Understanding vapor barriers

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Abstract
The function of a vapor barrier is to retard migration of water vapor. Where it is located in an assembly and its permeability is a function of climate, the characteristics of the materials that coprise the assembly and the interior conditions. Vapor barriers are not tpically intended to retard migration of air. That is the function of air barriers.

Date
4/2005

Author(s)
Joseph Lstiburek

Page(s)
40-47

Source
ASHRAE (American Soc Heating Refrigeration & Air Condition Engineers

Keyword(s)
vapor barriers; moisture problems; hygrothermal regions

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