Cargo Hold Coatings
Recommended Working Procedures
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Introduction
Successful in service performance of cargo hold coating systems
depends not only on the correct choice of coating but also on the
procedures adopted for surface preparation and paint application.
This document is designed to assist ship operators, shipyar ds and
contractors achieve the optimum preparation and application
standards so maximising performance of cargo hold coatings
applied at maintenance and repair drydocking. For simplicity, each
section assumes surface preparation by abrasive blasting.
Hold Condition - Pre Contract
Prior to commencement of the contract it is essential that the holds
are clean, dry and in a condition suitable for surface pr eparation and
application of hold coatings. The points listed below briefly outline
the minimum requirements:
Typical condition of cargo hold after 3 years in ser vice with a conventional coating system.
Typical condition of cargo hold prior to refurbishment.
• Prior to work commencing, holds must be certified gas fr ee.
• Heavy scale must be removed.
• Debris and cargo residues must be removed.
• All grease and oil must be removed in accordance with SSPC-SP1.
• All hot work must be complete.
• Any blisters on existing coatings must be br oken by appropriate
means prior to fresh water washing.
• Prior to surface preparation, surfaces must be thoroughly fresh
water washed and allowed to dry.
Adoption of hydroblasting as a method
of surface preparation continues to
increase worldwide.
“Successful in service
performance of cargo hold
coating systems depends not
only on the correct choice of
coating but also on the
procedures adopted for surface
preparation and paint application.”
Pitted steel after grit blasting to Sa2 (ISO 8501-1 : 1988, SSPC-SP6).
Substrate condition commonly found in bulk carriers greater than 10 years of age.
Gritblasting to Sa2 (ISO 8501-1 : 1988, SSPC-SP6) on hatch coaming area.
Surface Preparation
Compressed Air
Surface preparation must be in accordance with the agreed specification.
Air used for abrasive blasting must be clean, oil-fr ee and dry.
The pressure should be at least 7kg/cm 2 (100 p.s.i.) at the nozzle.
Accepted standards include:
Abrasive Blasting:
ISO 8501-1 : 1988, SSPC
Abrasive
Hydroblasting:
International Paint Hydroblasting Standards
Abrasives used for blasting should be clean, dry and fr ee from dirt,
Slurryblasting:
International Paint Slurryblasting Standards
oil, grease, organic or water soluble matter. Consult International
Mechanical Preparation:
ISO 8501-1:1988, SSPC
Paint for recommendations on suitable abrasive material.
Abrasive Sweeping:
International Paint Abrasive Sweep Standards
Surface Profile
The surface profile required will depend upon the type of coating to
be applied. Measurement on site should be by pr ofile gauge or
other instrument agreed by all parties prior to commencing
surface preparation.
Scaffolding (Staging)
Type
Staging should be designed to allow thor ough cleaning and acceptable
substrate access. International Paint recommend that staging should
be the ‘turn over’ type, when local safety r egulations permit.
Tubular scaffolding should not mask surfaces to be coated. Wher e
contact with surfaces is necessary, spade ends should be used.
Tubular scaffolding should be plugged or capped prior to abrasive
blasting to prevent ingress of grit and dirt (which may be subsequently
dislodged, leading to coating contamination).
Layout
Staging should afford easy and safe access to all surfaces to be
coated, but should be at least 150mm to 300mm (6" to 12") fr om
Mobile platform being lowered into a cargo hold.
vertical surfaces to be coated.
Typical staging configuration used during cargo hold refurbishment contract.
Distance between staging levels should not exceed two metr es
Cleaning
(6.5 feet) and the staging layout should be such that ventilation is
If abrasive blasting or abrasive sweeping is carried out, the bulk of
not restricted.
spent abrasive and dust must be r emoved prior to the initial
Care should be taken when removing scaffolding in order to minimise
blasting inspection.
damage to a freshly applied coating. All coating damages should be
Following acceptance of the preparation standard, all remaining traces
repaired in accordance with the recommendations of the International
of abrasive and dust should be r emoved from all areas using industrial
Paint Representative on site.
vacuum cleaners fitted with brushes, or by other suitable methods
Mobile Platforms
agreed by the International Paint Representative on site.
If mobile platforms or ‘cherry pickers’ ar e used, they should be
When preparing surfaces by other means, all traces of debris should
capable of giving access to all parts of the cargo hold. Operatives
also be removed by appropriate methods.
should not have to lean or str etch excessively to gain suitable access.
Final examination of the prepared substrate prior to coating application
must be undertaken on completion of all cleaning operations.
Dehumidification
Dehumidification equipment, when used must be of adequate
capacity to maintain the condition of pr epared steelwork to the
specified standard.
Cargo hold hatch covers must remain open
during coating curing period.
“For optimum performance
of cargo hold coatings, close
control of dry film thickness
is essential.”
Coatings Application
Dry Film Thickness
All products must be applied in line with detailed advice pr ovided by
For optimum performance of cargo hold coatings, close contr ol of
International Paint on can (container labels), Pr oduct (Technical) Data
dry film thickness is essential. Over application may r esult in slow
Sheets and Material Safety Data Sheets.
cure and solvent entrapment, whereas under application can lead to
The coating system must be applied in accor dance with the agreed
reduced in service performance.
specification. All coatings should be applied by airless spray , except
As a guide, the minimum dry film thickness of a high build cargo
for stripe coats where brush or roller is recommended.
hold scheme should be 85% of the specified dry film thickness. The
Airless spray equipment must be in good working or der and be
capable of performing to the output r equirements defined in the
Product (Technical) Data Sheets.
Air Pressure
Available air pressure and capacity for spray equipment should be at
least 5.5kg/cm2 and 1.4m3/min (80 p.s.i. and 50 cfm).
Pump Ratios
It is recommended that airless spray pump ratios of 40:1 or gr eater
should be used.
maximum should not be in excess of double the specified thickness
(per coat and total scheme).
For cargo hold areas which are difficult to paint due to their
configuration (e.g. heavily stiffened bulkheads, where a degree of
overthickness is unavoidable), an excess thickness of 10% over the
above maximum is acceptable.
For example, with a 2 x 125 micr on dry film thickness scheme
(2x4.9 mils) specified, the maximum dry film thickness applied to
‘difficult areas’ must not exceed 550 microns (21.7 mils).
Tip Size
Airless spray tips must be the size stipulated on the Pr oduct
(Technical) Data Sheet or as agreed with the International Paint
Representative on site. Tips must be in good condition.
Mixing
Efficient mechanical stirrers or power agitators should be used to
ensure complete mixing of the coating (applicable for 1-pack and
2-pack coatings).
Steel Temperatures
Coatings may only be applied to pr operly prepared surfaces which
have been maintained in a dry condition with the steel temperatur e
at least 3°C (5°F) above the dew point for mor e than one hour.
Cargo hold coating must be carried out under acceptable
atmospheric conditions, otherwise adverse effects may occur.
For example, steel temperatures below 10°C (50°F) may retard
coating cure and may lead to a r eduction in coatings performance.
Curing and drying characteristics of coatings ar e dependent on
ambient temperature, humidity and ventilation levels employed.
For specific guidelines on the above, please consult your
International Paint Representative.
Airless spray coating application via the use of a mobile platform.
Stripe Coats
KEY AREAS FOR STRIPE COAT APPLICATION
IN CARGO HOLDS
Stripe coating is an essential part of good painting practice in cargo
holds. Typical areas where stripe coats should be applied include:
• backs of stiffeners
• cut outs i.e. scallops, etc
Welded areas on Hatch Coamings
Welded areas of
Frame Feet and
Bracket Toes
All welded areas
on Bulkhead
Corrugations
• welds
• areas of difficult access (corners etc)
• ladders and hand rails
• areas of properly prepared pitting
Welds between
Hopper Sloping
Plate and Tank
Top
In general, stripe coats should be applied by brush or r oller
depending on the items concer ned.
Connection of
Bulkhead Stool
to Hopper
Sloping Plate
• Areas of properly prepared pitting and ladders/hand rails
(neither shown in above diagram) also r equire stripe coat application
In exceptional circumstances it may be acceptable to apply a stripe
coat to the backs of stiffeners by narrow-angle airless spray. The use
of spray applied stripe coats however, should be discussed and
Safety
agreed with the International Paint Representative on site.
The ventilation system must prevent the solvent vapour concentration
in the hold from exceeding 10% of the lower explosive limit (or less
than this if required by local regulations).
Ventilation at this level or at least 5 complete air changes per hour is
required. Provision must be made for 24 hour surveillance of
ventilation equipment.
If, for any reason, the hatch covers cannot be open during coating
application and curing (e.g. as a r esult of bad weather) the same
ventilation requirements are still needed and should be maintained for
at least 48 hours after completion of coatings application, otherwise
release of solvent from the coatings during drying/curing may cr eate
Typical stripe coat application to side shell frames.
an explosive atmosphere.
Heating
If heating is necessary to satisfy the painting or curing specification it
Ventilation Layout
should be by means of a heat exchange system, i.e. air admitted to
During in situ applications, the hatch covers should be open and
the hold should not pass directly through a combustion chamber.
forced ventilation (via flexible trunking) should be in place and r emain
Provision must be made for 24 hour surveillance of equipment.
operational for at least 24 hours after completion of the coating
Lighting
application.
Lighting during surface preparation and painting must be electrically
Coating solvents are generally heavier than air, and therefore, the
protected (Ex) so as not to ignite any solvent vapour . The lighting
ventilation system and trunking must be capable of extending to
should provide suitable illumination for all work and be suf ficiently
the lower most parts of the hold. Trunking should be arranged so
powerful (mains supplied) at all times.
that continuous air movement occurs in all ar eas and no dead
Time to First Cargo Loading
spaces exist.
Adequate time must be given to any fr eshly applied cargo hold
Ventilation must be arranged so as not to r e-introduce abrasive dust
coating prior to loading the first cargo. The factors which determine
and solvent vapour, for example, into the holds.
this period are varied and should be discussed with Inter national
Equipment should be electrically safe; it should be designed so that
sparks or hot surfaces/bearings are not in contact with solvent laden
air. Fan motors must be outside the extraction airstr eam.
Paint on a case-by-case basis. In all cases hatch covers should
remain open for as long as possible after completion of the coating
procedure.
Guidelines of cure time versus potential coatings damage fr om a first
loaded cargo are available from International Paint on request.
Repairs
These procedures are recommended for the repair of damages either at the initial coating stage or during
cargo hold maintenance. The procedure recommended will depend upon the type and extent of r epair
involved.
Major Repairs
Where major repairs are required, work should be carried out in accor dance with all the previous sections.
Successful completion of cargo hold
refurbishment on typical Panamax bulk carrier.
Minor Repairs
These are repairs to areas damaged, either at the initial coating stage, (e.g. caused by destaging) or caused
during the in service period (e.g. cargo induced damages, subsequent corr osion etc).
The principle requirements are:
• Fresh water wash to remove all salt contamination and any r emaining cargo residues.
• Degrease according to SSPC-SP1 solvent cleaning to r emove oil, dirt etc.
• The area to be repaired must be dry.
• Remove any corrosion by means of either:
- vacuum blasting
- mechanical cleaning i.e. disc sander or grinder.
• Abrade coated area immediately surrounding repair to provide a key for subsequent paint adhesion.
• Apply the paint system in accordance with the agreed specification. If small areas are involved and application is by brush (or roller), several coats may
be required to achieve the correct dry film thickness.
• All products must be applied in line with detailed advice pr ovided by International Paint on can (container) labels, Pr oduct (Technical) Data Sheets and
Material Safety Data Sheets.
• Consult International Paint for details on minimum cur e times prior to cargo loading/service entry following coating r epairs.
Health and Safety
Most cargo hold coatings contain volatile flammable organic solvents which can form explosive mixtur es with air. Whilst applying cargo hold coatings
the use of personal protection equipment to protect against potential health hazards is required. Appropriate precautions must be taken whilst applying
coatings in the confines of a ship’s cargo hold.
Detailed attention must be given to the following points:
• Danger of explosion or fire.
• Ensure that the holds and surrounding areas are flame and spark-free.
• Provision of adequate ventilation.
• Provision of suitable breathing equipment for workers.
• Prevention of skin irritation.
• Ensure that suitable protective clothing and equipment is available and wor n.
• Rescue equipment e.g. independent air supply (air cylinder) to be available for use in emergencies.
• Use only coatings which have been specifically formulated for use in cargo holds.
Consult International Paint for detailed Health and Safety advice.
Cargo hold following full coating refurbishment.
November 2004
International Paint Ltd is part of Akzo Nobel, the Netherlands based company serving customers thr oughout the world
with healthcare products, coatings and chemicals. Consolidated sales for 2003 totalled EUR 13 billion.
Akzo Nobel currently employs approximately 64,300 people in more than 80 countries.
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Important Notes:
All representations and statements concerning the product(s) in this brochure are accurate to the best of our knowledge. Statem ents made in this
brochure are advisory only and are not intended to be specific r ecommendations or warranties of any product, combination of products or fitness for any
particular purpose. To the extent permitted by law, we do not accept any liability to any person for any loss or damage (dir ect or indirect) that may arise
from any use of or reliance on any of the methods or information contained in this br ochure for any purpose.
Unless otherwise agreed in writing, all products supplied and technical advice or r ecommendations given are subject to the Conditions of Sale of our
supplying company. Any warranties, if given, are contained in those standard Conditions of Sale and are the only ones made with respect to any
products we sell to you or advice or r ecommendations we give to you.
, International and all products mentioned in this brochure are trademarks of or are licensed to Akzo Nobel.
© Akzo Nobel, 2004
International Paint Ltd, Stoneygate Lane, Felling, Gateshead NE10 0JY.
Tel: +44 (0)191 402 2775 Fax: +44 (0)191 401 2320
www.international-marine.com
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about the product in question. Copies of our Pr oduct Data Sheets and Material Safety Data Sheets ar e available on request or from our website:
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