Precautions asbestos

Contractors, construction or demolition workers or persons working in attics or demolishing block walls should note the presence of vermieulite and follow applicable asbestos precautions. In some cases this will require Type 3 precautions. 

Although the percentage of asbestos in the vermiculite may be below the limit normally treated as asbestos, the elevated levels detected upon disturbance indicate that asbestos precautions will be necessary to protect the workers performing removal and to prevent contamination of the rest of the building or home. These precautions include ... 

Inhalation of certain fine dusts may constitute a health hazard. Eor example, exposure to siUca, asbestos, and beryllium oxide dusts over a period of time results ki the potential risk of lung disease. OSHA regulations specify the allowable levels of exposure to kigestible and respkable materials. Material Safety Data Sheets, OSHA form 20, available from manufacturers, provide information about hazards, precautions, and storage pertinent to specific refractory products. 

SmaH quantities of carbon tetrachloride can be shipped in 1, 5, and 55 gaHon (208 L) metal containers. Larger quantities are shipped by tank tmck, tank car, barge, and ship. Seamless stainless steel. Teflon, or seamless bronze hose is recommended with asbestos. Teflon, Viton, or neoprene gaskets. Special precautions should be taken to prevent contact with aluminum, magnesium metal, and their aHoys (48). 

Table 5.27 Summary of precautions for work involving asbestos...

Ensure that employees liable to be exposed to asbestos receive adequate information, instruction and training - so that they are aware of the risks and the precautions which should be observed. 

Asbestos An lAQ investigation often includes inspection above accessible ceilings, inside shafts, and around mechanical equipment. Where material suspected of containing asbestos is not only present, but also has deposited loose debris, the investigator should take appropriate precautions. This might include disposable coveralls and a properly fitted respirator. 

As a solvent, acetone is used in varnishes, lacquer, cellulose acetate fiber, cellulose nitrate (an explosive), and as a carrier solvent for acetylene in cylinders. Acetylene is stored at about 225 psi but is so explosively reactive that as an extra precaution the cylinder is filled with asbestos wool soaked in acetone. Acetylene is extremely soluble in acetone, and the asbestos keeps it from sloshing around when the cylinder is half empty. Acetone also is used in smaller volumes for the manufacture of pharmaceuticals and chloroform (the anesthetic). 

And in the case of asbestos, as in other cases, other proponents of precautions for risks are frequently opposed to further restrictions associations representing the fire brigades have for a long time opposed a ban. 

Plant personnel, if trained but not certified, can perform minor repairs (approximately the size of a hand), taking special precautions regarding dust, sweep, or vacuum particles suspected of containing asbestos. The fibers are so small that they cannot be seen and can pass through normal vacuum cleaner filters and get back into the air. The dust should be removed by a wet-mopping procedure or by specially designed HEPA vacuum cleaners used by trained asbestos contractors. 

As a precaution should fire occur, the workers should be provided either with protective helmets, equipped with a fresh air supply, or with masks and absorbers, and they should also wear protective clothing of asbestos or thick wool. If a violent fire occurs, the building must be evacuated, since to remain in an atmosphere containing a high concentration of nitrogen dioxide, even for a short time, is very dangerous. This is discussed in more detail on p. 407. 

Care in assembly. Since this is a gaseous reaction, it is essential that the apparatus be free from leaks thus, corks are eliminated wherever possible. The ends of the combustion tube and the top of the condenser are drawn to the diameter of the connecting tubes and joined by a piece of thick-walled rubber tubing. Care should be taken to have the ends of the glass tubes come into contact. The rubber tube situated between the furnace and condenser is protected by the asbestos screen, but a further essential precaution is taken, namely, that this end of the combustion tube extend a considerable distance from the furnace. 

A bent dropping funnel is inserted through a cork in the inlet end of the combustion tube, the first 15 cms. of which is loosely packed with asbestos and is kept outside the air bath. The liquid is allowed to drop in slowly from the funnel. A small flame is lighted under the tube where the liquid drops, and the flames gradually increase in size as the catalyst is approached this precaution is to prevent breakage. 

Talc has been used in the manufacture of crayons for many years. Recently, it was reported in the U.S. press that tremolite asbestos, anthophyllite asbestos, and chrysotile were detected in some crayons at concentrations ranging from 0.03% to 2.86% (CPSC 2000). In response, the Consumer Product Safety Commission (CPSC 2000) examined crayons from several U.S. manufacturers to determine whether asbestos was present. Trace amounts of anthophyllite asbestos were found in some of the crayons. The CPSC (2000) concluded that the risk that children would be exposed to fibers through inhalation or ingestion of talc-containing crayons is extremely low, but recommended that, as a precaution, crayons should not contain these fibers. The manufacturers have agreed to reformulate their crayons using substitute materials (CPSC 2000). 

The boiling-point of a liquid compound is determined by simply distilling a little of the pure dry compound using a small distilling flask with a thermometer carefully placed in the neck of the flask so that the top of the mercury bulb is just below the outlet. Wrapping the neck of the flask and the thermometer with asbestos paper, to prevent sudden cooling by drafts of air, is a precaution that insures more accurate results. 

Since the synthetic membrane of membrane cells replaces the older asbestos fiber diaphragm cells, no control precautions are necessary. Graphite (or later, titanium) cathodes avoid the use of mercury eliminating the need for mercury control. However, if membrane cells are operated on the same site as mercury cells, they do require a separate brine circuit from the mercury cells to maintain their mercury-free status. 

Special consideration must be given to physical characteristics in the choice of catalyst support. Since asbestos fibers are not porous to any extent, catalysts supported on asbestos are held in the inter-fibrilar spaces. When asbestos is used, precautions must be taken to prevent the felt-like mass from compacting and increasing the resistance to gas flow. For this purpose, asbestos-supported catalysts are used in numerous thin layers, each layer on a separate perforated plate. Despite its resistance to temperature effects, asbestos is not favored as a support and the more rigid materials preferred. 

Asbestos characteristics and hazards, precautions for removal, protective clothing, and types of respirators. 

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