Document 3QYZRB2kJ4D1jeY45jboo6nq0

126 Txvcntx-fifth National Safety Congress -titstion. Instead, high velocity ventilating apparatus should be installed, functioning as closely to the point of generation of the harmful substance as is possible. Individual machines should be so equipped if possible. Baffles may be in* trodoced to prevent air stream disturb ances or to increase the intake efficiency at the nozzle. Down-draft systems should be preferred for the collection of dust or gases of high specific gravity. Even after the installation of exhaust ever. the engineer interested in ascer taining not only exposure but also effi ciency of control should realize control cannot be folly effective nor the efficiency of any protective device determined with out scientific tests. Assumption, guess work. unscientific procedure or apparatus have no place in an engineering program. The engineer must test each step unless it has been previously proved, carefully cal culating in advance to avoid false protec tion. systems, the engineer must study the type of maintenance required to keep them operating at jeak efficiency. Mos aics should not be permitted to become covered nor moved out of proper posi tion. Exhaust piping must be kept dust light. Blower efficiencies must be con stantly checked 1o ms&re that intake ve locities arc proper. The best ventilating system is a false protection if it does not function property or if it is so poorly maintained that it falls below its designed rating. The engineer must exercise ex treme ore to provide a dean source of He must be familiar with dust counting, air sampling, and chemical analysis tech nique. having such determinations made by established and proper methods. If such tests are beyond the scope of his ability or equipment and if the engineer considers such tests absolutely essential, then his executives should permit him to obtain experts qualified to make such sur veys as his problem may require. The need for-an accurate engineering approach to any control measure cannot be over emphasized. replacement air for the work place. He may find it necessary to install filtering and heating devices. The engineer must study the proper disposal of the collected or expelled material to be positive it vritl not drift back into the work plaee. Employee Protection. While the pri mary engineering means of protection against possible occupational diseases should be mechanical correction, the en gineer will find instances where even the best systems must be supplemented by individtial protection. He must carefully study such exposures to provide the high est efficiency of protection, yet obtain a device easy for the operator to wear con tinuously. When the engineer has been successful in obtaining such a device, he Canchtafaa. Every engineer realizes control of any industrial disease expo sure is divided, part of such control fall ing- within the jurisdiction of the indus trial physician and part within his own engineering province. Medical knowledge is mvaluable in the detection of early symptoms and in the administration of statable preventive treatment. The en gineer should gladly obtain the services of an industrial physician to make a study of the plant, to assist in the classi fication of the hazardous operations and working locations. By such coordination he will speed central of the exposure. Each individual occupational disease exposure must be studied, analyzed, and controlled individually. While genera] must educate workers to use it. Sanitation. Clean washing facilities and toOets should be provided. Lunch rooms should be not only clean but also well lighted and attractive and should be un der the supervision of the plant physician. Scientific Testa. Up to this pomi the engineer has deduced that an exposure exists, and from accumulated data has devised his means of prevention. How data may be available upon common ex posures. the solution can be found only in Individual treatment. Such exposures cannot be compared to ordinary safety engineering efforts- A circular saw is a circular saw wherever it may be operat ing. but industrial disease exposure varies within plants and certainly varies between different manufacturing establishments; even though they may produce a like product or article. ADJOURNMENT y-f. Safety Belts TUESDAY AFTERNOON SESSION October 6. 1936 This session sms called to order by the Detroit Edison Co. Detroit. ilfdu. Chairman George Opp, Safety Engineer, who introduced the successive speakers: Safe Design and Construction of Safety Belts By DR. E P. SKINKER Assistant Director of Research. Brooklyn Sfiam Co., Brooklyn, N. Y. Safety belts for linemen and for in frequent repair work will always be jus tified. This does not appear to be true of window cleaners* belts. Window cleaner accidents are so frequent that insurance costs as much as one dollar per day per 'man. Tins should be avoided by designs that would make window cleaners* belts unnecessary. Failure of a lineman's belt In service and of a new lineman's belt before going into service prompted our investigations. Many of the belts we bad in service were found to be inadequate to meet an emer gency of reasonable expectancy. A study of the safety belt specifications and test data at that time made it apparent that safety belts were designed with tensile strength sufficient to hold a man securely while doing his task but with no definite requirement to allow for slipping or other accidents. The hardware was tested to 1,503 pounds but the leather seldom reached 1,000 pounds. This seems ridicu lous since the leather deteriorates and the portance. As legal evidence of adequate safety protection, records of periodic proof tests are much better than of visual in spections. Fabric in good condition may be given repeated proof tests without in jury to Itself. Defective belts can be re moved from service by such proof tests plus Inspection. In contrast with this, leather is not uniform, and always stretches under test which will gradually wear out the belt; leather docs not have the original strength and it takes an ex pert to inspect leather even when new. In our experience, linemen's fabric safety belts that look badly worn and are dis carded have over 60 per cent of their original strength. Leather for this service most have suit able tanning and oiling to discourage dry rot and moisture. Similarly, fabric should be protected against mildew by robber or by impregnation with suitable rot-proofing compound. In practice h is difficult to tell what compound is best because of the many variable factors. metal docs not. Wc purchased new fabric belts and tested all our old leather ones to destruc tion. In general the tough old leather one had little elongation and those leather belts with considerable elongation did not have the proper strength. In changing to fabric belts wc had another reason of more fundamental im To get tbe full use from the belting material the method of fastening the hard ware It of importance. Thera is consider able advantage In using large diameter rolls for any terminal equipment. If the roller or bar is small the outer layer of the material may take all the load and break, then the second layer and so oo