These test methods cover the nondestructive measurement of the dry film thickness of nonmagnetic coatings applied over a ferrous base material using commercially available test instruments. The test methods cover the use of instruments based on magnetic measuring principles only. Test Method A provides for the measurement of films using magnetic pull-off gages and Test Method B provides for the measurement of films using magnetic flux gages.

These test methods are not applicable to coatings that will be readily deformable under the load of the measuring instruments, as the instrument probe must be placed directly on the coating surface to take a reading.