ATLANTA - Air Quality Sciences (AQS), in conjunction with the Greenguard Environmental Institute (GEI), has announced a new test method that measures the ability of newly manufactured building materials to resist mold growth. Once tested, a newly manufactured product, such as insulation, receives a 1 to 4 performance rating - 1 being highly susceptible to mold growth and 4 being highly resistant to mold growth.

"This easy-to-use rating system will greatly assist architects and specifiers by taking the guesswork out of selecting the best building materials that resist mold growth as well as supporting product manufacturers in their efforts to provide products that meet this critical need," said Marilyn S. Black, Ph.D., CEO, and chief scientist with AQS. The Greenguard Environmental Institute will use this rating system to develop product certification criteria for mold resistance as more data becomes available on key construction materials.

"The test method that supports the rating system determines microbial resistance of new materials as manufactured and not as installed, soiled, or weathered. As such, the test does not guarantee product performance, since installation, modification of materials, weathering, aging, and building operation and maintenance may impact the microbial resistance of materials," Dr. Black said. The test method is based on the U.S. Environmental Protection Agency's (EPA's) research guide, published as ASTM D 6329-98 (2003), Standard Guide for Developing Methodology for Evaluating the Ability of Indoor Materials to Support Microbial Growth Using Static Environmental Chambers.

Air Quality Sciences conducted a trial of the test method, including a nine-month laboratory study (Phase 1), followed by a yearlong pilot study of products submitted for testing (Phase 2). According to the company, results confirmed and validated the choice of mold, consistency of results from control samples, the time course of mold growth, and that different materials respond differently. Ten manufacturers of products, including insulation, accepted an invitation to participate in Phase 2 of the study.

The final pilot study report will be available free from the Greenguard Website ( A white paper that provides perspective on the usefulness of this new test method and rating system is currently available on the Aerias - AQS IAQ Resource Center Website ( or

Publication date: 06/05/2006