Blog - Slip Testing
Welding Fume Assessment NSW Mid North CoastPosted 18th June 2014, Carl Strautins
Safe Environments recently undertook a workplace investigation on the NSW mid-north coast to the potential exposure of welding’s to metal fume during fabrication. Our Occupational Hygienists regular undertake assessments in Northern NSW including areas such as Coffs Harbour, Tamworth, Armidale, Port Macquarie, Tweed Heads, Maitland and Lismore.
What are the hazards of welding fume
The hazards of welding fume include respiratory health effects, the toxicity and extend being dependant on what the metal fume comprises. This can be assessed by the base metal that is to be welded along with the metal and fluxing agents within the welding rod.
The base metal that was being welding in this case was mild steel, which comprises iron and small amounts of carbon. Iron as a welding fume is a respiratory tract and skin irritant which is relatively benign compared with other metals that affect the Central Nervous System (CNS) or have a carcinogenic nature.
Phosgene Gas Concerns from Welding Painted Metal
One of the clients concerns was the paint on the surface of a metal that was to be welded and the toxic fume that may be released and breathed in. Some of the toxic material may in phosgene, which was used as chemical weapons during the First World War. Phosgene reacts within the lungs and interferes with the gas exchange system and in large doses end with suffocation.
The solution to eliminating the potential of phosgene being release from the painted surface during welding was to grind back the area where the welding is to occur.
What controls may reduce concentration of welding fume
During the inspection of the workplace on the NSW North Coast, there was a combination of general dilution fans and an extraction system. General dilution fans are used to basically disperse the welding plume. The intent of this control measure is to reduce the concentration of the welding fume within the breathing zone. The area where the welding was being conducted was in a large metal building which is fairly open to the elements. Due to it being winter and the cold weather, the fans were not operating, which therefore was not effective in reducing the concentration of the welding fume.
The fans need to be operating at all times to disperse the high concentration welding plumes
The extraction that used was not considerably effective as it was essentially openings within ductwork which was attached to the walls; rather than the use of Local Exhaust Ventilation (LEV). Local Exhaust Ventilation (LEV), sucks and captures the high concentration welding fume away before it reaches the welders breathing zone. For Local Exhaust Ventilation (LEV) to be effective, the opening to the ductwork should generally be no further than 1-2 times the diameter of the opening of the inlet.
Where the concentrations of welding fume cannot be reduced effectively through these measures, other controls such as Personal Respiratory Protection (RPE) should be considered. In fact a more appropriate methods should initially be to use Personal Respiratory Protection (RPE) until there is sufficient statistical data to provide evidence that the welding exposures are well below the Exposure Standards (ES).
If your workplace is based in NSW North Coast such as Coffs Harbour, Tweed Heads, Port Macquarie, Newcastle, Lismore, please contact Safe Environments to undertake a welding fume assessment.