Document ymzNXRpL60o6B691V5GErjLvE

clean air to provide a safe atmosphere 7 Personal protective devices, such as spe cial clothing or eye and respiratory pro tection 8 Good housekeeping, including clean liness of the workplace, waste disposal, adequate 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 time, 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 engineenng conrols 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 stitution, it is always advisable to experiment on a small scale before making the new sol vent part of the operation or process For example, carbon tetrachloride can be re placed by solvents such as methyl chloro form, 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 m place of organic solvents Benzene can be replaced by tol uene in most lacquers, synthetic-rubber solutions, and paint removers Natural rub ber cements with aliphatic hydrocarbon solvents can perform virtually the same func tion as benzene cements The felt-hat industry has controlled the hazard of mercunahsm by substituting mercury-firee carroting materials Foundries using parting compounds that contain free silica can mini mize the silicosis hazard by substituting relatively harmless powders Sandstone grinding wheels have been largely replaced by artificial abrasive wheels usually made of aluminum oxide Changing the process A change in process often offers an ideal chance to improve working conditions Most such changes, of course, are made to improve quality or reduce cost of production, only occasionally to improve the in-plant environ ment Yet, we must always keep this possible benefit in mind This applies to the safety engineer 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 gready reduced by changing to hand filing Brush painting or dipping instead of spray paint ing will minimize the concentration of air borne contaminants from toxic pigments Other examples of change of process are arc welding in place of riveting, vapor de greasing to replace hand-washing of parts, airless spraying techniques and electrostatic devices to minimize overspray as replace ments for hand-spraying, and machine appli cation of lead oxide to battery grids which reduced lead exposure in making storage batteries In buying individual machines, the need for accessory ventilation, noise suppression, vibration and heat control should be con sidered before purchase Often the best approach is to thrash out these requirements with the supplier m advance Isolation or enclosure Some potentially dangerous operations can be isolated from the people nearby, which solves the exposure problem The isolation can be by a physical barrier (such as an acous tic box to contain noise from a whining blower or a screaming np saw), or by time (such as providing semi-automatic 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 operations requiring relatively few workers or where control by any other method is too difficult or too expensive The job is iso lated from the rest of the operation and thus the majority of the workers are not exposed to the hazard The workers actually con cerned with the operation can then be pro- 1287