Improved moisture permeability measurement method

This paper describes the development of a new method for measuring water vapor transport through common building materials. The method represents an improvement in flexibility over the standard ASTM cup methods in terms of allowing isothermal and nonisothermal testing. The method also accounts for convective boundary layers on both sides of the test material. This paper contains preliminary test results using gypsum board materials. Future testing will attempt to gain transport data for these and other materials under likely operating environments.