ASTM D7330-15

5.1 The determination of surface appearance change in pile yarn floor covering is useful in quality and cost control during manufacture of pile yarn floor covering. This test method is considered satisfactory for acceptance testing of commercial shipments because current estimates of between laboratory precision are acceptable, and this test method is commonly used in trade for acceptance testing.

5.2 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 comparative tests that are as homogenous as possible, drawn from the same lot of material as the samples that resulted is desparate results during initial testing and randomly assigned in equal numbers to each laboratory. The test results from the laboratories involved shall be compared using a statistical test for unpaired data, a probability level chosen prior to the testing series. If a 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.

1.1 This test method covers the assessment of changes of surface appearance of pile floor coverings after exposure to actual or simulated foot traffic. This test method applies to pile yarn floor coverings that are, or have been, installed; laboratory floor-trafficked samples; or textiles floor coverings trafficked by mechanical traffic simulators. The subjective assessment is facilitated by use of reference scales that are based on digital images of representative pile yarn floor covering styles and constructions.

1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.3 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.