Water vapor permeation test method is mainly divided into two categories: gravimetric method and sensor method, with the latter method being the earliest used one. Gravimetric method is the arbitration method of water vapor permeation testing. Data system of sensor method should be calibrated with that of gravimetric method.

For water vapor permeation testing, gravimetric method is not only the most widely used approach, but also the arbitration method. It is the standard of those data systems obtained through other water vapor permeation test methods.