The ASTM D3816/D3816M-96 (2020) standard test method is used for the measurement of the water permeability of pressure sensitive tapes. This method evaluates the relative water permeability of the tape at its smallest size, which is typically perpendicular to the backing. The test determines the tape's water resistance by looking at its performance when exposed to water in an environment. Certain tapes allow water to freely penetrate along the tape interface or backing path, while tape thickness is often the primary barrier. This method helps evaluate the tape's suitability in wet conditions and prevents possible water permeability paths.