This method provides for the determination of the steady state thermal resistance of a fabric or layers of fabrics and for the determination of the temperature regulating factor (TRF) as defined below. This test method is considered satisfactory for acceptance testing of commercial shipments because the round robin testing shows high precision and no bias for testing of textile fabrics and foams.

5.1.1 If there are differences of practical significance between reported test results for two laboratories (or more), comparative test should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, use the samples for such a comparative test that are as homogeneous as possible, drawn from the same lot of material as the samples that resulted in disparate results during initial testing and randomly assigned in equal numbers to each laboratory. The test results from the laboratories involved should be compared using a statistical test for unpaired data, a probability level chosen prior to the testing series. If bias is found, either its cause must be found and corrected, or future test results for that material must be adjusted in consideration of the known bias.

This test method is useful in quality and cost control during manufacture. It can be used to establish criteria for establishing thermal and comfort parameters for textiles particularly used in the clothing industry.