Standardization News

Mold Growth on External Building Products

Consumers who are purchasing building materials for homes want to be assured that the materials are mold resistant. A proposed new ASTM standard will allow for a mold-resistance rating to be given to specific materials, depending on how the materials perform to the test method.

The proposed new standard, WK32079, Test Method for Determination of Mold Growth on Building Products Designed for Exterior Applications Using an Environmental Chamber and Direct Inoculation, is being developed by Subcommittee G03.04 on Biological Deterioration, part of ASTM Committee G03 on Weathering and Durability.

WK32079 describes an environmental chamber and the operation conditions to evaluate in a four-week period the relative resistance to mold growth on building products to be used outdoors. According to Judy LaZonby, president and technical director, MicroStar Lab Ltd, and chairman of G03.04, as well as D01.28 on Biodeterioration, WK32079 will be more aggressive than a proposed standard currently being developed by D01.28 for interior applications.

"Material that is exposed to outdoor weather conditions must withstand more severe challenges than materials designed for interior exposures," says LaZonby. "If a chamber method is going to be useful in determining a mold growth rating for exterior products, the challenge will need to be more severe than that used for evaluating interior surfaces."

Primary users of the standard will be manufacturers of building materials, chemical companies with mold-resistant chemistries and independent laboratories evaluating mold-resistant products.

All interested parties are invited to join G03.04 in the ongoing development of WK32079. LaZonby notes that many of the people currently involved in the development of WK32079 are primarily interested in indoor mold growth and that it would be very helpful to have more people involved whose area of expertise is in mold growth on exterior building products.

CONTACT Technical Information: Judy LaZonby, MicroStar Lab Ltd. • Crystal Lake, Ill. • Phone: 815-526-0954 • Email: O ASTM Staff: Jeffrey Adkins • Phone: 610-832-9738 • Email: O Upcoming Meeting: Jan. 29-31, 2012 • January Committee Week • Atlanta, Ga.

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