6 Test specimens6.1 Form, shape and

6 Test specimens6.1 Form, shape and preparation6.1.1 The methods used for the preparation of test specimens can have a significant impact on their apparent durability. Therefore, the method used for specimen preparation shall be agreed upon by the interested parties. It should preferably be closely related to the method normally used to process the material in typical applications. A complete description of the method used for the preparation of test specimens shall be included in the test report.6.1.2 The dimensions of the test specimens are normally those specified in the appropriate test method for the property or properties to be measured after exposure. When the behaviour of a specific type of article is to be determined, the article itself should be exposed whenever possible.6.1.3 If the material to be tested is an extrusion- or moulding-grade polymer in the form of granules, chips, pellets or some other raw state, specimens to be exposed shall be cut from a sheet produced by the appropriate method. The exact shape and dimensions of the specimens will be determined by the specific test procedure used for measurement of the property of interest. The procedures used to machine or cut individual test specimens from a larger sheet or article may affect the results of the property measurement, and hence the apparent durability of the specimens. For preparation of test specimens,the procedures described in ISO 293, ISO 294-1, ISO 294-2 and ISO 294-3, ISO 295 and ISO 3167 have been found to be satisfactory.6.1.4 In some cases, individual specimens used for property measurement may need to be cut from a larger specimen which has been exposed. For example, materials that delaminate at the edges may be exposed in the form of larger sheets from which individual test specimens are cut after exposure. The effects of any cutting or machining operation on the properties of individual test specimens are usually much larger when the test specimens are cut from a large piece after exposure. This is especially true for materials that embrittle on exposure. Follow the procedures described in ISO 2818 for preparation of test specimens by machining. Only cut individual test specimens for property measurement from larger specimens that have been exposed when this preparation procedure is specifically specified.