The ASTM D1894 standard explains testing to find the static and kinetic coefficients of friction (starting and sliding) for plastic film and sheeting while sliding over itself or other surfaces under specific conditions. The tester may use a stationary sled with a moving plane or a stationary plane with a moving sled. Both test methods yield the same coefficients of starting and sliding friction. The ASTM D1894 test also allows for recording data while heating the plane to non-ambient temperatures while keeping the sled at ambient temperature (23 degrees C).