Working Safely in Confined Spaces

Technical Advisory on Working Safely in Confined Spaces

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


Oxygenenrichment • Leakingoxygenfromgascuttingequipment,e.g.,cuttingtorch

• Flammablematerialscatchesfiremoreeasily

Combustibleparticulates • Flourmills→airborneflourdust


• Fire/explosion


• Painting,cleaning→solvent/acidexposure


• Skinburns• Systemiceffects,e.g.,

liverpoisoning,blooddisorders,ifabsorbedthroughskinintobloodstream

Heat • Poormechanicalventilation

• Crowdedspace• Hotwork• Heatgenerating

machinery• Thick/heavyprotective


• Heatcramps,heatexhaustion,heatstroke

Noise




Ergonomichazards

• Limitedspace• Awkwardworking

position,e.g.,manualhandling/lifting


Poorlighting Insufficientartificiallighting Slips,trips,falls

Roadtraffic Roadmanholeworkwithoutpropercordoningortrafficdiversion

Injury,death




Trappedinsidematerial→ breathingdifficulty→suffocation

Entrapment Taperingorinwardlyslopingandsmoothwalls,e.g.,cyclones

Trappedatbottomend,breathingdifficulty → asphyxiation

Mechanicalhazards Movingorrotatingparts,e.g.,belts,gears

Injury,death


electricalcables• Noprovisionofgrounding• Wetspaces• Humidenvironment→

decreasedelectricalresistance

Electrocution→burns,death




Severeinjury,drowning,death




Injury,death

Radiation • UltravioletandInfraredradiationfromwelding

• Non-destructivetesting(Xray)• Maintenanceoflevel

instrumentationusingradioactiveisotopes

• Skinburns,cataract,arceye,geneticchanges,cancer

Asbestos • Removalofpartitionwallsinships

• Asbestosis,mesothelioma,lungcancer



• Death



• Gastrointestinaldisease,hepatitisAandpoisoning

16 17


Oxygenenrichment • Leakingoxygenfromgascuttingequipment,e.g.,cuttingtorch

• Flammablematerialscatchesfiremoreeasily

Combustibleparticulates • Flourmills→airborneflourdust


• Fire/explosion


• Painting,cleaning→solvent/acidexposure


• Skinburns• Systemiceffects,e.g.,

liverpoisoning,blooddisorders,ifabsorbedthroughskinintobloodstream

Heat • Poormechanicalventilation

• Crowdedspace• Hotwork• Heatgenerating

machinery• Thick/heavyprotective


• Heatcramps,heatexhaustion,heatstroke

Noise




Ergonomichazards

• Limitedspace• Awkwardworking

position,e.g.,manualhandling/lifting


Poorlighting • Insufficientartificiallighting • Slips,trips,falls

Roadtraffic • Roadmanholeworkwithoutpropercordoningortrafficdiversion

• Injury,death




• Trappedinsidematerial→ breathingdifficulty→suffocation

Entrapment • Taperingorinwardlyslopingandsmoothwalls,e.g.,cyclones

• Trappedatbottomend,breathingdifficulty → asphyxiation

Mechanicalhazards • Movingorrotatingparts,e.g.,belts,gears

• Injury,death


electricalcables• Noprovisionofgrounding• Wetspaces• Humidenvironment

→ decreasedelectricalresistance

• Electrocution→burns,death




• Severeinjury,drowning,death




• Injury,death

Radiation • Ultravioletandinfraredradiationfromwelding

• Non-destructivetesting(Xray)

• Maintenanceoflevelinstrumentationusingradioactiveisotopes

Skinburns,cataract,arceye,geneticchanges,cancer

Asbestos Removalofpartitionwallsinships

Asbestosis,mesothelioma,lungcancer



Death



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

20 21

• 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=

42 43

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.

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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


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)


Communicationprocedureswithotherpersonnelinvolvedinconfinedspacework,inparticularstandbyattendants(Includecommunicationduringroutineworkandemergencies)

Emergencyresponseplan(Includeidentificationofhazardousconditions,evacuationconditionsandself-rescueprocedures)

Usageandlimitationsofportablegasinstrumentsandresponsetoalarms(Includeunderstandingtheresponsesandreadingsofgasinstrumentsinnormalatmosphericconditionsandabnormalconditionssuchasoxygendeficiencyandtoxicatmospheres)


(Includesusageofrescueandpersonalprotectiveequipmentusedforrescueinconfinedspaceswithhazardousconditions,entryandnon-entryrescuemethodsandretrievaltechniquesforinjuredpersonnel)





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)


Communicationprocedureswithotherpersonnelinvolvedinconfinedspacework,inparticularstandbyattendants(Includecommunicationduringroutineworkandemergencies)

Emergencyresponseplan(Includeidentificationofhazardousconditions,evacuationconditionsandself-rescueprocedures)

Usageandlimitationsofportablegasinstrumentsandresponsetoalarms(Includeunderstandingtheresponsesandreadingsofgasinstrumentsinnormalatmosphericconditionsandabnormalconditionssuchasoxygendeficiencyandtoxicatmospheres)


(IncludesusageofrescueandPPEforrescueinconfinedspaceswithhazardousconditions,entryandnon-entryrescuemethodsandretrievaltechniquesforinjuredpersonnel)




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


STAGEIII:ISSUANCEByAUTHORISEDMANAGER

Iamsatisfiedthat: (a) thelevelsofoxygen,flammablegasandtoxicsubstancesarewithinthepermissiblerange.(Referto StageII)

(b)theconfinedspaceisadequatelyventilated.

(c) effectivestepshavebeentakentopreventanyingressofdangerousgases,vapoursoranyotherdangerous substancesintotheconfinedspace.

(d)allreasonablypracticablemeasureshavebeentakentoensurethesafetyandhealthofpersons whowillbeenteringorworkingintheconfinedspace.


STAGEIVa:POSTINGOFENTRyPERMIT

Ishallensurethatthecopyoftheentrypermitispostedattheentrancetotheconfinedspace,includingwherereasonablypracticable,asketchoftheareawithintheconfinedspacewheretheentryistobemadeorworkistobeconducted.



Thepermithasbeenremovedforthefollowingreasons:

Remarks:


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.


• Suppliedairrespiratorsshouldbeworn.

10.2.2 BrushandRollerPainting• Dilutionorforcedventilationshouldbeprovidedtodilutethesolventvapourstobelow

theirPELs.

• Theblowersshouldbelocatedoutsidetheconfinedspace.

• Therequiredairflowratedependsontheamountofpaintusedandthe%ofsolventsinthepaint:

• Theairshouldbesuppliedatornearthepersonscarryingoutthework.


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:


Note: 1. Thenecessarysafetymeasuresmustbecompliedwithbeforetheapplicationishandedovertotheconfinedspace safetyassessorforhisevaluation.

2. Wherereasonablypracticable,applicanttoprovideasketchoftheareawithintheconfinedspace

Wheretheentryistobemadeorworkistobeconductedonaseparatesheetofpaperandattachitwiththepermit.

STAGEII:EVALUATIONByCONFINEDSPACESAFETyASSESSOR


STAGEIII:ISSUANCEByAUTHORISEDMANAGER

Iamsatisfiedthat: (a) thelevelsofoxygen,flammablegasandtoxicsubstancesarewithinthepermissiblerange.(Referto StageII)

(b)theconfinedspaceisadequatelyventilated.

(c) effectivestepshavebeentakentopreventanyingressofdangerousgases,vapoursoranyotherdangerous substancesintotheconfinedspace.

(d)allreasonablypracticablemeasureshavebeentakentoensurethesafetyandhealthofpersons whowillbeenteringorworkingintheconfinedspace.



Ishallensurethatthecopyoftheentrypermitispostedattheentrancetotheconfinedspace,includingwherereasonablypracticable,asketchoftheareawithintheconfinedspacewheretheentryistobemadeorworkistobeconducted.


STAGEIVb:NOTIFICATIONOFREMOVALOFENTRyPERMIT

Thepermithasbeenremovedforthefollowingreasons:

Remarks:


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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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.

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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

.

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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

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ckou

t-ta

gout

(LO

TO)t

ois

olat

esy

stem

.

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omin

entd

ispl

ayo

fap

prop

riate

sig

nboa

rds

ata

llen

tran

ces

toth

eco

nfine

dsp

ace

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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

)

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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

.

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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

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pew

orke

r

Pote

ntia

lofb

eing

st

ruck

by

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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

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aint

ain

com

mun

icat

ion

betw

een

liftin

gcr

ewa

nd

co-w

orke

rs

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esen

ceo

fLift

ing

Supe

rvis

or

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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

.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(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

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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?


iv) Areallconfinedspaceopeningscoveredeffectivelytopreventobjectsfromfallingthrough?

v) Istheresufficientandsuitablelightingprovidedforentryintoandworkinconfinedspace?

vi) Areallelectricalinstallationandequipmentusedofgoodconstruction,soundmaterialandproperlymaintained?

vii) Areallmovingpartsandequipmentinsidetheconfinedspacelockedoutandtagged?

viii)Arewarningsignspostedattheentrancesofconfinedspace?

8.EmergencyPreparednessandRescue

i) Isawrittenrescueplanestablished?





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




yes No



• AuthorisedManager • ConfinedSpaceSafetyAssessor • Confinedspaceattendant • RescuePersonnel






3.RiskAssessment








• Evaluationoftheneedtoenterorcarryoutworkintheconfinedspace;

• Aconfinedspaceentrypermit; • Thetypesofatmospherictestingrequiredand

theinterpretationofresultsofthetests; • Thesafetyandhealthprecautionstobetaken


• TheprovisionandsafeuseofsafetyequipmentandPPE;and








5.AtmosphericTestingandMonitoring



iii) Aretheresultsrecordedontheentrypermit?







i) Aresafemeansofaccessandegressprovidedforthemovementofentrantstoandwithintheconfinedspace?timesintheconfinedspaceduringthevalidityoftheconfinedspaceentrypermit?









i) Isawrittenrescueplanestablished?





vi) Arerecordsofeverytestandexaminationoftherescueequipmentbyacompetentpersonavailableforinspection?


9.Training


ii) Haveallappointedrescuepersonnelreceivedadequatetraininginrescueoperation,includingfirstaidandproperusageofpersonalprotectiveequipmentandotherrescueequipment?





yes No



• AuthorisedManager • ConfinedSpaceSafetyAssessor • Confinedspaceattendant • RescuePersonnel






3.RiskAssessment








• Evaluationoftheneedtoenterorcarryoutworkintheconfinedspaceidentified?

• Aconfinedspaceentrypermit; • Thetypesofatmospherictestingrequiredand

theinterpretationofresultsofthetests; • Thesafetyandhealthprecautionstobetaken


• Theprovisionandsafeuseofsafetyequipmentandpersonalprotectiveequipment;and








5.Atmospherictestingandmonitoring










i) Aresafemeansofaccessandegressprovidedforthemovementofentrantstoandwithintheconfinedspace?









i) Hasawrittenrescueplanbeenestablished?

ii) Aresufficientsuppliesofrescueequipmentprovided/madereadilyavailable?

iii) Aretherescueequipmentproperlymaintained?

iv) Arerecordsofeverytestandexaminationoftherescueequipmentbyacompetentpersonavailableforinspection?


9.Training


ii) Haveallappointedrescuepersonnelreceivedadequatetraininginrescueoperation,includingfirstaidandproperusageofPPEandotherrescueequipment?


78 79

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).


• 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


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.


• 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.


• NoriskassessmentwasconductedbeforetheISOtankinspection.

• Nosuitablegas-testinginstrumentwasavailableonsitesotheISOtankhadnotbeentestedandcertifiedsafeforentry.

• NoventilationandairmonitoringwereprovidedwhentheworkerenteredtheISOtank.

• Noproperlightingwasprovidedfortheworkertocarryoutthetankinspection.

LessonsLearnt:ItisimportantforManagementtoshowcommitmentandputinplaceaneffectiveworkplacesafetyandhealthmanagementprogramme.Throughthis,operationswithin theorganisationwouldbeguidedthroughasafetypolicyandestablishmentofasafetymanagementsystem.

82 83

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.


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.

86 87

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

88 89

15. ListOfTables

Table1:Theeffectsandsymptomsofdifferentlevelsofoxygendeficiency 13onhumans.

Table2:LELandUELvaluesforflammablesubstances. 14

Table3:Examplesofotherhazards,thesituationswheretheycanoccur 16andtheirharmfuleffects.

Table4:Typesofgashazardsandtheirmeasurementprinciples. 32

Table5:Exampleofcorrectionfactorsusingmethaneasacalibrationgas. 39

Table6:Thekeyelementsfortraininginconfinedspacework. 61

90 91

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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Working Safely in Confined Spaces