Document 8VMp5wX2rROM733kwMBV7MMGa

-- i-i/iTi-ji in air Breathed by the Employees i/hi Io Cutting and installing ''Kayla" Insulation Plan Authors: K. H. Warwick B. L. Murray Doctor Hull, Plant Medical Director, requested a plant-uidu industrial hygiene study to determine the potential erposura of insulators to csbcstcs fiber dust concentrations, table I gives the results of seven separate tests, including 24 breathing zone level air samples and shows an average dust concentration cf 5.2 Billion particles per cubic foot ci air. A ''threshold linit value" of 2" nppcf of air has been suggested.1 When three asplcyees, cr less, hand-cut and apply "Eaylo" insulation, the concentration cf dust is considered safe from the health standpoint; however, with 6 man the dust count exceeds the ILV. It is at this phase of the operation that exhaust ventilotion should be used, excessive du3t concentrations can bo expected when the insulation is renoved from piping and tanks, Agcin, exhaust venti lation should be used to nove the dust away from the employees, if possible; otherwise, respirators_are advised. "laylo" insulation contains 12 to 12% asbestos and 5.G to 7.4% crystalline-free silica. This material is received in block ond pipe fora ana the insulator measures and marks the material into appropriate sizes and cuts it with a hand saw. The insulation material is wired into position around the tank or pipe. The tasks of cutting and apply ing the "Xaylo" insulation are shown in Figures 1 and 2. The air samples were collected with a nidget lapinger and a Uni-Jet sampler, drawing 0.1 cubic feat of air per ninutc through lapinger flasks containing 10 cillilitcrs af distilled water. Dust counts, made by the Light Field Microscopic Counting Technique, appear in Table I. This study has revealed that further research work is needed to: 1. Attain cn established figure for the "threshold limit value" 2. Utilise ezhaust ventilation to remove the dust from the work area. 3; Determine the particle else of the asbestos fiber where the dust count exceeds 5 mppef. 4. Obtain Range Finding Tests on animals exposed to different percents of asbestos fiber. 5. Continue our plant-wide study in support of these conclusions. .1 Cook, Wurren A., ond Focle, Robert E., Letter doted February 12, 1UGC - Tha University of Michigan School of Public Health. .2 l'ccla, R. 2,, Industrial Hygiene Survey - Construction Insulation Shop, Dullding 511-2013. Report 52-IH-l-U-l (March 21, 1982). A G 3 0 81j UCC 015601