1 General
1.1 ThepresentGuidanceNotehasbeendevelopedforthesafeconductofCASSurveys.Although thisGuidanceNotemakesexplicitreferencetotheCASsurveyandtoattendingsurveyor(s)itshouldbe usedalsoinconnectionwithanythicknessmeasurementworkrequiredbytheCAS.
2 Conditionsforsurvey
2.1 TheCompanyshouldprovidethenecessaryfacilitiesforasafeconductoftheCASsurvey.
2.2 In cases where the provisions of safety and required access are judged by the attending surveyor(s)nottobeadequate,theCASsurveyofthespacesinvolvedshouldnotproceed.
2.3 Inordertoenabletheattendingsurveyor(s)tocarryouttheCASsurvey,provisionsforproper andsafeaccessshouldbeagreedbetweenCompanyandRecognisedOrganisation.
2.4 DetailsofthemeansofaccessareprovidedintheSurveyPlanningQuestionnaire.
2.5 Tanksandspacesshouldbesafeforaccess*.Tanksandspacesshouldbegasfreeandshouldbe ventilated.Priortoenteringatank,voidorenclosedspace,itshouldbeverifiedthattheatmosphereinthe tankisfreefromhazardousgasandcontainssufficientoxygen.
2.6 Tanksandspacesshouldbesufficientlycleanandfreefromwater,scale,dirt,oilresidues, corrosionscale,sedimentsetc.,torevealsignificantcorrosion,deformation,fractures,damagesorother structuraldeteriorationaswellastheconditionofthecoating. Inparticularthisappliestoareasthatare subjecttothicknessmeasurement.
2.7 Sufficientilluminationshouldbeprovidedtorevealsignificantcorrosion,deformation,fractures, damagesorotherstructuraldeteriorationaswellastheconditionofthecoating.
2.8 Where soft coatings have been applied, safe access should be provided for the attending surveyor(s)toverifytheeffectivenessofthecoatingandtocarryoutanassessmentoftheconditionsof internalstructures,whichmayincludespotremovalofthecoating.Whensafeaccesscannotbeprovided,
thesoftcoatingshouldberemoved.
2.9 Theattendingsurveyor(s)shouldalwaysbeaccompaniedbyatleastoneresponsibleperson assignedbytheCompanyexperiencedintankandenclosedspacesinspection.Inadditionabackup teamofatleasttwoexperiencedpersonsshouldbestationedatthehatchopeningofthetankor spacethatisbeingsurveyed.Theback-upteamshouldcontinuouslyobservetheworkinthetankor space and should keep lifesaving and evacuation equipment ready for use.
* Referenceismadetochapter10oftheInternationalSafetyGuideforOilTankersandTerminals(ISGOTT)-Entryinto andworkinginenclosedspaces.
3 Access to structures
3.1 Foroverallsurvey,meansshouldbeprovidedtoenabletheattendingsurveyor(s)toexaminethe structureinasafeandpracticalway.
3.2 Forclose-upsurvey,oneormoreofthefollowingmeansforaccess,acceptabletotheattending surveyor(s),shouldbeprovided:
- permanentstagingandpassagesthroughstructures
- temporarystagingandpassagesthroughstructures
- liftsandmoveableplatforms
- raftsorboats
- otherequivalentmeans.
3.3 Surveysoftanksorspacesbymeansofraftsorboatsmayonlybeundertakenwiththeagreement
oftheattendingsurveyor(s),whoshouldtakeintoaccountthesafetyarrangementsprovided,including weatherforecastingandshipresponseinreasonableseaconditions.
3.4 Whenraftsorboatswillbeusedforcloseupsurveythefollowingconditionsshouldbeobserved:
.1 Onlyroughduty,inflatableraftsorboats,havingsatisfactoryresidualbuoyancyand stabilityevenifonechamberisruptured,shouldbeused;
.2 Theboatorraftshouldbetetheredtotheaccessladderandanadditionalpersonshould
bestationeddowntheaccessladderwithaclearviewoftheboatorraft;
.3 Appropriatelifejacketsshouldbeavailableforallparticipants;
.4 Thesurfaceofwaterinthetankshouldbecalm(underallforeseeableconditionsthe expectedriseofwaterwithinthetankshouldnotexceed0.25m)andthewaterlevel eitherstationaryorfalling.Onnoaccountshouldthelevelofthewaterberisingwhile theboatorraftisinuse;
.5 Thetankorspacemustcontaincleanballastwateronly.Evenathinsheenofoilonthe waterisnotacceptable;
.6 Atnotimeshouldthewaterlevelbeallowedtobewithin1mofthedeepestunderdeck webfaceflatsothatthesurveyteamisnotisolatedfromadirectescaperoutetothetank hatch.Fillingtolevelsabovethedecktransversesshouldonlybecontemplatedifadeck accessmanholeisfittedandopeninthebaybeingexamined,sothatanescaperoutefor thesurveypartyisavailableatalltimes;
.7 Ifthetanks(orspaces)areconnectedbyacommonventingsystem,orInertGassystem, thetankinwhichtheboatorraftistobeusedshouldbeisolatedtopreventatransferof gasfromothertanks(orspaces).
3.5 Inadditiontotheaboveraftsorboatsalonemaybeallowedforinspectionoftheunderdeckareas fortanksorspaces,ifthedepthofthewebsare1.5morless.
3.6 If the depth of the webs is more than 1.5 m, rafts or boats alone may be allowed only:
.1 whenthecoatingoftheunderdeckstructureisinGOODconditionandthereisno evidenceofwastage;or
.2 ifapermanentmeansofaccessisprovidedineachbaytoallowsafeentryandexit.This meansofaccessistobedirectfromthedeckviaaverticalladderandasmallplatform shouldbefittedapproximately2mbelowthedeck.
Ifneitheroftheaboveconditionsaremetthenstagingshouldbeprovidedforthesurveyoftheunder deckarea.
4 Equipmentforsurvey
4.1 Thicknessmeasurementshouldnormallybecarriedoutbymeansofultrasonictestequipment. Theaccuracyoftheequipmentshouldbeproventotheattendingsurveyor(s)asrequired.
4.2 Oneormoreofthefollowingfracturedetectionproceduresmayberequiredifdeemednecessary
bytheattendingsurveyor(s):
- radiographicequipment
- ultrasonicequipment
- magneticparticleequipment
- dyepenetrant
- otherequivalentmeans.
4.3 Explosimeter,oxygen-meter,breathingapparatus,lifelines,ridingbeltswithropeandhookand whistlestogetherwithinstructionsandguidanceontheiruseshouldbemadeavailableduringtheCAS survey. Asafetycheck-listshouldbeprovided.
4.4 AdequateandsafelightingshouldbeprovidedforthesafeandefficientconductoftheCAS
survey.
4.5 Adequateprotectiveclothingshouldbemadeavailableandused(e.g.safetyhelmet,gloves, safetyshoes,etc)duringtheCASsurvey.
5 MeetingsandCommunicationArrangements
5.1 The establishment of proper preparation and the close co-operation between the attending surveyor(s)andtheCompanyísrepresentativesonboardpriortoandduringtheCASsurveyarean essentialpartinthesafeandefficientconductoftheCASsurvey.DuringtheCASsurveyonboardsafety meetingsshouldbeheldregularly.
5.2 Prior to commencement of the CAS survey a survey meeting should be held between the attending surveyor(s), the Companyís representative(s) in attendance, the TM Firm Operator (as applicable)andtheMasteroftheshipforthepurposetoascertainthatallthearrangementsenvisagedin
theSurveyPlanareinplace,soastoensurethesafeandefficientconductofthesurveyworktobe carriedout.
5.3 Thefollowingisanindicativelistofitemsthatshouldbeaddressedinthemeeting:
.1 scheduleofthevessel(i.e.thevoyage,dockingandundockingmanoeuvres,periods alongside,cargoandballastoperationsetc.);
.2 provisions and arrangements for thickness measurements (i.e. access, cleaning/de- scaling,illumination,ventilation,personalsafety);
.3 extentofthethicknessmeasurements;
.4 acceptancecriteria(refertothelistofminimumthicknesses);
.5 extentofcloseupsurveyandthicknessmeasurementconsideringthecoatingcondition andsuspectareas/areasofsubstantialcorrosion;
.6 executionofthicknessmeasurements;
.7 takingrepresentativereadingsingeneralandwhereunevencorrosion/pittingisfound;
.8 mappingofareasofsubstantialcorrosion;
.9 communication between attending surveyor(s), the TM operator(s) and Company representative(s)concerningfindings.
5.4Acommunicationsystemshouldbearrangedbetweenthesurveypartyinthetankorspacebeing examined,theresponsibleofficerondeckand,asthecasemaybe,thenavigationbridge.This systemshouldalsoincludethepersonnelinchargeofhandlingtheballastpump(s)ifraftsorboats
are used. The communication arrangements should be maintained throughout the CAS survey.
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