This test method is considered satisfactory for quality control testing.

If there are differences of practical significance between reported test results for two laboratories, comparative tests should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, use test samples as homogeneous as possible, drawn from the material from which the disparate test results were obtained, and randomly assigned in equal number to each laboratory for testing. The test results from the two laboratories should be compared using a statistical test for unpaired data, at a probability level chosen prior to the testing series. If a bias is found, either its cause must be found and corrected, or future results for the source material must be adjusted in consideration of the known bias.

The stiffness of fabric relates to its resistance to bending with further processing and use. It measures the fiber and yarn bending capabilities, the cohesion of individual fibers and yarns relative to their displacement and binders or finishes that hold them in place.

1.1 This test method covers the determination of the stiffness of fabrics by measuring the force required to push a specimen into a slot of predetermined width with a metal blade working at a predetermined capacity.

For other methods for testing stiffness, refer to Test Methods D 1388, D 4032, and D 5732.

1.2 This test method is applicable to fabrics of any fiber content whose stiffness does not exceed the capacity of the Penetrator Beam apparatus. Specimens can be taken from fabrics, rolls, or end products.

1.3 The values stated in SI units are to be considered as standard; the values inch-pound units are included for information only.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.