1.1 This test method covers the measurement of the out-of-plane response of geosynthetics to a force that is applied perpendicular to the initial plane of the sample.

1.2 When the geosynthetic deforms to a prescribed geometric shape (segmented sphere or elliptic) formulations are provided to convert the test data to biaxial tensile stress-strain values. These formulations cannot be used for other geometric shapes. With other geometric shapes, comparative data on deformation versus pressure is obtained.

1.3 This test method is more commonly used to test geomembranes. Permeable materials may also be tested in conjunction with an impermeable material.

1.4 This test method requires a large diameter pressure vessel (greater than 450 mm). Information obtained from this test method may be more appropriate for design purposes than many small scale index tests such as Test Method D638 or Test Method D751 (Bursting Strength).

1.5 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only.

1.6 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.