The method involves filling a test cup with the test fluid (fuel or fuel surrogate), sealing test sample over the open end of the cup, and then placing the sealed container into an oven at the desired test temperature and measuring the weight loss over time. Permeation rates are calculated from the rate of weight loss and the exposed area of the test sample.
Standard permeation test temperatures are 40 °C and 60 °C. Standard test fluids are Fuel C, Fuel CE10 and Fuel CM15. Other fluids, such as Fuel CMTBE15, and other volatile liquids may be tested according to this procedure as desired (SAE J1681). The method is not applicable for measuring permeation of higher boiling materials that will not completely evaporate from the exterior surface of the sample at the test temperature.