Document LJmbpy6VYpenqyZ5pkQBgDqNd

-. h UNITED STATES GYPSUM COMPANY 1000 East Nortnwest Hignway/Des Plaines. Illinois 50016 RESEARCH CENTER COSf 2'2 Croofs; j-jjn August 20, 1979 Mr. D. C. Klinger.smith, P..E. Staff Engineer ' Concord College Athens, West Virginia 24712 ' Dear Mr. Klingensmith: This is in response to your letter of August 13, 1979, requesting information on AUDICOTE Acoustical Plaster. Although we have no samples or other confirmation that the United States Gypsum- Company product, AUDICOTE Acoustical Plaster, was actually used in the Alexander Fine Arts Center at Concord College, we submit the following information to assist you. . AUDICOTE consists primarily of expanded perlite aggregate and other inorganic minerals which together total approximately 90ijt and a foaming agent (approximately 2X) . This composition produces the lightweight open structure which accounts for its excellent acoustical and aesthetic qualities. AUDICOTE Acoustical Plaster contains only a minor amount of asbestos (approximately 7^s), which is added to provide body to the wet mortar, thereby reducing the tendency of the mortar to flow and sag when applied to the ceiling. The small amount of asbestos fibers is securely embedded in the mortar matrix and should not be released to the air unless it is forcefully pulverized or abraded. I am not aware of, nor can I conceive of, a hazardous exposure resulting from a properly installed and maintained AUDICOTE Acoustical Plaster ceiling. However, if there is concern about the surface, for whatever reason, I would suggest that the ceiling be painted, if it has not been painted in the past. This would have the added benefit of improving both the appearance and the light reflectance. We would recommend a thin, spray-applied coat of vinyl latex ceiling flat paint such as USG TEXOLITE Standard, appropriately thinned for spray application. Use a slow, uniform motion. Cover surface in one pass. Do net pass over the same area several times, as this builds up paint unnecessarily. Allow at least overnight drying between coats. Brush or roller painting is not recommended. 6 r*0 )5 067-t Mr. D. C. Xiir.ger.smith, P. E. Concord College August 20, 197? Page Two The paint must be 'a permeable type, rather than a sealer cr ' bridging type. A heavy coat of paint, or numerous applications of paint, will obviously impair the acoustical efficiency of AUDICOTE Acoustical Plaster. 1 trust that this information serves your needs. If you require further information, please feel free to contact the writer. Sincerely, . ..<=> TKenneth S. Freeman, Manager \consumer Product Safety 'Research and Develocmer.t KSF/a $f>0 15 Q67S 0513