation,dryness,swelling
• Skinburns• Systemiceffects,e.g.,
liverpoisoning,blooddisorders,ifabsorbedthroughskinintobloodstream
Heat • Poormechanicalventilation
• Crowdedspace• Hotwork• Heatgenerating
machinery• Thick/heavyprotective
clothing/equipment• Strenuousactivity
• Heatcramps,heatexhaustion,heatstroke
Noise
• Jackhammering• Cutting• Ventilationfans• Hydro-jetting• Grit/shotblasting
• Shorttermorlongtermhearingloss(noise-induced-deafness)
• Poorcommunication →accidents
Ergonomichazards
• Limitedspace• Awkwardworking
position,e.g.,manualhandling/lifting
• Musculoskeletaleffects,e.g.,backache,musclecramps/strains
Poorlighting • Insufficientartificiallighting • Slips,trips,falls
Roadtraffic • Roadmanholeworkwithoutpropercordoningortrafficdiversion
• Injury,death
Engulfment • Collapsinglooselypackedparticles,e.g.,flour,catalyst
• Steppingonlooselypackedparticles
• Inadvertentopeningoffeedlinestoconfinedspace
• Trappedinsidematerial→ breathingdifficulty→suffocation
Entrapment • Taperingorinwardlyslopingandsmoothwalls,e.g.,cyclones
• Trappedatbottomend,breathingdifficulty → asphyxiation
Mechanicalhazards • Movingorrotatingparts,e.g.,belts,gears
• Injury,death
Electricalhazards • Improperelectricalwiring• Poorhousekeepingof
electricalcables• Noprovisionofgrounding• Wetspaces• Humidenvironment
→ decreasedelectricalresistance
• Electrocution→burns,death
Fallingfromheight • Improperlybarricadedopenings,e.g.,towertrays
• Scaffoldingwithoutproperguardrails
• Workingatheightwithoutproperuseofsafetyharness
• Severeinjury,drowning,death
Fallingobjects • Limitedstorageandworkingspace
• Poorhousekeepingpractices
• Inadequatesecuringoftools,structuralmaterials
• Injury,death
Radiation • Ultravioletandinfraredradiationfromwelding
• Non-destructivetesting(Xray)
• Maintenanceoflevelinstrumentationusingradioactiveisotopes
Skinburns,cataract,arceye,geneticchanges,cancer
Asbestos Removalofpartitionwallsinships
Asbestosis,mesothelioma,lungcancer
Drowning • Inadvertentopeningofliquidsupplylines
• Fallingfromheighttobottom
Death
Biologicalhazards • Viruses,bacteriaindecomposingwasteorwater
• Insects,rodents,snakes
Gastrointestinaldisease,hepatitisAandpoisoning
Table 3: Examples of other hazards, the situations where they can occur and their harmful effects.
7.1 ConfinedSpaceEntryPermitAformalcheckisnecessarytoensurethatalltheelementsofasafesystemofworkareinplacebeforepersonsareallowedtoenterorworkinconfinedspaces.Nopersonshallenterorworkinaconfinedspacewithoutavalidentrypermit.
It is recommended that an entry permit clearly identifies the roles and responsibilities ofpersonswhomayauthoriseparticularjobsandwhoareresponsibleforspecifyingthenecessaryprecautions(e.g.,isolation,atmospherictesting,emergencyarrangements,etc).
However, the entry permit does not entitle the applicant to carry out hotwork or any otherhazardouswork.Separatepermits-to-work (PTW)mustbeobtainedtocarryout theseworks.Apermit-to-worksystemforentryintoaconfinedspaceshallbeestablishedandimplemented.Theconfinedspaceentrypermit(hereinafterreferredtoasentrypermit)andPTWensurethat:
• Theconfinedspacework iscarriedoutwithcarefulconsiderationonsafetyandhealthofpersonswhoarecarryingoutthework;
• Suchpersonsareinformedofthehazardsassociatedwithconfinedspacework;and
• Thenecessarysafetyprecautionsaretakenandenforcedwhenconfinedspaceworkisbeingcarriedout.
7.2 InformationRequiredonTheEntryPermitTheentrypermitshouldinclude:
• Identificationoftheconfinedspace;
• Locationoftheconfinedspace;
• Purposeofentry;
• Entrydateandtimeduration;
• Validityofthepermit(dateandtimeofcompletion/expirationofentry/work);
• Potentialhazardsintheconfinedspace:
i. Atmospherichazards
ii. Non-atmospherichazards
• Control measures (how hazards will be controlled so that the space is safe to enter).Thefollowingaresomeofthesemeasures:
i. Isolation:
De-energisationandlockout/tagout(LOTO);
Blanking/bleeding/isolationofpipes;
Removalofmechanicalbelt/linkages.
7. WorkingSafelyInConfinedSpaces
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ii. PersonalProtectiveEquipment(PPE):Safetyhelmet;Safetyshoes;Eyeprotection;Handprotection;Fallprotection/lifelines;Respiratoryprotection;Protectiveandreflectiveclothing;Otherpersonalequipment,suchas:- Pocket/Personalgasdetector;- Torchlight.
iii. Otherprecautions:Barricadesandsignboards.
iv. Emergencyresponse:Awell-rehearsedrescueplan;Rescueequipment;Nameandcontactnumberofemergencyresponders.
• Nameofconfinedspaceattendant;• Provisionofventilation;• Lightingarrangement;
i. Useofflame-prooflight(protectedlight)• Resultsoftheatmospherictestingoftheconfinedspace:
i. Oxygen;ii. Flammablegases;iii. Othertoxicgases.
• Namesandsignaturesofsupervisor,confinedspacesafetyassessor(CSSA),andauthorisedmanager.
PleaserefertoAnnex3forasampleofaconfinedspaceentrypermit.
7.3 RiskAssessmentA Risk Assessment shall be jointly conducted by the supervisor and the authorised managerbeforetheapplicationforentryorworkinaconfinedspace.
7.4 IssuanceofEntryPermitAnentrypermitproceduretypicallyconsistsofthefollowingstages:
7.4.1 STAGE1—ApplicationofEntryPermitbySupervisorThesupervisorshould:
• Statethemeasureswhichwillbetakentoensurethesafetyandhealthofthepersonswhowillenterorcarryoutworkintheconfinedspacebasedonthecompletedriskassessment;
• Inspectandpreparethepre-entryrequirementsfortheconfinedspace;
• Highlighttheintendedworktotheconcernedpersonnel;and
• CompleteandforwardtheentrypermittotheCSSA.
7.4.2 STAGE2—EvaluationbyConfinedSpaceSafetyAssessorTheCSSAshould:
• Inspectthesite/areatogetherwiththeapplicant;
• Determinepossibleatmospherichazardsandestablishappropriatesamplingstrategy,suchasmeasurementmethod,numberandlocationofsamplingpoints;
• Usesuitableandproperlycalibratedatmosphericgas/vapourtestinginstruments;
• Conductthetestinthefollowingsequence:
i. testforlevelofoxygencontent;
ii. testforlevelofflammablegasorvapour;and
iii. testtheconcentrationoftoxicgasorvapour,whereapplicable.
• Conductthetestinamannerthatwillnotendangerhimselforothers;
• Recordtheresultsofthetestintheentrypermit;
• Highlightanydeviationfromtheacceptablelimitstotheauthorisedmanager;and
• Endorseandforwardthepermittotheauthorisedmanager.
7.4.3 STAGE3—IssuancebyAuthorisedManagerTheauthorisedmanagermayissueanentrypermitifheissatisfiedthat:
• Thelevelofoxygenintheconfinedspaceiswithintherangeof19.5%to23.5%byvolume;
• Thelevelofflammablegasesorvapoursintheconfinedspaceislessthan10%ofitslowerexplosivelimit;
• ThelevelsoftoxicsubstancesintheatmosphereandtoxicsubstancesintheatmosphereoftheconfinedspacedonotexceedthePELsspecifiedintheFirstScheduleoftheWorkplaceSafetyandHealth(GeneralProvisions)Regulations;
• Theconfinedspaceisadequatelyventilated;
• Effectivestepshavebeentakentopreventanyingressofdangerousgases,vapoursoranyotherdangeroussubstancesintotheconfinedspace;and
• All reasonable practicable measures have been taken to ensure the safety and health ofpersonswhowillbeenteringorworkingintheconfinedspace;
7.4.4 STAGE4—PostingofEntryPermitThesupervisorshould:
• Clearly post a copy of the permit at the entrance to the confined space, including wherereasonablypracticable,asketchoftheareawithintheconfinedspacewheretheentryistobemadeorworkistobeconducted;and
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• Ensurethatthecopyofthepermitisnotremoveduntil:
i. thedateoftheexpiryofthepermit;
ii. therevocationofthepermit;or
iii. thepersonenteringorworkingintheconfinedspacehaslefttheconfinedspaceafterachievingthepurposeoftheentryorcompletingthework,asthecasemaybe;whicheveristheearliest.
PleaserefertoAnnex4forpermitapplicationflowchart.
7.5 DisplayofEntryPermitAcopyoftheentrypermitissuedbytheauthorisedmanagershallbedisplayedbythesupervisorclearlyattheentrancetotheconfinedspacesothatentrantsareinformedoftheconditionofthespaceandthemeasurestakentoensuresafeentry.
7.6 ReviewandEndorsementofEntryPermitItisthedutyoftheauthorisedmanagertoreviewandassesstheneedtocontinuetheworkintheconfinedspaceonadailybasisandrevoketheentrypermitifhethinksfittodoso.
If thework intheconfinedspaceneedstobecontinuedaftertheassessment,theauthorisedmanager shall endorse the entry permit by signing on the permit or by using other equallyeffectivemeans.PleaserefertoAnnex3forasampleofconfinedspaceentrypermit.
7.7 RevocationofEntryPermitIf,afterissuinganentrypermit,theauthorisedmanagerdeterminesthatcarryingouttheworkintheconfinedspaceposesorislikelytoposearisktothesafetyandhealthofpersonsintheconfinedspace,hemayordertheworktoceaseimmediatelyandrevoketheentrypermit.
Theauthorisedmanagershallterminateentryandcancelthepermitwhen:
• Theentryoperationscoveredbytheentrypermithavebeencompleted;or• Aconditionthatisnotallowedundertheentrypermitarisesinornearthepermitspace.
For example, the authorised manager is to revoke the entry permit when the monitoringequipmentalarmsounds;indicatingthedeficiencyofoxygenlevel,or10%ofLEL,orPELoftoxicgasisexceeded.
7.8 Re-certificationofConfinedSpacesWhenahazardousatmosphere(referto7.11.13.1) inaconfinedspaceisdetectedbyperiodictestsorcontinuousmonitoring,thesupervisororconfinedspacesafetyassessorshallwithdrawthe entry permit. A“no entry” sign shall be clearly displayed at the entrance of the confinedspace.Theauthorisedmanagershallrevoketheentrypermit.
Thesupervisor,CSSAandtheauthorisedmanagershallevaluatehowthehazardousatmospheredeveloped.Effectivemeansshallbeprovidedtoremovetheatmospherichazardsintheconfinedspace.
Uponremovalof theatmospheric hazards, thesupervisor shall raisea“new”entry permit fortheconfinedspace, ifentryorwork intheconfinedspaceistobecontinued.Theapplicationprocedurestatedin7.4shallapply.
Nopersonshallre-entertheconfinedspaceuntiltheconfinedspacehasbeenre-certifiedsafeforentryandanewentrypermitisissuedbyauthorisedmanager.
7.9 RecordKeepingEmployersarerequiredtokeeprecordsofworkinconfinedspaces,includingentrypermitsandtestresultsfortwoyearsasstipulatedundertheWSH(ConfinedSpace)Regulations.
7.10 ControlofHazardousEnergyItisimportanttoensure,asmuchaspossible,thattheconfinedspaceisisolatedbeforeentry.This is to prevent materials from coming into the space via pipelines or vents and to ensurethatequipmentinsidethespacedoesnotstartupwhiletheentrantisinside.Thisprocedureisalsotoprotectpersonnelfrominjuryduetounexpectedenergisation,start-uporthereleaseofstoredenergyfromthemachines,equipmentorprocessesduringtherepairormaintenanceofequipment.
7.10.1 EnergyIsolationandLockoutBeforeallowinganypersontoenteraconfinedspace,theauthorisedmanagershallensurethatallpotentiallyhazardousservicesandenergysourcesnormallyconnectedtothatspaceareisolatedinordertoprevent:
• The introduction of any materials, contaminants, agents or conditions harmful to peopleoccupyingtheconfinedspace;and
• Theactivationorenergisationinanywayofequipmentorserviceswhichmayposearisktothehealthorsafetyofpersonswithintheconfinedspace.
Theauthorisedmanagershallensurethatpositivestepsaretakentoachievethefollowing:
• Prevention of accidental introduction into the confined space of materials, throughequipmentsuchaspiping,ducts,vents,drains,conveyors, servicepipesorfireprotectionequipment.
• De-energisation and lockout, or if lockout is not practicable then tagout, or both lockoutandtagout,ofmachinery,mixers,agitatorsorotherequipmentcontainingmovingpartsintheconfinedspace.Thismayrequireadditionalisolation,blockingorde-energisingofthemachineryitselftoguardagainstthereleaseofstoredenergy(e.g.,springs).
• Isolationofallotherenergysourceswhichmaybeexternalto,butstillcapableofadverselyaffectingtheconfinedspace(e.g.,heatingorrefrigeratingmethods).
PleaserefertoAnnex6formoreinformation.
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7.10.2 FormsofHazardousEnergyEnergy sources can come in many forms but not limited to electrical, mechanical, hydraulic,pneumatic,chemical,thermal,gravitational,ionisingandnon-ionisingradiation.Itisnecessarytoisolateallmechanical,electricalequipmentandallotherenergysourcesconnectedtoaconfinedspacetopreventthemfromunintentionalactivation.Ifgasesorvapourscanentertheconfinedspace, physical isolation of pipelines, valves, and so on needs to be locked and tagged usinglockoutandtagoutprocedures.Inallcases,acheckisrequiredtoensureisolationiseffective.
7.11 GeneralRequirements7.11.1 OpeningsofConfinedSpacesBeforeanentrancecover isremoved,anyknownunsafeconditionsshallbeeliminated.Whenentrancecoversare removed, theopeningshallbepromptlyguardedbya railing, temporarycover,orothertemporarybarrier.Thiswillpreventanyonefromfallingthroughtheopening.Thebarrierorcovershallpreventforeignobjectsfromenteringthespaceandprotecteachemployeeworkinginit.Ifitisinatrafficflowarea,adequatebarriersshallbeerectedtodivertthetraffic.
Itisnecessarytotakeprecautionswhenopeningthecoverstotanksandwithinotherconfinedorenclosedspacesintheeventthespaceisunderpressureorhazardousmaterialshaveleakedfrominternalpipingsystems.Itisimportanttoleaveatleasttwonutsonoppositesidesofthecoverinplaceuntilthecovercanbecrackedandanyinternalpressurehasreleased.
7.11.2 BarricadeItisessentialtousesafetybarrierstoseparateworkersfromhazardsthatcannotbereasonablyeliminated by other engineering controls. Selection of suitable barriers will depend on thenatureofthehazardandthesizeoftheareaorequipmenttobecordonedoff.Thesupervisormustdetermineifsafetybarrierswillbeneededfortheconfinedspaceentrypriortoanyworkersenteringtheconfinedspace.
7.11.3 Communication/WarningSignsWarning sign/s can be used to inform workers about the confined spaces. It is critical for theworkerstoknowthelocationoftheconfinedspace,itshazards,therequiredsafeworkproceduresandpermittoentertheconfinedspace.
Figure 4: Examples of Confined Space warning signs.
Confinedspace Nounauthorisedentry
For details on specifications for graphical symbols on safety colours and safety signs,kindlyrefertoSingaporeStandard,SS508-2:2008andSS508-4:2008.
7.11.4 ConfinedSpaceAttendant(CSA)CSAshouldbeappointedwhereanypersonentersorcarriesoutanyworkinaconfinedspaceandremainoutsidetheconfinedspaceto:
• Monitorpersonsenteringandworkingintheconfinedspace;
• Maintainregularcontactwiththepersonsintheconfinedspaceandwhennecessaryassistthemtoevacuateshouldtheneedarise;and
• Alerttherescuepersonneltoactivatetherescueoperationinanemergency.
7.11.5 AccessandEgressWhere the possibility for inadvertent or unauthorised entry to a confined space exists, it isrequiredtouseappropriatemeanstopreventsuchanentry(e.g.,abarrierorsafetywarningsignthatisclear,legibleandvisible).
A safe way in and out of the confined space should be provided for the individuals carryingoutthework.Whereverpossible,quick,unobstructedandreadyaccessandegressshouldbeallowed. It is essential that the means of escape be suitable for use by every individual whoenterstheconfinedspacesothatheorshecanescapequicklyinanemergency.
Thesizeofopeningsusedforaccesstoandegressfromconfinedspacesneedstobeadequatetoallowreadypassage.Openingsprovidingaccessneedtobesufficientlylargeandfreefromobstruction to allow the passage of persons wearing the necessary protective clothing andequipment, and to allow adequate access for rescue purposes. These openings need to bekept clear whenever a confined space is occupied.Where practicable, it is necessary to havean alternative opening for insertion of hoses, ventilation ducts, power lines and other cablesrequiredforthework.
Certainconfinedspacesmayhavedesigndeficiencieswhichincreasethelevelofentryrisktoanunacceptablelevel.Theseincludespaceswhoseopeningsaretootightforsafepassageorwhichareofconvolutedconstruction,orwhichinvolveexcessivedistancestoapointofescape.Structuralmodifications(e.g.,themakingoftemporaryopenings)willbenecessarybeforeentryispossibleinthesecases.
7.11.6 DisplayofNameandIdentificationBadgeThepersonenteringaconfinedspacemustdisplayhisnameand identificationbadgeat theentrancetotheconfinedspace. It isalsothedutyoftheresponsiblepersonoftheentranttoensurethathedoesthesame.
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7.11.7 CommunicationAneffectiveandreliablemeansofcommunicationamongentrantsinsidetheconfinedspace,andbetween entrants and attendants, is required. When choosing a means of communication, it isadvisabletogivecarefulconsiderationtoallanticipatedconditionsinsidetheconfinedspace(e.g.,visibility, possibility of a flammable atmosphere, and noise levels) and to the personal protectiveequipmentinuse(e.g.,earmuffsandbreathingapparatus).
Thecommunicationsystemusedcanbebasedonspeech,handsignals,telephone,radio,andsoon.Whateversystemisused,itisimportantthatallmessagescanbecommunicatedeasily,rapidlyandunambiguouslybetweenrelevantpeople.Itisimportanttotakenoteonthelimitedpenetrationofradiosignalsintobuildings,vesselsandbelow-groundstructures.Theadvantagesofhavingapersonoutsidetheconfinedspaceindirectvoiceandvisualcontactwiththeentrantsareclear.Thisalsofacilitatesthemonitoringofentrantsforthesymptomsorbehaviouraleffectsofexposuretohazards.
Itisimportantthatconfinedspaceentrant(s)areinformedquicklyifasituationarisesontheoutsidewhich could endanger the entrants, such as problems with a supplied air system or ventilationsystem.
It is essential that the means of raising the alarm and setting in motion the emergency rescueproceduresareeffectiveandreliable.Itisalsonecessarythatthelineofcommunicationbeavailableatalltimesduringthework.
Itisrequiredtohaveanappropriatemeansofcommunicationbetweenthepersonworkinginsideaconfinedspaceandtheattendantstationedoutside,whetherbyvoice,ropetugging,tappingorbyabattery-operatedcommunicationsystemspeciallydesignedforconfinedspaceuse.Notethatradiofrequency/wirelessdevicesdonotworkeffectivelyinconfinedspacessuchastanksorsewers,wherethereismetalorconcreteshieldingbetweentheinteriorofthespaceandtheoutside.
Bodyalarmdevicesmaybeusefulinaconfinedspacewherecommunicationbetweenentrantsandattendantsisdifficult.Thesearedesignedtosoundifthewearerdoesnotmoveduringaspecifiedperiodoftime.
7.11.8 LightingandElectricalEquipmentAdequateandsuitablelightingshallbeprovidedforentryandworkinaconfinedspace.Accessandpassageintoaconfinedspaceshallbeprovidedwithilluminationofnotlessthan50lux.Allportablehand-held lightings provided in confined spaces shall be operated at a voltage not exceedingalternativecurrent(AC)55voltsbetweentheconductorandearthordirectcurrent(DC)110volts.
Temporarylightsshallbeequippedwithguardstopreventaccidentalcontactwiththebulb,exceptwhentheconstructionofthereflectorissuchthatthebulbisdeeplyrecessed.
Temporarylightsshallbeequippedwithheavy-dutyelectriccordswithconnectionsandinsulationmaintainedinsafecondition.Temporarylightsmaynotbesuspendedbytheirelectriccordsunlesscordsandlightsaredesignedforthismeansofsuspension.Splicesshallhaveinsulationequaltothatofacable.
Temporarylightsandelectricalservicesshouldbeprotectedbyanearthleakagecircuitbreaker(ELCB).
Workingspaces,walkways,andsimilarlocationsshallbekeptclearofcordssoasnottocreateahazardtoworkers.AllelectricalequipmentshouldbeprotectedbyanELCB.
Fordetailsonlightingofworkplace,kindlyrefertoSingaporeStandard,SS531:Part1toPart3.
7.11.9 RespiratoryProtectiveEquipment
7.11.9.1 GeneralGuidelinesonSelectionofRespiratoryProtectiveEquipmentItisrecommendedthatrespiratoryprotectiveequipment(RPE)beusedasalastresortwhenalloftheothercontrolmeasuresinthehierarchyofcontrolareeitherinadequateorimpractical,orintheeventofanemergencywhereentryisrequiredforrescuepurposes.
Theauthorisedmanagerisadvisedtoalwaysaimtoachieveasafeatmospherewhererespiratoryprotectiveequipmentwouldnotbenecessary.Ifthisisnotpracticable,appropriaterespiratoryprotective equipment should be considered depending on the likely concentration ofcontaminantand/oroxygenlevelintheconfinedatmosphere.
Respiratorsaredevicesthatallowworkerstobreathesafelywithoutinhalingharmfullevelsoftoxicgasesorparticles. It iscriticaltohaveacompetentpersontodeterminetheappropriaterespiratoryprotectiveequipmentbaseduponconditionsandtestresultsoftheatmosphereandtheworkactivitytobeperformed.Itisimportantthatthebreathingapparatusfitsproperlyandissafetouse.Careneedstobetakenintheselectionofthedeviceandinitsuse.Itisalsoimportantnottouseanydamagedordefectiveprotectivedevices.
Selectionofrespiratoryprotectivedevicesisgenerallybasedon:• Typeofaircontaminantspresent(i.e.,articles,vapours,gases);• Hazardofexposure(i.e.,IDLH,eyeirritant,Toxicity);• Warningpropertiesofcontaminants;• Levelofexposure;• Exposuretime;• Workactivity;• Characteristicsandlimitationsoftherespiratorequipment;and
• Levelofprotectionneeded.
Fordetailsonselection,useandmaintenanceof respiratoryprotectivedevices,kindlyrefertoSingaporeStandard,SS548:2009CodeofPracticeforSelection,Use,CareandMaintenanceofRespiratoryProtectiveDevices.
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7.11.9.2 TypesofRespiratoryProtectiveDevices
Figure 5: Types of Respiratory Protective Devices.
AIRPURIFyINGRESPIRATORS
SUPPLIEDAIRREPIRATORS
OPENCIRCUITBREATHINGAPPARATUS
CLOSECIRCUITBREATHINGAPPARATUS
PARTICULATEFILTER
GAS/VAPOURCARTRIDGE
COMBINATIONFILER CCBA
SCBAAIRLINE
RESPIRATORyPROTECTIONEqUIPMENT
OnlySuppliedAirRespirators(SCBAandairlines)arerecommendedforuseinconfinedspaceswherethereislackofoxygen(oxygendeficiency).
Figure 6: Example of SCBA.
7.11.9.2.1 Self-ContainedBreathingApparatus(SCBA)SCBA is a system that supplies its own air through a tankand is independent of the surrounding air. It providesreliableprotectionagainsthazardousenvironments.Itisthechoicewhendealingwithanyoxygendeficientatmospherethat is Immediately Dangerous toLifeor Health (IDLH),orany environment that is unknown or has unknown levelsof contaminants or have poor warning properties, and/orwherelargeconcentrationsofcontaminantsareexpected.This ispossiblebecausethewearercarrieshisownsupplyofbreathableair.IfSCBAisused,theminimumservicetimeoftheSCBAshouldbecalculatedontheentrytimeplusthemaximum work period, plus twice the estimated escapetimeasasafetymargin.
The limitation of this system is that it is often difficult towork with because it requires special support equipmentand training. In addition, because of their weight andrestrictiveness,theiruserequiresmorephysicaleffort.
Figure 7: More physical effort is required when using SCBA due to their weight and restrictiveness.
7.11.9.2.2 AirlineRespiratorAnairlinerespiratorisrecommendedwhenentrywithanormalSCBAisphysicallyrestrictedand/ortheworkdurationislongerthantheservicetimeoftheSCBA.
Breathing air from an airline respirator normally comes from a trolley-mounted cylinder(s)positionedinsafezonesincloseproximitytotheuser,fromacompressororacombinationofboth.The breathing air is then supplied to the user by the breathing hose which is normallyconnectedtoalightweightharnesstoprovidetheuserwithanuninterruptedairsupply.
WhencomparedtothemoreconventionalSCBA,thisarrangementprovidesgreaterfreedomofmovementandlessfatiguetotheuser.
7.11.9.2.3 AirPurifying(Cartridge)RespiratorAirPurifying(Cartridge)Respiratorsoffernoprotectionagainstoxygendeficiency.
It is basically a filtering system that cleans the airbeing inhaled. Air-Purifying Respirators (APR) can removecontaminantsintheairthatthepersonbreathesbyfilteringoutparticulates(e.g.,dusts,metalfumes,mists,etc.).OtherAPRspurifyairbyadsorbinggasesorvapoursonasorbent(absorbing material) in a cartridge or canister. They aretight-fittingandareavailableinseveralforms:
• Half-face mask (covering the face from the nose tobelowthechin),or
• Fullfacepiece(coveringthefacefromabovetheeyestobelowthechin).Respiratorswithafullfacepiecealsoprotecttheeyesfromexposuretoirritatingchemicals.
Figure 8: Example of Air Purifying (cartridge) Respirator.
ThelimitationofAPRisthatthesystemdependsonthesurroundingairforoxygenandfiltersthecontaminantsfromtheperson’sbreathingair.Itiscriticalthattheatmosphereoftheconfinedspacecontainsatleast19.5%oxygen.Itisalsoneccessarytoknowtheapproximateconcentrationofcontaminantstoensurethattherespirator’scapabilitiesarenotexceeded.TheconcentrationofcontaminantscannotexceedtheIDLHlevelsanditisnecessaryforthepersontobefit-testedtoensurethecorrectsizeofrespiratorbeforeuse.
Itisimportantnottouseanykindoffilteringrespiratoryprotectiondevice:
• Inoxygendeficientatmospheres(lessthan19.5vol.%O2);
• Inpoorlyventilatedareasorconfinedspaces,suchastanks,tunnels,orvessels;
• In atmospheres where the concentrations of the toxic contaminants are unknown or areIDLH;or
• When the concentration of a contaminant is higher than the maximum permissibleconcentrationand/orthefilterclasscapacity.
Itisalsoimportanttoensurethat:
• Itfitsproperly;and
• Ifbothgasesandparticlesarepresent,thecombinationfilterisusedtofilteroutbothgasesandparticles.
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7.11.9.2.4 FitTestingIt is important to conduct qualitative or quantitative fit testing for all wearers of filteringrespiratoryprotectiondevicestoensurethatthefacialsealisgood.Itisalsocrucialthatfittestingisalwaysperformedbythemanufacturerortheirauthorisedpartner.
Qualitativefittestingcomprisestwosteps:
• Asensitivitytestwithadilutedtestsolution(withoutfilteringdevice)tocheckifthewearercandetectortastethetestsolution.
• Theactualtestwillbeconductedusingaconcentratedtestsolution.Intheactualfittesting,the user is asked to wear the filtering device and perform the following tasks; to breathenormally, to breathe deeply, to turn his head from side to side, to move his head up anddown,talking,bendingover,joggingonthespotandthenbacktobreathingnormally.
Ifthetestsolutioncannotbetastedaftercompletingalltheabove,thequalitativefittestingisasuccessandtheuserwillbegivenacertificateforwearingthisfilteringrespiratoryprotectiondevice.Aretestwillberequired,ifotherfilterrespiratorydevicesaretobeused.
Quantitative fit testing is normally performed with special equipment by a trained operator.Withthistest,noanswerisrequiredfromtheuser.Thiseliminatesanypossibilityofasubjectiveperception.
PleaserefertoSingaporeStandard,SS548:2009CodeofPracticeforSelection,Use,CareandMaintenanceofRespiratoryProtectiveDevices
7.11.9.2.5 OtherPersonalProtectiveEquipment(PPE)ProtectiveClothingAllpersonsenteringaconfinedspaceshallwearafull-suitworkclothing.Itisimportantfortheclothingmaterialsworntoprovideappropriateprotectionagainsttoxicorirritatingsubstances.Ifthehazardsareheatorcold,protectionfromover-exposuretothesehazardsshouldbeworn.Itisnecessaryforsuchclothingtocomplywithapplicablecodesorinternationalstandards.
HeadProtectionAhardhatisrequiredwhenthereisdangerofheadinjury.Itisimportanttowearasafetyhelmetwhichcomplieswithapplicablecodesorinternationalstandards.
EyeandFaceProtectionEyeprotectionisrequiredinallconfinedspaces.Ifeye-irritatingchemicals,vapoursordustsarepresent,itisnecessarytowearapairofappropriatesafetygoggles.Itiscriticaltouseeyeandfaceprotectionequipmentwhichcomplieswithapplicablecodesorinternationalstandards.
HandProtectionGlovesandprotectiveclothingmadeofasuitableresistantmaterialaretobeworntoprotectthehandsfromexposuretopotentialinjuries.Specialtyglovesmayberequiredtoprotectagainstheat,cold,orwhenhandlingslipperymaterialortools.
FootProtectionSpecial foot protection may be worn to protect against slippery surfaces, electricity, fallingobjects, chemicals, or sparks. Safety shoes are required to comply with applicable codes orinternationalstandards.
HearingProtectionAllpersonsarerequiredtowearhearingprotectioniftheyareexposedtoexcessivenoise.
SafetyHarnessItiscriticalforsafetyharnessestobewornwhenthereisapotentialoffallingfromheight.Whenwearing it, exercise care that such equipment would not introduce a hazard or unnecessarilyhinderfreemovementwithinaconfinedspace.Itisimportanttogivecarefulconsiderationtothepossiblehazards/rescuearrangementsduringtheselectionofthetypeofsafetyharness.Thesafetyharnessisrequiredtocomplywithapplicablecodesorinternationalstandards.
7.11.10 GasTestingandMonitoringoftheConfinedSpaceAtmosphereItisneversafetotrustoursenseswhenweneedtodetermineiftheairinaconfinedspaceissafeforbreathing.Thelackofoxygenandthepresenceofmanytoxicorflammablegasesinaconfinedspacecanneitherbeseen,tastednorsmelt.
Therefore, it is important for a confined space to be tested to ensure that the atmosphere issafe for persons to enter. It is also important to continuously monitor after entry so that theatmosphereismaintainedattheacceptable/safelevel.
Atmospherictestingisrequiredfortwopurposes:
• Toevaluatethehazardsintheconfinedspace;and
• Toverifythatitissafeforentryintotheconfinedspace.
Nopersonshallenteraconfinedspaceuntilitistestedtobefreefromanygashazards.Ifentryisrequired,theauthorisedentrantmustbeequippedwithanappropriatesuppliedairrespiratorandotherPPEasperdefinedbyhazardsanalysis.
Itisimportantthatsatisfactorygastestingiscarriedoutbyaconfinedspacesafetyassessor,asspecifiedinWSH(ConfinedSpaces)Regulations,beforeentryintoanyconfinedspace.Checktheoxygenlevelandthepossiblepresenceofflammableand/ortoxicgasestodetermineifentryispermitted.
Itiscrucialtocarryouttheinitialtestingfromoutsidetheconfinedspacebydrawingtheairfromthe atmosphere using suitable sampling devices while performing the atmospheric hazardsassessment.
Ifentryisabsolutelynecessary,itisimportanttoensurethelevelofflammablegases/vapoursislessthan10%LEL.Theconfinedspacesafetyassessorisrequiredtowearsuitablebreathingapparatus (BA) and is authorised by the authorised manager to enter. In accordance withRegulation10(2)(b)oftheWSH(ConfinedSpaces)Regulations,itshallbethedutyofanypersonnottopermitordirectanypersontoenterorworkinanyconfinedspaceunlessheisauthorisedto,andheiswearingasuitableBA.
Itisalsonecessarytorecordallgastestingresultsandattachittotheentrypermit.
30 31
TypeofGasHazard Example
GasMeasurementPrinciples
CatalyticSensor
InfraredSensor
PIDSensor
ElectrochemicalSensor
ColorimetricTubes
Toxic Ammonia X X
FlammableinInert Propane
X(withdilution
probe)X
Toxic&Flammable Benzene X X X
Toxic&Flammable
CarbonMonoxide X X X
Oxygendeficiency Nitrogen X
Toxic HydrogenSulphide X X
7.11.11 WhattoTestandWhataretheAcceptableLimitsIt is the responsibility of the CSSA to know and establish what atmospheric hazards may bepresentintheconfinedspace.Oncetheatmospherichazardsareknown,thecorrectgastestingequipmentandtheircorrespondingalarmconcentrationsontheequipmentmustbepre-set.Thepre-setwouldprovideawarningonthedangerouslevelaccordingtothelimitvaluesforthesubstanceofconcern.
Asaminimum,thefollowingshallbetested:oxygenreading,flammablegasesandvapoursreading,andtoxicgasesandvapoursreading.
Theacceptablelimitsare:
• Oxygenreading: ≥19.5%Vol.to≤23.5%Vol.
• Flammablegasesandvapoursreading: ≤10%LEL
• Toxicgasesandvapoursreading: ≤PELvalues
7.11.12 TypesofTestingMethods/EquipmentWithout the right gas detection equipment, it is not possible to recognise the danger of theatmosphereearlyenoughtoensurethatpropercountermeasuresaretaken.Itisalsoimportanttoknowthatnotallthegashazardsidentifiedcanbemeasuredwithanelectronicgasdetectioninstrument.
Duetothedifferentphysicalandchemicalpropertiesofthegases,differentdetectionprinciplesmaybeusedtoascertainthattheatmosphereissafe.Therearevarioustypesofportableandtransportableelectronicgastestinginstrumentswhichmaybeusedforthedetectionofthegashazardsfoundinconfinedspace.
Table 4: Types of gas hazards and their measurement principles.
These instrumentsmaybeavailableeitherasasinglegasmonitoring instrument for justonegasorcontaminant,oramulti-gasmonitoring instrumentthatwill typicallymeasureoxygen,flammablegasesandtoxicgases.
Itisrecommendedthatforconfinedspaceentrytesting,wheneverpossible,useanExapprovedelectronic gas detection instrument that is capable of detecting OX/EX/TOX simultaneously.Usingeitherdiffusionoractivesamplingviamanualorelectricalpumpwillwarntheuserswhenconcentrationlevelsintheconfinedspaceareunsafe.
It is important that training on the use of these instruments include instrument calibration,equipmentmaintenanceandtheproperinterpretationoftheinstrumentreadingsandwarningalarms.Whenindoubt,itisadvisablefortheCSSAtocheckwiththeinstrumentmanufacturersformoredetails.
As mentioned, not all gases can be measured with an electronic gas detection instrument.Thecolorimetric tubesarestillacommonmethodusedbymanygastesters.Thesetubesareimpregnated with chemicals that will react in the presence of a specific gas or vapour. Thereactionwillproduceacolourchangeandfromthelengthofthecolourchangeortheintensityofthecolourchange,theconcentrationofthisgasorvapourcanbedetermined.
7.11.13 TestingProceduresandConsiderationsACSSAshallbeappointedtotesttheatmosphereofaconfinedspacebeforeentrybyanypersonintotheconfinedspace.
Stepstobetakenbeforeandwhengastestingisconducted:
• Determineequipmenttypefortheatmospherictesting;
• Checktoseeiftheatmospherecanbetestedfromoutside.Determineiftheatmospherecanbetestedatalldepthsbeforeentry;
• Ensurethatthegastestinginstrumentiscalibratedorfunctiontested(referto7.11.15.4);
• Ensurethattherightandnecessaryaccessoriesareused;
• Brief all persons concerned on the hazards to be expected, their limit values and actionneededwheninstrumentalarmcomeson;
• Briefallpersonsconcernedontheemergencyprocedure,keycontactsandassemblypoint;
• Usesuitableaccessoriessuchaswateranddustfilterandfloatprobewhensamplingfromconfined space with liquid.The sampling hose or sensor may come into contact with theliquid.Thiscouldresultincontaminationofthehoseandsaturationofsensorfilterstherebyblockingthegasentrytotheinstrument;
• Ensure all depths are tested in the following sequence; start with oxygen, followed byflammablegasesandvapoursandfinallytoxicgasesandvapours;
• Recordallresultsandupdatethisinformationontheentrypermitdocument;
• Evaluateanddeterminethefrequencyofre-testsandnotifyallconcerned;and
• Evacuate everyone in the confined space immediately whenever an atmospheric hazardis detected during entry, while working or when re-tests are done. Re-evaluate the spacethoroughlytodetermineifthedynamicsinithaschangeddrastically.Itisimportanttotakeallrequiredmeasuresbeforeanyre-entryistotakeplace.
32 33
Itisessentialthatallprecautionsbeestablished,briefedandmaintainedthroughouttheentiredurationoftheworkscopetoensurethattheatmospherewithintheconfinedspaceissafeatalltime.
7.11.13.1 SequenceforAtmosphericGasTestingIt is importanttomonitortheatmospherichazards intheconfinedspacedusingacalibrated,directreadoutinstrument.Alwaystestforoxygenfirst,followedbyflammablegasesandvapoursandthenfortoxicgasesandvapours.
It is critical for the test results to satisfy the following criteria before the entry permit can beissued:
• Oxygenreading: ≥19.5%Vol.to≤23.5%Vol.
• Flammablegasesandvapoursreading: ≤10%LEL
• Toxicgasesandvapoursreading: ≤PELvalues
7.11.13.2 ResponseTimeWhenperforminggastestingbeforeentry,itisimportanttoestablishtheequipmenttypetobeused.Itiscriticaltoknowthelimitationsoftheseequipmenttypesandthattheyareunderstoodbyallcompetentgastesters.Itisimportanttopre-inspecttheaccessoriestoensurethattheyareoftherightmaterialandarefunctioningproperly.Itisalwaysessentialtoconductleaktestsonthesamplinghoseandcleanitbypurgingitwithfreshairbeforeeachgastest.
Dependingonthemakeormodelsfromthegasdetectionequipmentmanufacturers,itiscriticalforthemeasurementvaluesforeachatmospherichazardmonitoredtobeinaccordancetotheresponsetimeofthegastestinginstruments.
Theresponsetimenormallyusedbygasdetectionequipmentmanufacturers isreferredtoast90.Thisisthetimeitwilltakeforthesensortoread90%ofthetargetgasconcentrationintheatmosphere.Thismeansthatthetimeittakesforthesensortoreadthefullconcentrationwillbemuchlongerthanthet90time.Itisthereforeextremelyimportanttobuildinasafetymargintoensurethatthereadingofthegasconcentrationiscorrect.Forexample,ifthegasdetectioninstrument is used in the diffusion mode for horizontal entry, it is recommended to time theentryinaccordancetotheresponsetimewiththesafetyfactorsothatthedevicehassufficienttimetoreactto100%ofthegasesinthatspacebeforetheentrantproceedstothenextlocation.
7.11.13.3 DifferentDepthsWhenperforminggastestingbeforeentry,itisimportanttodeterminetheproperequipmentto be used. It is critical to know the limitations of these equipment types and that they areunderstoodbyallcompetentgastesters.Itisimportanttopre-inspecttheaccessoriestoensurethattheyareoftherightmaterialandarefunctioningproperly.
Itisalsoimportantthatthegastestersunderstandandtakeintoaccountthegeometryoftheconfinedspaceandthephysicalpropertiesofthegasestobemonitored.Thesegasescouldbefoundstratifiedatdifferentlevelsorlocationsoftheconfinedspace.(SeeFigure9.)
Figure 9: Test air at 3 or more elevations: top, mid-point and bottom.
Thegeneralruleofthumbforgastestingusingsamplinghoseforaverticalorhorizontalentryis10secondsforeachmetreofthesamplinghose.Alternatively,thefollowingcanbeusedtoworkoutthesamplingtimerequired:Factorstoconsider:
• SamplingDistance;
• Internal/ExternalPumpwCapacity;and
• Diameterofthesamplinghose.
Example:Samplinghoselength:30metres;PumpCapacity:0.5litres/min;HoseDiameter:0.6cm.
• Area=πr2
• Area=3.14x0.3x0.3=0.283cm2
• TotalVolume=3000x0.283=849cm3
• Samplingtime=849/500=1.7min(or102sec)
Ifthesamplingisdonemanuallybyusingarubberhandpump,itisimportanttoknowwhatairvolumeisdrawnperstroke.Typically,thevolumeis40cm3ormore.Whenusinglonghoses,itisimportanttoknowthenumberofpumpstrokesrequiredforthegastoreachtheinstrumentfromthepointofsampling.
Itisrecommendedtoobservetheresponsetimerequiredbythegasinstrumentandthetotalsamplingtimeinaccordancewiththesamplingdepth.Waituntilthereadingisstabilisedbeforerecordingthereadoutdisplayonthegasdetectorinstrument.
1.Lighterthanair(fore.g.,methane)
2.Sameasair(fore.g.,carbonmonoxide)
3.Heavierthanair(fore.g.,hydrogensulphide)
34 35
7.11.14 ContinuousMonitoringandFrequencyofTestsEvenwhentheconfinedspaceistestedandcertifiedsafeforanypersontoenter,atleastonepersoninagroupworkinginthesamevicinityshallbeequippedwithsuitableinstrumentformeasuringoxygen,combustibleandtheidentifiedtoxiccontaminants.
Figure 10: At least one person in a group working in the same vicinity of a confined space is equipped with a portable gas detector.
ItisimportantfortheCSSAtodeterminethefrequencyofthere-testingoftheatmosphere.
In addition to the continuous ventilation requirement, it is essential to conduct the periodicretesting,takingthefollowingfactorsintoconsideration:• Thepossibilityorlikelihoodofachangeinthespacebythepotentialreleaseofthehazardous
materials;• Whencontinuousoccupationexceeds6hours;• Whenaconfinedspaceisvacatedforasignificantperiodoftime≥30min,withoutthespace
beingmonitoredcontinuously;• Whentheatmospherichazardsinaconfinedspacearedetectedbytheconfinedspacesafety
assessorduringperiodictestingorcontinuousmonitoring,allpersonsintheconfinedspaceshallvacatetheconfinedspaceimmediately;
• Theconfinedspaceentrypermitshallbecancelledimmediatelyand“NoEntry”signsmustbeprominentlydisplayedattheentrancetopreventunauthorisedentry;
• An evaluation shall be made to determine how the hazardous atmosphere wasdeveloped;and
• Nopersonshallre-entertheconfinedspaceuntilithasbeenre-certifiedsafeforentryandanewconfinedspaceentrypermitisissued.
7.11.15 MaintenanceofEquipment(General)Itisimportantthatthegasmonitoringinstrumentusedfortestingtheconfinedspaceisingoodworkingcondition.Itisnecessarytoperformpropermaintenanceandcalibrationinaccordancewiththemanufacturer’sguidelines.Additionally,itisnecessarytokeepanequipmentlogbook/recordsoftheresultssuchascalibrationperformed,partsreplacement,andsoon.
All gas sensing devices will require routine calibrationand/orqualitativecheckstoensurethattheyareoperatingwithin the manufacturer’s specifications. Over time, thesensor signal may drift or decay resulting in inaccuratemeasurements.
Dueto itsoperatingprinciple, thecatalyst inthecatalyticsensor may lose its ability to bring about a combustionreaction,andcertainvapourssuchasH2S,leadedgasolineandsiliconesmaypoisonthecatalyst.Thesedecays,willnotbeknownunlessthesensorisexposedtothetestgas.
The accuracy of a gas detection instrument dependslargely on the accuracy of the test gas used for thecalibration. Therefore, it is essential to use only the testgas and calibration kit/equipment recommended by themanufacturer.
Figure 11: A poisoned catalyst sensor.
ItisimportanttoperformzeroadjustmentusingcleanairorN2firstbeforecalibratingthesensorwiththetestgas.Itisalsoimportantthatallgasdetectioninstrumentsareservicedbytrainedpersonnelonly.
7.11.15.1 CalibrationCalibrationistheadjustmentofthebaselineandsensitivityofthesensor/electronicscircuit,thatis,itisbasedonanexposuretoaknowngasinwhichthesensor/instrumentisadjustedtothatconcentration.
Calibrationsarerequiredonaperiodicbasis.Allsensorsregardlessoftheoperationalprinciple,willdriftoveraperiodoftimeandrequireadjustments.Sensorsmayalsoexperiencedriftafteranover-exposuretothetargetedgas,orafterexposuretoextremeenvironmentalconditions,afteraseverephysicaljolt,orifaFunctionTestproducesalessthansatisfactoryresult.Itisimportanttoobservetheresponsetimesofthesensors,thestabilityofthesensorsignal,andtherecoverytimesofthesensorsduringthisperiod.
Thecalibrationintervalforeachofthesesensorsfromthedifferentmakersoftheinstrumentsmay be different. It is advisable to refer to the manufacturer’s guidelines as indicated in theinstructionmanualfortheroutinetestandre-calibrationinterval.
7.11.15.2 CorrectionFactorMost gas testing instruments for flammable gases and vapours measuring up to the lowerexplosivelimitsareusuallycalibratedusingmethanegas.
Ifthisinstrumentisusedformeasuringflammablegasesandvapoursotherthanmethane,thesensitivityforthesegasesisdifferent.Thereadoutmaynotbetheactualreadingofthemeasuredgas.
Basedonthesensitivitychartprovidedbymostmanufacturers,iftheinstrumentiscalibratedtobutane,itwouldshowahigherreadingwhenthegastestinginstrumentisusedformethaneandhydrogenmeasurementandalowerreadingforhexane,ethylacetate,andsoon.
Poisonedsurface
Heatedplatinumcoil
36 37
Figure 12: An example of sensitivity chart.
Forconfinedspaceswithvariousflammablegasespresent,itisrecommendedthatthecalibrationbedoneusingthegasthatthesensoris leastsensitivetosoastohaveahighersafetyfactor.Whereapplicable,itisimportanttocalibrateusingatargetgas.
In the event where the target gas is not available for calibration, it is necessary to take thecorrection factor into consideration. For example, if the instrument is calibrated to methaneandthisisusedtomeasurebutane,itisimportanttousethecorrectionfactorprovidedbytheinstrumentmanufacturersothatthereadingiscorrected.
Thegivenvaluesaretypicalvaluesforcalibrationwithmethane(CH4)andareapplicabletonewsensorswithoutadditionalfiltermaterials.TheLELformethaneinthetableis5%byvol.
CalibrationGas
X-am3000,PacEx2 Methane Propane Pentane
Acetone 2.20 1.16 1.00
Ammonia 0.60 0.32 0.27
Benzene 2.50 1.32 1.14
Butadiene-1,3 2.00 1.05 0.91
n-Butane 2.00 1.05 0.91
n-Butylalcohol 4.50 2.37 2.05
2-Butanone 2.60 1.37 1.18
n-Butylacetate 3.90 2.05 1.77
Cyclohexane 2.50 1.32 1.14
Cyclopentane 2.50 1.32 1.14
Diethylether 2.30 1.21 1.05
Aceticacid 2.50 1.32 1.14
Ethane 1.40 0.74 0.64
Ethylalcohol 1.70 0.89 0.77
Ethene 1.50 0.79 0.68
Ethine 1.20 0.63 0.55
Ethylacetate 2.60 1.37 1.18
n-Heptane 3.00 1.58 1.36
n-Hexane 2.30 1.21 1.05
Carbonmonoxide 1.20 0.63 0.55
Methane 1.00 0.53 0.45
Methylalcohol 1.50 0.79 0.68
n-Nonane 4.00 2.11 1.82
n-Octane 2.90 1.53 1.32
n-Pentane 2.20 1.16 1.00
Propane 1.90 1.00 0.86
i-Propylalcohol 2.70 1.42 1.23
n-Propylalcohol 2.70 1.42 1.23
Propene 1.80 0.95 0.82
1,2-Propyleneoxide 2.10 1.11 0.95
Toluene 2.50 1.32 1.14
Hydrogen 1.20 0.63 0.55
o-Xylene 3.50 1.84 1.59
m-Xylene 3.50 1.84 1.59
p-Xylene 4.00 2.11 1.82
NoteAsthevalueofthecorrectionfactormayvaryslightlybetweenmeters,thementionedvaluesbelowareonlyexamples.Itisadvisablefortheusertocheckspecificallyfortheirequipment.
AppliedGasorVapourin%LEL
Inst
rum
entR
eadi
ngin
%L
EL
0
50
100
0 50 100
Toluene,Xylene,Nonane
Hexane,Ethylacetate
Propane,Butane,Acetone
LinearrespondMethane,Ammonia
38 39
• Afteranover-exposuretothetargetedgas;• Afterexposuretoextremeenvironmentalconditions (Examplesofextremeenvironmentalconditions,+55°Cinanengineroom,positively
pressuredatmosphereinanundergroundtunnel,wateringresswhenworkingoutdoors,indrains,sewers,etc.);
• Afteraseverephysicaljoltorwasdropped;• Whenchangingshift;or• Whenindoubt.
Thisfunctiontesttypicallytakeslessthanaminutetoperformanditisnotnecessarytomakeacalibrationadjustmentunlessreadingsareofffromtheexpectedvalue.
7.11.15.5 MethodsofFunctionTestingCalibrationorfunctiontestingcanbeperformedwiththefollowingaccessories:
• Aknowncalibrationgasthatcomesincompressedgascylinderswithtraceablestandardoranalysiscertificateswhichareavailableasasingleoramixtureofgas.Itisimportantthatexpiredcylindersshouldnotbeused;
• Aregulatortoreducethecylinderpressuretoaworkableflowofgas;or
• Aflexiblesamplelineandacalibrationadapterwhichfitsoverthesensorinlet.
CalibrationGas
X-am3000,PacEx2 Methane Propane Pentane
Acetone 2.20 1.16 1.00
Ammonia 0.60 0.32 0.27
Benzene 2.50 2.50 1.14
Butadiene-1,3 2.00 2.00 0.91
n-Butane 2.00 2.00 0.91
n-Butylalcohol 4.50 2.37 2.05
2-Butanone 2.60 1.37 1.18
n-Butylacetate 3.90 2.05 1.77
Cyclohexane 2.50 1.32 1.14
Cyclopentane 2.50 1.32 1.14
Diethylether 2.30 1.21 1.05
Aceticacid 2.50 1.32 1.14
Ethane 1.40 0.74 0.64
Ethylalcohol 1.70 0.89 0.77
Ethene 1.50 0.79 0.68
Ethine 1.20 0.63 0.55
Ethylacetate 2.60 1.37 1.18
n-Heptane 3.00 1.58 1.36
n-Hexane 2.30 1.21 1.05
Carbonmonoxide 1.20 0.63 0.55
Methane 1.00 0.53 0.45
Methylalcohol 1.50 0.79 0.68
n-Nonane 4.00 2.11 1.82
n-Octane 2.90 1.53 1.32
n-Pentane 2.20 1.16 1.00
Propane 1.90 1.00 0.86
i-Propylalcohol 2.70 1.42 1.23
n-Propylalcohol 2.70 1.42 1.23
Propene 1.80 0.95 0.82
1,2-Propyleneoxide 2.10 1.11 0.95
Toluene 2.50 1.32 1.14
Hydrogen 1.20 0.63 0.55
o-Xylene 3.50 1.84 1.59
m-Xylene 3.50 1.84 1.59
p-Xylene 4.00 2.11 1.82
Table 5: Example of correction factors using methane as a calibration gas.
Forexample:The instrument has been calibrated on methane and is now reading 10% LEL in a pentaneatmosphere.Tofindtheactual%LELpentane,multiplybythenumberfoundattheintersectionofthemethanecolumn(calibrationgas)andthepentanerow(gasbeingsampled),inthiscase,2.20.Therefore,theactual%LELpentaneis22.0%(10x2.20).
Note:Multiplieraccuracyis+/-30%,subjecttochangewithoutnoticependingadditionaltesting.Ifthesensorisusedinatmospherescontainingunknowncontaminants(silicones,sulfur,lead,orhalogencompoundvapors)methaneistherecommendedcalibrationgas.Periodiccomparisonofmethaneandpentanereadingsisrecommendedwhenusingthischart.
7.11.15.3 LimitationsThecombustiblegasdetectioninstrumentsusingcatalyticsensorareusuallynotdesignedtodetectthepresenceofcombustiblematerialssuchasfibreordusts.
Most of these combustible gas detection instruments are also not gas specific, that is, theyare broad range sensors that detect any gases or vapours that can be burnt in the reactionchamber.Ifthepresenceofothergasesinthespaceisdifferentfromthatwhichtheinstrumentiscalibratedto,itmayadverselyinfluencetheresultsofthegastesting.Undersuchconditions,itisrecommendedthatthecalibrationismadeusingthegasthatthesensorisleastsensitiveto.
Itisalsoimportanttonotethatsomecombustiblegasesandvapoursarealsotoxicinnatureandbyusinga%LELmeasuringinstrument,itmaynotbesufficienttodeterminethehealthhazardeffectsofthesesubstancesintheppmrange.
7.11.15.4 FunctionTestAfunctiontestisaqualitativeexposuretogastoverifythatthecalibrationisstillvalidandtheinstrumentisfunctioningproperly.
Afunctiontestisanexposuretoatestgasofknownconcentrationlongenoughtoensurethatthesensorisrespondingwithinthesensor’sresponsetimeandthatthedisplayiswithin10%ofthecalibrationgasconcentration.Itisalsoimportantforthealarmstobeactivatedatthepresetlevel.
Afunctiontestisrecommendedtobeperformedunderthefollowingconditions:• Beforeuseoftheinstrument;
If the instrument does not perform properly after the function test, it is advisable that thecalibrationisperformedbytrainedpersonnelorissenttomanufacturer.
Sequenceoffunctiontest:• Attachthecalibrationadaptertothegasdetectioninstrument;• Connectthehoseandthecalibrationgastothecalibrationadapter;• Switchonthegasdetectioninstrument(forinstrumentthatcomeswithfunctiontest
mode,pleasefollowtheproceduregivenbythemanufacturer);• Supplythecalibrationgasbyturningtheregulatorvalvemanually;• Checkthedisplayonthegasdetectioninstrument;
NoteMultiplieraccuracyis+/-30%,subjecttochangewithoutnoticependingadditionaltesting.Ifthesensorisusedinatmospherescontainingunknowncontaminants(silicones,sulfur,lead,orhalogencompoundvapours)methaneistherecommendedcalibrationgas.Periodiccomparisonofmethaneandpentanereadingsisrecommendedwhenusingthischart.
Figure 13: Example of “function test” system.
O209
OO
ExhaustgasCalibrationcradle Standardcylinderregulator
Openthecylinderbyturningtheknobontheregulatorthathasapre-adjustedflowofabout0.5L/min
40 41
7.12.1.1 PurgeTimeThe amount of time that is required to remove the contaminants is dependent on theconcentrationofthecontaminantsandthecapacityoftheairmovingdevicesused.Ifnofurthercontaminant release is expected (static condition), the following formula* can be used tocalculatetheamountoftimeneeded.
•
Where: T(min)isthetimerequired
Q(m3/min)isthequantityofthesuppliedpurgingmedium
V(m3)istheconfinedspacevolume
Co(ppm)istheinitialconcentrationofthecontaminants
C(ppm)isthefinalconcentrationofthecontaminantsafterTmins
* The above requirements assume an ideal mixing and distribution of supplied air. In practice, higher rate of ventilation may be necessary depending on the efficiency of supplied air distribution.
7.12.2 VentilationIt is unsafe to enter any confined space when adequate ventilation is absent. Adequate andeffectiveventilationisrequiredthroughoutthevalidityperiodoftheentrypermit.Evenwhentheconfinedspacehasbeencertifiedsafeforentry,newcontaminantsmaybeintroducedfromthechangeinconditions,orwhenworkperformedinthespacesuchasweldingreleasesnewcontaminants.
Assuch,itisimportanttoprovideanadequateandeffectiveventilationtoalwaysmaintainthecontaminantsconcentrationlevelaslowaspossible,andthelevelofoxygenwithinsaferange.
7.12.2.1 TypeofVentilationanditsUsesDuetotheuniquecharacteristicsofconfinedspaces,naturalventilationisusuallynotadequateand would require the use of mechanical ventilation. Mechanical ventilation can largely beclassifiedintotwomaintypes:• Forced(supplied)ventilation;and
• Localexhaustventilation(LEV).
• EnsurethattheaudibleandvisualA1/A2alarmareshown;• Checkthattheconcentrationmatchesthatofthetestgascalibrationgasbottle,indicating
theinstrumentisworkingproperly;and
• Turnofftheregulatorvalveandremovedevice.
If the sensor in the instrument does not perform properly after function test, it should becalibrated.
7.11.15.6 SamplingHosesThequalityandtypeofsamplinghosewillhaveagreatinfluenceonthemeasuringresults.Itisthereforeimportanttounderstandwhattypeofhoseistobeusedforwhatgases.Hosesthatarenotsolventresistantwillabsorbhydrocarbongasesandthismaycauseunderreporting.
ThehosematerialshouldpreferablybePTFE(Teflon)orViton.
There are exceptions when detecting gases such as HCN, CL2 and NO2. No hoses can berecommendedforthesegasesastheabsorptionofthehoseortheriskofcondensationofthevapourontheinnersurfaceofthehosewillgiveaninaccuratereading.
ForSO2,NH3andvapourofhydrocarbons,onlyVitonhoseuptoamaximumof5metrescanbeused.Thisappliestomostgasdetectioninstrumentsregardlessofthetypeofsamplingmethodsused(i.e.,internalelectricalpump,externalelectricalormanualhandpump.)
Theabsorptionandcondensationeffectsofgasesmentionedabovearebasedonphysicallaws.Itwillapplytomostapplicationswhensamplingthesegasesandvapoursbyusinghoseofanymaterial.The recommendation is to use instruments with peak holding modes or minimum/maximumvaluedisplayandlowertheentireinstrumentintotheconfinedspace.
Inaddition,ifthehosesarenotcleanedorpurgedwithfreshair,thismayresultinout-gassingthusgivingapluserrorinthenextgastest.Tocheckifthehosesareinfluencingthemeasurementresultseitherbyabsorbingorout-gassing,cleanairandacalibrationgasneedtobeused.
Itisalsorecommendedthataleakagetestbeperformedbeforeeverygastestingtoensurethatthereareno leakages fromthehose.Thiscanbedonebyblockingthe inletof thehose.Thealarmwillbesetoffifitisaninstrumentwithelectricalpump.Ontheotherhand,thepumpwillcollapseifitisamanualhandpump.
7.12 PurgingandVentilationWhenaconfinedspaceisknowntocontainhazardouscontaminants,itiscrucialtopurgethespaceadequatelybeforeanyentry.Subsequently,continuousventilationshouldbeprovidedtomaintainasafeworkenvironment.Itisalsoimportanttonotethatpurgingandventilationdonotexcludetheneedforgastesting.
7.12.1 PurgingPurgingofaconfinedspace isconductedbeforeanyentryandthepurpose istoremoveanyexistingcontaminantsbydisplacingthehazardousatmospherewithanothermediumsuchasair,water,steamorinertgases.Thechoiceofasuitablemediumwilldependonfactorssuchasnatureofthecontaminantsandtheirconcentrations.
InertingInertingisaformofpurgingwhichinvolvesremovingoxygenfromtheconfinedspacebydisplacingitwithinertgasessuchasnitrogen(N2)andcarbondioxide(CO2).Inertingiscommonlyusedtoremovethepotentialhazardsoffireandexplosionbyreducingoxygentoaconcentrationthatisbelowthelevelthatcansupportcombustion.Wheninerting,caremustbetakentoensurethatfollowingthepurgingofthecontaminantswithinertgases,thespacemustbeventilatedwithfreshairtorestoretheatmospheretonormalatmosphericcondition.Also,whenpurgingflammablesubstances,theequipmentusedsuchasnozzlesandpipesmustbebondedtothespacetopreventthebuildupofstaticchargeswhichcancauseignition.
V T
Co C
Q= Ln=
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confined space from a contaminant-free source. Forexample,itisnotappropriatetoplacetheairmovingdevicebehind a diesel generator where the exhaust gas of thegeneratorcouldbedrawnintotheconfinedspace.
For a continuous release of contaminant into a confinedspace,theforcedventilationQ(m3/min)requiredtodilutethecontaminant(molecularweightMW)whichisgeneratedataconstantrateofE(gm/min),toapermissibleexposureconcentrationofC(ppm)at250Cand760mmHgis:
•
Factorstoconsiderindeterminingthetypeofventilationtouseinclude:
• Thenatureofcontaminants;
• Theconfigurationofthespace;and
• Theexpectedworktobeperformedintheconfinedspace.
7.12.2.1.1 Forced(Supplied)VentilationForcedorsuppliedventilationintroducesfreshair intotheconfinedspacethroughtheuseofamechanicalairmovingdevicessuchasablower.Theconstantsupplyoffreshairinsufficientquantitywillhelptomaintainthelevelofoxygeninthespacewithinthesaferange,aswellasdilutethelevelofcontaminantsreleasedintheconfinedspacetoanacceptable level.Forcedventilationusedtodilutecontaminantsisusuallymoresuitablewhen:
• Thecontaminants releasedareof relatively lowtoxicity (asageneralguide,contaminantswithPELofequalorhigherthan500ppmisdeemedtobeslightlytoxic);
• Therateofemissionorreleaseisrelativelyconstantandisofsmallquantities;
• Contaminantsaregasesorvapoursorfinelysuspendedsolids;
• Thereleaseofthecontaminantsiswidespread;or
• Thereissufficientdistancebetweentheworkerandthesourceandalloweffectivedilutiontotakeplace.
It is important toensure that theairmovingdevice isplacedwhere theair isdrawn into the
Figure 14: Example of forced ventilation using blower as a mechanical air moving device.
VentilatingConfinedSpacesRichwithFlammableGases/VapoursIn some instances, ventilating confined spaces that are filled with flammable gases/vapours can be dangerous, especially if the original concentration of the flammablecontaminantwasabovetheUpperExplosiveLimit(UEL)range.Byventilatingwithfreshair,itwill“leanout”theconcentrationofthecontaminantandlowerittobelowtheUELandwithintheexplosionrange.Thiswouldmakeignitionforfireandexplosionpossible.Insuchcases,theuseofexhaustventilationordilutionventilationusinginertmediumsuchasnitrogen(N2)shouldbeconsidered.
7.12.2.1.2 LocalExhaustVentilation(LEV)Exhaust ventilation is achieved by pulling air out ofthe confined space and in the process, removing thecontaminants from inside the space. LEV is a specificapplication of exhaust ventilation where the extractionis applied directly at the contaminant source. The useof LEV should be considered when dilution ventilationis not effective due to restrictions in the confined spaceor when high local concentrations of contaminants mayoccurduringworkactivitiessuchasweldingandchemicalcleaning.Ingeneral,LEVissuitablewhen:
• Thereleasedcontaminantsareofrelativelymoderatetohightoxicity(asageneralguide,contaminantswithPELof lower than 500 ppm is deemed to be moderate tohightoxicity);
• Therateofemissionorreleaseisoflargequantity;
• Thecontaminantsarefumesorsolidsthataredifficulttoremovebydilutionventilation;
• Thereleaseofthecontaminantsislocalised;and
• There is insufficientdistancebetweentheworkerandthesourcetoalloweffectivedilutiontotakeplace.
ForLEVtobeeffective,itiscrucialtoplacetheexhausthood
Figure 15: Example of local exhaust ventilation.
closetothecontaminants’source.Itisimportantthattheexhaustedairisdischargedoutsidetheconfinedspacetoavoidre-introductionintothespace.Inaddition,itisalsoimportantthatthefancapacityisadequatetopullthecontaminantsintotheexhausthood,movethemalongtheductanddischargeintotheatmosphereoutsidethespace.
AsLEVremovesairfromtheconfinedspace,itcreatesaslightnegativelypressuredenvironmentin the space.Therefore, it is important that replacement air is provided in the form of supplyventilation.
Where: E(gm/min)istherateofcontaminantgeneration
MWisthemolecularweightofcontaminant
Q(m3/min)isthequantityoftheairsupplied
C(ppm)isthePELofcontaminant
Ex24.5x106
MWxCQ =
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7.12.2.1.3 Push-pullSystemA push-pull system uses a combination of both forced ventilation and exhaust ventilation. Itusuallyprovidesmoreeffectiveventilationofthespacethanusinganyoftheventilationsystemalone,andisrecommendedforusewheneverpracticable.Thepush-pullsystemintroducesfreshairintothespacewhileremovingcontaminantsbyexhaustingthem.
Figure 16: Example of a push-pull system.
Forceventilation
Exhaustventilation
7.12.2.2.1 AirMovingDevicesTherearetypicallythreetypesofairmovingdevicesthatareusedinthemechanicalventilationofconfinedspaces.Theseare:
Figure 17: Example of axial-flow fan.
Axial-flowFansAxial-flowfansaredesignedtomoveairparalleltotheaxisofrotationoftheblades.Theoperatingprincipleissimilartothatofstandingfansusedathome.Axial-flowfanscanbeusedforbothforcedorexhaustventilationandaremosteffective for moving high volumes of air under relativelylowairflowresistance,suchaswhenminimalornotubingis attached. However, care is necessary when flammablegases/vapoursarepresentasthefanmotorisinthedirectpath of the airflow and can act as an ignition source. It isimportant to consider using an explosion-proofed fan forsuchanapplication.
Centrifugal-flowFansCentrifugal-flow fans, or radial-flow fans, move airperpendicular to the axis of rotation of the blades.Centrifugal-flow fans tend to be heavier, bulkier andgenerallyproducedlowerairflowbuthigherstaticpressureascomparedtoaxial-flowfans.Thisabilitytogeneratehighstatic pressure is important in application such as in LEVespeciallywherelongrunsofductingmaybeused.
VenturiEductorVenturieductorsarepoweredbycompressedairorsteam.The air or steam is released into the eductor through anozzle at high velocity and this, in turn, induces air intotheinletandforcesitalongthetubefordischargeathighvelocity. Eductors are usually lighter, more compact andlessexpensivebuttheyarenotabletomovelargevolumesof air and require a significant supply of compressed airor steam to operate. In addition, the high velocity airmovement may also generate static electricity that couldserveasanignitionsource.
Figure 18: Example of centrifugal-flow fan.
Figure 19: Example of venturi eductor.
Figure 20: Example of flexible non-collapsible ducting.
7.12.2.3 DuctingDuctingisusedwidelyandextensivelytochannelairtoandfromconfinedspaces.Therearetwomaintypesofductingcommonlyused:• Flexiblecollapsibleducting;and• Flexiblenon-collapsibleducting.
It isimportantthattheductinglengthbeasshortaspossibleandthatthenumberofelbowsorbendsintheductarekepttoaminimumtoreducefrictionloss.Frictionlosswillreducetheefficiencyoftheventilationandcouldpotentiallyresultinlowerthanthedesigned/calculatedcapacity.
7.12.2.3.1 FlexibleCollapsibleDuctingFlexiblecollapsibleducting,suchasplasticmaterialtubingiscommonlyused.Suchductinglacksstructuralsupportandcanonlybeusedforforcedventilation.Whiletheyusuallycostlessandaremoreflexible,thelackofstructuralsupportcanoftenresultinlesseffectiveventilationduetoincreasedstaticpressuredropacrosstheducting.
Particular care is required when using plastic material tubings as they are more susceptibletowearandtearduringuse. It isalsoimportanttonotethatsuchplasticmaterialtubingsarecombustible. When they catch fire, smoke/toxic gas will be emitted and travel back to theconfinedspace.
7.12.2.3.2 FlexibleNon-collapsibleDuctingAnothertypeofductingused is theflexiblenon-collapsibleducting. It usually has a wire helix that provides the shapeandpreventscollapse.Suchductingoffersstrength,flexibilityand can be compacted for storage. Flexible non-collapsibleductingcanbeusedforbothforcedandexhaustventilation.
7.12.2.4 EffectiveVentilationAnother key component of ventilation in the confinedspaceistoensurethattheventilationsystemsinplaceareeffective.Asageneralprinciple,ventilationsystemsshouldbesetupwiththefollowingconsiderations:
• Longconfinedspace;
• Deepconfinedspace;
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• Preventshort-circuiting;
• Preventre-circulationofexhaustair;
• Removelighter-than-aircontaminants;or
• Removeheavier-than-aircontaminants.
7.12.2.4.1 LongConfinedSpaceForalongconfinedspace,freshairisblowninatoneendofthespaceandthecontaminatedairisbeingexhaustedattheotherend.Ifnecessary,useaseriesoffans(donotconnectthem)tomoveairthroughlongdistances.
Figure 21: An example of providing effective ventilation system by using a series of fans to move air through a long confined space.
7.12.2.4.3 PreventShort-circuitingTopreventshort-circuitinginaconfinedspacethathasonlyoneopening,useapowerfulblowertoblowcleanairintotheentirespaceoralongductingtoreachthebottomofthespace.
Figure 22: An example of providing effective ventilation system by blowing fresh air at the bottom of a deep confined space.
Figure 23: An example of preventing short-circuiting in a confined space.
7.12.2.4.4 PreventRe-circulationofExhaustAirTopreventre-circulationofexhaustairinaconfinedspace,positiontheairintakeawayfromanycontaminatedsource.Thisincludesfacingawayfromtheopeningofaconfinedspace.
7.12.2.4.2 DeepConfinedSpaceForadeepconfinedspace,thefreshairisblownintothebottom,andthecontaminatedairisbeingexhaustednearthetop.
Figure 24: An example of preventing re-circulating of exhaust air in a confined space.
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7.12.2.4.5 RemoveLighter-than-airContaminantsToremovelighter-than-aircontaminantsfromaconfinedspacethathastwoopeningsatthetopofthespace,useablowerandductworktointroducefreshairtothebottomofthespace.Placeanexhaustfanattheotheropeningtodrawthecontaminatedairfromthetop.
Beforeanyoneisauthorisedtoenteraconfinedspace, it iscrucialtohavetrainedemergencyrescuepersonnelavailablewhenanentrantneeds help. It is important for suchpersonnel toreachthesitepromptlyandknowhowtodealwiththeemergency.
Inanyunplannedrescue,suchaswhensomeoneinstinctivelyrushes intohelpadownedco-worker,itcaneasilyresultinadoublefatalityorevenmultiplefatalitiesiftherearemorethanonewould-berescuers.
REMEMBER:AnunplannedrescuewillprobablybeyourLAST.
It is“A MUST” to have a written and established rescue operation plan on-site that includesequipment,suchasretrievaldevices,breathingandresuscitatingapparatus,readyforemergencyuse immediately.Theseverityofaccidentscanbereducedwithtimelyalerts fromattendantsoutsidetheconfinedspace.Awell-trainedandfullyequippedrescueteamcanensureaspeedyresponseinanemergency.
8.1 EstablishmentofRescueOperationPlansAwrittenrescueoperationplanshallbeestablished for thepurposeof rescuingpersons inaconfinedspace.Therescueoperationplanshall:• Havenamesofthedesignatedrescuepersonnelavailable;• Indicatethemethodsofrescuetoretrievepersonsinsideaconfinedspace;• Prescribethetypesandavailabilityofequipmentnecessaryforrescue;and• Provideaneffectivemeanstosummonthedesignatedrescuepersonnelinatimelymanner.
8.2 RescueArrangementsTheriskassessmentwilldeterminewhatrescuearrangementsarenecessary.Thearrangementswilldependonthenatureoftheconfinedspace,therisksidentifiedandthetypesofemergencysituationswhichareforeseeable.Itisimportanttonotethepossibleemergenciesintheconfinedspace,andanyotherforeseeableaccidentforarescueoperation.Forexample,theincapacitationofaperson,whollyorpartially,followingafallinsideaconfinedspace.
Possibleconfinedspacerescuestrategiesincludethefollowing:
• Self-rescue when the circumstances, the nature of the hazards and the control measuresavailableallow;
• Rescuebyteammembers(trainedrescuepersonnel)usingnon-entrymethodsiffeasible;
• Rescuebyteammembers(trainedrescuepersonnel)usingasafeentrytechnique;and
• Rescue using a safe entry technique by the local public emergency services subject toadequatetimebeingavailable(thisdependsonthenatureofthehazardsandtheresponsetimeoftheemergencyservices).
8.EmergencyAndRescueProcedures
Figure 25: An example of providing effective ventilation system on how to remove lighter-than-air contaminants.
7.12.2.4.6 RemoveHeavier-than-airContaminantsToremoveheavier-than-aircontaminantsfromaconfinedspacethathastwoopeningsatthetopofthespace,useanexhaustfanandductworktocapturethelow-lyingcontaminants.Placeablowerattheotheropeningtoprovidefreshairtothespace.
Figure 26: An example of providing effective ventilation system on how to remove heavier-than-air contaminants.
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The risk assessment shall determine the combination of confined space rescue strategiesappropriatefortheparticularsituation.
Itisimportantforsuitableandsufficientemergencyarrangementstotakeaccountof:
• Rescueconsiderations;
• Rescuelogistics;
• Trainingofrescuepersonnel;
• Provisionofrescueequipment;and
• Provisionofsafetydatasheet.
8.3 RescueConsiderationsItisadvisabletoalwaysconsideraconfinedspaceasimmediatelydangeroustolifeandhealth(IDLH)unlessprovenotherwise.Planandprepareemergencyresponseandrescueproceduresforallconfinedspaceentrywork.Theseproceduresmustbeinplacebeforeanyworkcommences.Itisimportanttonotethataveryshortperiod,approximatelyfourminutes,withoutadequatebreathingcancauseaworkertosufferpermanentbraindamageduetolackofoxygen.
8.3.1CharacteristicsWhenDecidingtheAppropriateRescuePlanIt is importanttoconsiderthefollowingcharacteristicswhendecidingtheappropriaterescueplanforaconfinedspaceentrywork:
InternalConfigurationi. Open—therearenoobstacles,barriers,orobstructionswithinthespace.Oneexampleisa
watertank.
ii. Obstruction—thespacecontainssometypeofobstructionthatarescuerwouldneedtomanoeuvre. For example, a baffle or mixing blade. Large equipment, such as a ladder orscaffold,broughtintothespaceforworkpurposeswouldbeconsideredanobstructionifthepositioningorsizeoftheequipmentwouldmakerescuemoredifficult.
Elevationi. Elevated—apermitspacewheretheentranceoropeningisabovegroundby4feetormore.
Thistypeofspaceusuallyrequiresknowledgeofhighanglerescueproceduresbecauseofthedifficultyinpackagingandtransportingavictimtothegroundfromthespace.
ii. Non-elevated—apermitspacewiththeentrancelocatedlessthan4feetaboveground.Thistypeofspacewillallowtherescueteamtotransportaninjuredworkernormally.
PortalSizei. Restricted—Aportalof24inchesorlessinthesmallestdimension.Portalsofthissizearetoo
smalltoallowarescuertosimplyenterthespacewhileusingSCBA.Theportalsizeisalsotoosmalltoallownormalspinalimmobilisationofaninjuredworker.
ii. Unrestricted—Aportalofgreaterthan24inchesinthesmallestdimension.Theseportalsallowrelativelyfreemovementintoandoutofthepermitspace.
SpaceAccessi. Horizontal—Theportalislocatedonthesideofthepermitspace.Useofretrievallinescould
bedifficult.
ii. Vertical—Theportalislocatedonthetoporbottomofthepermitspace.Rescuersmustclimbdownorupthepermitspacerespectivelytoenterit.Verticalportalsmayrequireknowledgeofropetechniques,orspecialpatientpackagingtosafelyretrieveadownedentrant.
For confined space entry, it is important for the authorised manager to designate a standbyworker;oneormoreworkerswhoaretrainedinindustrialfirstaid,andalsotrainedinconfinedspaceemergencyandrescueprocedures.Itisnecessarythatthedesignatedstandbyworkerbepresentandremainattheentrancetotheconfinedspaceatalltimeswhilehisco-workerisintheconfinedspace.
Theauthorisedmanagershallensurethatopeningsforentryandexittoaconfinedspaceareofadequatesizetopermitrescueofallpersonswhomayenteraconfinedspace.Theopeningsarenotobstructedbyfittingsorequipmentwhichcouldimpederescue.Itisimportantthatrescuersbetrainedinandfollowestablishedemergencyproceduresanduseappropriateequipmentandtechniques(suchaslifelines,respiratoryprotection,andstandbyperson).
8.3.2 ConductingofDrillsIt is important that all parties involved in a potential rescue operation understand and agreeon the emergency and evacuation procedures. It is necessary to include all steps for saferescueintheconfinedspaceentryprocedures.Itisalsocriticalforarescuetobewellplannedand evidence to be made available that indicates drills have been frequently conducted onemergencyprocedures.A rescue drill inaconfinedspace shallbe heldat leastonce inevery12months.Therecordofsuchadrillshouldbekeptandshouldincludethetime,dateofdrill,personnelinvolved,ashortdescriptionofthedrillandtheevaluationofthedrill.
Itisalsoimportanttonotethatworkerswhoarenottrainedinproperrescueproceduresshouldnotundertakeorbepermittedtoundertakerescueoperations.
8.4 RescueLogisticsItisimportanttogivecarefulconsiderationonthemeansofraisingthealarmandcarryingoutarescue.Thisemergencyplanneedstobesuitableandsufficientforallanticipatedaccidents.
Itisnecessarytoputinplacemeasuresthatenablethoseintheconfinedspacetocommunicatetoothersoutsidethespacewhocaninitiaterescueproceduresorsummonhelpinanemergency.Theemergencycanbecommunicatedinanumberofways,forexample,bythetugofarope,byradioorbymeansofa“loneworker”alarm.Whateverthesystem,itshouldbereliableandtestedfrequently.Dependingontheriskassessment,itmaybenecessarytohaveoneormorestandbypersonslocatedoutsidetheconfinedspacewhosefunctionistokeepthoseinsideinconstantdirectcontactincludingvisualwherefeasible,incaseofanemergency.
It is also important to give careful consideration on the selection of an appropriate confinedspacerescuestrategy.Retrievalusingnon-entrymethodsispreferabletorescuebyentryandshouldbeusedwherepracticable.
Whereentry isnecessary, it is importanttoensuretherescuersareprotectedfromtheriskofinjuryandtoaddressanyemergencysituation.
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It is critical to consider the necessary precautions to protect the rescuers during the riskassessment,andmakeadequateprovisionswhenpreparingtheemergencyplan.
Themethodofretrievingacasualtyfromaconfinedspaceneedstobecarefullyplanned.Liftingequipment will often be needed in combination with a safety harness and line, as even thestrongestpersonisunlikelytobeabletoliftorhandleanunconsciouspersononhisownusingonlyarope.Itiscriticaltoproperlyadjustthelineandtheharnesswornsothatthewearercanbesafelydrawnthroughanymanholeoropening.
TheuseofBAwilloftenbeconsideredasameansofprotectingtherescuersfromthecauseoftheemergency.BAmayeitherbeoftheself-containedorair line-fedtypes. Inthecaseofthelatter,asuitablesupplyofbreathingairqualityisessentialandthelengthoftheairlineneedstobetakenintoaccount.TheuseofRPEofthecanisterrespiratororcartridgetypeisnotacceptableforusebyrescuers.
The number, size and location of access/egress openings will have an important bearing onthechoiceofrescuemethodsandequipment.Itwilloftenbenecessarytocheckthatapersonwearing suitable equipment can safely and readily pass through such openings. In case ofrestrictedopenings,airline-fedbreathingapparatusoffersamorecompactalternative.
Itmaybeappropriatefortheoccupantsofaconfinedspacetouseequipmentknownas“escapebreathingapparatus”or“self-rescue”devices insituationswheretherewillbetimetoreact toananticipatedemergency.Forexample,smoke logging intunnelsorreactingtoatmosphericmonitoringdevices.Thesedevicesareintendedtoallowtheusertimetoexitthehazardarea.Theyaregenerallycarriedbytheuserorthosestationedinsidetheconfinedspace,butarenotuseduntilneeded.Theyaredesignatedtooperateforonlyashortdurationbuttheyaresufficienttoallowtheusertomovetoasaferplace.Itisimportanttohaveitattheareawheresuchhazardsareexpectedinanemergency.
Itiscriticaltomakearrangements(includingmeansofcommunications)tosummonthelocalpublicemergencyservices(e.g.,localfireorambulanceservice)withoutdelaywhenanaccidentoccurs.Thiswillhelptoprovidethemwithallknowninformationabouttheconditionsandrisksofenteringtheconfinedspaceuponarrival.
Relianceonthelocalpublicemergencyservicestocarryoutrescueisnotacceptableiftheriskassessmentdeterminesthatatimelyrescueisnecessary.Forexample,ifresuscitationislikelytobenecessaryasaconsequenceofanincident(e.g.,theexposureofaconfinedspaceoccupantto a severe oxygen-deficientatmosphere), itgenerally beginswithin 4minutesof thepersoncollapsing. It is important that emergency planners be mindful of these considerations whendevisingtherescuestrategy.
Where there are a number of entrants into a confined space, it is important to establish themethodofcarryingoutafull-scaleevacuation.Measurestopreventopeningsfrombecomingbottleneckswouldbenecessary.
Itisimportanttoensurethelightingconditionintheconfinedspaceisadequatetofacilitateasuccessfulrescue.Obstructionsintheconfinedspaceandthepresenceoffogormistduetohighhumiditymayleadtopoorvisibility.Iftheexistenceofaflammableatmosphereispossible,anylighting,includinghand-heldtorches,willhavetobeintrinsicallysafe.
8.5 TrainingofRescuePersonnelIt is importantforanypersonappointedtocarryoutanyemergencyarrangementstoreceiveappropriateinstructionandtrainingtoenablehimtoperformthatroleeffectively.Suchtrainingincludesfirstaid,CPR,theproperuseofPPEandotherequipmentnecessaryforcarryingouttherescueoperationandasanauthorisedentrant.Theleveloftrainingwillvaryaccordingtothecomplexityandskillcontentoftherole.Itisnecessarytoconductrefreshertrainingasoftenaspossibletomaintainanacceptablelevelofcompetence.
Familiaritywithproceduresandequipmentisessential.Itcanbedevelopedandfine-tunedbyfrequentdrillsandrealisticsimulation.
Allrescuepersonnelneedtounderstandthelikelycausesofanemergency.Theywillneedtobe familiar with the rescue plan and procedures developed for each type of confined spacethattheymayencounter.Theyneedtobeabletorapidlysize-upanemergencysituationandevaluatetheirabilitytoconductasaferescue.Thesefactorsneedtobegivenconsiderationinthedevelopmentofatrainingprogramme.Itisimportanttodesignthetraininginsuchawaythatrescuersarecapabletoperformrescuesinasafeandtimelymanner.
Rescuers need to be fully familiar with the equipment for use in rescue, communications ormedicalpurposesandoperation.Theywouldneedtocheckthattheequipmentisfunctioningwellbeforeuse.Itisimportantforpotentialusersofbreathingapparatustoreceiveappropriateformaltraining.Itiscriticalfortrainedpersonstocarryouttheresuscitationproceduresefficiently.Designatedfirst-aidersneedappropriatecurrentcertification.
It is necessary to evaluate the capability of rescuers and others involved in the emergencyarrangementusingobjectivecriteria.Itisimportantfortrainersandinstructorstobeappropriatelyqualifiedandexperiencedtocarryouttheirroleseffectively.
8.6 ProvisionofRescueEquipmentSuitableandsufficientrescueequipmentisneededtorespondtoanemergencyinatimelyandsafemanner.Itisimportanttolisttheappropriateequipmentforthelikelytypeofemergenciesintheriskassessment.Itiscrucialtomaintaintherescueequipmentproperlyandmakethemreadilyavailablewheneverandwhereverconfinedspaceworkisundertaken.
Forexample,rescueequipmentmayinclude:
• Fullbodyharnesswithretrievallineattached;
• Hand-cranked mechanical winch and tripod (required when entrant is five feet or morebelowtheentrance);
• Ladder;
• Explosion-prooflighting;
• Breathingapparatus;
• Stretcher;
• Approvedheadprotection;and
• Resuscitatingapparatus.
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RescueequipmentwilloftenincludeSCBA.Itsdurationinuseisgovernedbythesizeandnumberofcylindersanditstype(open-orclose-circuit).
8.6.1 SuppliedAir-breathingApparatusIfthehazard/riskassessmentrecognisesaneedforabreathingapparatus,(e.g.,theconcentrationofanairbornesubstancemeetsorexceedstheoccupationalexposurelimit),onlytwotypesmaybeusedinconfinedspaces(See7.11.9).Botharesupplied-airpressure;demandtypeswhichareSCBAandairlinerespirators.
Theairlinerespiratorisavariationoftheself-containedbreathingapparatuswhereitreplacestheback-mountedtankandprovidesasourceofbreathingair.Herearesomepointerstonotewhenselectingairlinerespirators:
• Itislightertowearbutthelengthofthehosewilllimittheuser’smovement.
• Itisimportanttohaveanescapebottletoprovideanemergencysupplyofair.
• Itiscriticaltouseanapprovedcompressor.
It isessentialto includecontinuousexplosiveatmosphericmonitoringforentry intoconfinedspacesusingBA.ItiscriticalforthesuppliedbreathingairtomeetthepurityrequirementsthatarementionedinthemostrecenteditionofSS548:2009CodeofPracticeforSelection,Use,CareandMaintenanceofRespiratoryProtectiveDevices.
8.6.2 FullBodyHarnesswithLifelineIt is important for the worker entering the confined space to wear an acceptable full bodyharnessattachedtoalifeline.Thelifelineitselfisattachedtoapersonalhoistingdevicethatwillfacilitaterescuethroughanarrowopening.Thelifelinecablediametermustbeaminimumof3/16inch(or4.7mm)wireropeorotheracceptablerigging,capableofa10to1safetyfactor.Wheretheuseofafullbodyharnessandlifelinewouldcreateanadditionalhazardorwouldnotbereasonablypracticable,itwouldbeimportanttohaveanalternativesafemethodofaccessandegress.
8.6.3 Hoist/RetrievalSystemItisessentialtohaveaproperretrievalsystemforbothworkersandequipmenttofacilitateentryintoandexitfromaconfinedspace.Proprietarysystemsareavailableconsistingofaheavy-dutylifeline,tripodandpersonnelwinch.Typically,awinchhasamechanicaladvantageofbetween2:1 and 6:1, which makes it possible for a worker to be quickly extracted from the confinedspace should the need arise. It is critical to ensure that all hoisting components are capableofsupportingaworkerwitha4-to-1safety factor. It is important toensure thatallhoistsareequippedwithanadequatebrakemechanism.Thiswouldallowforimmediatefallarrestandtheimmediateretrievaloftheworkeratalltimesthroughthehoistingmechanism.Aretrievalsystemcapableofremovingaworkerwithin2.5minutesorlessisnecessary.Useshop-fabricatedhoiststhatareapprovedbyanengineerandcheckallequipmentcarefullybeforeuse.Itisessentialnottouseharnessesorretrievallinesshowingsignsofwear.
8.6.4 ResuscitatingEquipmentIt isessentialtomakeearlyarrangementsifresuscitationisnecessaryfromanaccident.Thesearrangementswill includetrainingofpotentialrescuersinresuscitationtechniquesandintheuse of any resuscitation or ancillary equipment. It is important to seek appropriate medical
advicebeforeanysystemisinplaceforprovidingresuscitation.Atthesametime,alsotakeintoconsiderationthelevelofavailableexpertise.
Ancillarydevicesmaybeneededfororalresuscitation:theseavoiddirectcontactbetweenthemouthsofthevictimandrescuer,forexample,byusingspecialtubesandmouthpieces.However,ifresuscitationisneededasaresultofexposuretotoxicgases,oralmethodsarenotappropriatesincetheycouldputtherescueratrisk.Insomecases,equipmentforartificialrespirationasafollow-upto,or inplaceof,oralresuscitationisappropriate. It is importantfortheequipmenttobeoperatedbysomeonewiththenecessaryspecialist training,or itcanbekeptavailable,properlymaintained,onsiteforusebyapersonprovidingprofessionalmedicalhelp.
8.6.5 PersonalProtectiveEquipment(PPE)It is essential to conduct a proper assessment of conditions and identify work processes thatrequireadditionalprotectiveequipmentforthetasktobeundertaken.Forexample,thepossibilityofpersonalexposuretotoxicsubstancesandtraumaticinjuryrequirestheconsiderationoffullbodyprotection.
Itisnecessarytoprovideappropriatefirstaidequipmentandmakeavailableforemergencies.Itisimportanttohavefirst-aiderstrainedtodealwiththeforeseeableinjuries.
Itisessentialtomaintainandinspectallequipmentprovidedforanemergency.Inspectionalsoincludes periodic examinations and tests according to the manufacturer’s instructions or theappropriaterequirementsofhealthandsafetylegislation.
Theexaminationofropes,harnesses,lifelines,protectiveclothing,andotherspecialequipmentwill normally consist of a thorough visual examination of all their parts for deterioration ordamage,inparticular,onthosepartsthatareload-bearing.Itisnecessaryfortheexaminationstobecarriedoutregularlyandarecordkeptofthem.
It is necessary to acquire certificates of test and safe working loads when purchasing liftingequipment,suchasropes,harnesses,lifelines,shackles,andsoon.Itisimportanttoensurethattheyarenotfurthertested(asthiscouldweakenthem).Itisnecessarytoscrapordisposetheequipmentiftheyaredamaged.Otherwise,returnthemtothemanufacturerorothercompetentrepairerswhocancarryoutthenecessaryremedialworkandsupplyanewcertificationoftestandsafeworkingloadfortherepairedequipment.
Communication equipment can facilitate a confined space rescue by saving time in relayinginstructions and medical information. Reliable communication can have a calming effect onrescuers,leadingtoamoreefficientoperation.
8.6.6 AvailabilityandMaintenanceAsaguide,thefollowingrecommendationsaregoodpractices:
• Equipmentplacedon-sitelocationsshouldbecheckeddaily;
• Equipmentbasedinthelocationshouldbecheckedonaweeklybasis;and
• Equipmentlocatedinstoragelocationsshouldbecheckedmonthly.
56 57
It is necessary to complete a maintenance/audit survey form while conducting maintenancechecks.Itisimportantfortheformtocoverthefollowing:
• Dateofinspection;
• Nameofpersonconductinginspection;
• Location;
• Inspectionfrequency;
• Type;
• Condition;
• Remedialactionrequired;and
• Furtheractionrequired.
Itisthedutyofthecompetentpersontoexerciseallduediligenceduringsuchchecks.
8.7 ProvisionofSafetyDataSheet(SDS)TheSDSandotherrelatedinformationofahazardoussubstanceshallbemadeavailabletothemedicalfacilitytreatingtheinjuredasaresultofexposuretohazardoussubstancesfoundinaconfinedspace.
It is essential to provide training to all personnel involved in confined space entry or work.Thisistoensurethattheyunderstandthehazardsassociatedwithconfinedspacework,entryprocedures,measurestopreventandcontrolhazards,safetyprecautionstotake,andemergencyprocedures.
9.1 PersonneltobeTrainedIt is necessary to provide training to all personnel who are directly or indirectly involved inconfinedspaceentryorwork.These includeconfinedspaceentrants,attendants,supervisors,rescuepersonnel,safetyassessorsandauthorisedmanagers.Itisimportanttohavethetrainingthat is consistent with their duties and responsibility. In practice, some of the duties can beperformedbythesameperson.Itisimportantthattrainingisconductedbyacompetenttrainer.
EntrantApersonrequiredtoenterconfinedspacestocarryoutinspectionsorwork.Heisrequiredtofollowentryandworkprocedureswhencarryingoutwork inconfinedspaces. It is importantforthepersontounderstandthefunctionsofportablegas/vapourmeasuringinstrumentsusedfor continuous monitoring of the atmosphere in the confined space, and evacuate from theconfinedspacewhentheinstrument’salarmisactivated.
ConfinedSpaceAttendantApersonappointedtomonitorentrantsenteringandworkinginaconfinedspace.Itisimportantforhimtomaintainregularvisualand/orverbalcontactwiththeentrantsintheconfinedspaceandinformthemtoevacuatethespaceshouldtheneedarise.Inanemergency,heshallalerttherescuepersonneltoactivatetherescueoperation.
SupervisorApersonwhooverseesentryandworkinconfinedspaces.Hehastoapplyfortheentrypermitandensurethattheissuedentrypermitisdisplayedprominentlyattheentrancetotheconfinedspace prior to work and to remove it upon termination of the permit. He is responsible forensuring that entrants and standby attendants adhere to entry procedures, and that rescueequipmentandappointed rescue personnelare availablewhenconfined space work is to becarriedout. It isessential forhimtobriefallentrantsontheworktobeperformedinsidetheconfinedspacebeforeheallowsthemtoentertheconfinedspace.
RescuePersonnelPersonswhocarryoutanyrescueworkinconfinedspaces.
ConfinedSpaceSafetyAssessorAcompetentpersonappointedtotesttheatmosphereofconfinedspacesbeforeentry,andtoconductperiodictesting.Whenahazardousatmosphereisdetectedduringperiodictesting,heistoalertentrantsinsidetheconfinedspacetovacatethespaceimmediately.
9. TrainingforPersonnelInvolvedinConfinedSpaceEntryandWork
58 59
KeyElementsofTraining
Entr
ant
Confi
ned
Spac
eA
tten
dant
CSSA
Resc
ue
Pers
onne
l
Supe
rvis
or
Aut
hori
sed
Man
ager
Legislationrequirementsonconfinedspacework(ToincluderequirementsonconfinedspaceworkundertheWSHActanditssubsidiarylegislation,whichisrelevanttotrainees’industryofwork)
Dutiesandresponsibilitiesofallpersonnelinvolvedinconfinedspacework(Entrant,attendant,supervisor,CSSA,rescuepersonnel&authorisedmanager)
Identificationandrecognitionofconfinedspaces(Typesofconfinedspacesincludinguniqueconfinedspaces,whicharerelevanttotrainees’industryofwork)
Knowledgeofconfinedspacehazards,includingsymptomsandconsequencesofexposuretothehazards(Shouldincludecommonconfinedspacehazardssuchasflammablegases/vapours,oxygenenrichment,oxygendeficiency,toxicgases/vapoursandotherphysicalandbiologicalhazards.)
RiskAssessment(Toincludehazardidentification,severityofconsequence,likelihoodandriskmatrix)
ConfinedSpaceProgrammeandEntryPermitSystem
(Toincludesafeworkproceduresforentryintoandworkinginsideconfinedspaces,aswellascontentsontheentrypermitandtheirinterpretation)
v
Controlorpreventivemeasurestoeliminate,minimiseorcontrolconfinedspacehazards
(Includepurgingandventilationofconfinedspacesforentryorcontinuousoccupancy,de-energisingofenergysources,isolationofconfinedspacefromhazardousmaterialsandlockout/tagout)
Selection,use,fitandmaintenanceofpersonalprotectiveequipmentuseforworkinconfinedspace
(Includingfitcheckofairpurifyingrespirators,properstorageandcleaningofPPEusedforconfinedspacework)
Safeuseofequipmentinconfinedspaceentryandwork
Communicationprocedureswithotherpersonnelinvolvedinconfinedspacework,inparticularstandbyattendants
(Includecommunicationduringroutineworkandemergencies)
Emergencyresponseplan
(Includeidentificationofhazardousconditions,evacuationconditionsandself-rescueprocedures)
Usageandlimitationsofportablegasinstrumentsandresponsetoalarms
(Includeunderstandingtheresponsesandreadingsofgasinstrumentsinnormalatmosphericconditionsandabnormalconditionssuchasoxygendeficiencyandtoxicatmospheres)
Selection,maintenance,storageandusageofemergencyrescueequipmentandrescuemethods
(Includesusageofrescueandpersonalprotectiveequipmentusedforrescueinconfinedspaceswithhazardousconditions,entryandnon-entryrescuemethodsandretrievaltechniquesforinjuredpersonnel)
Firstaid(IncludesCPR)
Gasmonitoringinstrumentsandequipment,gastestingmethodsandprocedures
(Includetheusageandlimitationsofvariousgasmonitoringinstrumentsandequipment,gastestingmethodsandproceduresofgastestingindifferentconfinedspaceconfigurations)
AuthorisedManagerApersonwhohasoverallcontrolofalltheworkcarriedoutinaconfinedspaceataworkplace.Hisdutiesincludeissuingandrevokingentrypermits,ensuringthatconfinedspaceshavebeenrendered,asfaraspracticable,freeofhazardsforsafeentryandwork,andthatmeasureshavebeentakentoeliminateorcontroltherisk(s)identifiedintheriskassessmentconducted.Itisnecessaryforhimtoreviewandassesstheneedtocontinueconfinedspaceworkonadailybasis.
9.2 PlanninganEffectiveTrainingProgrammeAneffectivetrainingprogrammecanbeplannedusinga5-stepprocess.i. Conductatrainingneedsassessment Determinethegapsandidentifytheareaandleveloftrainingrequired.
ii. Setgoalsandobjectives Describethedesiredendresultoftrainingandstatewhatparticipantsshouldbeabletodo
attheendofthetrainingprogramme.
iii. Selecttrainingmethods Methodsoftrainingincludelectures,discussions,demonstrationsandlaboratorysessions.
iv. Developandpresentthelessons Lessonplanning,programmepreparation,selectingthefacility,printedmaterials,social
amenitiesanddelivery(useofaudio-visualmaterials).
v. Evaluationofeffectivenessoftraining Programmeevaluationintheformoforalorwrittentestsandskilldemonstration.
9.3 ElementsofTrainingandTrainingCoursesItisimportantforaneffectivetrainingsessiontocompriseboththeoryandhands-ontrainingandbepresentedinawaythatcanbeeasilyunderstoodbytheparticipants.Wherehands-onexercisesareprovided,itisimportantforsuchexercisestoberealisticandreflectiveoftheactualconditionswhicharelikelytobeencounteredatwork.
Itisvitalfortheextentanddepthtowhichthetrainingelementsarecoveredbeconsistentwiththedutiesandresponsibilitiesofthevariouspersonnelinvolvedinconfinedspaceentryorwork.
Records of all confined space training, including refresher and supplementary training arerequired to be properly documented and kept by the employer for as long as the personscontinuetobeinvolvedinconfinedspacework.
9.3.1 KeyElementsofTrainingThetablebelowliststhekeyelementsoftrainingforconfinedspacework.
60 61
KeyElementsofTraining
Legislationrequirementsonconfinedspacework
(ToincluderequirementsonconfinedspaceworkunderWSHActanditssubsidiarylegislation,whichisrelevanttotrainees’industryofwork)
Dutiesandresponsibilitiesofallpersonnelinvolvedinconfinedspacework
(Entrant,attendant,supervisor,confinedspacesafetyassessor,rescuepersonnel&authorisedmanager)
Identificationandrecognitionofconfinedspaces
(Typesofconfinesspacesincludinguniqueconfinedspaces,whicharerelevanttotrainees’industryofwork)
Knowledgeofconfinedspacehazards,includingsymptomsandconsequencesofexposuretothehazards
(Shouldincludecommonconfinedspacehazardssuchasflammablegases/vapours,oxygenenrichment,oxygendeficiency,toxicgases/vapoursandotherphysicalandbiologicalhazards.)
RiskAssessment
(Toincludehazardidentification,severityofconsequence,likelihoodandriskmatrix)
ConfinedSpaceProgrammeandEntryPermitSystem(Toincludesafeworkproceduresforentryintoandworkinginsideconfinedspaces,aswellascontentsontheentrypermitandtheirinterpretation)
Controlorpreventivemeasurestoeliminate,minimiseorcontrolconfinedspacehazards(Includepurgingandventilationofconfinedspacesforentryorcontinuousoccupancy,de-energisingofenergysources,isolationofconfinedspacefromhazardousmaterialsandlockout/tagout)
Selection,use,fitandmaintenanceofPPEuseforworkinconfinedspace(Includingfitcheckofairpurifyingrespirators,properstorageandcleaningofPPEusedforconfinedspacework)
Safeuseofequipmentinconfinedspaceentryandwork
Communicationprocedureswithotherpersonnelinvolvedinconfinedspacework,inparticularstandbyattendants(Includecommunicationduringroutineworkandemergencies)
Emergencyresponseplan(Includeidentificationofhazardousconditions,evacuationconditionsandself-rescueprocedures)
Usageandlimitationsofportablegasinstrumentsandresponsetoalarms(Includeunderstandingtheresponsesandreadingsofgasinstrumentsinnormalatmosphericconditionsandabnormalconditionssuchasoxygendeficiencyandtoxicatmospheres)
Selection,maintenance,storageandusageofemergencyrescueequipmentandrescuemethods
(Includesusageofrescueandpersonalprotectiveequipmentusedforrescueinconfinedspaceswithhazardousconditions,entryandnon-entryrescuemethodsandretrievaltechniquesforinjuredpersonnel)
Firstaid(IncludesCPR)
Gasmonitoringinstrumentsandequipment,gastestingmethodsandprocedures
(Includetheusageandlimitationsofvariousgasmonitoringinstrumentsandequipment,gastestingmethodsandproceduresofgastestingindifferentconfinedspaceconfigurations)
KeyElementsofTraining
Legislationrequirementsonconfinedspacework
(ToincluderequirementsonconfinedspaceworkunderWSHActanditssubsidiarylegislation,whichisrelevanttotrainees’industryofwork)
Dutiesandresponsibilitiesofallpersonnelinvolvedinconfinedspacework
(Entrant,attendant,supervisor,confinedspacesafetyassessor,rescuepersonnel&authorisedmanager)
Identificationandrecognitionofconfinedspaces
(Typesofconfinesspacesincludinguniqueconfinedspaces,whicharerelevanttotrainees’industryofwork)
Knowledgeofconfinedspacehazards,includingsymptomsandconsequencesofexposuretothehazards
(Shouldincludecommonconfinedspacehazardssuchasflammablegases/vapours,oxygenenrichment,oxygendeficiency,toxicgases/vapoursandotherphysicalandbiologicalhazards.)
RiskAssessment
(Toincludehazardidentification,severityofconsequence,likelihoodandriskmatrix)
ConfinedSpaceProgrammeandEntryPermitSystem(Toincludesafeworkproceduresforentryintoandworkinginsideconfinedspaces,aswellascontentsontheentrypermitandtheirinterpretation)
v
Controlorpreventivemeasurestoeliminate,minimiseorcontrolconfinedspacehazards(Includepurgingandventilationofconfinedspacesforentryorcontinuousoccupancy,de-energisingofenergysources,isolationofconfinedspacefromhazardousmaterialsandlockout/tagout)
Selection,use,fitandmaintenanceofpersonalprotectiveequipmentuseforworkinconfinedspace(Includingfitcheckofairpurifyingrespirators,properstorageandcleaningofPPEusedforconfinedspacework)
Safeuseofequipmentinconfinedspaceentryandwork
Communicationprocedureswithotherpersonnelinvolvedinconfinedspacework,inparticularstandbyattendants(Includecommunicationduringroutineworkandemergencies)
Emergencyresponseplan(Includeidentificationofhazardousconditions,evacuationconditionsandself-rescueprocedures)
Usageandlimitationsofportablegasinstrumentsandresponsetoalarms(Includeunderstandingtheresponsesandreadingsofgasinstrumentsinnormalatmosphericconditionsandabnormalconditionssuchasoxygendeficiencyandtoxicatmospheres)
Selection,maintenance,storageandusageofemergencyrescueequipmentandrescuemethods
(IncludesusageofrescueandPPEforrescueinconfinedspaceswithhazardousconditions,entryandnon-entryrescuemethodsandretrievaltechniquesforinjuredpersonnel)
Firstaid(IncludesCPR)
Gasmonitoringinstrumentsandequipment,gastestingmethodsandprocedures
(Includetheusageandlimitationsofvariousgasmonitoringinstrumentsandequipment,gastestingmethodsandproceduresofgastestingindifferentconfinedspaceconfigurations)
In-depthKnowledgeWorkingKnowledgeAwareness
Table 6: The key elements for training in confined space work.
Inaddition toanyexternalor internal training, it isalso important toattendthe trainingandcertificationbyequipmentmanufacturersonhowtousetheirspecialisedequipment.
Theseequipmentmaybe:
• SCBAforwork;
• SCBAforrescueinhazardoussituations;
• Respiratoryprotectivedevices;
• Gasmonitoringinstruments,portablegasdetectorsanditsaccessories;and
• Rescueequipment.
In-house briefings and training on workplace specific procedures are still required to beconducted to ensure that all are informed before any confined space entry or work. Suchworkplacespecificproceduresmayinclude:
• Entrypermitsystem;
• Communicationprocedures;and
• Emergencyresponseplan.
62 63
9.3.2 TrainingCoursesThefollowingcoursesarerecommendedforconfinedspacework:
• SafetyOrientationCourse(Manhole)forWorkers
• CompressedAirWorksCourse
• SafetyInstructionCourse(Manhole)forSupervisors
• ConfinedSpaceSafetyAssessorCourse
• ManholeSafetyAssessorCourse
• ShipyardSafetyAssessors(HotworkCertification)Course
• OccupationalFirstAidCourse
• ConfinedSpaceEntryandRescueCourse
For more information on Ministry of Manpower’s (MOM) accredited training providers foroccupationandhealthpersonnel,pleasevisit:http://www.mom.gov.sg/publish/momportal/en/communities/workplace_safety_and_health/building_capabilities/developing_competencies/occupational_safety.html
FormoreinformationonConfinedSpaceEntryandRescueCourseconductedbyCivilDefenceAcademy,pleasevisit:http://www.scdf.gov.sg/General/E_Services/courses_seminars.html
9.4 CriteriaforTraining,RefresherorSupplementaryTrainingPersonnel who are involved in confined space entry or work should be trained before theycommenceonanyconfinedspacework.Itisimportanttonotethatsituationsmayarisewhenrefreshertrainingorsupplementarytrainingisrequiredtoensurethatconfinedspaceworkcancontinuetobecarriedoutsafely.Itisvitalfortheemployerorprincipaltoconsiderconductingrefreshertrainingorsupplementarytrainingonnewtopicsinthefollowingsituation:
• Theriskassessmentorentryprocedureshavebeenreviewedandchanged;
• Changeindutiesorappointmentofnewduties;
• Workinvolvinganewtypeofconfinedspaceornewhazardswhichwereneverencounteredbefore;and
• Thepersonnelinvolveddemonstratedalackofunderstandingofhisdutiesoranysafeworkprocedure.
9.5 CompetencyofTrainersThe competency of the trainers plays an important part in ensuring that the contents of thetrainingaresuccessfullyconveyedtothetrainees,andthattraineesareaccuratelyassessedandevaluatedontheirunderstandingofthetrainingcontents.
Itisnecessaryforalltrainerstohaveathoroughworkingknowledgeonthevarioustopicsthattheyaretrainingin.Suchknowledgecouldbeacquiredthroughacombinationoftraining(bothformal and informal), education and experience.To ensure relevancy, trainers are required tohaveexperienceinconfinedspacework,eitherpastorcurrent,inthespecificindustrieswhichtheirtargetedtraineesareinvolvedin.
9.6 AssessmentofTrainingAspartofthetrainingprocess,itisnecessarytoconductanassessmenttoevaluateeachtrainee’sunderstandingofthetrainingcontents.Thisistoensurethatoverallobjectivesofthetrainingprogramme have been achieved and that all who have undergone the training have a clearunderstandingofthetrainingcontents.
64 65
PERMITFORENTRyINTOCONFINEDSPACES
S/NO RAReferenceNo.
LOCATION:COMMENCEMENT
DATE:// TIME:HRS
IDENTITyOFCONFINEDSPACE:COMMENCEMENT
DATE:// TIME:HRS
PURPOSEOFENTRy:
STAGEI:APPLICATIONBySUPERVISOR
1.Potentialatmospherichazards:
Potentialnon-atmospherichazards:
2.Controlmeasures:Ihavehighlightedmyintentiontoentertheconfinedspaceatthesafetymeetingandithasbeencoordinated.Further,Ishalltaketheundermentionedcontrolmeasurespriortotheentryintothespaceandduringthecourseofworkinthespace:-
Pre-EntryRequirements PersonalProtectiveEquipment(PPE)ParticularsofConfinedSpaceAttendant
VentilationLightingFlame-prooflightBarricadesandsignboardsDe-energisation/lockout-tagout(LOTO)Blanking/bleedingofpipesPersonalgasdetectorTorchlight
SafetyhelmetEyeprotectionHandprotectionSafetyharness/lifelinesRespiratoryprotectionOtherPPE:Name/identificationbadge
Name:NRIC/FIN:Department:Company:ContactNo:
NAME:SIGNATURE:DATE://TIME:HRS
Note: 1. Thenecessarysafetymeasuresmustbecompliedwithbeforetheapplicationishandedovertotheconfinedspace safetyassessorforhisevaluation.
2. Wherereasonablypracticable,applicanttoprovideasketchoftheareawithintheconfinedspacewheretheentry istobemadeorworkistobeconductedonaseparatesheetofpaperandattachitwiththepermit.
STAGEII:EVALUATIONByCONFINEDSPACESAFETyASSESSOR
NAME:SIGNATURE:DATE://TIME:HRS
STAGEIII:ISSUANCEByAUTHORISEDMANAGER
Iamsatisfiedthat: (a) thelevelsofoxygen,flammablegasandtoxicsubstancesarewithinthepermissiblerange.(Referto StageII)
(b)theconfinedspaceisadequatelyventilated.
(c) effectivestepshavebeentakentopreventanyingressofdangerousgases,vapoursoranyotherdangerous substancesintotheconfinedspace.
(d)allreasonablypracticablemeasureshavebeentakentoensurethesafetyandhealthofpersons whowillbeenteringorworkingintheconfinedspace.
NAME:SIGNATURE:DATE://TIME:HRS
STAGEIVa:POSTINGOFENTRyPERMIT
Ishallensurethatthecopyoftheentrypermitispostedattheentrancetotheconfinedspace,includingwherereasonablypracticable,asketchoftheareawithintheconfinedspacewheretheentryistobemadeorworkistobeconducted.
NAME:SIGNATURE:DATE://TIME:HRS
STAGEIVa:POSTINGOFENTRyPERMIT
Thepermithasbeenremovedforthefollowingreasons:
Remarks:
NAME:SIGNATURE:DATE://TIME:HRS
Note: 1. THISPERMITISSTRICTLyFORENTRyINTOTHESPACEONLy.
2. ITDOESNOTENTITLETHEAPPLICANTTOCARRyOUTHOT-WORKORANyOTHERHAZARDOUSWORK.
Resultofgasmonitoring: Permissibleentrylevel
Oxygen % 19.5%-23.5%
Flammablegas %LEL lessthan10%LEL
%ofsolventsinpaint Volume(m3)ofairrequiredperlitreofpaintused
30 600
40 800
50 1000
60 1200
70 1400
10. Annexes
10.1Annex1:GuidelinesforWeldingInConfinedSpaces10.1.1 LocalExhaustVentilationSystem• Aportablelocalexhaustventilationsystemshouldbeusedtoremoveweldingfumesatthe
sourceofgeneration.
• Thelocalexhaustventilationsystemcaneitherbeamechanicalfumeextractororapneumaticairmover.
• Theminimumairflowrateperweldingpointis10m3/minandtheexhausthoodshouldbelocatedascloseaspossibletotheweldpoint.
• Theexhaustfumesshouldbedischargedintotheopenair(i.e.,outsidetheconfinedspace)orpassedthroughanaircleanerifre-circulationisrequired.
• Filterrespiratorsshouldbewornunlessthefumescanbeeffectivelyremovedbylocalexhaustventilation.
10.1.2 DilutionorForcedVentilation• Ifalocalexhaustventilationsystemisnotpracticable,adilutionventilationsystemshould
beused.
• Theminimumdilutionairshouldbe30m3/minperwelderandthedilutionairshouldbesuppliedasneartothewelderaspossible.
• Theairblowersshouldbelocatedoutsidetheconfinedspace.
• Thereshouldbeadequateopeningsforventingthedilutedair.
• Suppliedairrespiratorsshouldbeusediflocalexhaustventilationisnotprovided.
10.2Annex2:GuidelinesforPaintinginConfinedSpaces10.2.1 SprayPainting• Dilutionorforcedventilationshouldbeprovidedtodilutetheflammablevapourstobelow
10%ofitslowerexplosivelimit.
• Theblowersshouldbelocatedoutsidetheconfinedspace.
• Thereshouldbeadequateopeningsforventingthedilutedair.
• Suppliedairrespiratorsshouldbeworn.
10.2.2 BrushandRollerPainting• Dilutionorforcedventilationshouldbeprovidedtodilutethesolventvapourstobelow
theirPELs.
• Theblowersshouldbelocatedoutsidetheconfinedspace.
• Therequiredairflowratedependsontheamountofpaintusedandthe%ofsolventsinthepaint:
• Theairshouldbesuppliedatornearthepersonscarryingoutthework.
• Thereshouldbeadequateopeningsforventingthedilutedair.
10.3Annex3:SampleofConfinedSpaceEntryPermit
66 67
10.4Annex4:SampleFlowchartofPermitApplication
ENTRy/WORKCOMMENCES**
Supervisorremovesthepermitbasedonthefollowingconditions-
• Permitexpired; • Permitrevoked;or • Workcompleted;orwhicheverisearliest.
No
Yes
Supervisorinspectsandpreparestheworksitefortheintendedwork
Highlightsandcoordinatestheintendedworkinthesafetymeeting
SupervisorraisesanentrypermitandsubmitsittotheCSSA
CSSAconductsgastestingoftheconfinedspaceandrecommendsadditional
measures*,ifneedbe.
No
Yes
** It is the responsibility of the supervisor to ensure that the work conditions remains safe at all times
STAGE4Notificationofremovalofentrypermit
STAGE3ApprovalbyAuthorisedManager(AM)
STAGE2EvaluationbyConfinedSpaceSafetyAssessor(CSSA)
STAGE1ApplicationbySupervisor
* Recommended safety measures will differ depending on the work process and site conditions
Issuanceofentrypermit
AMissuesentrypermittoSupervisor
Supervisordisplaystheentrypermitattheentranceoftheconfinedspace
AMevaluatestheresultofgasmonitoringandensuresthatallpossibleprecautionsand
measureshavebeenimplementedandenforced
CSSAendorsesentrypermitandforwardsittoAuthorisedManager(AM)
ConfinedspacesFitforentry
STAGE4APostingofentrypermit
PERMITFORENTRyINTOCONFINEDSPACES
S/NO RAReferenceNo.
LOCATION:COMMENCEMENT
DATE:// TIME:HRS
IDENTITyOFCONFINEDSPACE:COMMENCEMENT
DATE:// TIME:HRS
PURPOSEOFENTRy:
STAGEI:APPLICATIONBySUPERVISOR
1.Potentialatmospherichazards:
Potentialnon-atmospherichazards:
2.Controlmeasures:Ihavehighlightedmyintentiontoentertheconfinedspaceatthesafetymeetingandithasbeencoordinated.Further,Ishalltaketheundermentionedcontrolmeasurespriortotheentryintothespaceandduringthecourseofworkinthespace:-
Pre-EntryRequirements PersonalProtectiveEquipment(PPE) ParticularsofConfinedSpaceAttendant
VentilationLightingFlame-prooflightBarricadesandsignboardsDe-energization/lockout-tagout(LOTO)Blanking/bleedingofpipesPersonalgasdetectorTorchlight
SafetyhelmetEyeprotectionHandprotectionSafetyharness/lifelinesRespiratoryprotectionOtherPPE:Name/identificationbadge
Name:NRIC/FIN:Department:Company:ContactNo:
NAME:SIGNATURE:DATE://TIME:HRS
Note: 1. Thenecessarysafetymeasuresmustbecompliedwithbeforetheapplicationishandedovertotheconfinedspace safetyassessorforhisevaluation.
2. Wherereasonablypracticable,applicanttoprovideasketchoftheareawithintheconfinedspace
Wheretheentryistobemadeorworkistobeconductedonaseparatesheetofpaperandattachitwiththepermit.
STAGEII:EVALUATIONByCONFINEDSPACESAFETyASSESSOR
NAME:SIGNATURE:DATE://TIME:HRS
STAGEIII:ISSUANCEByAUTHORISEDMANAGER
Iamsatisfiedthat: (a) thelevelsofoxygen,flammablegasandtoxicsubstancesarewithinthepermissiblerange.(Referto StageII)
(b)theconfinedspaceisadequatelyventilated.
(c) effectivestepshavebeentakentopreventanyingressofdangerousgases,vapoursoranyotherdangerous substancesintotheconfinedspace.
(d)allreasonablypracticablemeasureshavebeentakentoensurethesafetyandhealthofpersons whowillbeenteringorworkingintheconfinedspace.
NAME:SIGNATURE:DATE://TIME:HRS
STAGEIVa:POSTINGOFENTRyPERMIT
Ishallensurethatthecopyoftheentrypermitispostedattheentrancetotheconfinedspace,includingwherereasonablypracticable,asketchoftheareawithintheconfinedspacewheretheentryistobemadeorworkistobeconducted.
NAME:SIGNATURE:DATE://TIME:HRS
STAGEIVb:NOTIFICATIONOFREMOVALOFENTRyPERMIT
Thepermithasbeenremovedforthefollowingreasons:
Remarks:
NAME:SIGNATURE:DATE://TIME:HRS
Note: 1. THISPERMITISSTRICTLyFORENTRyINTOTHESPACEONLy.
2. ITDOESNOTENTITLETHEAPPLICANTTOCARRyOUTHOTWORKORANyOTHERHAZARDOUSWORK.
Incaseofemergency,pleasecontactHSEDepartmentatTel.no.xxxx(internal)orxxxx-yyyy(External)
Resultofgasmonitoring: Permissibleentrylevel
Oxygen % 19.5%-23.5%
Flammablegas %LEL lessthan10%LEL
Toxicgas ppm
Othertoxicgas ppm
FITFORENTRy NOTFITFORENTRy
Permitexpired Permitrevoked Workcompleted
DAILyENDORSEMENTByAUTHORISEDMANAGER
DAy2
DATE:
NAME:
SIGNATURE
DAy3
DATE:
NAME:
SIGNATURE
DAy4
DATE:
NAME:
SIGNATURE
DAy5
DATE:
NAME:
SIGNATURE
DAy6
DATE:
NAME:
SIGNATURE
DAy7
DATE:
NAME:
SIGNATURE
68 69
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lRis
kEv
alua
tion
5.R
esp
onsi
bili
ty6.
Ref
eren
ce
No.
Task
Ste
pH
azar
d/Pr
e-Cu
rsor
Exis
ting
Con
trol
Mea
sure
SL
Risk
Le
vel
Add
itio
nal
Cont
rol
Mea
sure
SL
Risk
Lev
elD
esig
nati
onD
ocum
entf
or
Refe
renc
e
01.
Entr
yin
to
confi
ned
spac
e•
Poor
ven
tilat
ion
(resu
lting
in
asph
yxia
tion
or
suffo
catio
n)
•Po
tent
ialo
ftox
ic
gase
s,va
pour
sor
fu
mes
(res
ultin
gin
po
ison
ing)
•H
ighl
ight
ent
ry
requ
irem
enti
nVS
CC
Mee
ting
•Ad
equa
tev
entil
atio
n
•Va
lide
ntry
per
mit
•Bu
ddy
syst
em
•D
ualt
ags
yste
m
•Po
rtab
leg
asd
etec
tor
•Pe
riodi
cga
sm
onito
ring
of
the
confi
ned
spac
e(e
very
6
hour
s)
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Co
nfine
dSp
ace
Ass
esso
r
•Pr
ojec
tMan
ager
•XY
Z-A
BC-0
01(E
ntry
in
toC
onfin
edS
pace
)
•XY
Z-A
BC-0
02(G
as
Mon
itorin
g)
Poor
ligh
ting
(resu
lting
in
slip
s,tr
ips,
falls
)•
Adeq
uate
gen
eral
ligh
ting
•Pe
rson
alto
rchl
ight
3C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
-
Wor
king
ath
eigh
t(r
esul
ting
ins
erio
us
inju
ryfr
onfa
ll)
•En
sure
that
ladd
ers
are
free
from
def
ect
•En
sure
that
ung
uard
ed
light
enin
gho
les/
ope
ning
s
are
cove
red
•Ad
opt3
-ptc
onta
ctw
hen
usin
gla
dder
•Ad
equa
teli
ghtin
gon
ac
cess
way
s
•Sl
owa
ndc
aref
ul
mov
emen
tsw
hile
mak
ing
insp
ectio
n
5A
Med
ium
--
-•
Pipe
For
eman
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
-
02.
Visu
alin
spec
tion,
id
entifi
catio
nan
dm
arki
ngo
fpi
pes
pool
s(o
fpi
pelin
e)to
be
dism
antle
d.
•Aw
kwar
dpo
stur
e(re
sulti
ngin
er
gono
mic
inju
ries)
•O
bser
vep
rope
rbod
ypo
stur
e
•En
sure
ade
quat
ew
orki
ng
spac
e/p
latf
orm
2B
Low
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
-
•Sl
ippe
ry/
Wet
su
rfac
es(r
esul
ting
in
slip
s/tr
ips/
falls
)
•Cl
ean
ups
lippe
ry/
wet
re
sidu
aln
earp
ipel
ine
iden
tified
•Ad
equa
tew
orki
ngli
ghts
•PP
E(s
afet
ysh
oes)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Po
tent
ialo
fbei
ng
stru
ckb
yob
ject
du
ring
insp
ectio
npr
oces
s(re
sulti
ngin
la
cera
tion
orb
ruis
e)
•Pr
oper
PPE
(saf
ety
helm
et)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
03.
Dis
man
tling
of
iden
tified
pi
pes
pool
sby
loos
enin
gan
dre
mov
ing
fast
ener
sin
way
of
flan
ged
pipe
co
nnec
tions
,us
ing
hand
tool
s.
Han
dto
ols
incl
ude
span
ners
,ha
mm
ero
rch
isel
.
•Ig
nitio
nof
resi
dual
s/c
ombu
stib
les
(resu
lting
infi
rea
nd
expl
osio
n)
•H
ighl
ight
spe
cific
di
sman
tling
requ
irem
ents
in
VSC
Cm
eetin
g
•Va
lid‘d
ism
antli
ngo
fpip
es’
perm
it
•Lo
ckou
t-ta
gout
(LO
TO)t
ois
olat
esy
stem
.
•Pr
omin
entd
ispl
ayo
fap
prop
riate
sig
nboa
rds
ata
llen
tran
ces
toth
eco
nfine
dsp
ace
•U
seo
fade
quat
efla
me
proo
flig
hts
with
cab
les
in
good
con
ditio
n
•N
o‘h
ot-w
ork’
inth
eco
nfine
dsp
ace
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Sh
ipE
ngin
eer/
O
ffice
r
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•XY
Z-A
BC-0
03(P
erm
itto
wor
kSy
stem
)
•XY
Z-A
BC-0
04
(Dis
man
tling
/Te
stin
gof
Oil,
Gas
,Ch
emic
al&
Ste
am
Pipe
lines
/Val
ves
&
Hea
ting
Coils
)
•Po
tent
ialo
ftox
ic
gase
s,va
pour
sor
fu
mes
(res
ultin
gin
po
ison
ing)
•Ad
equa
tev
entil
atio
n
•Po
rtab
leg
asd
etec
tor
•Im
med
iate
eva
cuat
ion
of
the
confi
ned
spac
eup
on
dete
ctio
nof
toxi
cga
s(b
riefin
gto
wor
kers
)
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Sl
ippe
ry/
Wet
su
rfac
es(r
esul
ting
in
slip
s/tr
ips/
falls
)
•U
seo
fcon
tain
ers/
pla
stic
ba
gsfo
rcol
lect
ing
syst
em
disc
harg
eon
ope
ning
fla
nge
conn
ectio
ns.
•St
and-
byo
ilsp
illc
ontr
ol
equi
pmen
t(ra
gs,s
aw
dust
,etc
)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Aw
kwar
dpo
stur
e(re
sulti
ngin
er
gono
mic
inju
ries)
•O
bser
vep
rope
rbod
ypo
stur
e.2
BLo
w-
--
-•
Pipe
For
eman
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Pi
nch
poin
tsa
nd
shar
ped
ges
(han
d&
fin
geri
njur
ies)
•Br
iefin
gon
avo
idan
ceo
fth
epi
nch
poin
thaz
ards
of
dism
antle
dpi
pes
•Pr
oper
PPE
(use
ofh
and
glov
es)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Po
tent
ialo
fbei
ng
stru
ckb
yob
ject
du
ring
ham
mer
ing
proc
ess
(resu
lting
in
lace
ratio
nor
bru
ise)
•M
aint
ain
prop
er
tech
niqu
eon
fast
ener
re
mov
al.
•Pr
oper
han
dto
ols
•PP
E
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
04.
Secu
ring
and
rem
oval
ofp
ipe
spoo
lout
oft
he
posi
tion
and
outo
fcon
fined
sp
ace.
•Pi
nch
poin
ts
and
shar
ped
ges
(resu
lting
inh
and
&
finge
rinj
urie
s)
•M
aint
ain
prop
er
com
mun
icat
ion/
co
-ord
inat
ion
amon
gco
-w
orke
rs
•Pr
oper
PPE
(Use
ofh
and
glov
esa
tall
times
)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Po
tent
ialo
fbei
ng
stru
ckb
yob
ject
du
ring
liftin
gor
ha
ndlin
gpr
oces
s(re
sulti
ngin
la
cera
tion
orb
ruis
e)
•Q
ualifi
edri
gger
tos
ecur
edi
sman
tled
pipe
forl
iftin
gpr
iort
ore
mov
alo
flas
t2
fast
ener
s
•U
seo
fval
idli
ftin
gge
ars
(slin
gw
ires/
web
bing
sl
ing)
•U
seo
fgui
dero
pe
•Ba
rric
ade
liftin
gzo
ne
•M
aint
ain
com
mun
icat
ion
betw
een
liftin
gcr
ewa
nd
co-w
orke
rs
•Pr
esen
ceo
fLift
ing
Supe
rvis
or
•Br
iefin
gof
the
liftin
gpl
anb
efor
eth
elif
ting
oper
atio
ns
•Su
perv
isor
toe
nsur
eth
at
allw
orke
rsn
otin
volv
ed
inth
elif
ting
oper
atio
nar
ecl
earf
rom
the
liftin
gzo
ne.
•Si
gnal
men
tob
est
atio
ned
atd
esig
nate
dlo
catio
ns
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•XY
Z-A
BC-0
5(L
iftin
gO
pera
tions
)
05.
Hou
seke
epin
g•
Slip
pery
/W
et
surf
aces
(res
ultin
gin
sl
ips/
trip
s/fa
lls)
•Re
mov
eal
loil/
oily
wat
er
cont
aine
rs/b
ags
from
th
eta
nka
ndc
lean
the
affec
ted
area
.
2A
Low
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
10.5Annex5:SampleofRiskAssessment
Risk
Ass
esm
entR
efer
ence
No.
RA
-001
Xy
ZSH
IPyA
RD
PT
ELT
D
Pipe
and
Boi
lerD
epar
tmen
tD
ism
antli
ngo
fPip
esS
pool
sCo
nfin
edS
pace
usi
ng
hand
tool
s(c
old
wor
ks)
MrA
Engi
neer
Risk
A
sses
men
tW
orks
heet
Dep
artm
ent
Task
Eva
luat
ion
Cond
ucte
dby
Sign
atur
e/D
ate
Des
igna
tion
CX
XM
rBA
sst.
Prod
.Man
ager
Cost
Cen
ter/
Sec
tion
Dat
eCo
mpl
eted
/Rev
ised
Revi
ewed
by
Sign
atur
e/D
ate
Des
igna
tion
MrC
Prod
.Man
ager
Occ
upat
ion
App
rove
dby
Sign
atur
e/D
ate
Des
igna
tion
1.H
azar
dId
enti
ficat
ion
2.Ri
skE
valu
atio
n3.
Ris
kCo
ntro
l4.
Res
idua
lRis
kEv
alua
tion
5.R
esp
onsi
bili
ty6.
Ref
eren
ce
No.
Task
Ste
pH
azar
d/Pr
e-Cu
rsor
Exis
ting
Con
trol
Mea
sure
SL
Risk
Le
vel
SL
Risk
Lev
elD
esig
nati
onD
ocum
entf
or
Refe
renc
e
01.
Entr
yin
to
confi
ned
spac
e•
Poor
ven
tilat
ion
(res
ultin
gin
A
sphy
xiat
ion
or
Suffo
catio
n)
•Po
tent
ialo
ftox
ic
gase
s,va
pour
sor
fu
mes
(res
ultin
gin
po
ison
ing)
•H
ighl
ight
ent
ry
requ
irem
enti
nVS
CC
Mee
ting
•Ad
equa
tev
entil
atio
n
•Va
lide
ntry
per
mit
•Bu
ddy
syst
em
•D
ualt
ags
yste
m
•Po
rtab
leg
asd
etec
tor
•Pe
riodi
cga
sm
onito
ring
of
the
confi
ned
spac
e(e
very
6
hour
s)
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Co
nfine
dSp
ace
Ass
esso
r
•Pr
ojec
tMan
ager
•XY
Z-A
BC-0
01(E
ntry
in
toC
onfin
edS
pace
)
•XY
Z-A
BC-0
02
(Gas
M
onito
ring)
•Po
orli
ghtin
g(re
sulti
ngto
slip
s,tr
ips,
falls
)
•Ad
equa
teg
ener
alli
ghtin
g
•Pe
rson
alto
rchl
ight
3C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
-
•W
orki
nga
thei
ght
(resu
lting
ins
erio
us
inju
ryfr
onfa
ll)
•En
sure
that
ladd
ers
are
free
from
def
ect
•En
sure
that
ung
uard
ed
light
enin
gho
les/
open
ings
ar
eco
vere
d
•Ad
opt3
-poi
ntc
onta
ct
whe
nus
ing
ladd
er
•Ad
equa
teli
ghtin
gon
ac
cess
way
s
•Sl
owa
ndc
aref
ul
mov
emen
tsw
hile
mak
ing
insp
ectio
n
5A
Med
ium
--
-•
Pipe
For
eman
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
-
02.
Visu
al
insp
ectio
n,
iden
tifica
tion
and
mar
king
of
pipe
spo
ols
(of
pipe
line)
tob
edi
sman
tled.
Awkw
ard
post
ure
(res
ultin
gin
erg
onom
ic
inju
ries)
•O
bser
vep
rope
rbod
ypo
stur
e
•En
sure
ade
quat
ew
orki
ng
spac
e/pl
atfo
rm
2B
Low
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
-
Slip
pery
/wet
sur
face
s(r
esul
ting
ins
lips/
trip
s/fa
lls)
•Cl
ean
ups
lippe
ry/w
et
resi
dual
nea
rpip
elin
eid
entifi
ed
•Ad
equa
tew
orki
ngli
ghts
•PP
E(s
afet
ysh
oes)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
Pote
ntia
lofb
eing
st
ruck
by
obje
ctd
urin
gin
spec
tion
proc
ess
(resu
lting
inla
cera
tion
orb
ruis
e)
Prop
erP
PE(s
afet
yhe
lmet
)2
CM
ediu
m-
--
-•
Pipe
For
eman
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
03.
Dis
man
tling
of
iden
tified
pi
pes
pool
sby
loos
enin
gan
dre
mov
ing
fast
ener
sin
way
of
flan
ged
pipe
co
nnec
tions
,us
ing
hand
tool
s.
(Han
dto
ols
incl
ude
span
ners
,ha
mm
ero
rch
isel
.)
Igni
tion
ofre
sidu
als/
com
bust
ible
s(re
sulti
ng
infi
rea
nde
xplo
sion
)
•H
ighl
ight
spe
cific
di
sman
tling
requ
irem
ents
in
VSC
Cm
eetin
g
•Va
lid“d
ism
antli
ngo
fpi
pes”
per
mit
•Lo
ckou
t-ta
gout
(LO
TO)t
ois
olat
esy
stem
.
•Pr
omin
entd
ispl
ayo
fap
prop
riate
sig
nboa
rds
ata
llen
tran
ces
toth
eco
nfine
dsp
ace
•U
seo
fade
quat
efla
me
proo
flig
hts
with
cab
les
in
good
con
ditio
n
•N
o“h
otw
ork”
inth
eco
nfine
dsp
ace
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Sh
ipE
ngin
eer/
O
ffice
r
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
•Pi
pew
orke
r
•XY
Z-A
BC-0
03
(Per
mit
toW
ork
Syst
em)
•XY
Z-A
BC-0
04
(Dis
man
tling
/tes
ting
ofo
il,g
as,c
hem
ical
&
ste
amp
ipel
ines
/va
lves
&h
eatin
gco
ils)
Pote
ntia
loft
oxic
gas
es,
vapo
urs
orfu
mes
(r
esul
ting
inp
oiso
ning
)
•Ad
equa
tev
entil
atio
n
•Po
rtab
leg
asd
etec
tor
•Im
med
iate
eva
cuat
ion
of
the
confi
ned
spac
eup
on
dete
ctio
nof
toxi
cga
s(b
riefin
gto
wor
kers
)
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Sl
ippe
ry/
Wet
su
rfac
es(r
esul
ting
in
slip
s/tr
ips/
falls
)
•U
seo
fcon
tain
ers/
pla
stic
ba
gsfo
rcol
lect
ing
syst
em
disc
harg
eon
ope
ning
fla
nge
conn
ectio
ns.
•St
and-
byo
ilsp
illc
ontr
ol
equi
pmen
t(ra
gs,s
awd
ust,
etc)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Aw
kwar
dpo
stur
e(r
esul
ting
in
ergo
nom
icin
jurie
s)
•O
bser
vep
rope
rbod
ypo
stur
e.2
BLo
w-
--
-•
Pipe
For
eman
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Pi
nch
poin
tsa
nd
shar
ped
ges
(han
d&
fin
geri
njur
ies)
•Br
iefin
gon
avo
idan
ceo
fth
epi
nch
poin
thaz
ards
of
dism
antle
dpi
pes
•Pr
oper
PPE
(use
ofh
and
glov
es)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Po
tent
ialo
fbei
ng
stru
ckb
yob
ject
du
ring
ham
mer
ing
proc
ess
(res
ultin
gin
la
cera
tion
orb
ruis
e)
•M
aint
ain
prop
erte
chni
que
onfa
sten
erre
mov
al.
•Pr
oper
han
dto
ols
•PP
E
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
04.
Secu
ring
and
rem
oval
ofp
ipe
spoo
lout
oft
he
posi
tion
and
outo
fcon
fined
sp
ace.
•Pi
nch
poin
ts
and
shar
ped
ges
(res
ultin
gin
han
d&
fin
geri
njur
ies)
•M
aint
ain
prop
er
com
mun
icat
ion/
co
-ord
inat
ion
amon
gco
-w
orke
rs
•Pr
oper
PPE
(Use
ofh
and
glov
esa
tall
times
)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Po
tent
ialo
fbei
ng
stru
ckb
yob
ject
du
ring
liftin
gor
ha
ndlin
gpr
oces
s(re
sulti
ngin
la
cera
tion
orb
ruis
e)
•Q
ualifi
edri
gger
tos
ecur
edi
sman
tled
pipe
forl
iftin
gpr
iort
ore
mov
alo
flas
t2
fast
ener
s
•U
seo
fval
idli
ftin
gge
ars
(slin
gw
ires/
web
bing
sl
ing)
•U
seo
fgui
dero
pe
•Ba
rric
ade
liftin
gzo
ne
•M
aint
ain
com
mun
icat
ion
betw
een
liftin
gcr
ewa
nd
co-w
orke
rs
•Pr
esen
ceo
fLift
ing
Supe
rvis
or
•Br
iefin
gof
the
liftin
gpl
anb
efor
eth
elif
ting
oper
atio
ns
•Su
perv
isor
toe
nsur
eth
at
allw
orke
rsn
otin
volv
ed
inth
elif
ting
oper
atio
nar
ecl
earf
rom
the
liftin
gzo
ne.
•Si
gnal
men
tob
est
atio
ned
atd
esig
nate
dlo
catio
ns
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•XY
Z-A
BC-0
5(L
iftin
gO
pera
tions
)
05.
Hou
seke
epin
g•
Slip
pery
/W
et
surf
aces
(res
ultin
gin
sl
ips/
trip
s/fa
lls)
•Re
mov
eal
loil/
oily
wat
er
cont
aine
rs/b
ags
from
th
eta
nka
ndc
lean
the
affec
ted
area
.
2A
Low
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
70 71
Risk
Ass
esm
entR
efer
ence
No.
RA
-001
Xy
ZSH
IPyA
RD
PT
ELT
D
Pipe
and
Boi
lerD
epar
tmen
tD
ism
antli
ngo
fPip
esS
pool
sCo
nfin
edS
pace
usi
ng
hand
tool
s(c
old
wor
ks)
MrA
Engi
neer
Risk
A
sses
men
tW
orks
heet
Dep
artm
ent
Task
Eva
luat
ion
Cond
ucte
dby
Sign
atur
e/D
ate
Des
igna
tion
CX
XM
rBA
sst.
Prod
.Man
ager
Cost
Cen
ter/
Sec
tion
Dat
eCo
mpl
eted
/Rev
ised
Revi
ewed
by
Sign
atur
e/D
ate
Des
igna
tion
MrC
Prod
.Man
ager
Occ
upat
ion
App
rove
dby
Sign
atur
e/D
ate
Des
igna
tion
1.H
azar
dId
enti
ficat
ion
2.Ri
skE
valu
atio
n3.
Ris
kCo
ntro
l4.
Res
idua
lRis
kEv
alua
tion
5.R
esp
onsi
bili
ty6.
Ref
eren
ce
No.
Task
Ste
pH
azar
d/Pr
e-Cu
rsor
Exis
ting
Con
trol
Mea
sure
SL
Risk
Le
vel
SL
Risk
Lev
elD
esig
nati
onD
ocum
entf
or
Refe
renc
e
01.
Entr
yin
to
confi
ned
spac
e•
Poor
ven
tilat
ion
(resu
lting
in
Asp
hyxi
atio
nor
Su
ffoca
tion)
•Po
tent
ialo
ftox
ic
gase
s,va
pour
sor
fu
mes
(res
ultin
gin
po
ison
ing)
•H
ighl
ight
ent
ry
requ
irem
enti
nVS
CC
Mee
ting
•Ad
equa
tev
entil
atio
n
•Va
lide
ntry
per
mit
•Bu
ddy
syst
em
•D
ualt
ags
yste
m
•Po
rtab
leg
asd
etec
tor
•Pe
riodi
cga
sm
onito
ring
of
the
confi
ned
spac
e(e
very
6
hour
s)
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Co
nfine
dSp
ace
Ass
esso
r
•Pr
ojec
tMan
ager
•XY
Z-A
BC-0
01(E
ntry
in
toC
onfin
ed
Spac
e)
•XY
Z-A
BC-0
02
(Gas
M
onito
ring)
•Po
orli
ghtin
g(r
esul
ting
tos
lips,
trip
s,fa
lls)
•Ad
equa
teg
ener
alli
ghtin
g
•Pe
rson
alto
rchl
ight
3C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
-
•W
orki
nga
thei
ght
(res
ultin
gin
ser
ious
in
jury
fron
fall)
•En
sure
that
ladd
ers
are
free
fr
omd
efec
t
•En
sure
that
ung
uard
ed
light
enin
gho
les/
ope
ning
s
are
cove
red
•Ad
opt3
-ptc
onta
ctw
hen
usin
gla
dder
•Ad
equa
teli
ghtin
gon
ac
cess
way
s
•Sl
owa
ndc
aref
ul
mov
emen
tsw
hile
mak
ing
insp
ectio
n
5A
Med
ium
--
-•
Pipe
For
eman
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
-
02.
Visu
al
insp
ectio
n,
iden
tifica
tion
and
mar
king
of
pipe
spo
ols
(of
pipe
line)
tob
edi
sman
tled.
•Aw
kwar
dpo
stur
e(re
sulti
ngin
er
gono
mic
inju
ries)
•O
bser
vep
rope
rbod
ypo
stur
e
•En
sure
ade
quat
ew
orki
ng
spac
e/p
latf
orm
2B
Low
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
-
•Sl
ippe
ry/
Wet
su
rfac
es(r
esul
ting
in
slip
s/tr
ips/
falls
)
•Cl
ean
ups
lippe
ry/
wet
re
sidu
aln
earp
ipel
ine
iden
tified
•Ad
equa
tew
orki
ngli
ghts
•PP
E(s
afet
ysh
oes)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Po
tent
ialo
fbei
ng
stru
ckb
yob
ject
du
ring
insp
ectio
npr
oces
s(r
esul
ting
in
lace
ratio
nor
bru
ise)
•Pr
oper
PPE
(saf
ety
helm
et)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
03.
Dis
man
tling
of
iden
tified
pi
pes
pool
sby
loos
enin
gan
dre
mov
ing
fast
ener
sin
way
of
flan
ged
pipe
co
nnec
tions
,us
ing
hand
tool
s.
Han
dto
ols
incl
ude
span
ners
,ha
mm
ero
rch
isel
.
•Ig
nitio
nof
resi
dual
s/c
ombu
stib
les
(res
ultin
gin
fire
and
ex
plos
ion)
•H
ighl
ight
spe
cific
di
sman
tling
requ
irem
ents
in
VSC
Cm
eetin
g
•Va
lid‘d
ism
antli
ngo
fpip
es’
perm
it
•Lo
ckou
t-ta
gout
(LO
TO)t
ois
olat
esy
stem
.
•Pr
omin
entd
ispl
ayo
fap
prop
riate
sig
nboa
rds
ata
llen
tran
ces
toth
eco
nfine
dsp
ace
•U
seo
fade
quat
efla
me
proo
flig
hts
with
cab
les
in
good
con
ditio
n
•N
o‘h
ot-w
ork’
inth
eco
nfine
dsp
ace
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Sh
ipE
ngin
eer/
O
ffice
r
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•XY
Z-A
BC-0
03
(Per
mit
tow
ork
Syst
em)
•XY
Z-A
BC-0
04
(Dis
man
tling
/Te
stin
gof
Oil,
Gas
,Ch
emic
al&
Ste
am
Pipe
lines
/Val
ves
&
Hea
ting
Coils
)
•Po
tent
ialo
ftox
ic
gase
s,va
pour
sor
fu
mes
(res
ultin
gin
po
ison
ing)
•Ad
equa
tev
entil
atio
n
•Po
rtab
leg
asd
etec
tor
•Im
med
iate
eva
cuat
ion
of
the
confi
ned
spac
eup
on
dete
ctio
nof
toxi
cga
s(b
riefin
gto
wor
kers
)
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
•Pi
pew
orke
r
Slip
pery
/wet
sur
face
s(r
esul
ting
ins
lips/
trip
s/fa
lls)
•U
seo
fcon
tain
ers/
plas
tic
bags
forc
olle
ctin
gsy
stem
di
scha
rge
ono
peni
ng
flang
eco
nnec
tions
.
•St
and-
byo
ilsp
illc
ontr
ol
equi
pmen
t(ra
gs,s
awd
ust,
etc.
)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
•Pi
pew
orke
r
Awkw
ard
post
ure
(res
ultin
gin
erg
onom
ic
inju
ries)
Obs
erve
pro
perb
ody
post
ure.
2B
Low
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
•Pi
pew
orke
r
Pinc
hpo
ints
and
sha
rp
edge
s(h
and
&fi
nger
in
jurie
s)
•Br
iefin
gon
avo
idan
ceo
fth
epi
nch
poin
thaz
ards
of
dism
antle
dpi
pes
•Pr
oper
PPE
(use
ofh
and
glov
es)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
•Pi
pew
orke
r
Pote
ntia
lofb
eing
st
ruck
by
obje
ctd
urin
gha
mm
erin
gpr
oces
s(r
esul
ting
inla
cera
tion
orb
ruis
e)
•M
aint
ain
prop
erte
chni
que
onfa
sten
erre
mov
al
•Pr
oper
han
dto
ols
•PP
E
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
•Pi
pew
orke
r
04.
Secu
ring
and
rem
oval
ofp
ipe
spoo
lout
oft
he
posi
tion
and
outo
fcon
fined
sp
ace.
Pinc
hpo
ints
and
sha
rp
edge
s(r
esul
ting
inh
and
&fi
nger
inju
ries)
•M
aint
ain
prop
er
com
mun
icat
ion/
co-o
rdin
atio
nam
ong
co-w
orke
rs
•Pr
oper
PPE
(use
ofh
and
glov
esa
tall
times
)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
•Pi
pew
orke
r
Pote
ntia
lofb
eing
st
ruck
by
obje
ctd
urin
glif
ting
orh
andl
ing
proc
ess
(resu
lting
in
lace
ratio
nor
bru
ise)
•Q
ualifi
edri
gger
tos
ecur
edi
sman
tled
pipe
forl
iftin
gpr
iort
ore
mov
alo
flas
t2
fast
ener
s
•U
seo
fval
idli
ftin
gge
ars
(slin
gw
ires/
web
bing
sl
ing)
•U
seo
fgui
dero
pe
•Ba
rric
ade
liftin
gzo
ne
•M
aint
ain
com
mun
icat
ion
betw
een
liftin
gcr
ewa
nd
co-w
orke
rs
•Pr
esen
ceo
fLift
ing
Supe
rvis
or
•Br
iefin
gof
the
liftin
gpl
anb
efor
eth
elif
ting
oper
atio
ns
•Su
perv
isor
toe
nsur
eth
at
allw
orke
rsn
otin
volv
ed
inth
elif
ting
oper
atio
nar
ecl
earf
rom
the
liftin
gzo
ne.
•Si
gnal
men
tob
est
atio
ned
atd
esig
nate
dlo
catio
ns
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•XY
Z-A
BC-0
5(L
iftin
gO
pera
tions
)
05.
Hou
seke
epin
g•
Slip
pery
/W
et
surf
aces
(res
ultin
gin
sl
ips/
trip
s/fa
lls)
•Re
mov
eal
loil/
oily
wat
er
cont
aine
rs/b
ags
from
the
tank
and
cle
anth
eaff
ecte
dar
ea.
2A
Low
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
Risk
Ass
esm
entR
efer
ence
No.
RA
-001
Xy
ZSH
IPyA
RD
PT
ELT
D
Pipe
and
Boi
lerD
epar
tmen
tD
ism
antli
ngo
fPip
esS
pool
sCo
nfin
edS
pace
usi
ng
hand
tool
s(c
old
wor
ks)
MrA
Engi
neer
Risk
A
sses
men
tW
orks
heet
Dep
artm
ent
Task
Eva
luat
ion
Cond
ucte
dby
Sign
atur
e/D
ate
Des
igna
tion
CX
XM
rBA
sst.
Prod
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ager
Cost
Cen
ter/
Sec
tion
Dat
eCo
mpl
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/Rev
ised
Revi
ewed
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ate
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ager
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ion
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n3.
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ntro
l4.
Res
idua
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kEv
alua
tion
5.R
esp
onsi
bili
ty6.
Ref
eren
ce
No.
Task
Ste
pH
azar
d/Pr
e-Cu
rsor
Exis
ting
Con
trol
Mea
sure
SL
Risk
Le
vel
SL
Risk
Lev
elD
esig
nati
onD
ocum
entf
or
Refe
renc
e
01.
Entr
yin
to
confi
ned
spac
e•
Poor
ven
tilat
ion
(res
ultin
gin
A
sphy
xiat
ion
or
Suffo
catio
n)
•Po
tent
ialo
ftox
ic
gase
s,va
pour
sor
fu
mes
(res
ultin
gin
po
ison
ing)
•H
ighl
ight
ent
ry
requ
irem
enti
nVS
CC
Mee
ting
•Ad
equa
tev
entil
atio
n
•Va
lide
ntry
per
mit
•Bu
ddy
syst
em
•D
ualt
ags
yste
m
•Po
rtab
leg
asd
etec
tor
•Pe
riodi
cga
sm
onito
ring
of
the
confi
ned
spac
e(e
very
6
hour
s)
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Co
nfine
dSp
ace
Ass
esso
r
•Pr
ojec
tMan
ager
•XY
Z-A
BC-0
01(E
ntry
in
toC
onfin
edS
pace
)
•XY
Z-A
BC-0
02
(Gas
M
onito
ring)
•Po
orli
ghtin
g(r
esul
ting
tos
lips,
trip
s,fa
lls)
•Ad
equa
teg
ener
alli
ghtin
g
•Pe
rson
alto
rchl
ight
3C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
-
•W
orki
nga
thei
ght
(resu
lting
ins
erio
us
inju
ryfr
onfa
ll)
•En
sure
that
ladd
ers
are
free
from
def
ect
•En
sure
that
ung
uard
ed
light
enin
gho
les/
ope
ning
s
are
cove
red
•Ad
opt3
-ptc
onta
ctw
hen
usin
gla
dder
•Ad
equa
teli
ghtin
gon
ac
cess
way
s
•Sl
owa
ndc
aref
ul
mov
emen
tsw
hile
mak
ing
insp
ectio
n
5A
Med
ium
--
-•
Pipe
For
eman
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
-
02.
Visu
al
insp
ectio
n,
iden
tifica
tion
and
mar
king
of
pipe
spo
ols
(of
pipe
line)
tob
edi
sman
tled.
•Aw
kwar
dpo
stur
e(re
sulti
ngin
er
gono
mic
inju
ries)
•O
bser
vep
rope
rbod
ypo
stur
e
•En
sure
ade
quat
ew
orki
ng
spac
e/p
latf
orm
2B
Low
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
-
•Sl
ippe
ry/
Wet
su
rfac
es(r
esul
ting
in
slip
s/tr
ips/
falls
)
•Cl
ean
ups
lippe
ry/
wet
re
sidu
aln
earp
ipel
ine
iden
tified
•Ad
equa
tew
orki
ngli
ghts
•PP
E(s
afet
ysh
oes)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Po
tent
ialo
fbei
ng
stru
ckb
yob
ject
du
ring
insp
ectio
npr
oces
s(r
esul
ting
in
lace
ratio
nor
bru
ise)
•Pr
oper
PPE
(saf
ety
helm
et)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
03.
Dis
man
tling
of
iden
tified
pi
pes
pool
sby
loos
enin
gan
dre
mov
ing
fast
ener
sin
way
of
flan
ged
pipe
co
nnec
tions
,us
ing
hand
tool
s.
Han
dto
ols
incl
ude
span
ners
,ha
mm
ero
rch
isel
.
•Ig
nitio
nof
resi
dual
s/c
ombu
stib
les
(resu
lting
infi
rea
nd
expl
osio
n)
•H
ighl
ight
spe
cific
di
sman
tling
requ
irem
ents
in
VSC
Cm
eetin
g
•Va
lid‘d
ism
antli
ngo
fpip
es’
perm
it
•Lo
ckou
t-ta
gout
(LO
TO)t
ois
olat
esy
stem
.
•Pr
omin
entd
ispl
ayo
fap
prop
riate
sig
nboa
rds
ata
llen
tran
ces
toth
eco
nfine
dsp
ace
•U
seo
fade
quat
efla
me
proo
flig
hts
with
cab
les
in
good
con
ditio
n
•N
o‘h
ot-w
ork’
inth
eco
nfine
dsp
ace
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Sh
ipE
ngin
eer/
O
ffice
r
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•XY
Z-A
BC-0
03(P
erm
itto
wor
kSy
stem
)
•XY
Z-A
BC-0
04
(Dis
man
tling
/Tes
ting
ofO
il,G
as,C
hem
ical
&
Ste
amP
ipel
ines
/Va
lves
&H
eatin
gCo
ils)
•Po
tent
ialo
ftox
ic
gase
s,va
pour
sor
fu
mes
(res
ultin
gin
po
ison
ing)
•Ad
equa
tev
entil
atio
n
•Po
rtab
leg
asd
etec
tor
•Im
med
iate
eva
cuat
ion
of
the
confi
ned
spac
eup
on
dete
ctio
nof
toxi
cga
s(b
riefin
gto
wor
kers
)
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Sl
ippe
ry/
Wet
su
rfac
es(r
esul
ting
in
slip
s/tr
ips/
falls
)
•U
seo
fcon
tain
ers/
pla
stic
ba
gsfo
rcol
lect
ing
syst
em
disc
harg
eon
ope
ning
fla
nge
conn
ectio
ns.
•St
and-
byo
ilsp
illc
ontr
ol
equi
pmen
t(ra
gs,s
awd
ust,
etc)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Aw
kwar
dpo
stur
e(r
esul
ting
in
ergo
nom
icin
jurie
s)
•O
bser
vep
rope
rbod
ypo
stur
e.2
BLo
w-
--
-•
Pipe
For
eman
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Pi
nch
poin
tsa
nd
shar
ped
ges
(han
d&
fin
geri
njur
ies)
•Br
iefin
gon
avo
idan
ceo
fth
epi
nch
poin
thaz
ards
of
dism
antle
dpi
pes
•Pr
oper
PPE
(use
ofh
and
glov
es)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Po
tent
ialo
fbei
ng
stru
ckb
yob
ject
du
ring
ham
mer
ing
proc
ess
(res
ultin
gin
la
cera
tion
orb
ruis
e)
•M
aint
ain
prop
erte
chni
que
onfa
sten
erre
mov
al.
•Pr
oper
han
dto
ols
•PP
E
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
04.
Secu
ring
and
rem
oval
ofp
ipe
spoo
lout
oft
he
posi
tion
and
outo
fcon
fined
sp
ace.
•Pi
nch
poin
ts
and
shar
ped
ges
(res
ultin
gin
han
d&
fin
geri
njur
ies)
•M
aint
ain
prop
er
com
mun
icat
ion/
co
-ord
inat
ion
amon
gco
-w
orke
rs
•Pr
oper
PPE
(Use
ofh
and
glov
esa
tall
times
)
2C
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rsu
perv
isor
•Pi
pew
orke
r
•Po
tent
ialo
fbei
ng
stru
ckb
yob
ject
du
ring
liftin
gor
ha
ndlin
gpr
oces
s(re
sulti
ngin
la
cera
tion
orb
ruis
e)
•Q
ualifi
edri
gger
tos
ecur
edi
sman
tled
pipe
forl
iftin
gpr
iort
ore
mov
alo
flas
t2
fast
ener
s
•U
seo
fval
idli
ftin
gge
ars
(slin
gw
ires/
web
bing
slin
g)
•U
seo
fgui
dero
pe
•Ba
rric
ade
liftin
gzo
ne
•M
aint
ain
com
mun
icat
ion
betw
een
liftin
gcr
ewa
nd
co-w
orke
rs
•Pr
esen
ceo
fLift
ing
Supe
rvis
or
•Br
iefin
gof
the
liftin
gpl
anb
efor
eth
elif
ting
oper
atio
ns
•Su
perv
isor
toe
nsur
eth
at
allw
orke
rsn
otin
volv
ed
inth
elif
ting
oper
atio
nar
ecl
earf
rom
the
liftin
gzo
ne.
•Si
gnal
men
tob
est
atio
ned
atd
esig
nate
dlo
catio
ns
5A
Med
ium
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
•Pi
pew
orke
r
XYZ-
ABC
-05
(Lift
ing
Ope
ratio
ns)
05.
Hou
seke
epin
gSl
ippe
ry/w
ets
urfa
ces
(res
ultin
gin
slip
s/tr
ips/
falls
)
Rem
ove
allo
il/oi
lyw
ater
co
ntai
ners
/bag
sfr
omth
eta
nka
ndc
lean
the
affec
ted
area
.
2A
Low
--
--
•Pi
peF
orem
an
•Pi
peC
harg
eman
•Pi
pe
Subc
ontr
acto
rSu
perv
isor
•Pi
pew
orke
r
72 73
10.6Annex6:EnergyIsolationandLockoutMethods10.6.1 LockoutDevicesBeforeaworkercarriesoutworkinaconfinedspace,theAuthorisedManagershouldensurethatalloftheenergisedsystemsthatarepartoftheconfinedspacearedisconnectedfromthepowersource,andthecontrolsarelockedout,andremainlockedout,topreventaccidentalstart-up.Energisedsystemsincludeelectrical,mechanical,steam,compressed(pneumatic)gas,hydraulic,gravity,wind,andradiationdevices.
Lockoutmeansthedisconnection,blockingorbleedingofallsourcesofenergythatmaycreateamotionoractionbyanypartofamachineanditsauxiliaryequipment.
Figure 27: Example of an electrical lockout.
Figure 28: Example of valves and piping lockout.
10.6.2 MethodsofIsolationfromContaminantsAconfinedspaceshouldbeisolatedbeforeentryispermitted.Themethodofisolationshouldbe in accordance with one of the following methods or by an alternative method ensuringequivalentsecurity:
• Removethespoolpieceorexpansion joint inpipingthat leadstoentranceof theconfinedspaceandthenblankorcapitsopenend.Theblankorcapshouldbeidentifiedtoindicateitspurpose.Blanksorcapsshouldbeofamaterialthatiscompatiblewiththeliquid,vapourorgaswithwhichtheyareincontact.Thematerialshouldalsohavesufficientstrengthtowithstandthemaximumoperatingpressure,includingsurges,whichcanbuildupinthepiping.
Figure 30: Example of isolation by inserting a spade (blank) in piping between the flanges.
• Insertion of a suitable full-pressure spade (blank) in piping between the flanges near theconfinedspace.Thefull-pressurespade(blank)shouldbeidentifiedtoindicateitspurpose.
Figure 29: Example of isolation by discounting/removing a spool piece or expansion joint from piping systems.
Spade(Blank)
Removetheexpansionjoint Blankthepiping’sopenend
An energy-isolating device is a mechanical device thatphysically prevents the transmission or release of energy,includingbutnotlimitedtothefollowing:
• Amanuallyoperatedelectricalcircuitbreaker;
• Adisconnectswitch;
• Amanuallyoperatedswitchbywhich theconductorsof a circuit can be disconnected from all ungroundedsupply conductors and, in addition, no pole can beoperatedindependently;
• Alinevalve;
• Ablock;and
• Anysimilardeviceusedtoblockorisolateenergy.
Push buttons, selector switches and other control circuittypedevicesarenotenergyisolatingdevices.
The Authorised Manager must ensure that all lines andsystems that may allow hazardous materials to enter aconfinedworkspaceareblankedoff.Materialusedintheconstructionoftheblankmusttakethelinepressureandcorrosionpropertiesintoconsideration.
Where it is impractical to employ blanks or blinds, as inwelded piping systems, develop and implement safeworkprocedures thatensureequivalentprotection forallworkersexposedtothehazard.
External processes, for example, heating or refrigeratingmethods,shouldalsobeconsideredastheyarecapableofadverselyaffectingtheconfinedspace.
74 75
CONFINEDSPACEPLANCHECKLIST
WorkplaceName:WorkplaceNo:Date:
ElementsofConfinedSpacePlanReferenceDocumentName&No
yes No
1.ResponsibilitiesofPersonnel
i) Havethefollowingkeypersonnelwhoareinvolvedinconfinedspaceentryorworkbeenappointed?
• AuthorisedManager • ConfinedSpaceSafetyAssessor • ConfinedSpaceAttendant • RescuePersonnel
ii) Arethedutiesandresponsibilitiesofallemployees(includingkeypersonnel)clearlystipulated?
2.ConfinedSpaceIdentification
i) Haveyouidentifiedalltheconfinedspaceswithinyourworkplace?
ii) Doyoukeeparecordofallidentifiedconfinedspaces?
ii) Haveallaffectedemployeesbeeninformedoftheexistenceoftheseconfinedspacesandwarnedofthepossiblehazards?
3.RiskAssessment
i) Haveallconfinedspaceentryorworkbeenevaluatedtoassessthenecessityofconductingsuchworkwithintheworkplace?
ii) Hasariskassessmentbeenconductedtoidentify,evaluateandcontrolallrisksarisingfromentryorworkinconfinedspaces?
iii) Aretheriskcontrolmeasuresselectedbasedonthehierarchyofcontrolformanagementofconfinedspacehazards?
iv) Areconfinedspacehazardsre-evaluatedwhennewoperationsorworkproceduresareintroducedorwhencurrentoperationsorworkproceduresarealtered?
4.SafeWorkProcedures&ConfinedSpaceEntryPermit
i) Havesafeworkproceduresbeenestablishedforallconfinedspaceworks?
ii) Dothesafeworkproceduresforconfinedspacecoverthefollowingkeyareas?
• Evaluationoftheneedtoenterorcarryoutworkintheconfinedspaceidentified?
• Aconfinedspaceentrypermit; • Thetypesofatmospherictestingrequiredandthe
interpretationofresultsofthetests; • Thesafetyandhealthprecautionstobetaken
duringentryintotheconfinedspaceandduringanemergencysituation;
• Theprovisionandsafeuseofsafetyequipmentandpersonalprotectiveequipment;and
• Themeanstopreventunauthorisedentryintotheconfinedspace,includingthedisplayofwarningsigns.
iii) Arethefollowinginformationprovidedontheconfinedspaceentrypermit?
• Thelocationandidentityoftheconfinedspace; • Thepurposeofentryintotheconfinedspace; • Theresultsofthegastestingoftheatmosphereof
theconfinedspace;and • Thevalidityoftheconfinedspaceentrypermit.
iv) Isacopyoftheconfinedspaceentrypermitandasketchofworkareadisplayedprominentlyattheentrancetotheconfinedspace?
v) Areidentificationbadgesofentrantsdisplayedattheentrancetotheconfinedspace?
vi) Aretheentrypermitskeptforaminimumof2yearsfromthedateofapproval?
5.Atmospherictestingandmonitoring
i) IsthespacetestedbyaCSSAforoxygenlevels,flammableand/ortoxicgases,vapoursorfumesbeforeanentrypermitisissued?
ii) Arethetestresultswithintheacceptablecriteria?
iii) Areallconfinedspaceopeningsbarricadedorguardedproperlyafteropening?
iv) Istheatmosphereinthespacetestedatperiodicintervalssubsequently?
v) Aretheperiodictestresultsrecorded?
6.VentilationProvisions
i) Isadequateventilationprovidedandmaintainedatalltimesintheconfinedspaceduringthevalidityoftheconfinedspaceentrypermit?
ii) Istheairsupplyfortheventilationsystemfromasourceorareawhichisfreeofcontaminants?
7.GeneralSafetyProvisions
i) Aresafemeansofaccessandegressprovidedforthemovementofentrantstoandwithintheconfinedspace?timesintheconfinedspaceduringthevalidityoftheconfinedspaceentrypermit?
ii) Areallpressurisedconfinedspacesdepressurisedandrenderedsafepriortoopening?
iii) Areallconfinedspaceopeningsbarricadedorguardedproperlyafteropening?
iv) Areallconfinedspaceopeningscoveredeffectivelytopreventobjectsfromfallingthrough?
v) Istheresufficientandsuitablelightingprovidedforentryintoandworkinconfinedspace?
vi) Areallelectricalinstallationandequipmentusedofgoodconstruction,soundmaterialandproperlymaintained?
vii) Areallmovingpartsandequipmentinsidetheconfinedspacelockedoutandtagged?
viii)Arewarningsignspostedattheentrancesofconfinedspace?
8.EmergencyPreparednessandRescue
i) Isawrittenrescueplanestablished?
ii) Areallpressurisedconfinedspacesdepressurisedandrenderedsafepriortoopening?
iii) Areallconfinedspaceopeningsbarricadedorguardedproperlyafteropening?
iv) Areallconfinedspaceopeningscoveredeffectivelytopreventobjectsfromfallingthrough?
v) Istheresufficientandsuitablelightingprovidedforentryintoandworkinconfinedspace?
vi) Arerecordsofeverytestandexaminationoftherescueequipmentbyacompetentpersonavailableforinspection?
v) Areregulardrillsconducted?
9.Training
i) Havethepersonsenteringtheconfinedspacereceivedadequatesafetyandhealthtrainingpertainingtothehazardsassociatedwithentry/workintheconfinedspace?
ii) Haveallappointedrescuepersonnelreceivedadequatetraininginrescueoperation,includingfirstaidandproperusageofpersonalprotectiveequipmentandotherrescueequipment?
iii) Aretrainingrecordsmaintainedandmadeavailableforinspection?
• Whereneitherofthemethodsdescribedinitem(a)nor(b)ispracticable,isolationbymeansofclosingandlocking,orclosingandtagging,orboth,ofatleasttwovalvesinthepipingleadingtotheconfinedspaceisrecommended.Adrainvalvebetweenthetwoclosedvalvesshouldalsobekeptandtaggedopentoatmosphereaspartofthismethod.
10.6.3 MethodsofIsolationfromMovingPartsBeforeentryispermittedtoanyconfinedspacethatinitselfcanmove,orinwhichagitators,fans or other moving parts which may pose a risk to personnel are present, the possibilityof movement should be prevented by using one of the methods described below or byalternative methods offering equivalent security. Equipment or devices with stored energy,including hydraulic, pneumatic, electrical, chemical, mechanical, thermal or other types ofenergy,shouldbereducedtoazeroenergycondition.
Thepersonenteringtheconfinedspaceshouldproceedasfollows:
• Thepersonenteringtheconfinedspaceoracompetentpersonauthorisedinwritingbytheemployershouldplacealockortag,orboth,ontheopencircuitbreakeroropenisolatingswitch supplying electric power to equipment with hazardous moving parts. This is toindicatethatapersonisinaconfinedspaceandthatsuchisolationshouldnotberemoveduntilallpersonshavelefttheconfinedspace.Whenalockisused,thekeyshouldbekeptinthepossessionofthepersonmakingentryorthecompetentperson.Sparekeysshouldnotbeaccessibleexceptincasesofemergency.
• Whereapowersourcecannotbecontrolledreadilyoreffectively,abeltorothermechanicallinkageshouldbedisconnectedandtaggedtoindicatethatapersonisinaconfinedspace,andthatthebeltorlinkageshouldnotbereconnecteduntilallpersonshavelefttheconfinedspace.
• Wherethemethodsdescribedinitems(a)and(b)arenotpracticable,moveablecomponentsshouldbelocked,andswitches,clutchesorothercontrolsshouldbetaggedtoindicatethatapersonisinaconfinedspace.Thelocksandtagsshouldnotberemoveduntilallpersonshavelefttheconfinedspace.
• Wheremorethanonepersonisintheconfinedspace,theisolatingdeviceshouldbeeither:
i) lockedortagged,orboth,byeachpersonenteringtheconfinedspace;or
ii) lockedortagged,orboth,byacompetentpersonauthorisedinwritingbytheemployer.
• Wherethe lockingor tagging isundertakenbyacompetentpersonauthorised inwritingbytheemployer,allpersonsenteringtheconfinedspaceshouldverify,orhaveitverifiedtothem,thatisolationiseffectivebeforetheirentry.
10.6.4 RemovalofMeansofIsolationThelocks,tags,blanksorotherprotectivesystemsshouldonlyberemovedafterthecompetentperson, authorised in writing by the employer, ensures that work has been suspended orcompleted,andallpersonshavevacatedtheconfinedspace.
10.7Annex7:ConfinedSpacePlanChecklist
76 77
CONFINEDSPACEPLANCHECKLIST
WorkplaceName:WorkplaceNo:Date:
ElementsofConfinedSpacePlanReferenceDocumentName&No
yes No
1.ResponsibilitiesofPersonnel
i) Havethefollowingkeypersonnelwhoareinvolvedinconfinedspaceentryorworkbeenappointed?
• AuthorisedManager • ConfinedSpaceSafetyAssessor • Confinedspaceattendant • RescuePersonnel
ii) Arethedutiesandresponsibilitiesofallemployees(includingkeypersonnel)clearlystipulated?
2.ConfinedSpaceIdentification
i) Haveyouidentifiedalltheconfinedspaceswithinyourworkplace?
ii) Doyoukeeparecordofallidentifiedconfinedspaces?
ii) Haveallaffectedemployeesbeeninformedoftheexistenceoftheseconfinedspacesandwarnedofthepossiblehazards?
3.RiskAssessment
i) Haveallconfinedspaceentryorworkbeenevaluatedtoassessthenecessityofconductingsuchworkwithintheworkplace?
ii) Hasariskassessmentbeenconductedtoidentify,evaluateandcontrolallrisksarisingfromentryorworkinconfinedspaces?
iii) Aretheriskcontrolmeasuresselectedbasedonthehierarchyofcontrolformanagementofconfinedspacehazards?
iv) Areconfinedspacehazardsre-evaluatedwhennewoperationsorworkproceduresareintroducedorwhencurrentoperationsorworkproceduresarealtered?
4.SafeWorkProcedures&ConfinedSpaceEntryPermit
i) Havesafeworkproceduresbeenestablishedforallconfinedspaceworks?
ii) Dothesafeworkproceduresforconfinedspacecoverthefollowingkeyareas?
• Evaluationoftheneedtoenterorcarryoutworkintheconfinedspace;
• Aconfinedspaceentrypermit; • Thetypesofatmospherictestingrequiredand
theinterpretationofresultsofthetests; • Thesafetyandhealthprecautionstobetaken
duringentryintotheconfinedspaceandduringanemergencysituation;
• TheprovisionandsafeuseofsafetyequipmentandPPE;and
• Themeanstopreventunauthorisedentryintotheconfinedspace,includingthedisplayofwarningsigns.
iii) Arethefollowinginformationprovidedontheconfinedspaceentrypermit?
• Thelocationandidentityoftheconfinedspace; • Thepurposeofentryintotheconfinedspace; • Theresultsofthegastestingoftheatmosphereof
theconfinedspace;and • Thevalidityoftheconfinedspaceentrypermit.
iv) Isacopyoftheconfinedspaceentrypermitandasketchofworkareadisplayedprominentlyattheentrancetotheconfinedspace?
v) Areidentificationbadgesofentrantsdisplayedattheentrancetotheconfinedspace?
vi) Aretheentrypermitskeptforaminimumof2yearsfromthedateofapproval?
5.AtmosphericTestingandMonitoring
i) IsthespacetestedbyaCSSAforoxygenlevels,flammableand/ortoxicgases,vapoursorfumesbeforeanentrypermitisissued?
ii) Arethetestresultswithintheacceptablecriteria?
iii) Aretheresultsrecordedontheentrypermit?
iv) Istheatmosphereinthespacetestedatperiodicintervalssubsequently?
v) Aretheperiodictestresultsrecorded?
6.VentilationProvisions
i) Isadequateventilationprovidedandmaintainedatalltimesintheconfinedspaceduringthevalidityoftheconfinedspaceentrypermit?
ii) Istheairsupplyfortheventilationsystemfromasourceorareawhichisfreeofcontaminants?
7.GeneralSafetyProvisions
i) Aresafemeansofaccessandegressprovidedforthemovementofentrantstoandwithintheconfinedspace?timesintheconfinedspaceduringthevalidityoftheconfinedspaceentrypermit?
ii) Areallpressurisedconfinedspacesdepressurisedandrenderedsafepriortoopening?
iii) Areallconfinedspaceopeningsbarricadedorguardedproperlyafteropening?
iv) Areallconfinedspaceopeningscoveredeffectivelytopreventobjectsfromfallingthrough?
v) Istheresufficientandsuitablelightingprovidedforentryintoandworkinconfinedspace?
vi) Areallelectricalinstallationandequipmentusedofgoodconstruction,soundmaterialandproperlymaintained?
vii) Areallmovingpartsandequipmentinsidetheconfinedspacelockedoutandtagged?
viii)Arewarningsignspostedattheentrancesofconfinedspace?
8.EmergencyPreparednessandRescue
i) Isawrittenrescueplanestablished?
ii) Areallpressurisedconfinedspacesdepressurisedandrenderedsafepriortoopening?
iii) Areallconfinedspaceopeningsbarricadedorguardedproperlyafteropening?
iv) Areallconfinedspaceopeningscoveredeffectivelytopreventobjectsfromfallingthrough?
v) Istheresufficientandsuitablelightingprovidedforentryintoandworkinconfinedspace?
vi) Arerecordsofeverytestandexaminationoftherescueequipmentbyacompetentpersonavailableforinspection?
v) Areregulardrillsconducted?
9.Training
i) Havethepersonsenteringtheconfinedspacereceivedadequatesafetyandhealthtrainingpertainingtothehazardsassociatedwithentry/workintheconfinedspace?
ii) Haveallappointedrescuepersonnelreceivedadequatetraininginrescueoperation,includingfirstaidandproperusageofpersonalprotectiveequipmentandotherrescueequipment?
iii) Aretrainingrecordsmaintainedandmadeavailableforinspection?
CONFINEDSPACEPLANCHECKLIST
WorkplaceName:WorkplaceNo:Date:
ElementsofConfinedSpacePlanReferenceDocumentName&No
yes No
1.ResponsibilitiesofPersonnel
i) Havethefollowingkeypersonnelwhoareinvolvedinconfinedspaceentryorworkbeenappointed?
• AuthorisedManager • ConfinedSpaceSafetyAssessor • Confinedspaceattendant • RescuePersonnel
ii) Arethedutiesandresponsibilitiesofallemployees(includingkeypersonnel)clearlystipulated?
2.ConfinedSpaceIdentification
i) Haveyouidentifiedalltheconfinedspaceswithinyourworkplace?
ii) Doyoukeeparecordofallidentifiedconfinedspaces?
ii) Haveallaffectedemployeesbeeninformedoftheexistenceoftheseconfinedspacesandwarnedofthepossiblehazards?
3.RiskAssessment
i) Haveallconfinedspaceentryorworkbeenevaluatedtoassessthenecessityofconductingsuchworkwithintheworkplace?
ii) Hasariskassessmentbeenconductedtoidentify,evaluateandcontrolallrisksarisingfromentryorworkinconfinedspaces?
iii) Aretheriskcontrolmeasuresselectedbasedonthehierarchyofcontrolformanagementofconfinedspacehazards?
iv) Areconfinedspacehazardsre-evaluatedwhennewoperationsorworkproceduresareintroducedorwhencurrentoperationsorworkproceduresarealtered?
4.SafeWorkProcedures&ConfinedSpaceEntryPermit
i) Havesafeworkproceduresbeenestablishedforallconfinedspaceworks?
ii) Dothesafeworkproceduresforconfinedspacecoverthefollowingkeyareas?
• Evaluationoftheneedtoenterorcarryoutworkintheconfinedspaceidentified?
• Aconfinedspaceentrypermit; • Thetypesofatmospherictestingrequiredand
theinterpretationofresultsofthetests; • Thesafetyandhealthprecautionstobetaken
duringentryintotheconfinedspaceandduringanemergencysituation;
• Theprovisionandsafeuseofsafetyequipmentandpersonalprotectiveequipment;and
• Themeanstopreventunauthorisedentryintotheconfinedspace,includingthedisplayofwarningsigns.
iii) Arethefollowinginformationprovidedontheconfinedspaceentrypermit?
• Thelocationandidentityoftheconfinedspace; • Thepurposeofentryintotheconfinedspace; • Theresultsofthegastestingoftheatmosphereof
theconfinedspace;and • Thevalidityoftheconfinedspaceentrypermit.
iv) Isacopyoftheconfinedspaceentrypermitandasketchofworkareadisplayedprominentlyattheentrancetotheconfinedspace?
v) Areidentificationbadgesofentrantsdisplayedattheentrancetotheconfinedspace?
vi) Aretheentrypermitskeptforaminimumof2yearsfromthedateofapproval?
5.Atmospherictestingandmonitoring
i) IsthespacetestedbyaCSSAforoxygenlevels,flammableand/ortoxicgases,vapoursorfumesbeforeanentrypermitisissued?
ii) Arethetestresultswithintheacceptablecriteria?
iii) Areallconfinedspaceopeningsbarricadedorguardedproperlyafteropening?
iv) Istheatmosphereinthespacetestedatperiodicintervalssubsequently?
v) Aretheperiodictestresultsrecorded?
6.VentilationProvisions
i) Isadequateventilationprovidedandmaintainedatalltimesintheconfinedspaceduringthevalidityoftheconfinedspaceentrypermit?
ii) Istheairsupplyfortheventilationsystemfromasourceorareawhichisfreeofcontaminants?
7.GeneralSafetyProvisions
i) Aresafemeansofaccessandegressprovidedforthemovementofentrantstoandwithintheconfinedspace?
ii) Areallpressurisedconfinedspacesdepressurisedandrenderedsafepriortoopening?
iii) Areallconfinedspaceopeningsbarricadedorguardedproperlyafteropening?
iv) Areallconfinedspaceopeningscoveredeffectivelytopreventobjectsfromfallingthrough?
v) Istheresufficientandsuitablelightingprovidedforentryintoandworkinconfinedspace?
vi) Areallelectricalinstallationandequipmentusedofgoodconstruction,soundmaterialandproperlymaintained?
vii) Areallmovingpartsandequipmentinsidetheconfinedspacelockedoutandtagged?
viii)Arewarningsignspostedattheentrancesofconfinedspace?
8.EmergencyPreparednessandRescue
i) Hasawrittenrescueplanbeenestablished?
ii) Aresufficientsuppliesofrescueequipmentprovided/madereadilyavailable?
iii) Aretherescueequipmentproperlymaintained?
iv) Arerecordsofeverytestandexaminationoftherescueequipmentbyacompetentpersonavailableforinspection?
v) Areregulardrillsconducted?
9.Training
i) Havethepersonsenteringtheconfinedspacereceivedadequatesafetyandhealthtrainingpertainingtothehazardsassociatedwithentry/workintheconfinedspace?
ii) Haveallappointedrescuepersonnelreceivedadequatetraininginrescueoperation,includingfirstaidandproperusageofPPEandotherrescueequipment?
iii) Aretrainingrecordsmaintainedandmadeavailableforinspection?
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11.1 Case1:ExplosionfromChemicalStorageTank
TheIncident:Twoworkerswerekilledwhentheywerewashingthe interiorofachemicalstoragetank inalubricationoilmanufacturingplant.Theywerestandingoutsidethestoragetankandusingthehydro-jettowashitsinteriorwallduringthecleaning.Whenthehydro-jethitthewallofthetank,itcausedasparkwhichignitedanexplosion.
Findings:• Thestoragetankwasnotpurgedorventilatedafterbeingrinsedwithsolvents.Whenthe
solventvapourised,itformedaflammablemixture.
• Theleveloftheflammabilityinthetankwasmorethan100%LEL.
• Thecompanydidnotimplementasafeworkprocedure(SWP)andapermit-to-work(PTW)systemforconfinedspacework.
• Noriskassessmentwasconductedbeforethecleaningofthestoragetanks.
• Nosuitablegas-testinginstrumentwasavailableonsite.Thelevelofflammabilityinsidethestoragetankshadnotbeentestedandcertifiedsafeforcleaning.
• Allworkerswerenottrainedinconfinedspaceworkandnosafetyattendantwasappointedtokeepwatch.
• No ventilation and air monitoring were provided when the workers cleaned the storagetank.
11. CaseStudies
LessonsLearnt:ItisimportantforManagementtoshowcommitmentandput in place an effective WSH management programme.Through this, operations within the organisation wouldbeguidedthroughasafetypolicyandestablishmentofasafetymanagementsystem.
Before carrying out any cleaning work, it is importantto conduct a risk assessment to identify and evaluateany possible hazards. It is necessary to put in place anyreasonably practicable control measures that will help toreducetherisktoanacceptablelevel.
Before the cleaning, it is necessary to rinse and purgethe storage tank thoroughly. It is critical to conduct gastesting to ensure that the level of the flammability is atthe acceptable/safe level for the workers to carry out thecleaning.
Figure 31: Exploded chemical storage tank.
Itisalsoimportanttoappointasafetyattendanttokeepwatchandcontinuouslymonitortheatmospheresothatitismaintainedatacceptable/safelevels.
Inaddition,itisessentialtoestablishsafeworkproceduresandimplementthemtoensurethatstoragetankcleaningcanbecarriedoutsafelywithoutendangeringthesafetyoftheworkersandotherworkersinthevicinity.
11.2Case2:ExposuretoPhosgeneGasduringGasTesting
TheIncident:Somepipelinesofachemicalplantwerecontaminatedwithtoxicgasesduetoprocessdeviation.Theseareasneededtobeisolatedandpurgedtoensurethattheywerefreeoftoxicgases.
After the purging, an engineer was tasked to perform a gas test with a portable phosgenedetectoratavalveoutletbeforehandingovertotheMaintenanceSection.Whilehewasopeningthemanualvalveslowly,suddenly,somephosgenevapoursescapedfromthevalvecausinghimtoinhalethetoxicgas.
The injuredengineerwassubsequentlypulledawaybya technicianandtwosub-contractorswhowerewithhimtowitnessthetest.
Findings:• An isolation valve at the upstream which was connected to the buffer tank was not fully
closed.Thishadcausedthevapourtoleakfromthetankintothepipelines.
• The potential hazard of the workers exposed to the toxic gases during testing of isolatedpipelinesfortoxicgaseswasnotfullyaddressedbythesafeworkprocedures(SWP).
• Allworkerswerenottrainedinconfinedspaceworkandnosafetyattendantwasappointedtokeepwatch.
• Noriskassessmentwasconductedbeforetheengineercarriedoutthegastesting.
• NoonewaswearinganybreathingapparatusduringgastestingalthoughasetofSCBAwasplacedonstandbyoutsidetheroom.
• No ventilation and air monitoring were provided when the engineer conducted the gastesting.
LessonsLearnt:It is important for Management to show commitment and put in place an effective WSHmanagement programme.Through this, operations within the organisation would be guidedthrough a safety policy and establishment of a safety management system and proper workprocedures.
Beforecarryingoutanygastesting, it is importanttoconductriskassessmentto identifyandevaluateanypossiblehazards.Itisnecessarytoputinplaceanyreasonablypracticablecontrolmeasuresthatwillhelptoreducetherisktoanacceptablelevel.
Itiscriticalforallindividualswhocarryoutgastestingtobeproperlytrainedandfullyinstructedonthepotentialhazards inconnectionwith thework. It isalsonecessary for themtoputonappropriateprotectiveequipmentduringthegastesting.
80 81
Itisalsoimportanttoappointasafetyattendanttokeepwatchandcontinuouslymonitortheatmospheresothatitismaintainedatacceptable/safelevels.
Itisessentialtoconductregularleaktestsforallvalves,connectorsandjoints.Theinspectionwillhelptoidentifyanywornoutpartsoranydefectsthatwouldrenderthemunfitforserviceandtorepairorreplacebeforethenextuse.
Inaddition,itisessentialtoestablishsafeworkproceduresandimplementthemtoensurethatgastestingcanbecarriedoutsafelywithoutendangeringthesafetyoftheworkersandotherworkersinthevicinity.
11.3Case3:ToxicPoisoninginFoodReactor
TheIncident:Two workers were tasked to clean a food reactor in the thermal processing room after theproductionofafoodflavour.Thefoodreactorwasabout1.8meterstallandtheywerewashingtheinternalwallfromastandoutsidethereactor.
Duringthewashing,oneof theworkers foundastubbornstainat thebottomof thereactor.Afterseveralattempts,hedecidedtoclimbinsidethereactortoremovethisstain.Whilehewascleaning,hecomplainedofastrongsmellandfaintedinsidethereactor20minuteslater.Inordertorescuehim,hisco-workerclimbedintothereactor.Immediatelytheco-workerfeltdifficultyinbreathingandfaintedtoo.Bothworkersdiedinthisincident.
Findings:• Aconcentrationofhydrogensulphide(H2S)wasdetectedwithinthefoodreactor.H2Scould
beformedunderhightemperaturereactionsduringthemanufacturingoffoodflavours.
• Thecompanydidnotimplementasafeworkprocedure(SWP)andapermit-to-work(PTW)systemforconfinedspacework.
• Allworkerswerenottrainedinconfinedspaceworkandnosafetyattendantwasappointedtokeepwatch.
• Noriskassessmentwasconductedbeforethecleaningofthefoodreactor.
• Nosuitablegas-testing instrumentwasavailableonsitesothe foodreactorhadnotbeentestedandcertifiedsafeforentry.
• No ventilation and air monitoring were provided when the workers entered the foodreactor.
LessonsLearnt:ItisimportantforManagementtoshowcommitmentandputinplaceaneffectiveworkplacesafetyandhealthmanagementprogramme.Throughthis,operationswithintheorganisationwouldbeguidedthroughasafetypolicyandestablishmentofasafetymanagementsystem.
Beforecarryingoutanycleaningandmaintenanceofthereactor, it is importanttoconductariskassessmenttoidentifyandevaluateanypossiblehazards.Itisnecessarytoputinplaceanyreasonablypracticablecontrolmeasuresthatwillhelptoreducetherisktoanacceptablelevel.
It is necessary to establish and implement lockoutproceduresforthecleaningandmaintenanceofthereactor.Thefoodreactorisapressurevesselwithasteamjackettoraise the temperature during production. Therefore, it iscritical for the management to practice due diligence inensuringthattheworkersworkedsafelyinsidethereactor.
It is also important to appoint a safety attendant to keepwatchandcontinuouslymonitortheatmospheresothatitismaintainedatacceptable/safelevels.
It is also important for workers who carry out cleaning ofthefoodreactortobeproperlytrainedandfullyinstructedonthepotentialhazardsinconnectionwiththework.Itisalso necessary for them to put on appropriate protectiveequipmentduringthecleaning.
Inaddition,itisessentialtoestablishsafeworkproceduresandimplementthemtoensurethatfoodreactorcleaningcanbecarriedoutsafelywithoutendangeringthesafetyoftheworkersandotherworkersinthevicinity.
Figure 32: Food reactor.
11.4Case4:DeathbySuffocationAworkerwascarryingoutavisualinspectionintheinterioroftheISOtanktoensurethatthetankwascleanandfreefromresidue.Hewaslaterfoundunconsciousinsidethetankbyhisco-worker.Theworkersuffocatedandwaspronounceddeadonthespot.
Findings:• Nitrogen (N2) was used to expel chemical di-octyl-phthalate (DOP) from the ISO tank and
thereforetheatmosphereinsidethetankwasfilledwithN2.
• Thevolumeoftheoxygenwasfoundbelow19.5%,thereforeitwasnotsafefortheworkertoworkundersuchconditions.
• Thecompanydidnotimplementsafeworkprocedures(SWP)andapermit-to-work(PTW)systemforconfinedspacework.
• Allworkerswerenottrainedinconfinedspaceworkandnosafetyattendantwasappointedtokeepwatch.
• NoriskassessmentwasconductedbeforetheISOtankinspection.
• Nosuitablegas-testinginstrumentwasavailableonsitesotheISOtankhadnotbeentestedandcertifiedsafeforentry.
• NoventilationandairmonitoringwereprovidedwhentheworkerenteredtheISOtank.
• Noproperlightingwasprovidedfortheworkertocarryoutthetankinspection.
LessonsLearnt:ItisimportantforManagementtoshowcommitmentandputinplaceaneffectiveworkplacesafetyandhealthmanagementprogramme.Throughthis,operationswithin theorganisationwouldbeguidedthroughasafetypolicyandestablishmentofasafetymanagementsystem.
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Beforecarryingoutanycleaningwork,itisimportanttoconductariskassessmenttoidentifyand evaluate any possible hazards. It is necessary to put in place any reasonably practicablecontrolmeasuresthatwillhelptoreducetherisktoanacceptablelevel.
Beforetheinspection,itisnecessarytoventilatetheISOtankthoroughly.Itiscriticaltoconductgas testing to ensure that the atmosphere in the tank is safe for the worker to carry out theinspection.
Itisalsoimportanttoappointasafetyattendanttokeepwatchandcontinuouslymonitortheatmospheresothatitismaintainedatacceptable/safelevels.
Itisessentialtoestablishsafeworkproceduresandimplementthemtoensurethattheinspectionof ISOtankcanbecarriedoutsafelywithoutendangeringthesafetyoftheworkerandotherworkersinthevicinity.
ItisimportantforworkerswhocarryouttheISOtankinspectiontobeproperlytrainedandfullyinstructedonthepotentialhazardsinconnectionwiththework.Itisalsonecessaryforthemtoputonappropriateprotectiveequipmentduringtheinspection.
Itiscriticaltoprovideadequateandsuitablelightingwithilluminationofnotlessthan50luxfortheworkerstodotheirinspectionintheISOtanks.Itisalsoimportanttonotethatallportablehand-held lightingsprovided inconfined spaceshall beoperatedatavoltagenotexceedingalternative current (AC) 55 volts between the conductor and earth or direct current (DC) 110volts.
MembersoftheWorkingCommittee
WSHCIndustryCommittees
MrLeeYeokHoon(JurongShipyardPteLtd)Chairman
MrPKRaveendran(SembawangShipyardPteLtd)
MrSohHongKuanBernard(RotaryEngineeringLtd)
MrYeoTiongJoo(OCWSLogisticsPteLtd)
SCIC MrTayChengPheng(ChevronPhillipsChemicalsAsiaPteLtd)
SISO MrWendellHarms(PfizerAsiaPacificPteLtd)
SLP MrSohChengSengJacob(SingaporeRefiningCompanyPteLtd)
EquipmentSafety MsAngSiewLanVeronica(DräegerSafetyAsiaPteLtd)
MOM MsColleenLow
WSHC ErTanKeeChong
ThisTAwasdevelopedwithinputsfrommembersoftheworkingcommittee.WorkplaceSafetyandHealthCouncil(WSHC)wouldliketothankthemfortheirvaluablecontributionstothisTA.
12. Acknowledgements
Thetwoconfinedspacewarningsigns(Figure4)aretakenfromISO7010:2003(P004&W001)andreproducedwithpermission fromthe InternationalOrganisation forStandardisation, ISO.CopyrightremainswithISO.
Thepicturesusedforillustrationpurposes(Figure5,6,7,8,11,12and13)inthisTAarereproducedwithcourtesyofDrägerSafetyAsiaPteLtd.
Thepicturesusedforillustrationpurposes(Figure17,18,19and20)inthisTAarereproducedwithcourtesyofAirSystemsInternational,Inc.
The pictures used for illustration purposes (Figure 14 and 15) in thisTA are reproduced withcourtesyofLandTransportAuthority.
84 85
ThefollowingreferenceswereusedwithpermissiongrantedfromtheindividualorganisationtoWorkplaceSafetyandHealthCouncil(WSHC):
WorkplaceSafetyandHealthAct2005,MinistryofManpower,Singapore.
Workplace Safety and Health (Risk Management) Regulations 2005, Ministry of Manpower,Singapore.
Workplace Safety and Health (Shipbuilding & Ship-repairing) Regulations 2008, Ministry ofManpower,Singapore.
Workplace Safety and Health (Confined Space) Regulations 2009, Ministry of Manpower,Singapore.
WorkplaceSafetyandHealth2008NationalStatistics,WSHCouncil,Singapore.
SingaporeStandardCP84:2000CodeofPracticeforEntry intoandSafeWorkinginConfinedSpace,SPRINGSingapore.
SingaporeStandardCP88 :Part3:2004CodeofPracticeforTemporaryElectrical Installations,Part3:ShipbuildingandShip-repairingYards,SPRINGSingapore.
SingaporeStandardSS508-1:2004GraphicalSymbols—SafetyColoursandSafetySigns—DesignPrinciplesforSafetySignsinWorkplacesandPublicAreas.
SingaporeStandardSS508-3:2004GraphicalSymbols—SafetyColoursandSafetySigns—SafetySignsusedinWorkplacesandPublicAreas.
SingaporeStandardSS508-4:2008SpecificationforGraphicalSymbols—SafetyColoursandSafetySigns—DesignPrinciplesforGraphicalSymbolsforUseinSafetySigns.
SingaporeStandardSS531 :Part1 :2006CodeofPractice forLightingofWorkPlacesPart1:Indoor.
SingaporeStandardSS531 :Part2 :2008CodeofPractice forLightingofWorkPlacesPart2:Outdoor.
SingaporeStandardSS531 :Part3 :2008CodeofPractice forLightingofWorkPlacesPart3:LightingRequirementsforSafetyandSecurityofOutdoorWorkPlaces.
SingaporeStandardSS548:2009CodeofPracticeforSelection,Use,CareandMaintenanceofRespiratoryProtectiveDevices.
13. References AGuidetoSafetyinConfinedSpace,NIOSH,USA.
A Guide to Working Safely in Confined Spaces, Workplace Health and Safety Queensland,Australia.
CodeofPracticeForConfinedSpaceWork,ManitobaLabour&ImmigrationWSH,Canada.
Code of Practice for Working in Confined Spaces — Safe Work in Confined Spaces, NationalAuthorityforOccupationalSafetyandHealth,Ireland.
ConfinedSpaceProgram,OaklandCommunityCollege,USA.
ConfinedSpaceSafePractice,IACS,UK.
Not Designed to be Occupied — How to Work Safely in a Permit-required Confined Space,OregonOSHA,USA.
RequirementsforWorkinConfinedSpaces,UniversityofDelaware,USA.
SafeWorkinConfinedSpace,HealthandSafetyExecutive,OSHA,USA.
SafeWorkinginaConfinedSpace,AustralianStandard,Australia.
Safety in Confined Spaces — Safe Working in a Confined Space, Department of Labour-TeTariMahi,NewZealand.
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Figure1:Numberofworkplacefatalitiesbytypeofincident,2007and2008 09(NationalStatistics,WorkplaceSafety&Health2008).
Figure2:Exampleoftheriskmanagementapproach. 12
Figure3:TheFireTriangle. 15
Figure4:ExamplesofConfinedSpacewarningsigns. 24
Figure5:TypesofRespiratoryProtectiveDevices. 28
Figure6:ExampleofSCBA. 28
Figure7:MorephysicaleffortisrequiredwhenusingSCBAduetotheir 28weightandrestrictiveness.
Figure8:ExampleofAirPurifying(Cartridge)Respirator. 29
Figure9:Testairat3ormoreelevations:top,mid-pointandbottom. 35
Figure10:Atleastonepersoninagroupworkinginthesamevicinityof 36aconfinedspaceisequippedwithaportablegasdetector.
Figure11:Apoisonedcatalystsensor. 37
Figure12:Anexampleofsensitivitychart. 38
Figure13:Exampleof“functiontest”system. 41
Figure14:Exampleofforcedventilationusingblowerasamechanicalair 44movingdevice.
Figure15:Exampleoflocalexhaustventilation. 45
Figure16:Exampleofapush-pullsystem. 46
Figure17:Exampleofaxial-flowfan. 46
Figure18:Exampleofcentrifugal-flowfan. 46
Figure19:Exampleofventurieductor. 47
Figure20:Exampleofflexiblenon-collapsibleducting. 47
Figure21:Anexampleofprovidingeffectiveventilationsystembyusing 48aseriesoffanstomoveairthroughalongconfinedspace.
Figure22:Anexampleofprovidingeffectiveventilationsystemby 48blowingfreshairatthebottomofadeepconfinedspace.
Figure23:Anexampleofpreventingshort-circuitinginaconfinedspace. 49
Figure24:Anexampleofpreventingre-circulatingofexhaustairina 49confinedspace.
Figure25:Anexampleofprovidingeffectiveventilationsystemonhow 50toremovelighter-than-aircontaminants.
Figure26:Anexampleofprovidingeffectiveventilationsystemonhow 50toremoveheavier-than-aircontaminants.
14. ListOfFigures Figure27:Exampleofanelectricallockout. 74
Figure28:Exampleofvalvesandpipinglockout. 74
Figure29:Exampleofisolationbydiscounting/removingaspoolpiece 75orexpansionjointfrompipingsystems.
Figure30:Exampleofisolationbyinsertingaspade(blank)inpipingbetween 75theflanges.
Figure31:Explodedchemicalstoragetank. 80
Figure32:Foodreactor. 83
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15. ListOfTables
Table1:Theeffectsandsymptomsofdifferentlevelsofoxygendeficiency 13onhumans.
Table2:LELandUELvaluesforflammablesubstances. 14
Table3:Examplesofotherhazards,thesituationswheretheycanoccur 16andtheirharmfuleffects.
Table4:Typesofgashazardsandtheirmeasurementprinciples. 32
Table5:Exampleofcorrectionfactorsusingmethaneasacalibrationgas. 39
Table6:Thekeyelementsfortraininginconfinedspacework. 61
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Published in January 2010 by the Workplace Safety and Health Council in collaboration with the Ministry of Manpower.
Allrightsreserved.Thispublicationmaynotbereproducedortransmittedinanyformorbyanymeans,inwholeorinpart,withoutpriorwrittenpermission.Theinformationprovidedinthisguidebookisaccurateasattimeofprinting.Asaguide,thisbooklethasnolegalstanding.TheMinistryofManpowerandtheWorkplaceSafetyandHealthCouncildonotacceptanyliabilityorresponsibilitytoanypartyforlossesordamagearisingfromfollowingtheguidelines.
ThispublicationisavailableontheWorkplaceSafetyandHealthCouncilwebsite:www.wshc.gov.sg
Email:[email protected]
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