16. WELDING AND FLAME CUTTING
Fumes caused by different welding materials
General information
Welding fumes have a low content of gases. They are mainly mixtures of solid particles.
The amount and composition of these fumes depend upon:
the welding process
the filler metal
the shield gas
the current level
the base material
coating (painted, galvanized, dirty, corroded etc.)
Manual metal arc welding (rod welding) produces a lot of fumes (solid particles).
Gas welding with the filler metal produces little fumes, but in MAG welding there is
almost the same amount of fumes as in arc welding.
Painted coatings
Steel plate materials are normally painted with a workshop primer for anticorrosion
reasons. If the area on the plate where you are working is coated with a thicker layer of
paint, more than just the primer, there might be different fumes and gases created by
the burning process, depending on the paint quality. Prolonged exposure to the mixture
of fumes and gases created by burning paint and welding fumes can be hazardous if
ventilation has not been arranged and protective equipment is not used. Welding and
flame heating of any structures with painted coatings requires the use of protective
equipment, and it is recommended not to weld such items unless the paint has been
removed, or sufficient ventilation arranged.
84