ballast tk hempels

HEMPEL

CONTENTS Page

151.6 QUALITY ASSURANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151.5 SUPPLEMENTARY PROTECTION BY ANODES . . . . . . . . . . . . . . . . . . . . . . . .151.4 COATING SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141.3.2 The repair process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141.3.1 Materials for repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141.3 REPAIRS DURING NEWBUILDING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141.2.5 Bolted Items/piping system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .131.2.4 Stainless steel surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121.2.3 Conditions for paint application work . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121.2.2 Stripe coating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111.2.1 Paint application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111.2 APPLICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101.1.7 Water jetting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

81.1.6 Abrasive blasting/abrasive sweep blasting . . . . . . . . . . . . . . . . . . . . . . . . .81.1.5 Rain and other contamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71.1.4 Ventilation, dehumidifying, and heating . . . . . . . . . . . . . . . . . . . . . . . . . . . .61.1.3 Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61.1.2 Staging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41.1.1 Steel work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41.1 SURFACE PREPARATION AND ALLIED DISCIPLINES . . . . . . . . . . . . . . . . . . . .41.0.7 Sundries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41.0.6 Removal of wasted consumables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31.0.5 Supply of equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31.0.4 Authority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31.0.3 Responsibilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21.0.2 General conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21.0.1 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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HEMPEL’S TECHNICAL STANDARD Doc. No.: BTC-0100-W FOR BALLAST TANK COATING WORK Rev. No.: 4

- NEWBUILDING AND REPAIR of 15 systems types I, II and II Date: April 2004

COPYRIGHT HEMPEL A/S, DENMARK

HEMPEL

1.0 INTRODUCTION

1.0.1 Purpose

The purpose of this specification is to form a basis for a coating of the internal surfaces of all ballast tanksof the vessel which provides adequate corrosion prevention within the desired lifetime of the paint systemrelative to grouping of systems I, II or III.

First-class workmanship of all work should be carried out in strict accordance with this specification,including any amendments which have been decided upon by the parties in question.

The extent and quality of work to be carried out is the most comprehensive when systems of the highestlevel, group III, is to be established. Conversely, for a group I work, certain deviations will be acceptable.

The Shipyard will design and carry out the structural work in the tanks in a way that facilitates the bestpossible application of the coating system.

Concerning repairs, the steel work - new and old - in the tanks must be in such a condition that theapplication of the coating system will ensure a high quality result. Special attention must be given to weldingseams, pittings, and sharp edges.

Unless otherwise agreed in advance, the Shipyard will supply the skilled labour, all tools and equipmentrequired to carry out the surface preparation and the application of the coating system as specified, andaccording to local/national safety regulations.

For such a purpose, Subcontractors may be employed to carry out surface preparation and application work.The Subcontractor chosen should be well reputed and experienced, with proven satisfactory ability andcapacity to comply with the requirements for surface preparation and for the application of the ballast tankcoating systems.

Any deviations from the specification - will it be the design of the steel construction, the condition of thesteel surface (e.g. pit corrosion, contamination not possible to remove, or the like) - must be consideredfrom case to case and may influence durability of the ballast tank coating system in question, any possibleguarantee given will thus be influenced by such circumstances.

State of corrosion (pit corrosion) of the old steel surfaces may influence the choice of the coating system.

The existing paint system will also influence the choice of a new coating system for repair/maintenance.Possible old zinc silicate coatings will usually have to be followed with zinc silicate again. If a new organicsystem is selected, the old zinc silicate coating system must be removed completely

1.0.2 General conditions

The Shipyard, or on its behalf a Subcontractor, must make all necessary planning including a masterschedule containing all steps in the working process as described in this specification.

The schedule and the programme plans must comply with the approved painting specification.

Lines of communication and levels of authority must be laid down before work starts and agreed upon byShipyard, Subcontractor, Owner, and Hempel.

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Depending on the actual agreement, Hempel will/may have its own Coating Adviser(s) stationed/available atthe shipyard during the entire period of work, from the start of steel preparation until the coating system isfinally accepted by the Owner.

For large repair jobs, especially:A pre-job conference and ordinary job conferences must be held between Shipyard, Owner, Subcontractor,and Hempel.

The ordinary job conferences must be conducted most typically once every day or any time requested by anyof the parties involved. The entire specification must be jointly reviewed before the start of the work.

At these job conferences the agenda must contain the following points:a) Work progress in relation to the agreed programme.b) Possible impediments to progress.c) Requests for temporary stoppage of work.d) Additions or deletions.e) Any other matter which may affect the programme and/or the specification.

Each meeting to be minuted.

If considered necessary, the shipyard is to appoint a liaison officer through whom all communication takesplace.

Execution:The planning phase should be comprehensive and must be started in good time.

The master schedule programme chart must be submitted to the Owners and to Hempel for approval beforethe start of work, during the pre-job conference, or earlier.

1.0.3 Responsibilities

Responsibilities of Shipyard, possible Subcontractor, and Hempel must be agreed upon by all partiesinvolved and included as a part of the contract. The responsibility for executing the work rests solely with theShipyard/the Subcontractor and the presence of Hempel's Coating Adviser(s) shall not relieve theShipyard/the Subcontractor of the responsibility for correct execution of the work in hand and having hisown Quality Assurance.

1.0.4 Authority

Rules of authority of Owner, Shipyard, Subcontractor, and Hempel must be agreed upon by all partiesinvolved and laid down in writing.

1.0.5 Supply of equipment

The Shipyard or Subcontractor will supply all necessary equipment for grinding, abrasive blasting, painting,scaffolding, ventilation, dehumidification, heating and insulation (if necessary), high pressure fresh waterwashing equipment (if necessary), vacuum cleaning, lighting, possible wrapping of hydraulic pipes,compressed air and power supply, for personal protection (safety) of the labour-force, as well asconsumables, spares, maintenance, and all other necessary auxiliary equipment.

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1.0.6 Removal of wasted consumables

Shipyard or Subcontractor will remove spent abrasives, dirt, empty paint cans, used tool cleaner, etc.

1.0.7 Sundries

The Shipyard or Subcontractor must provide convenient and sufficient space for storage of equipment, toolsand all material and consumables including abrasives and paint. Paint must be stored according torecommendations in the technical data sheet for the product in question. As a general rule, the containersshould be shielded from direct sun and rain.

The Shipyard or Subcontractor must ensure that accessibility, material flow, cranage and sufficient workspace is maintained at all times.

The Shipyard or Subcontractor must provide Hempel's Coating Adviser(s) with adequately furnished officespace including telephone, changing lockers, toilets, and washing facilities.

The use of the above mentioned facilities must be possible at all times, and the Coating Adviser(s) must beadmitted on the premises 24 hours a day, seven days a week during the entire tank preparation andapplication period. Permission to photograph as necessary should be granted .

1.1 SURFACE PREPARATION AND ALLIED DISCIPLINES

1.1.1 Steel work

For systems II and III, acceptable rust degrees of raw steel are A and B according to ISO 8501-1:1988. Forsystem type I, rust degree C of new steel may be acceptable depending on the expected lifetime.

No openings, holes, etc. in structural members of tanks should be less than 50 mm in diameter anddistances between structural members should also be above 50 mm as dictated by the possibilities forproper application of the paint. The construction must be designed in such a way that it will not obstruct theabrasive blasting or the paint application according to this specification.

All welding seams must have a surface finish which ensures that the quality of the paint system will bemaintained in all respects. Holes in welding seams, undercuts, etc. should be avoided. If found, they maynecessitate extra stripe coating or filling. (However, if eg undercuts exceed recommendations ofclassification societies, remidial steel work will be necessary).

Protruding sharp edges/burrs to be chamfered (for system type I). All sharp edges to be broken (for systemtype II)/rounded (for system type III). Laminations to be removed. However, rolled profiles, etc. from thesteel mills normally have acceptably rounded edges.

The terms "chamfered", "broken" and "rounded" can be described as follows:

Chamfered:Removal of protruding sharp burrs on an edge (after chamfering, the edge will be slightly broken).

Broken:Removal of sharp edges at a distance of 1-2 mm (minimum 1 mm) on each side of the edge in a one-stepprocess.

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Rounded:Removal of sharp edges at a distance of 2-3 mm (minimum 2 mm) on each side of the edge in a three-stepprocess.

All loose weld spatters to be removed.

Well adhering weld spatters will need additional touch-up or must be removed (for systems types I and II).

All weld spatters must be removed (for system type III).

Requirements to the "surface quality" of welds are to be according to WELD REPLICA NACE RP 0178minimum Grade D-E (NACE Standard RP0178-95) the best (D) for system Type III.

Note: Use of Anti-Spatter agents is generally NOT recommended.

If certain small defective areas cannot be remedied immediately, these areas should be taped off for laterrepair and their positions noted. However, sufficient time should be allowed at the steel survey so that anyrepair work may be carried out immediately.

Before a survey, the surfaces must be cleaned and dried to allow adequate inspection.

It may be relevant to make a reference model of which the standard of steel finish quality is approved byall parties involved.

Bolted items, see Section 1.2.5.

All hot work like welding and flame-cutting on the outer side of a tank must be finished before the tank isreleased for abrasive blasting and painting, or must be executed in such a way that the temperature of thecoated side of the steel plates will not exceed 120C at any time.

Existing, old steel:The following demands have to be complied with if the same guarantee as is valid for a newbuildingcoated with the corresponding ballast tank coating system is to be given. If this is not possible, theextent of the guarantee must be based upon the actual condition.

It is recommended to make a rough abrasive blast cleaning - or high pressure water jetting - to facilitatevisual inspection and any necessary repair of the existing steel work. For tank bottoms with pit corrosionthis rough blasting will also provide a better basis for a decision between welding of corroded pits or repairby filling.

A main concern is the contamination from water soluble, corrosive salts (seawater, microbial influencedcorrosion). The preventive method will be to include a very thorough cleaning with plenty of fresh water,please see below.

In case of contamination cleaning procedures must be repeated and/or improved. Especially pit corrodedsteel will need special attention and the only possible way to remove contamination from the pits may oftenbe to let the abrasive blast cleaning be followed by a very thorough cleaning with fresh water. After repeatedcontrol and drying, the entire surface will need abrasive blast cleaning to obtain the specified degree ofcleaning. Alternatively, the pit corroded areas are cleaned by water jetting, any surplus of water is suckedup, allow to dry. Please see the procedure in section 1.1.7).

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Non-pitted steel, only lightly contaminated with water soluble salts, may often be possible to cleansufficiently by dry abrasive blasting.

The maximum allowable concentration of chlorides on steel surfaces immediately before application is: 7.0 mg/cm² as detected by the "Bresle Method". (This method will also reveal contamination from othertypes of water soluble salts. Please see Part 2 "Standard for Inspection of Ballast Tank Coating").

1.1.2 Staging

Suitable staging must be provided to allow good access to all surfaces without changing the system duringthe work progress.

The following is recommended, however, local safety rules must always be obeyed:

Staging to be constructed to ensure maximum safe access to all surfaces.

Staging to be constructed in a way that allows sufficient cleaning.

The staging should have as few contact points to the tank surface as possible. When free standing stagingis used, all contact between scaffolding poles and steel surfaces must be point contact only, ie spade endsto be fitted.

The working platforms must be placed so that they will provide a good working distance from the surface,minimum approx. 30 cm and approx. 50 cm at the maximum. This will provide a good spraying distance andallow ventilation inside the scaffolding.

Especially corrugated bulkheads must be staged to give adequate, safe access to recessed areas, but notcloser than 30 cm.

It is recommended to make the platforms with gratings to ease cleaning and ventilation. Open ends ofpiping (staging poles) to be plugged or capped.

If wooden boards are used, the distance between boards should be approximately 3 cm to ensure sufficientventilation.

Staging should have permanent fixtures allowing easy erection and dismantling of staging to minimizedamage to painted surfaces.

The staging should not be removed before final inspection of bulkheads and deckhead has been made. Note: Damage of intact paint film must be avoided whenever possible. However, any damaged spots mustbe repaired simultaneously with dismantling of the staging according to the procedure for repair of smallareas, as described later, section 1.3.

1.1.3 Lighting

Lighting in the tank must be sufficient. As general lighting 100-200 lux is recommended. This should becombined with 150 Watt low voltage hand-lamps for illumination during blasting, cleaning, stripe-coating andinspection (corresponding to approx. 500 lux or more).

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Lamps should be placed so that a clear, homogeneous light without shadows is provided on all surfaceswhere work is in progress.

All equipment for lighting must obey ruling safety regulations. Especially the use of explosion-proof electricalinstallations during application and drying of paint is of vital importance.

1.1.4 Ventilation, dehumidifying, and heating

Sufficient equipment for ventilation, dehumidifying, insulation, and heating is necessary to achieve thespecified result.

To obtain the best air circulation clean and dry air should be blown into the upper and middle regions of thetank and suction should also be arranged from the bottom of the tank. Spot ventilation should be arrangedin parts of the tanks where otherwise air would be left stagnant.

In addition suction should be arranged at all places where air pockets could prevent good ventilation.

The ventilation, dehumidifying, and heating equipment must have a sufficient capacity to maintain as idealconditions in the tank as possible, irrespective of variations in the outer climatic conditions (please refer tothe Application Instructions for the system in question). To prevent reintroducing dust, solvent vapour etc. apositive pressure above normal atmospheric pressure should be maintained inside the tank.

Any necessary heating of tank bottoms may take place by outside heating in a dry dock.

Insulation of exterior hull-sides will usually be necessary during wintertime in cold or temperate climates, butmay also be an advantage during warm summer days and in tropical climates to prevent excessive heatingof the steel.

Relative humidity of the air during abrasive blasting

If the steel is chemically clean, which is not necessarily the same as visually clean according to ISO8501-1:1988, it is agreed in the literature that corrosion will not appear as long as the air humidityis below 50% RH.

Experience indicates that a mean value of approx. 40% RH and never exceeding a value of 50% RHunder relevant, practical conditions of work will ensure an abrasive blasting process in a tankwithout any significant re-rusting. However, should re-rusting occur, this is a good indication of watersoluble substances, which must be removed.

Ventilation during abrasive blasting

The extent should be balanced between the demands for the relative humidity and the demands forvisibility.

Air humidity and ventilation during application and curing of paint

(Please see the recommendations given for each ballast tank coating system in the Technical DataSheet and Application Instructions for the paint(s) involved).

Note: The Contractor/Shipyard must ensure that ventilation fulfils ruling safety demands.

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1.1.5 Rain and other contamination

Watertight tents must be erected over hatches and openings into the tank where work is in progress.

Rain shutters and water guards should be provided over/around all tank openings. Water must be kept awayfrom the tanks during blasting, application, drying and curing.

To avoid dragging abrasive material, dirt, or other contamination down on the clean surface, steel gratingswith brushes on the sides must be placed at the hatch entrance, one for every tank where work is carriedout. When entering freshly blasted or painted tanks, take care not to spoil the coating. For instance usesoft-soled shoes or boots.

1.1.6 Abrasive blasting/abrasive sweep blasting

Before blasting, any deposits of grease or oil must be removed from the steel surface with a suitabledetergent followed by fresh water hosing. Minor spots of oil/grease may be cleaned with thinner and cleanrags - avoid smearing out the contamination. Possible alkali weld deposits, chemicals used for testing ofwelds, or soap residues from the pressure testing shall be removed by fresh water hosing.

Note: Occasionally, new steel plates may be contaminated with salts due to unfavourable conditions oftransportation or storage. One or more freshwater hosings will then be necessary before the abrasiveblasting is carried out (in severe cases even after blasting).Before blasting, existing, old steel surfaces must be checked for any contamination. Existing blisters mustbe broken. If thick rust scale has been removed or deep pittings have been encountered, control proceduresfor contamination must be carried out. If still contaminated, the abrasive blast cleaned steel surface willneed a repeated cleaning for salts and/or oil/grease followed by a final abrasive blast cleaning. Thealternative - with no repeated cleaning - will lead to a reduced performance of the ballast tank coatingsystem to be applied.

Before blasting is started, the ventilation and heating equipment must be installed and working so that thespecified air humidity and temperature have been established in the tank at the start of the work.

To avoid re-rusting of newly blasted surfaces it is necessary to keep the relative humidity at 50% (preferably40%) as a maximum (see 1.2.4 above). Keeping steel temperature at least 3°C above the dew point duringand after the blasting will provide additional safety against rerusting.

Newbuilding/new steelwork

To obtain full performance of the ballast tank coating according to the desired systems I, II or III, welds,burns, damaged and rusty shopprimer must be treated as follows:

I. Light abrasive blast cleaning (abrasive blast sweeping), Sa 1-2, alternatively by mechanical cleaningto St 3.

II. Abrasive blast cleaning, minimum Sa 2. Minor areas mechanical cleaned to St 3.

III. Abrasive blast cleaning to Sa 2½.

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If welds have previously been coated with a (shop)primer just after welding this (shop)primer must beremoved in order to obtain optimum performance. For system types II and III by abrasive blast(sweeping). For system Type I, secondary surface preparation of such priming will have to be decided onthe spot. Typically grinding by rough discs.

Intact shopprimer:I. Except for the general cleaning for dirt, oil, etc. as mentioned above, any zinc salted surfaces,

surfaces with well adhering deposits of eg black iron oxides (from plasma cutting) and the similarare to be prepared by a light disc sanding removing foreign matters. Chalk markings and platemarking not being compatible with the ballast tank coating to be removed as well.

II. Zinc salted surfaces, deposits of black iron oxides of plasma cutting and similar foreign matters tobe removed by a light abrasive sweep blasting. Chalk markings and plate marking of anon-compatible nature to be removed as well.

The shopprimer must have been checked randomly for excessive film thicknesses and areasdetected to have film thicknesses above approx 40 micron (as measured directly on the shopprimedsurface with equipment calibrated on smooth steel) are to be a sweep blasted in order to removemost of the shopprimer in said areas. Spot-checking for possible salt contamination of the surfaceto be executed before and after the abrasive sweep blasting.

III. As per II except that all surfaces to be abrasive sweep blasted. Fully intact, visually clean surfacescan be light cleaned only, for other areas at least 70% of the shopprimer should be removed in auniform way.

When blasting, the importance of working systematically must be stressed. Poorly blasted areas coveredwith dust are very difficult to locate during the blast inspection made after the rough cleaning.

In case of abrasive blast cleaning, the surface profile must be equivalent to Rugotest No. 3, BN9a-10 orKeane-Tator Comparator, 3.0 G/S. According to ISO 8503-1 the grade will be MEDIUM (G).

Note: if any doubt exists about the quality of primary surface preparation (before shoppriming), thesubstrate must be re-blasted in situ as defined above (systems types II and III).

As a minimum, the blasting abrasives to be used should comply with ISO 11124, ISO 11125, ISO 11126and ISO 11127 if not otherwise defined by Hempel.

Tank, staging, etc. must be cleaned after blasting to avoid dust and abrasives being embedded in thecoating.

Block assembly zones

Overlap zones must be treated with great care. Damage caused by over-blasting (relevant for system type III- possibly also type II) must be avoided, paint edges must be feathered and consecutive layers of paintcoatings given greater and greater overlaps - old layers being roughened corresponding to these overlaps(when sandpapering, use free-cut paper, grain size 80).

It is recommended that block-coated areas are as big as possible in order to reduce the extent of assemblyzones.

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Furthermore, these areas may be either masked off with tape - to keep them as narrow as possible - or leftwith a thin zinc epoxy primer coat applied on these areas after secondary surface preparation (systemstypes II and III).

Secondary surface preparation of block assembly zones are typically mechanical cleaning in case of systemtype I. For type II, preferably abrasive spot blasting. However, mechanical cleaning to St 3 may beacceptable if zones are narrow and an extra coat is applied on these areas. The procedure of masking offwith tape or using the zinc epoxy primer as described above may advantageously be used in this connection.For type III, spot blasting to Sa 2½ is, in principle, the only relevant procedure.

Full refurbishment

Depending on the size and construction of the ballast tank, the process of abrasive blasting and tankcoating application may be divided into two steps. To avoid damaging finished paint work, bulkheadsides/web frames and deckhead(s) should be completed before work on the bottom (incl. approx. 1 metreof the sides) is commenced.

Abrasive blasting and coating of the complete tank as a single process is also possible. An extra carefulcleaning of all parts inside the tank will be essential here.

Corroded pits deeper than approx. 2 mm, but not repaired by welding, are recommended to be filled withHEMPADUR EPOXY FILLER 35250 after blast priming has been carried out. Alternatively, high solids/solvent-free epoxy materials are used for filling and full coating.

Extent/amount of corroded pits/filling must be included in the Report. Depending on the actual conditions,extensive filling and many corroded pits may influence the guarantee given.Overlapping of old ballast tank coating demands extra care to be taken. Much attention has to be placedon proper feathering of edges.

Furthermore, the old paint system must be examined very carefully for any possible defects such as, but notlimited to, (micro-)blistering, weak intercoat adhesion, weak adhesion to the substrate and/or under filmcorrosion.

If such defects are not remedied, they will lead to reduced performance of the repair executed.

When overlapping old inorganic zinc silicate ballast tank coating with a new one, the overlap zone should bekept as narrow and as straight as possible to facilitate a good overlap - avoid damage by over-blasting.

1.1.7 Water jetting

This procedure will primarily be relevant for repair jobs. However, the very good removal of water solublesalts may also make it useful in other cases.

In case of damage/failure to steel, cleaning must be carried out to minimum WJ-2 (NACE 5/SSPC-SP 12,1995) - please also see Hempel's "Photo Reference for Steel Surfaces Cleaned by Water Jetting".

Edges to intact coating must be feathered and the surrounding area roughened by operating the nozzlesome distance away and/or by moving the nozzle fast across the area.

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To avoid excessive water mist and deposits of paint sludge in the tank, the recommended pressures are800-1000 bar (80-100 MPa, 11.000-15.000 psi).

As water jetting creates dense water mist, strong ventilations is recommended to increase visibility.

Sufficient dehumidification equipment must be used to dry out the tanks as quickly as possible between thewater jetting and the coating application. Local ventilators may be required to distribute the drying air evenlyin tanks. All "slurry" is to be removed before it dries.

New rust, "flash rust", will be acceptable as discoloration only, not as powdery, loose rust - an acceptabledegree is FR-2 according to the Hempel Standard "Hempel's Photo Reference for Steel Surfaces Cleaned byWater Jetting". Inhibitors are not to be used.

All surfaces must be free from contamination at the time of painting and the relative humidity is to be below85%.

Water jetting may be used supplementary to mechanical cleaning (spot-repair) as well as abrasive blasting.Many of the general remarks of chapter 1.1.6 will apply to water jetting also.

Note: For all surface preparation work the Contractor/Shipyard must ensure that safety regulations areobeyed.

1.2 APPLICATION

1.2.1 Paint application

The paint application is usually carried out as one operation to all interior areas of the tank, however, theapplication may be divided into two steps especially in case of full coating of large tanks:

1) Paint application on deckhead(s), sides, bulkheads and web frames, except the bottom and thelowest part of the vertical sides (approx. 1 metre).

2) Paint application on tank bottom and lowest part of the vertical sides.

Special attention to the overlap zones is required. Previously painted areas must be feathered and dry-sprayremoved to ensure good adhesion and a smooth surface.

With multi-coat systems the various coats in the system must be applied in the overlap zone with greaterand greater overlap of the subsequent coat over the preceding one.

Precautions must be taken against damage by over-blasting.

Overlap zones and adjacent areas should be easily accessible for inspection and repairs.

The same type of precaution must be taken in case of section painting when section joints are treated(please also see above, "Block assembly zones", under section 1.1.6).

Generally, items treated prior to fitting in the tanks must be fully coated.

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The climatic conditions during the various steps of the painting must maintain the steel temperature beforeand during application above the dew point. A steel temperature of minimum 3°C is recommended. Curingand ventilation conditions must be as described in the Application Instructions for the relevant ballast tankcoating.

1.2.2 Stripe coating

Stripe coating by brush of places difficult to reach by spray should always be done to ensure sufficient filmthicknesses on such areas. That means lightening holes, undercuts of welds, rough welds, etc. and whenneeded, also rear sides of facebars, stiffeners and bulb noses. Furthermore, areas which havedemonstrated improper film formation will need stripe coating/extra coating in order to remedy possibleporosities/low film thicknesses. Pit-corroded areas (old tanks) may also require additional coating, in somecases thinning of paint may be necessary in order to penetrate pits properly.

The number of stripe coats is much related to the "finish quality" of the steel work, the structure of thesteel work, and methods of spray application. However, one-coat systems (type I) will typically ask forminimum one, but often, two stripe coats. A type II system will typically ask for minimum two stripe coatsand for type III an extra, final stripe coat by spray (nozzle eg 0.017", 40) of all welds and free edges. Thisfinal spray-applied stripe coat may be applied before as well as after the last full coat - in a different shade.

Stripe coating by airless spray can also replace one of the (other) stripe coats by brush (all system types),however, cut outs and irregularities of welds such as deep undercuts and pinholes can only be "closed" bystripe coating with brush.

1.2.3 Conditions for paint application work

Improper film formation is not acceptable as this will reduce the protective properties of the paint (pinholes,reduced wetting/adhesion to the substrate). A good film formation free from pin holes, each layer, can beobtained by using adequate staging, spraying equipment and spraying methods. An application techniquewhich will ensure good film formation on all surfaces must be adopted. Avoid dry-spray/dust spraying. It isvery important to use nozzles of a correct size, not too big, (in most cases, .019"-.021" will be the "rightchoice"), and to have a proper, uniform distance of the spray gun to the surface, approx 50 cm is to beaimed at.

To obtain good atomizing, the viscosity of the paint must be suitable and the spray equipment must besufficient in output pressure and capacity to maintain a good, steady atomizing. At high ambienttemperatures, a controlled use of extra thinner may be necessary.

The paint layer must be applied homogeneously and as close to the specification as possible. Theconsumption of paint must be controlled and heavy layers must be avoided because of the risk of sags andcracks (in "corners").

The finished coating must appear as a homogeneous film free of pinholes/insufficient film formation. Areaswith imbedded dry-spray and abrasives are to be repaired by scraping or grinding and subsequent touch-up.Abrasives on surfaces are to be cleaned by scraping followed by touch-up if deemed necessary.

Sagging/runners of epoxy coatings are not to be repaired if they appear "free" and non-cracked whereassagging passing a "corner" is to be removed in the mentioned corner and touched up (see below). Stripecoating has to be carried out properly covering for instance uneven (hand) welds, undercuts, free (sharp)edges, cut-outs, rear sides and other similar irregular, difficult accessible surfaces.

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If zinc silicate films exhibit cracks, a thorough examination must be carried out to decide whether it is fine,hairlike cracking (checking-type) which does not reduce the mechanical properties of the cured paint film, orwhether the cracking clearly gives a low mechanical strength leading to flaking later on. The first mentionedtype does not necessarily need repair as opposed to the last mentioned type.For the standard specification, the following applies to the dry film thickness:

Minimum dry film thickness must be observed. This is evaluated according to the "80-20"-rule. The"80-20"-rule means that no more than 20% of the total number of measurements must be below thespecified minimum and not less than 80% of this value. Other acceptable rules than the "80-20"rule may be used, but HEMPEL'S paint specifications are based on this rule.

Maximum dry film thickness should never exceed 3 times the specified dry film thickness per coat as well asin total.

Such areas of high film thickness are furthermore to be checked for proper adhesion to the substrate, asimple test by knife is sufficient as the possible problem will be drastically reduced adhesion due toretained solvents in the zone of the coating next to the steel.

A proper application procedure will ensure that the actual maximum will not surpass the double of thespecified film thickness, per coat and in total.It is especially important is to avoid sagging/sliding, which can result in a "pool" of paint at a weld betweena vertical and horizontal structural member - later on causing cracking of the paint film due to stressescreated during final drying-out.

Dry film thickness control must not be carried out before the coating is sufficiently dry and hard. However,soon enough to make rectifying of too low film thicknesses possible - see Application Instructions for therelevant paint material. The measurements must be carried out using an electromagnetic dry film thicknessgauge calibrated with shims placed on a smooth steel substrate.

Besides control of dry film thicknesses and visually checking the paint film to show a uniform, pin hole free,smooth appearance, quality control in the form of destructive spot-testing can be executed to demonstratethe adhesive/cohesive properties of the paint system to be appropriate. (Pull-off test and adhesion test byknife).

Note: For all paint application work, the Contractor/Shipyard must ensure that safety regulations areobeyed.

1.2.4 Stainless steel surfaces

For ballast tanks of chemical carriers with stainless steel tanks, it is very important that the stainless steelplates and the adjacent weldings are properly prepared and painted.The surface preparation must be a dry abrasive blasting with a metal-free blasting material creating a sharp,uniform, dense surface profile all over the stainless steel.

As any progress of abrasive blasting is difficult to see, application of a thin coat, eg red paint, may facilitatethe job. This colour must be removed indicating that all areas of the stainless steel have been reached bythe blasting media.

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The abrasive blasting may be carried out after welding the steel profiles to stainless steel plates and a blastcoat, epoxy primer, eg HEMPADUR 15570, can be applied for further protection until full coating with anepoxy ballast tank coating system (for zinc silicate, the paint work is to be executed after all steel work hasbeen completed).

1.2.5 Bolted Items/piping system

Items assembled by bolts and, therefore, not later accessible for painting should before mounting becompletely coated according to the specification, at least on the contact faces. It is recommended to makeall bolts of stainless steel to avoid heavy corrosion of bolts and nuts. Protect the bolted items with platewashers of tetrafluoroethylene polymer ("Teflon") covered with plate washers of stainless steel. Allow forsufficient space for mounting and tightening of bolts. Hot dip galvanized bolts may be used, but a reducedlifetime is often observed.

Damage caused by mounting of bolted items to be repaired according to the repair procedures for smallareas, see Section 1.4.2.

When approved by Owner, pipes, supports etc. may be hot dip galvanized, or coated by fusion bonded epoxypowder or pipes may be made of GRP materials.

1.3 REPAIRS DURING NEWBUILDING

It is very important that all damage to the coating is repaired. Repair must be started as soon as possible. Itis important that the repaired areas, as well as the rest of the coated areas, are fully cured before the tanksare taken into use.

The primary way of detecting damage of newly coated surfaces is mainly by visual means, equipment beingstrong torchlight in the hands of skilled observers.

1.3.1 Materials for repair

For zinc silicate, repairs should be carried out using the same coating materials as specified for the mainwork.

Please note that repairs by brush application always require approx. double the number of coats ascompared to spray application.

For epoxy coatings either same coating materials or suitable alternatives including a possible use of anepoxy filler according to the relevant painting specification.

1.3.2 The repair process

General:Before mechanical treatment is started surfaces to be repaired have to be cleaned for any salts and othercontamination.

For ballast tank coatings of types I and II, repairs will usually be based on mechanical surface preparation,grinding and sanding where necessary - only under very unusual circumstances with extended damagesareas repairs by use of abrasive blast cleaning will be relevant.

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For type III ballast tank coating specification, blast cleaning may be more relevant, but the advantages ofthe abrasive blast cleaning to produce a good surface for coating application must always be evaluated incomparison with the risk of damage by overblasting, dragging abrasive materials to the tank, etc.

In conclusion, mechanical cleaning before spot-repair may be selected, however, applying additional filmthickness to "counteract" for the less optimum degree of surface preparation.

1.4 COATING SYSTEMS

Please see:

HEMPEL'S COATING SYSTEMS FOR BALLAST TANK COATING WORK - NEWBUILDING AND REPAIR.

1.5 SUPPLEMENTARY PROTECTION BY ANODES

It is strongly recommended to combine the ballast tank coating with a system of cathodic protection basedon sacrificial anodes made of zinc or aluminium alloys suited for cathodic protection of ship tanks. Thenumber, size and distribution of the anodes should be according to the recommendations given by thesupplier of the cathodic protective system with special emphasis on protection of the bottom part.

1.6 QUALITY ASSURANCE

Please see:

HEMPEL'S TECHNICAL STANDARD FOR BALLAST TANK COATING INSPECTION - NEWBUILDING AND REPAIR.

THE INFORMATION GIVEN IN THIS STANDARD WILL NOT BE COVERING ALL ASPECTS OF ATANKCOATING JOB. WHILST WE ENDEAVOUR TO ENSURE THAT ALL ADVICE WE GIVE RELATING TO THEUSE AND/OR APPLICATION OF OUR PRODUCTS (WHETHER IN THIS PAPER OR OTHERWISE) IS BOTHCORRECT AND USEFUL, WE HAVE NO CONTROL OF EITHER THE QUALITY OR CONDITION OF THESUBSTRATE OR THE MANY FACTORS AFFECTING THE USE AND APPLICATION OF OUR PRODUCTS.THEREFORE ALL PRODUCTS DELIVERED AND ANY TECHNICAL ASSISTANCE GIVEN BY US ARE SUBJECTTO OUR GENERAL CONDITIONS OF SALE, DELIVERY AND SERVICE, AND, UNLESS OTHERWISEEXPRESSLY AGREED IN WRITING, MANUFACTURER AND SELLER ASSUME NO LIABILITY IN EXCESS OFTHAT STATED THEREIN FOR RESULTS OBTAINED, INJURY, DIRECT OR CONSEQUENTIAL DAMAGEINCURRED FROM THE USE AS RECOMMENDED ABOVE OR OTHERWISE.

THE INFORMATION CONTAINED IN THIS STANDARD IS LIABLE TO MODIFICATION FROM TIME TO TIME INTHE LIGHT OF EXPERIENCE AND OUR POLICY OF CONTINUOUS PRODUCT DEVELOPMENT. IT ISAUTOMATICALLY VOID TWO YEARS FROM ISSUE.

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