Document VGaGdMnBErXZ6Y0KN93byKwd4

1 Supervisors Safety r-- Manual \ x { Better production without injury and ica.str from accident* t NAl IOX.AL SAfT/n COl'NCIL. CHICAGO. ILLINOIS t-vGII (1 * 411 FIRST EDITION' 1936 SECOND EDITION' 1961 } THIRD EDITION' COPYR1CHT 1967 NATIONAL SAFETY COUNCIL ALL RICHTS RESERVED So portion of this book may be reproduced by an\pmeets without written pernj.rion of the National S-`erv Council. 425 North Michigan Avenue, Chicago. III. t-Ootl LIBRARY OF CONCRESS CATALOG CARD NUMBER: 67-10644 PRINTED IN THE UNITED STATES OF AMERICA 4OM3670S Stock No. 1SI.0S-3 `< . . > * 'tt Heat shields, as well as ventilation, may also be used. A large radiant area may heat a person excessively, even if the air surrounding the person is not very hot. In these cases, it is more effective to provide a reflector to return the radiant energy toward its source than it would be to try to cool the person by air blast or to try to insulate the radiant source. Sheet aluminum reflectors completely surrounding, but not touch ing, a furnace will reflect 95 per cent (or more) of the radiant energy, and will themselves absorb so little heat that they will be cooled by natural circulation of the air around them. Not only will these reflec tors completely protect workmen from excessive radiation, they will also reduce the atmospheric temperature because they decrease the amount of heat received and re-radiated by other objects. The supervisor should not attempt to use makeshift remedies like asbestos or darkened metal shields. A rust)- iron panel, for example, will absorb radiation from the source, become heated, and then act as a radiator itself. There is another hot weather, or '`hot'* industry, problem that must be controlled. When people are exposed to high temperatures, they lose much salt in perspiration. A company physician, or outside physi cian, may prescribe salt tablets to prevent heat cramps or heat exhaus tion. Enteric-coated or impregnated salt tablets can be used to prevent nausea which affects some persons when they take salt. Heatstroke or sunstroke results from hot and humid conditions under which the body loses its ability to cool itself. It does not result only from exposure to the sun, but also it is commonly seen among men exposed to radiant heat from open flames or furnances. The only method of control is to reduce the temperature of the surroundings or to increase the ability of the body to cool itself, so that body tempera ture does not rise. Heat shields, discussed earlier in this section, arc of value here. Air contaminants For the most part, occupational diseases arc produced by material an individual breathes rather than by a material he swallows or absorbs through his skin. Few compounds poison by direct absorption through the skin. Some will on long-continued contact. Many materials are poisonous if swallowed, but the average person (in a nonfood indus try) does not go around eating or drinking the materials he works with. 107 i (- I V- \ I iLi Exhauit hood ot eonvoyor bolt transfer point exhausts dust to an isolated location ' j* v Approximately two-thirds of all occupational disease exposures fall into three classifications: 1. Exposures to organic* nonmetallic dusts (mostly from grinding opera* tions). This exposure includes that of silica and asbestos dusts. 2. Exposures to lead and its compounds. 3. Exposures to carbon monoxide. I v Exposures to all other dusts, vapors, gases, and fumes make up the remaining one*third, not counting exposures that produce occupational dermatitis. It is not difficult to recognize an exposure hazard, although spe cialized knowledge and instruments are needed to tell how severe it may be. The supervisor can, however, recognize a danger spot and ask for expert help. If a supervisor is not alert, a lot of harm can be done. Here are some of the things to watch for. . A process that produces dust fine enough to remain suspended in the air long enough to be breathed should be regarded as questionable until it can be proved safe. Silicosis, for example, is produced in hard P* *".*;*>* c: * j-.* .. . .:-v . * 4 r ,4.- ; ' * r-7`4 ^ rock mines. It can also be produced by dry grinding cutlery on naturally quarried sandstone wheels and by quarrying and dressing of granite, which contains free silica. There is a common belief that the danger of lung disease from grinding disappeared when the natural sandstone wheel was replaced. The Carborundum wheel and also the Alundum wheel in themselves arc not producers of silicosis. When they are used to grind castings that contain mold sand, however, they can still present a silicosis hazard. Methods of drilling rock with power machinery produce more dust than old-fashioned hand methods. This dust, however, is con trolled by applying water to the drill steel so that the dust forms a slurry instead of forming an air suspension. Processes in which inorganic materials are crushed, ground, or transported are potential sources of dust. They should either be con trolled by use of wet methods or should be enclosed and ventilated by local exhaust. Points where conveyors are loaded or discharged, trans fer points along the conveying system, and heads or boots of elevators should be enclosed and, usually, exhaust ventilated. Powdered mate ria! that is simply riding along on a belt or other conveyor should .ause no dust problem. The supervisor must check that someone does not cancel the effectiveness of built-in dust controls by tampering with them or by using them improperly. He must also check closely that required respiratory equipment is worn by those workers who need supplemen tary protection. - Fumes Welding, metalizing, and other hot operations produce fumes, many of which are harmful. Arc welding volatilizes metal which condenses--as the metal or its oxide--in the air around the arc. In addition, the rod coating is in part volatilized. These fumes, because they are extremely fine, are readily inhaled. ' Iron pigment in the lungs appears to have no effect in producing illness or disability. Its presence shows up in lung X-ray.s and may lead to a mistaken diagnosis of silicosis. More toxic materials---such as those formed when wcldine struc* hires that have been painted with red lead, or when welding galva nized metal--may produce severe symptoms of toxicity rather rapidly, 109 t*Vi :i ! M. 4 'K\ 1 i \ i 4 \ ii u I \ -n I unless fumes arc controlled or the welder is protected by respiratory protective equipment. When pouring leaded brass, zinc volatilizes from the molten mass and oxidizes in the surrounding air to produce a zinc fuine, which (in high concentrations) may produce the* rather nonspecific disease l i tiy ! rIT. a Vw It it Soldering fumes are pulled away from operator by duct (upper right). known as "metal fume fever" or "brass ague." The zinc carries with it a considerable amount of lead, which is also oxidized and suspended in the air. As a result, brass foundry workers may incur a chronic lead intoxication if they work a longtime in the trade. Most soldering operations, fortunately, do not require tempera* lures high enough to volatilize an appreciable amount of lead. How ever, some of the lead in the molten solder is oxidized by contact with air at the surface. If this oxide is mechanically dispersed into the; air, it mav produce a severe lead poisoning hazard. In operations where this might happen, such as soldering or lead no ' *;4T