5.1 This test method determines the extent and nature of cushion thickness change under static load. Creep data obtained by this test method are applicable to the cushion under the conditions of the particular test and are not necessarily the same as obtained in a complete pack in actual packaging environments. Data may be affected by magnitude of static load, specimen area, shape, and thickness, by varying ambient conditions of temperature, humidity, by friction in the movable platen guide system, and by actual cushion thickness. Vibration in the vicinity of the test fixtures may also influence data results.