Document jm0xKnxrGBbNq8GKee6ek6Qxk

1 I'upci!? 2.1^3 \-r?ys construction department AIR SURVEY 0iJ L. V. Thfc-cher ar.d A. L. Linch October 21, 1966 Problem: To determine: A. Whether or not the total air-borne asbestos dust count generated during the fabrication and installation of asbestos containing insulating materials exceeds, either at the source or in the breathing zone, the Threshold Limit Valve of 5 million particles per cubic foot (m.p.p.c.f.) established by the American Conference of Governmental Industrial Hygienists (ACGIH). f.'Sir: --** * .-* '4 B. Extent of air-borne asbestos contamination of the general shops area, surrounding grounds, and installation sites. C. Total dust count for use in the evaluation of over-all atmospheric dust loading and for detection of other potential dust problems. Note: Item C will involve little additional cost as the differential counting of the sample is nominal compared to the cost incurred in procuring the sample particularly where special set-ups of work, tools, and materials are involved. Procedure: I. Collection Two methods will be used for the initial 'survey: A. Station sampling - portable. 'Tht' "Unico Constant Rate Uni-Jet" "Freon - 12" powered sampler equipped with the improved standard midget impinger ("Unico 2000"; followed by an 0.8 micron, pore size millipore filter (Cat. No. MAWG037U)) will be used. The dust collected in "dust-free" distilled water in the \ impinger will be counted at the University of Pittsburgh Graduate School of Public Health by the method approved by the Asbestos Textile Institute. The dust collected on the bacffc-up filter will be counted also at the University " of Pittsburgh. This filter will collect the particles iu .he size range be*ovi 3 microns which is mot retained 05C in the first stage es well es larger pertlculete which might carry over from the impinger. The limit of resolution in counting is-1.3 microns. 0Gi2!o 00P 0900626 SC-DP-01460