Test Method D 4032 for testing stiffness of fabrics is considered satisfactory for quality control testing. It may also be used for acceptance testing of commercial shipments since the test method has been used extensively in the trade field. In cases of differences in values reported by purchaser and seller using Test Method D 4032 for acceptance testing, the statistical bias, if any, between the laboratories of the purchaser and the seller should be determined with each comparison being based on the testing of specimens taken homogeneously from a lot of material of the type being evaluated. Specimens should be randomly assigned in equal numbers to each of the laboratories.

The circular bend procedure gives a force value related to fabric stiffness, simultaneously averaging stiffness in all directions. The stiffness tests in Test Methods D 1388 are of the single directional type.

The circular bend procedure is simple to perform and may be used for knitted, woven, or nonwoven fabrics, provided gage capacity is in keeping with fabric range tested.

1.1 This test method covers the determination of the stiffness of fabrics by the circular bend procedure.

1.2 This test method is generally applicable to all types of fabrics, including woven, knitted and nonwovens, of any fiber content. For other methods of testing for stiffness, refer to Test Methods D 1388.

1.3 The values stated in SI units are to be considered as standard; the values in 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.