|1 Design of coating system|
|1||Selection of the coating
The selection of the coating system shall be considered by the
parties involved with respect to the service conditions and
planned maintenance. The following aspects, among other things
shall be considered:
- location of space relative to heated surfaces;
- frequency of ballasting and deballasting operations;
- required surface conditions;
- required surface
cleanliness and dryness; and
- supplementary cathodic
protections, if any (where coating is supplemented by cathodic
protection, the coating shall be compatible with the cathodic
Coating manufacturers shall have products with documented
satisfactory performance records and technical data sheets. The
manufacturers shall also be capable of rendering adequate
technical assistance. Performance records, technical data sheet
and technical a ssistance (if given) shall be recorded in the
Coating Technical File.
Coatings for application underneath sun-heated decks or on
bulkheads forming boundaries of heated spaces shall be able to
withstand repeated heating and/or cooling without becoming
Other coating systems with performance according to the test
procedure in annex 1.
A multi-coat system with each coat of contrasting colour is
The top coat shall be of a light colour in order to facilitate
|3||Coating pre-qualification test|
Epoxy-based systems tested prior to the date of entry into force
of this Standard in a laboratory by a method corresponding to the
test procedure in annex 1 or equivalent, which as a minimum meets
the requirements for rusting and blistering; or which have
documented field exposure for 5 years with a final coating
condition of not less than “GOOD” may be accepted.
For all other systems, testing according to the procedure in
annex 1, or equivalent, is required.
There shall be a minimum of two stripe coats and two spray coats,
except that the second stripe coat, by way of welded seams only,
may be reduced in scope where it is proven that the NDFT can be
met by the coats applied, in order to avoid unnecessary
over-thickness. Any reduction in scope of the second stripe coat
shall be fully detailed in the CTF.
Stripe coats shall be applied by brush or roller. Roller to be
used for scallops, ratholes, etc., only.
Each main coating layer shall be appropriately cured before
application of the next coat, in accordance with coating
manufacturer’s recommendations. Surface contaminants such as rust,
grease, dust, salt, oil, etc., shall be removed prior to painting
with proper method according to the paint manufacturer’s
recommendation. Abrasive inclusions embedded in the coating shall
be removed. Job specifications shall include the dry-to-recoat
times and walk-on time given by the
|5||NDFT (nominal total|
NDFT 320 µm with 90/10 rule for epoxy-based coatings; other
systems to coating manufacturer’s specifications.
Maximum total dry film thickness according to manufacturer’s
Care shall be taken to avoid increasing the thickness in an
exaggerated way. Wet film thickness shall be regularly checked
Thinner shall be limited to those types and quantities
recommended by the manufacturer.
|2 PSP (Primary surface preparation)|
Sa 2½; with profiles between 30-75 µm
Blasting shall not be carried out when:
- the relative humidity is above 85%; or
- the surface
temperature of steel is less than 3°C above the dew
Checking of the steel surface cleanliness and roughness profile
shall be carried out at the end of the surface preparation and
before the application of the primer, in accordance with the
|2||Water soluble salt limit|
equivalent to NaCl4
|< 50 mg/m2
of sodium chloride.|
Zinc containing inhibitor free zinc silicate based or
Compatibility with main coating system shall be confirmed by the
|3 Secondary surface preparation|
The steel surface shall be prepared so that the coating selected
can achieve an even distribution at the required NDFT and have an
adequate adhesion by removing sharp edges, grinding weld beads and
removing weld spatter and any other surface contaminant.
Edges shall be treated to a rounded radius of minimum 2 mm, or
subjected to three pass grinding or at least equivalent process
Sa 2½ on damaged shop primer and welds.
Sa 2 removing at least 70% of intact shop primer, which has not
passed a prequalification certified by test procedures in 1.3.
If the complete coating system comprising epoxy-based main
coating and shop primer has passed a pre-qualification certified
by test procedures in 1.3, intact shop primer may be retained
provided the same epoxy coating system is used. The retained shop
primer shall be cleaned by sweep blasting, high-pressure water
washing or equivalent method.
If a zinc silicate shop primer has passed the pre-qualification
test of 1.3 as part of an epoxy coating system, it may be used in
combination with other epoxy coatings certified under 1.3,
provided that the compatibility has been confirmed by the
manufacturer by the test in accordance with 1.7 of appendix 1 to
annex 1 without wave movement.
|3||Surface treatment after|
Butts St 3 or better or Sa 2½ where practicable. Small damages up
to 2% of total area:
St 3. Contiguous damages
over 25 m2 or over 2% of the total area of the tank, Sa 2½ shall
Coating in overlap shall be feathered.
requirements3||In case of full or partial blasting 30-75 µm, otherwise
as recommended by the coating manufacturer.|
|5||Dust6||Dust quantity rating “1” for dust size class “3”, “4” or
“5”. Lower dust size classes to be removed if visible on the surface
to be coated without magnification.|
|6||Water soluble salts|
NaCl after blasting/
|< 50 mg/m2 of sodium
|7||Oil contamination||No oil contamination.|
|1||Ventilation||Adequate ventilation is
necessary for the proper drying and curing of coating. Ventilation
should be maintained throughout the application process and for a
period after application is completed, as recommended by the coating
Coating shall be applied under controlled humidity and surface
conditions, in accordance with the manufacturer’s specifications.
In addition, coating shall not be applied when:
- the relative humidity is above 85%; or
- the surface
temperature is less than 3°C above the dew
Destructive testing shall be avoided.
Dry film thickness shall be measured after each coat for quality
control purpose and the total dry film thickness shall be
confirmed after completion of final coat, using appropriate
thickness gauges (see annex 3).
|4||Repair||Any defective areas, e.g., pin-holes,
bubbles, voids, etc., shall be marked up and appropriate repairs
effected. All such repairs shall be re-checked and