Down-draft ventilation table and booth for welders
Some welding tasks are performed on benches or the floor of a workshop. Welding fumes generated from the molten metal, flux and any impurities (paint, etc.) on the metal rise from the workpiece into the welder’s breathing zone. Depending on the materials being welded, the fumes may contain a variety of heavy metal and chemical substances which can affect the health of the employee. The arrangement of work also exposed welders to posture and manual handling problems.
Health effects may range from irritation of the eyes and respiratory tract to chronic breathing disorders, ‘industrial bronchitis’ or ‘welders’ lung.
Consultation between the health and safety representative and management and, as a result, designed a welding workstation which incorporated a down draft ventilation system and a welding booth. The down-draft table controls fumes, gasses and fine particles generated during the welding process at their source. The airborne contaminants are drawn down through the table, away from the employee’s breathing zone and through filters which capture the fumes, fine particles and gasses.
Some maintenance problems were experienced with the down-draft table:
- Access to the table’s filters was difficult for maintenance workers as the filters had been screwed in behind a sheet metal cover to create an air-tight enclosure.
- Filters of the same type were not easy to find (due to the manufacturer going out of business) and a different type of filter had to be used which, though effective, generated more suction through the table than was required.
Progressively these problems were eliminated through improved design.
The welding booth has solved manual handling problems via the installation of a jib hoist above the work station and by having the down draft table adjusted to approximately waist height. The booth’s three walls and sliding curtain across the front of the booth prevent welding ‘flashes’ to nearby employees.
Hierarchy of Controls:
- Risks to employee health and safety have been reduced by controlling welding fumes at the source.
- An improved manual handling posture.
- Reduced chance of welding flash eye injuries.