5.1 Light penetration may be used to control the quality of many TRMs. Light penetration is not indicative of field performance and therefore is not recommended for specifications.

5.2 The light penetration of TRMs may vary considerably depending on the composite materials used in the matrix of the mat or due to inconsistency within a given mat. To minimize variation, specific sample size and procedures are indicated in this test method to help ensure comparable results.

5.3 This test method may be used to determine the effect of different composite materials and make-up of TRMs.

5.4 This test method may be used for acceptance testing of commercial shipments of TRMs, but caution is advised since information on between laboratory precision is incomplete. Comparative tests as directed in 5.4.1 may be advisable.

5.4.1 In case of a dispute arising from differences in reported test results when using this test method for acceptance testing of commercial shipments, the purchaser and the supplier should conduct comparative tests to determine if there is a statistical bias between their laboratories. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the two parties should take a group of test specimens that are as homogeneous as possible and that are formed from a lot of material of the type in question. The test specimens should be randomly assigned in equal numbers to each laboratory for testing. The average results from the two laboratories should be compared using Student's t-test for unpaired date and an acceptable probability level chosen by the two begun. If bias is found, either its cause must be corrected, or the purchaser and supplier must agree to the light of the known bias.

1.1 This test method covers measuring the amount of light that penetrates through a Turf Reinforcement Mat.

1.2 This test method does not provide light penetration values for TRM under variable normal sun and soil conditions. This test method determines nominal light penetration.

1.3 The values stated as a percentage are to be regarded as the standard. The values provided in foot-candles are for information only.

1.4 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.