5.1 This test method is considered satisfactory for manufacturing quality control testing of a specific geosynthetic; however, caution is advised since information about between-laboratory precision is incomplete. Comparative tests as directed in 5.1.1 may be advisable.

5.1.1 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 from a lot of material of the type in question. Test specimens should then be randomly assigned in equal numbers to each laboratory for testing. The average results from the two laboratories should be compared using the appropriate statistical analysis and an acceptable probability level chosen by the two parties before testing is begun. If a bias is found, either its cause must be found and corrected or the purchaser and the supplier must agree to interpret future test results with consideration to the known bias.

5.2 This test method is not suitable for very limp geosynthetics or those that show a marked tendency to curl or twist at a cut edge.

5.3 The stiffness of a geosynthetic may change with storage.

5.4 No evidence has been found showing that bending length is dependent on specimen width. The tendency for specimens to curl or twist will affect the result, because of the rigidity provided at the edge. Consequently, the edge effect is less of an issue for a wider strip.