Document V3788Kev41dYL49kN1Bd276JZ

*.** *C* 144 E. I. ou Pont oc Ncmouws & Company Wilmington, Delaware inn // CC: J.A. Sigaan-Textlle Pibera-Wilm. J.A. Collina-M.L. Monaek J.R. Allen CNOINttftlNO DCPAHTMINT January 5, 1971 R. B. HATDEN TEXTILE FIBERS DEPARTMENT NEMOURS BUILDING, WILMINGTON INDUSTRIAL DEPARTMENTS MATERIALS ENGINEERING THERMAL INSULATION RELATIVE DUSTINESS STUDY Attached Is a copy of a study report by Haskell Lab. on the dustiness of thermal insulation materials. This study was Initiated by the Materials Engineering Group of BSD and was done in conjunction with Haskell Lab. and the Engineering . Test Center as a part of the Company Thermal Insulation Program. - The purpose of the study was to determine the relative potential dustiness, as received from the manufacturer, of the asbestos bearing thermal insulations presently In our engineering standards. With the Information contained in this report and the following information in this letter, it should be poesible to select insulations, when handled with reasonable care, that will fall within the presently established Threshold Limit Values (TLV) for asbestos dust. Conversely it points out the brands of insulation that present the greatest potential hazard. I recommend that the fiber count be used to determine the least hazardous material rather than the materials with higher coarse/ fine ratios (irresplrable/respirable) since the fiber counts are made on that are essentially respirable samples. Note -that the count of fibers greater than 5 microns in length represents only an Id minute sampling period. The Threshold Limit Values (TLV) established by the American Conference of Governmental Industrial Hygienists represent time-weighted Concentrations for a 7 or 8-hour work day mnd AO-hour work /* wr w 5v DUP 0901620 SC-DP-03315