What are the relevant standards for thickness of dry film measurement?

Owners or shipowners who buy paint are actually buying the dry film thickness of the paint to protect the steel structure. Of course, in actual coating construction, the thickness of the paint film cannot be completely uniform, so it is impossible to be good. But neither in quality nor in quantity, it cannot deviate too much from the specification. The quality mentioned here refers to the measured value, and the quantity refers to the number of points and area measured.

The main standards for dry film thickness measurement are:

IS02808 Paints and varnishes - Determination of film thickness

ISO 19840 Paints and varnishes—Corrosion protection of protective coating systems for steel structures—Machines and acceptance criteria for dry film thickness on roughened surfaces

Magnetic Thickness Gauge Measurement of SSPC PA2 Dry Film Thickness

American SSPC PA2 has very clear principles and procedures for the measurement of paint film thickness.

Conduct 5 sets of random tests per 100ft2 (10m2) (take the average of 3 readings for each set). NOTE: Individual readings are not specified, but are included in the average for "arbitrary point" tests

The average value of 5 groups of arbitrary tests (that is, the average value of 15 test points) shall not be higher than or lower than the specified thickness.

The thickness of a single test point shall not be lower than 80% of the specified thickness, nor shall it be higher than 120% of the specified thickness.

The average thickness at any test point per 100ft2 (10m2) of area shall not be less than the specified minimum thickness. The thickness of any test point within any loft2 (10m2) area shall not be lower than 80% of the specified minimum thickness. The reading of any Tester may be significantly lower than the specified value. If the average thickness of any test point within a specific 100ft2 (10m2) area is within or above the specified minimum thickness, but one or more arbitrary test points have a thickness below 8o% of the specified minimum thickness, additional testing may be required to limit areas that do not meet the requirements.

The average thickness of any test point within each 100it2 (10m2) area shall not be higher than the specified maximum thickness. The thickness of any test point within any 10oft2 (10m2) area shall not be higher than 120% of the specified maximum thickness. The reading of any Tester may be significantly higher than the specified value. If the average thickness of any test point within a specific 10of2 (10m2) area meets or falls below the specified maximum thickness, but the thickness of one or more arbitrary test points is higher than 120% of the specified maximum thickness, additional testing may be required to Limit non-compliant areas. Consult the manufacturer's information to determine whether a higher maximum thickness reading is permissible in specific cases.

For areas below 1000ft2 (10om2), randomly select and test three 100ft2 (10m2) areas. If the dry film thickness in those areas is within the specified range, proceed. If not in compliance, add tests to define the out-of-compliance area and start over.

For areas above 1000ft2 (10om2), test the thickness of the first 1000ft2 (100m2) as described above (such as dry film thickness), and then randomly select and test the area of ​​100ft2 (10m2) for each additional 1000ft2 (100m2).