20 Anti-fouling: Affection and Efficiency
231
20.3.4 Sun-Orientation
Test specimens are subjected to different sun-orientations which means one side of
the test specimen will always face the sun while the other side will always remain from
the sun. This is to check the correlation of growth of algae affecting the efficiency
of anti-fouling coating.
20.3.5 ASTM A36 Mild Steel
Test specimens are made from mild steel ASTM A36 which has a medium low-carbon
percentage in it, which is the standard steel being used for testing anti-fouling panels
in shallow submergence. The dimension of mild steel is 6 mm (Height) × 250 mm
(Length) × 200 mm (Width).
20.3.6 Sandblasting
ASTM D3623-78a specifies the parameters to be used in order to obtain a near-white
surface finish with a profile of 25–38 µm. Parameters in sandblasting are: size of
grit for sand is 46, pressure 620 kPa, angle 90°, distance from surface, 75–125 mm,
nozzle size, 9 mm.
20.3.7 Data Table
Test specimens are evaluated for surface fouling and physical condition of the antifouling paint for an interval of four days using the data table in Table 20.1.
Fouling Rating (F.R) is the fouling present on the test specimen which is intact
during inspection. The procedure to calculate the F.R. is described in the following.
Award each test specimen which is free from any bio-fouling a percentage rating
of 100. Reduce the rating to 95 when there is any bio-fouling occurring. If mature
forms of fouling are present, obtain the rating by subtracting from 95 the sum of the
number of individuals’ present and percent surface covered by.
Anti-Fouling rating (A.F) is the condition of the anti-fouling coating and it records
qualitative descriptions of the coating. The procedure to calculate the A.F. is described
in the following. Award an anti-fouling coating test specimen having no defect a
percentage rating of 100. Subtract the percent surface affected by the coating from
100 to obtain the rating of imperfect films.
Overall Performance (O.P) is the lowest percent rating of the two preceding values.
231
20.3.4 Sun-Orientation
Test specimens are subjected to different sun-orientations which means one side of
the test specimen will always face the sun while the other side will always remain from
the sun. This is to check the correlation of growth of algae affecting the efficiency
of anti-fouling coating.
20.3.5 ASTM A36 Mild Steel
Test specimens are made from mild steel ASTM A36 which has a medium low-carbon
percentage in it, which is the standard steel being used for testing anti-fouling panels
in shallow submergence. The dimension of mild steel is 6 mm (Height) × 250 mm
(Length) × 200 mm (Width).
20.3.6 Sandblasting
ASTM D3623-78a specifies the parameters to be used in order to obtain a near-white
surface finish with a profile of 25–38 µm. Parameters in sandblasting are: size of
grit for sand is 46, pressure 620 kPa, angle 90°, distance from surface, 75–125 mm,
nozzle size, 9 mm.
20.3.7 Data Table
Test specimens are evaluated for surface fouling and physical condition of the antifouling paint for an interval of four days using the data table in Table 20.1.
Fouling Rating (F.R) is the fouling present on the test specimen which is intact
during inspection. The procedure to calculate the F.R. is described in the following.
Award each test specimen which is free from any bio-fouling a percentage rating
of 100. Reduce the rating to 95 when there is any bio-fouling occurring. If mature
forms of fouling are present, obtain the rating by subtracting from 95 the sum of the
number of individuals’ present and percent surface covered by.
Anti-Fouling rating (A.F) is the condition of the anti-fouling coating and it records
qualitative descriptions of the coating. The procedure to calculate the A.F. is described
in the following. Award an anti-fouling coating test specimen having no defect a
percentage rating of 100. Subtract the percent surface affected by the coating from
100 to obtain the rating of imperfect films.
Overall Performance (O.P) is the lowest percent rating of the two preceding values.