Document oRYK0kejejgo6wLVz7vyDpNo

Fig 31-1 --Well-designed manifold system for acetylene cylinders Courtesy Linde Co , Division of Union Carbide Corp Most welding and cutting processes --for construction, demolition, maintenance, and repair--use portable, manually operated equipment The major portion of this chapter discusses ways of minimizing the hazards encountered in this type of intermittent op eration Since production line welding and cutting equipment is usually permanently installed, the source of a hazard can be mini mized through safe design The safety pro fessional, however, can use this chapter to help him check the operation and mainte nance of production line equipment The detailed specifications of ASI Stand ard Z49 1, Safety in Welding and Cutting, should be followed In addition, city, state, and Federal government codes and regula tions, where applicable, should be consulted This chapter uses the American Welding Society's welding and cutting definitions A welder is "one who is capable of per forming a manual or semiautomatic welding operation " A welding operator is "one who operates machine or automatic welding equipment " Gas Welding and Oxygen Cutting An oxygen-cutting process severs or re moves metal by the chemical reaction of the metal with oxygen at an elevated temperature maintained with heat from the combustion of fuel gases In the powder-cutting process, a finely divided material, such as iron powder, is added to the cutting oxygen stream The powder bursts into flame in the oxygen stream and starts cutting without preheating the ma terial to be cut Powder cutting is used on stainless and other steels, on many nonferrous metals, and on concrete in construction and demolition jobs Welding and cutting gases Oxygen is furnished to the consumer in steel cylinders, usually under a pressure of about 2200 psi at 70 F, or as a liquid to be gasified on the consumer's premises Pure oxygen will not bum or explode It supports combustion, that is, it causes other substances to bum when they are raised to the kindling temperature Combustible ma terials bum much more rapidly in oxygen than in air Oxygen forms explosive mixtures in certain proportions with acetylene, hydro gen, and other combustible gases A gas-welding process unites metals by heating them with the flame from the com bustion of a fuel gas or gases and sometimes includes the use of pressure and a filler metal This chapter was revised by Joseph Van Sickle, based upon reviews by selected members of the National Safety Council 919