MemBrain “Smart” Vapor Retarder Receives U.S. Patent 11/17/2004
VALLEY FORGE, PA -- It’s been named one of the year’s most innovative products, and now MemBrain® polyamide smart vapor retarder has been awarded a U.S. patent for its unique design.
MemBrain, unlike traditional polyethylene vapor retarders, allows closed building envelope systems to increase their drying potential with seasonal climatic changes. It can help reduce builder and contractor callbacks and the risk and liability concerns due to excess moisture in homes and buildings that is so common today.
The smart vapor retarder changes permeability from less than 1 perm at low humidity (such as during winter) to greater than 20 perms at high relative humidity (such as during summer).
The more typical vapor retarder material, polyethylene, while an excellent retarder of moisture penetration, does not allow drying when seasons change. When moisture penetrates the construction, it can condense on cold surfaces and accumulate in the wall cavity. Excess moisture can then result in moisture problems such as mold growth and rot.
With a high resistance to water vapor diffusion in winter, MemBrain reacts to relative humidity increases by altering pore size, allowing water vapor to pass through it. The lowered resistance supports the drying process.
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