Document 8VDedz06DgMaRB7O1L9BDxQzZ

BALDWIN. EHRET- HILL INCOR'OMATCO / J/..I **4 C*14 t**t*ti** **4 A**$ti**t ft*4*tit *00 IREUNJC AVCNOE . THENTON.N J.0D60: EXPORT 64*71 . CABLE: IEHILL July 14, 1967 Mr, w, H. Zane E,, I. DuPont Engineering Department Wilmington, Delaware 19808 Dear Zeke: We wish to confirm our telephone conversation of yesterday concerning the dust count test we made on Mono-Block during your visit, The dust count was made according to the Method for Determining Asbestos Dust Concentration specified by the A.sbestos Textile Institute, The equipment used was the permissable air sampling pump, manufactured by Mine Safety Appliances'Company. The results of the test are as follows: Particle Size - Microns 1-3 " 3-5 Particles/cubic foot 5000 approx. 3000 approx. The sampling time in determing the above information was 10 minutes. - We believe these results cannot be compared directly with the re sults you had on Calcium Silicate insulation, since it is not known if the sampling and count procedures were the same. In addition, the test conditions being at different locations would undoubtedly be quite varied. We definitely believe that if Calcium Silicate and Mono-Block were tested at the same location, using the same equipment and procedures, that Mono-Block would show a much lower count of particles per cubic foot compared with Calcium Silicate. It was good to see you yesterday and discuss this situation with you and if you need any further information please do not hesitate to contact us. Very truly yours', 093 E. B. McBride' , Director of Research F-BMcB/f DUP 0900841 SC-DP-01915