A SYSTEMS-APPROACH TO THE CONTROL OF WELDING FUMES AT SOURCE

A number of different hazards are presented in the electric arc welding of metals and effective control of many of these can be achieved using conventional engineering solutions. However, traditional methods of control of welding fumes by general and local exhaust ventilation are often found to be inadequate and are improperly used. Control of fumes at source by process modification can be used to complement existing control strategies. This paper presents a systematic approach to fume control by process modification. The effects on the rate of fume formation of the various welding parameters: the type of welding system, voltage, current, wire feed rate, gas shield and the type of materials to be welded are described. The effects of the fluxes and their constituents are given special consideration since the flux and slag system can act as a suppressant to the formation of metal oxide fumes yet can itself give rise to toxic fumes. Thus the correct selection of the components of the welding electrode, the flux and workpiece, as well as choice of welding parameters, forms an integral part of the systematic control strategy.