Document VJvqKZGYY8Jwgg2XkE0mJjvw

washing, toilet, and eating facilities, healthful drinking water, and control of insects and rodents 9 Special control methods for specific haz ards, such as reduction of exposure tune, film badges and similar monitoring de vices, continuous sampling with preset alarms, and medical programs to detect intake of toxic materials 10 Training and education to supplement en gineering controls Substitution Replacement of a toxic material with a harmless one is a very practical method of eliminating an industrial health hazard In many cases a solvent with a lower order of toxicity or flammability may be substituted for a more hazardous one In a solvent sub. sbtutaon, it is always advisable to experiment on a small scale before making the new solvent part of the operation or process For example, carbon tetrachloride can be replaced by sol vents such as methyl chloroform, dichloromethane, aliphatic petroleum hydrocarbons, or one of the fluorochlorohydrocarbons (The precautions listed earlier in this chapter should be reviewed ) Detergent-and-water cleaning solutions can be considered for use in place of organic solvents Benzene can be replaced by toluene in most lacquers, synthetic-rubber solutions, and paint removers Natural rub ber cements with aliphatic hydrocarbon solvents can perform virtually the same function as benzene cements The felt-hat industry has controlled the hazard of mercuriahsm by substituting mercury-free carrotmg materials Foundries using parbng compounds that contain free silica can mini mize the silicosis hazard by subsbtuting relabvely harmless powders Sandstone grinding wheels have been largely replaced by artificial abrasive wheels usually made of aluminum oxide Changing the process A change m process often offers an ideal chance to improve working condibons Most such changes, of course, are made to improve quality or reduce cost of producbon, only occasionally to improve the in-plant environ ment Yet, we must always keep this possible benefit in mind This applies to the safety professional more than anyone else In some cases, a process can be modified to reduce the exposure to a dust or fume and thus markedly reduce the hazard In the automobile industry, the amount of lead dust created by grinding solder seams with small high-speed sanding disks was greatly reduced by changing to hand filing Brush-painbng or dipping instead of spray painting will mini mize the concentrabon of airborne contam inants from toxic pigments Other examples of change of process are arc welding in place of riveting, vapor degreasing to replace hand washing of parts, airless spraying techniques and electrostatic devices to minimize over spray as replacements for hand-spraying, and machme apphcabon of lead oxide to battery grids which reduced lead exposure in making storage batteries In buving individual machines, the need for accessory ventilabon, noise suppression, vibration and heat control should be con sidered before purchase Often the best ap proach is to thrash out these requirements with the supplier in advance Isolation or enclosure Some potentially dangerous operabons can be isolated from the people nearby, which solves the exposure problem The isolation can be by a physical barrier (such as an acoustic box to contain noise from a whining blower or a screaming np saw), or by time (such as providing semi-automabc equipment so a person doesn't have to stay near the noisy machine constantly), or by distance (remote controls) Isolation is particularly useful for limited operabons requiring relabvely few workers or wheie control by any other method is too difficult or too expensive The job is iso lated from the rest of the operabon and thus the majority of the workers are not exposed to the hazard The workers actually con cerned with the operabon can then be pro tected by installing a ventilabon system which probably would not have been satisfactory if the operabon had not been isolated and thus able to be enclosed Enclosing the process or equipment is a desirable method of control since the en closure will prevent or minimize the escape 1085