1.1 This test method covers the procedure for determining the in-plane transmissivity of geosynthetics under varying normal compressive stresses using a radial flow apparatus. The test is intended to be an index test used primarily for geotextiles, although other products composed of geotextiles and geotextile-type materials may be suitable for testing with this test method.

1.2 This test method is based on the assumption that the transmissivity of the geosynthetic is independent of orientation of the flow and is therefore limited to geosynthetics that have similar transmissivity in all directions and should not be used for materials with oriented flow behavior.

1.3 This test method has been developed specifically for geosynthetics that have transmissivity values on the order of or less than 2 x 10^-4 m²/s. Consider using D4716 for geosynthetics with transmissivity values higher than 2 x 10^-4 m²/s.

1.4 The values stated in SI units are to be regarded as the standard. The values stated in parentheses are provided for information only.

1.5 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.