LOCATION AND M-FACTORS OF VAPOR BARRIERS WITHIN INSULATED BUILDINGS (AN ANALYTICAL APPROACH)

One Vapor barrier located near the warm surface of an insulated wall may not prevent the condensation of water vapor when outside temperatures enter into the sub-zero range. This condensation destroys the heat resistant function of the insulation. The addition of properly located vapor barriers of correct permeance will control the movement of vapor end prevent condensation within the insulation. This report is a technical analysis of the problem of controlling condensation in structures subjected to sub-zero ambient temperatures.