This International Standard specifies an index test method for determination of the tensile properties of joints and seams in geosynthetics, using a wide-width strip. The method is applicable to most geosynthetics. It is also applicable to geogrids, but the specimen dimensions may need to be altered. This test is not applicable to polymeric or bituminous geosynthetic barriers. This method quantifies the tensile strength of a joint or seam between geosynthetics. It can provide data to indicate the joint or seam tensile strength which can be achieved. A joint or seam efficiency can be calculated by comparison of the joint/seam tensile strength with the tensile strength of the unjointed material, as determined by ISO 10319. Procedures for measuring the tensile properties of both conditioned and wet specimens are included. Some modification of techniques may be necessary for particular geosynthetics, e.g. strong geosynthetics, meshes or geosynthetics made from glass fibre, to prevent them from slipping in the jaws or being damaged as a result of being gripped in the jaws. The basic test for joints or seams in all kinds of geosynthetics uses test specimens of 200 mm width, with the provision for the seam or joint to extend for 25 mm on each side, in order to provide joint or seam stability during the test (see Figure 1).