Abstract
Previously we studied the causes of errors in measurement of water vapor permeance of buiding materials by a test method using saturated salt solutions. To eliminate these errors, it is necessary to measure vapor pressure of air in test chambers of Two-Box Method. For this purpose, we developed two physicochemical measuring methods of sampled air from test chambers ; 1) refrigerating method which cools the sampled air under dew point temperature, and 2) exposing method which exposes the sampled air to water or saturated salt solutions. By either method, the vapor pressure of the sampled air can be shifted to the known value, thus permitting us to calculate the original vapor pressure by using the difference of total pressure in the sampling vessel. The values obtained by these method are in good accord with these derived by Assmann's psychrometer. Furthermore, the measuring method of vapor transfer coefficient of surfaces of the specimen is proposed. The values of natural convection measured by this method coincide with numerical values derived from Navier-Stokes formula.
