The ASTM D3985-17 standard provides a test method for measuring oxygen transmittance (OTR) of Plastic films and sheets using Coulomb Sensors. This method is suitable for evaluating the steady-state transport rate of oxygen through films, laminates, and coated materials, providing data such as oxygen transmittance, membrane permeability, and oxygen transmittance coefficient. Although OTR is an important determinant of Encasement protection, this test result alone cannot fully evaluate Encasement performance, so a comprehensive evaluation is usually required in conjunction with Miscellaneous testing. If the buyer and seller have agreed on the relevant conditions, this method can be used as a referee test. This method is related to the Miscellaneous Oxygen Transmittance Test Method, but the specific situation needs to be determined according to the actual test and standard.