Document DdG3DJJ5zDzKpJjnkKDbjvRxQ

THE TRAVELERS ENGINEERING DIVISION CHEMICAL REACTIONS Vol. V May 1976 ASBESTOS USES AND CONTROLS No. 3 Asbestos is a silicate mineral, a fibrous, naturally occurring material of varying chemical composition. The most common types of asbestos are chrysotile (magnesium silicate), crocidolite (sodium iron silicate) and amosite (iron magnesium silicate). Asbestos is used in well over three thousand products including building goods and consumer products. Some of these products include asbestos cement blocks, asbestos asphalt tile, gaskets, fireproof clothing, brake lining, furnace and boiler insula tion, building fireproofing compounds, and electrical insulation. Severe lung diseases can be caused by asbestos, such as asbestosis and/or cancer, through the inhalation of excessive quantities of the fiber. It takes approximately 15 to 20 years of exposure to airborne asbestos to develop diseases of the lung or of the gastrointestinal tract. Exposure to asbestos can cause three diseases about which we are concerned: Asbestosis, a fibrotic lung disease; bronchiogenic cancer, a cancer of the lung; and mesothelioma, a cancer of the chest lining or abdominal walls. The current allowable level of asbestos in the air is five fibers per cc greater than five microns in length for an eight-hour time-weighted average, and no greater than ten fibers per cc at any time during the day (greater than five microns in length). As of July 1, 1976, the eight-hour time-weighted average shall not exceed two fibers per cc greater than five microns in length, and no exposure at any time shall exceed ten fibers per cc greater than five microns in length. Airborne concentrations of asbestos fibers are determined by collection of the fiber on an 0.8 pore size micron filter of a cellulose acetate type. A sampling pump is placed on the worker and the filter is placed in the worker's breathing zone. The pump draws air through the filter and the fibers are collected on the cellulose acetate filter. The filter is then analyzed by phase contrast microscopy at 450 magnification to determine the fiber concentration in air. Workers who may be exposed or are at risk to airborne concentrations of asbestos in clude asbestos miners, insulation workers, demolition crews, brake reliners, ship builders and repairers, and construction workers. Control of the exposure to asbestos can take several routes.' Substitute another product that will do the same job; use personal protective equipment, such as NIOSH-MESA approved respirators; use adequate ventilation equipment before the fibers reach the breathing zone of the worker; practice good housekeeping by removing accumulated and settled dust by industrial vacuum cleaning; and wet the product to prevent expulsion of the dust into the air that the worker breathes. To prevent contamination away from the work place, clothes the workers wear should not be laundered at home. The clothing should be handled at the work place where workers are required to change to street clothing, and shower facilities are avail able. C *1 4833-26 PRINTED IN U.S.A. FIELD NOTES 7-21-76 - Rupert Bryan & Steve Singleton Breathing Zone Asbestos Sampling 15-4 Storeroom Cut,shake, re-store 3types of asbestos rope packing Folios: 526-499 3/4" diam., loose weave ? 1/2" diam., loose weave 526-553 Flat ribbon material 5 mins. 19-4 Handling and counting flat packing gaskets - 24 of them Rectangular manway packing shows a resin-type treatment Also some round ones - (five) Also 526-355 gaskets and 526-370 (about 50) 5 mins. 09-4 1/2" millboard cut with sabre saw 2 cuts & clean-up 6 mins. 20-4 l/8" millboard with scissors Cut & cleaned up 6 mins. 5-5 Control 6-5 Scoring and breaking strips of 1/4" millboard approx. 1/4 of job requirement Time = 5 min. 15 sec. Notes: 526-120 Johns Manville 1/2" millboard 526-118 Celotex 1/8" millboard Use 7010 rods for tacking because: u)strong tack b)allows for a better subsequent weld pass c)all position use rod d)doesn't need heated storage for a 30-day life