1 Lesson Topic 3.1 CLEANING AND GAS FREEING. 2 INTRODUCTION As Gas Free Engineering Personnel you will be expected to know the various methods available

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Lesson Topic 3.1Lesson Topic 3.1

CLEANING AND GAS CLEANING AND GAS FREEINGFREEING

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INTRODUCTIONINTRODUCTION

As Gas Free Engineering As Gas Free Engineering Personnel you will be expected to Personnel you will be expected to know the various methods know the various methods available to clean tanks and available to clean tanks and requirements to make them gas requirements to make them gas freefree..

Lesson Topic 3.1, Cleaning and Gas Freeing

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ENABLING OBJECTIVESENABLING OBJECTIVES

Describe the procedures, equipment and Describe the procedures, equipment and personnel safety precautions used with personnel safety precautions used with the Butterworthing method, Chemical the Butterworthing method, Chemical cleaning, Steam Cleaning, and Hot or cleaning, Steam Cleaning, and Hot or Cold washing in accordance with NSTM Cold washing in accordance with NSTM Chapter 074 Vol. 3, Gas Free Engineering, Chapter 074 Vol. 3, Gas Free Engineering, NSTM Chapter 631 Vol. 2, Preservation of NSTM Chapter 631 Vol. 2, Preservation of Ships in Service - Surface Preparation and Ships in Service - Surface Preparation and Painting, Manual for Cargo Tank Cleaning Painting, Manual for Cargo Tank Cleaning and OPNAVINST 5100.19, series.and OPNAVINST 5100.19, series.


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ENABLING OBJECTIVESENABLING OBJECTIVES

Describe the cleaning process, testing, Describe the cleaning process, testing, safety precautions and procedures safety precautions and procedures required for entry into DFM/F-76, CHT, required for entry into DFM/F-76, CHT, JP-5, and Gasoline tanks, in accordance JP-5, and Gasoline tanks, in accordance with NSTM Chapter 074 Vol. 3, Gas Free with NSTM Chapter 074 Vol. 3, Gas Free Engineering, NSTM Chapter 631 Vol. 2, Engineering, NSTM Chapter 631 Vol. 2, Preservation of Ships in Service - Surface Preservation of Ships in Service - Surface Preparation and Painting, NSTM Chapter Preparation and Painting, NSTM Chapter 541, Ship Fuel and Fuel Systems and 541, Ship Fuel and Fuel Systems and OPNAVINST 5100.19, series.OPNAVINST 5100.19, series.


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Tank CleaningTank Cleaning


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Tank Cleaning RequirementsTank Cleaning Requirements

• Maintenance cleaningMaintenance cleaning• Tank inspection or minor repairTank inspection or minor repair• Shipyard overhaul or major repairShipyard overhaul or major repair• Change of cargoChange of cargo• After a contaminated cargoAfter a contaminated cargo• Preparation for loadingPreparation for loading• Preparation for ballastingPreparation for ballasting• Activation and inactivation of vesselActivation and inactivation of vessel


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Spaces like fuel tanks are normally Spaces like fuel tanks are normally cleaned in a properly equipped shore cleaned in a properly equipped shore support facility.support facility.• Only properly equipped ships like oilers Only properly equipped ships like oilers

will clean such spaces as a matter of will clean such spaces as a matter of normal routine.normal routine.


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• Initial testing and evaluation of the space. Initial testing and evaluation of the space. • Prescribing conditions of entry for Prescribing conditions of entry for

cleaning.cleaning.

Gas Free Engineer responsibilities

NOTE: The GFE will know the various cleaning

methods for any given circumstance, in order to

evaluate any hazard that may develop during or

after cleaning.


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• Issuance of a provisional certificate Issuance of a provisional certificate • Specifying conditions during cleaningSpecifying conditions during cleaning• Testing and evaluation of the space after Testing and evaluation of the space after

cleaning.cleaning.• Collaboration, when necessary, with Collaboration, when necessary, with

cleaning personnel.cleaning personnel.

Gas Free Engineer responsibilitiesGas Free Engineer responsibilities


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• Inspecting personnelInspecting personnel

Precautions prior to tank cleaning


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• Inspecting personnelInspecting personnel– Proper clothingProper clothing– Proper equipmentProper equipment


NOTE: The safety observer should have a list of

the equipment to be allowed into the space.


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• Inspecting personnelInspecting personnel– Proper clothingProper clothing– Proper equipmentProper equipment

– Not intoxicated or on drugsNot intoxicated or on drugs


NOTE: The safety observer should have a list of

the equipment to be allowed into the space.


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• Common hazardsCommon hazards– Use caution when entering or leaving tanks to Use caution when entering or leaving tanks to

avoid are slipping or falling, low overheads, avoid are slipping or falling, low overheads, and electrical shock.and electrical shock.

• Physical hazards can be avoided byPhysical hazards can be avoided by– Proper instruction of personnelProper instruction of personnel– Good judgementGood judgement– Constant alertnessConstant alertness



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• Tending linesTending lines– Prevent lines and hoses from becoming Prevent lines and hoses from becoming

tangled.tangled.– Do not pull on hosesDo not pull on hoses– Do not climb on pipesDo not climb on pipes

Safety equipment


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• Provide sufficient lightingProvide sufficient lighting– Explosive proofExplosive proof– Cables should be tied upCables should be tied up– ScaffoldingScaffolding– Ladders with non-skid tipsLadders with non-skid tips– Safety nets, beltsSafety nets, belts

Safety equipment


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• Ensure that NO:Ensure that NO:– STEAM is admitted to tank with personnel STEAM is admitted to tank with personnel

insideinside– HIGH PRESSURE WATER is directed through HIGH PRESSURE WATER is directed through

manhole with personnel inside.manhole with personnel inside.

Safety precautions


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•Always be aware of potential Always be aware of potential danger due to the extremely danger due to the extremely hazardous situation inside a dark hazardous situation inside a dark fuel tank.fuel tank.

Safety precautions


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Tank Cleaning Tank Cleaning ApplicationsApplications


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Tank Cleaning ApplicationsTank Cleaning Applications

Many effective cleaning methods may be Many effective cleaning methods may be used to used to

clean a confined or enclosed space.clean a confined or enclosed space.


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Selection of method may be governed Selection of method may be governed by:by:• Materials availableMaterials available• The product involved (cleaning agent)The product involved (cleaning agent)• Time allottedTime allotted• Tank conditionTank condition


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• Effective when used in conjunction with Effective when used in conjunction with the Wheeler method.the Wheeler method.

• Suitable method of employing chemicals Suitable method of employing chemicals will be governed by:will be governed by:– Type of cleaningType of cleaning– Equipment availableEquipment available– Time allottedTime allotted

Chemical cleaning


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• Regardless of the method, all personnel Regardless of the method, all personnel shall be thoroughly indoctrinated in safe shall be thoroughly indoctrinated in safe handling of:handling of:– Chemical solventsChemical solvents– EmulsifiersEmulsifiers

Chemical cleaning


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Butterworthing


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• Requires heated water (or cleaning oil)Requires heated water (or cleaning oil)– High pressure (175 PSI)High pressure (175 PSI)– Revolving nozzleRevolving nozzle– Water temperature 165-185°FWater temperature 165-185°F

ButterworthingButterworthing


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• Nozzle raised and loweredNozzle raised and lowered



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• Tank stripped continuously until the Tank stripped continuously until the bottom is free of water, with the nozzle bottom is free of water, with the nozzle stream stirring sediment.stream stirring sediment.



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• Water is supplied through specially Water is supplied through specially constructed ground hose.constructed ground hose.



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• Most thorough method of cleaning tanks.

• Consists of melting down materials

• No set procedure can be established to suit all fuel tanks

Steam cleaningSteam cleaning


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• Temperature of tank walls during steam Temperature of tank walls during steam cleaning must not be allowed to exceed cleaning must not be allowed to exceed 230°F230°F..CAUTION: Excessive temperature may cause

buckling of walls, warping or cracking of

structures, and may also dangerously overheat

flammable or combustible materials within

boundary spaces..



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• Caution must be used when attempting to Caution must be used when attempting to steam clean tanks.steam clean tanks.

• Tanks containing gasoline must be steam Tanks containing gasoline must be steam cleanedcleaned..



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• Method of cleaning using water under Method of cleaning using water under pressure pressure

• In most instances, tanks containing In most instances, tanks containing hydrocarbons must be thoroughly hydrocarbons must be thoroughly steamed or treated with cleaning steamed or treated with cleaning compounds before being washed.compounds before being washed.

Water washingWater washing


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Method of Gas Freeing Method of Gas Freeing DFM / F-76 / JP-5 Tanks DFM / F-76 / JP-5 Tanks

and CHT systemsand CHT systems


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Gas Freeing DFM / F-76 / JP-5 Tanks Gas Freeing DFM / F-76 / JP-5 Tanks and CHT systemsand CHT systems

Written permission from the Written permission from the Commanding Officer is required to Commanding Officer is required to open tanks.open tanks.

Remove manhole cover.Remove manhole cover.• If presence of hydrocarbon vapors is If presence of hydrocarbon vapors is

suspected, suspected,

use non-sparking tools.use non-sparking tools.


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Gas Freeing DFM / F-76 / JP-5 Gas Freeing DFM / F-76 / JP-5 Tanks and CHT systemsTanks and CHT systems

Test for oxygen deficiencyTest for oxygen deficiency• Do not enter tankDo not enter tank• Use drop check methodUse drop check method


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Test for combustible vaporsTest for combustible vapors• Do not enter tankDo not enter tank• Use drop check methodUse drop check method


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Test for toxic conditionsTest for toxic conditions• Do not enter tankDo not enter tank• Use drop check methodUse drop check method


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• Testing tank every eight hours or as Testing tank every eight hours or as necessarynecessary

• Inspecting tanks for cleanlinessInspecting tanks for cleanliness• Ensuring safe atmospheric conditions existEnsuring safe atmospheric conditions exist• Certifying tank: Safe for Personnel Safe Certifying tank: Safe for Personnel Safe

for Hot Workfor Hot Work

Gas free engineer is Gas free engineer is responsible for:responsible for:


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Sewage Collection, Holding, and Sewage Collection, Holding, and Transfer SystemsTransfer Systems

• A heavy blanket of organic sludge can A heavy blanket of organic sludge can accumulate on the bottom of a tank during accumulate on the bottom of a tank during routine CHT operations.routine CHT operations.

• The underlying layer of sludge generates The underlying layer of sludge generates hazardous gases -- hydrogen sulfide and hazardous gases -- hydrogen sulfide and methanemethane


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• Potential hazards exist when personnel Potential hazards exist when personnel are working on, or in, an open tank.are working on, or in, an open tank.

• Enforce safety precautions to ensure that Enforce safety precautions to ensure that health and well being of personnel are health and well being of personnel are protected.protected.



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• CHT tank inspection and maintenance CHT tank inspection and maintenance requiring tank entry.requiring tank entry.



NOTE:All procedures for preparing a CHT tank for cleaning

must be followed and adhered i.a.w. written procedures

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• Safety precautions for personnel prior to Safety precautions for personnel prior to tank opening:tank opening:– Wear approved respiratory equipmentWear approved respiratory equipment



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• Safety precautions for personnel prior to Safety precautions for personnel prior to tank opening:tank opening:– Two people will be outside the tank to:Two people will be outside the tank to:

– Constantly observe personnel insideConstantly observe personnel inside– Render assistance if requiredRender assistance if required– Provide spare respiratory equipment for Provide spare respiratory equipment for

immediate useimmediate use



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• After opening tankAfter opening tank– Test the atmosphere of the spaceTest the atmosphere of the space

– O²O²– ExplosiveExplosive– ToxicsToxics

– If the tank is not gas free, repeat the If the tank is not gas free, repeat the washdown procedures; retest and washdown procedures; retest and certify gas free if safe.certify gas free if safe.



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– Recertification is made periodically: Recertification is made periodically: – No more than every eight hoursNo more than every eight hours and each and each

time the ship moves or as specified by the time the ship moves or as specified by the GFE.GFE.



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• VentilationVentilation– Force ventilate continuously Force ventilate continuously

taking suction from bottom oftaking suction from bottom of

tank and discharging directly tank and discharging directly

to weather deck.to weather deck.– Make one complete air change Make one complete air change

every three minutes.every three minutes.



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• Before tank entryBefore tank entry– Force ventilate for 30 minutes.Force ventilate for 30 minutes.– Clean thoroughly without enteringClean thoroughly without entering– Continue ventilation during washdownContinue ventilation during washdown– Gas Free Engineer tests tank.Gas Free Engineer tests tank.– If conditions are unsafe, continue ventilation If conditions are unsafe, continue ventilation

and washdown until certified and safe.and washdown until certified and safe.



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• Equipment and clothing worn by Equipment and clothing worn by personnel for tank entry.personnel for tank entry.– Respiratory protectionRespiratory protection– Coveralls (white CHT)Coveralls (white CHT)– BootsBoots– GlovesGloves– Head coveringHead covering



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• Protective equipment required for tank Protective equipment required for tank entry:entry:– Respiratory equipmentRespiratory equipment– Protective clothing (light-colored Protective clothing (light-colored

material coverall )material coverall )– Acid-resistant bootsAcid-resistant boots– Acid-resistant glovesAcid-resistant gloves

Gasoline TanksGasoline Tanks


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• All spaces into which gasoline vapors issue All spaces into which gasoline vapors issue must be constantly and thoroughly must be constantly and thoroughly ventilated.ventilated.

WARNING: BREATHING AIR RICH IN

GASOLINE VAPORS CAN CAUSE DEATH.



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• No person shall enter a gasoline No person shall enter a gasoline storage tank for any purpose without storage tank for any purpose without obtaining the Commanding Officer's obtaining the Commanding Officer's permission each time.permission each time.



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• Procedures for entering a tank certified Procedures for entering a tank certified gas free and safegas free and safe– Enter the tank and remove remaining sludgeEnter the tank and remove remaining sludge

NOTE: If only one person enters a tank, a safety

harness and tending line must be used.



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• After sludge removal and tank cleaningAfter sludge removal and tank cleaning– Retest and certify gas free and safe, or Retest and certify gas free and safe, or

unsafe.unsafe.– If unsafe then ventilate and repeat If unsafe then ventilate and repeat

washdown procedures until certified gas washdown procedures until certified gas free and safe.free and safe.



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• If safe, Work can now continue inside If safe, Work can now continue inside the tank without respiratory equipment the tank without respiratory equipment with:with:– Continuous ventilation Continuous ventilation – GFE approvalGFE approval



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• The frequency of testing to be performed The frequency of testing to be performed is stated on the gas free certificate.is stated on the gas free certificate.

WARNING: No welding or hot work shall be

performed on the tank until the Gas Free Engineer

certifies the tank is safe for hot work.



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REVIEW AND REVIEW AND SUMMARYSUMMARY


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Review and SummaryReview and Summary

Tank CleaningTank Cleaning Tank Cleaning ApplicationsTank Cleaning Applications Method of Gas Freeing DFM / F-76 / JP-Method of Gas Freeing DFM / F-76 / JP-

5 Tanks and CHT systems5 Tanks and CHT systems


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ANY ANY QUESTIONS?QUESTIONS?


Documents

1 Lesson Topic 3.1 CLEANING AND GAS FREEING. 2 INTRODUCTION As Gas Free Engineering Personnel you will be expected to know the various methods available