MIL-PRF-23236 Coating Systems For Ship StructuresThis specification covers four types of air pollution regulated ship and structure coatings that comply with the National Emission Standards for Hazardous Air Pollutants \(NESHAP\) for shipbuilding for state and federal regulations. There are nine classes of coating systems. There are four grades of coating systems based on temperature of application and cure. In addition to tanks, all paint systems qualified to this specification are suitable for use on any ship structures, interior or exterior, for corrosion control. Except for trace levels, all types are free of lead, chromium, cadmium, and asbestos \(see 3.2.3\). All types have levels of hazardous air pollutants \(HAPs\) that do not exceed applicable NESHAP levels \(see 3.2.2.2\). Dry Type V, VI, VII, and VIII coating residues and debris are non-hazardous waste under U.S. Environmental Protection Agency \(USEPA\) regulations in effect on the date of this specification. Type VII coating will not have any solvent added to either the base resin component or the hardener component.

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MIL-PRF-23236D

b. Unless otherwise specified in the manufacturer's data sheet, 24 hours dry time shall be allowed between

coats, and 1 week at 21 C (70 F) (nominal) or equivalent between the last coat and immersion. Edges shall not

receive extra paint thickness or be reinforced by additional coats unless such coating is specified in the

manufacturer's ASTM F718 and product data sheets under application instructions. At test inspection points, the

coatings shall be as specified for the appropriate type, class, and grade.

4.5.2.1 Immersion test for fuel and seawater ballast exposure (all types, Class 5, all grades). Two coated panels

shall be subjected to twenty-five cycles or to prior failure, whichever comes first, of the following test cycle. The

cycle comprises three operations that are carried out in the order specified with panels prepared as specified in 4.5.2:

a. Salt water immersion for 1 week (7 days): Immerse panels totally for 1 week in natural seawater or in

ASTM D1141, substitute ocean water, at a temperature of 27�6 �C (80�10 F). There shall be no more than 8 hours

between completion of step (a) and the beginning of step (b)

b. Aromatic fuel immersion for 1 week (7 days): Following salt water immersion, immerse the panels totally

in MIL-DTL-5624, ASTM D1655, or commercial JP-4, JP-5 at a temperature of 27�6 �C (80�10 �F). There shall be

no more than 8 hours between completion of step (b) and the beginning of step (c).

c. Hot water immersion for 2 hours: This operation is intended to simulate conditions encountered in the use

of tank cleaning equipment. Following fuel immersion, immerse the panels totally in hot, ASTM D1141 synthetic

seawater or natural seawater having a salinity of 33 to 35 parts per million chloride, for 2 hours at 80 �C (175 F)

(nominal).

Operations (a) to (c) constitute one complete test cycle. This cycle is repeated and coating deterioration

recorded after each complete cycle. If coating is still satisfactory after twenty cycles, wipe lightly with a soft cloth

and freshwater, allow 48 hours to thoroughly dry, and recoat the upper one third of one side of each panel, masking

off the edges, approximately 13 millimeters (0.5 inch), and the bottom portion of the panel with one coat of the

system finish coat of the coating system (or primer coat and finish coat if appropriate). Allow a 1-week dry time at

ambient laboratory conditions and complete immersion test with five additional test cycles. Test panels shall be

inspected at the end of the tenth, twentieth, and twenty-fifth cycles for imperfections (see 3.9.1). On completion of

testing, the coating system shall be evaluated for: Pinhole rusting, ASTM D4541, Type II tester, adhesion of both

the original and recoated surface areas, blistering larger than 1.5 millimeters (0.0625 inch) in diameter, and surface

imperfections larger than 1.5 millimeters (0.0625 inch). Type VII coating systems shall be evaluated for edge

rusting. The test results shall be in accordance with the requirements of 3.9.1.

4.5.2.2 Dedicated salt water ballast (all types, Class 7, all grades). Two test panels, prepared as specified in

4.5.2 shall be tested in accordance with either of the following cycles (cycle A or B):

4.5.2.2.1 Cycle A.

a. Salt water immersion for 5 days: Immerse panels completely with panels prepared as specified in 4.5.2 for

1 week in either natural seawater or ASTM D1141, substitute ocean water solution at a temperature of 27�6 �C

(80�10 �F).

Remove panels from test and allow to dry for 2 days.

c. Hot water immersion for 2 hours: This operation is intended to simulate conditions encountered in the use

of tank cleaning equipment. Following the drying period, immerse the panels totally in hot, synthetic seawater for 2

hours at 80 �C (175 �F) (nominal).

Operations (a) to (c) constitute one complete test cycle. This cycle is repeated and coating deterioration

recorded after each complete cycle. If coating is still satisfactory after twenty-five cycles, wipe lightly with a soft

cloth and freshwater, allow 48 hours to thoroughly dry, and recoat the upper one third of one side of each panel,

masking the portion from the edge to 13 millimeters (0.5 inch) inward, with one coat of the finish coat of the coating

system (or primer coat and finish coat if appropriate). Allow a 1-week dry time and complete immersion test with

twenty-five additional test cycles. Coating system shall be evaluated for pinhole rusting, ASTM D4541, Type II

tester, adhesion of both original and recoated surfaces, blistering larger than 1.5 millimeters (0.0625 inch) in

diameter, and surface imperfections larger than 1.5 millimeters (0.0625 inch). Type VII coating systems shall be

evaluated for edge rusting. Test results shall be as specified in 3.9.