Frequently asked questions about welding fumes

Q: Which respirator do I need when welding stainless steel?
A: When welding stainless steel with MIG or stick, the welding fumes often contain particles of chromium and nickel, of which chromium is more dangerous to inhale. 3M™ Adflo™ with particle filter offers you excellent protection in this application. TIG welding does not emit much welding fumes but creates large quantities of ozone gas. Read more below under ‘When does ozone form?'. Plasma cutting and plasma welding give rise to high temperatures, which can emit damaging oxides of nitrogen. Read more below under ‘What are nitrogen gases’?

Q: Do I really need respiratory protection when welding ordinary steel?
A: Although welding fumes from normal steel is not one of the most dangerous types, it is far from good for your health. Among other things, it contains particles of iron oxide, which can cause siderosis. (chronic inflammation of the lungs). When welding with MIG/MAG and stick, there are heavy fume emissions, meaning that both a respirator and good ventilation in the workplace are necessary. When welding ordinary steel, Adflo with particle filter is recommended.

Q: What sort of respirator is needed when welding surface-treated material?
A: When welding surface-treated material, a series of dangerous pollutants can be released; how dangerous depends on the type of surface treatment. When welding galvanised steel, zinc oxide particles are released. These can cause zinc ague, also known as fume fever. If you weld painted material you should be especially careful, as many paints can give off very dangerous air pollutants. When welding galvanised steel or material painted with lead primer, we recommend that you use Adflo with particle filter. This can be used in combination with an odour filter to minimise unpleasant odours. If the material is painted with two component paint or insulated with polyurethane, you should always contact a Safety Engineer. There is a risk that you will be exposed to some level of isocyanates, which are very dangerous to inhale and difficult to detect. In these cases we recommend you use Adflo with particle and odour filter or a compressed air respirator like Fresh-air C.

Q: What respiratory protection do I need in confined spaces?
A: If you are welding in confined or semi-ventilated areas – e.g. tanks, pipes or sealed rooms – you must make a risk assessment according to the requirements of Australian Standards AS2865 and AS1715. If Suitable use the Fresh-air C respirator, supplied with breathable compressed air, where you can be sure of getting enough oxygen, as well as higher protection against dangerous gases and particles. Adflo or Fresh-air C are never to be used in atmospheres immediately dangerous to life or health (IDLH). Always ask a Safety Engineer or Occupational Hygienist if you are unsure!

Q: Does shielding gases and alloyed electrodes affect my working environment?
A: When welding with MIG and TIG, the noble gases argon and helium are used as shielding gases. Neither argon nor helium is considered dangerous, but they can displace oxygen in unventilated areas, making the atmosphere oxygen deficient. In such cases, a compressed air respirator is required. When welding with MAG, carbon dioxide, or a mixture of carbon dioxide and a noble gas, is used as a shielding gas. Since parts of the shielding gas can be converted into carbon monoxide when the gas reaches the air, large quantities of carbon monoxide can form around the welding arc. Carbon monoxide cannot be filtered away. If the ventilation is bad, the oxygen level must be checked and a compressed air respirator used; we would recommend Fresh-air C. Alloyed electrodes are common when welding with MAG. The alloys often contain manganese or silicates. This means that large quantities of manganese oxide and silicates are diffused into the surrounding air when you are welding. Adflo with particle filter usually offers sufficient protection against alloy particles.

Q: When does ozone form?
A: When welding aluminium not only are particles of aluminium oxide produced but ozone gas is formed by the action of the UV radiation from the arc breaking down molecular oxygen. Ozone is also produced when welding stainless steel with TIG. Eventually ozone will be converted back to oxygen, a process that is speeded up when the ozone comes into contact with solid surfaces that act as a catalyst. Ozone cannot be filtered from the atmosphere but relies on being converted back to oxygen. At low ozone concentrations the use of the Adflo respirator system with particle filter reduces the amount of ozone reaching the welder. This is achieved by the fact that the particle filter (because of its large surface area) and the connecting tube to the welding helmet help to catalyse the conversion of ozone back to normal oxygen. At higher concentrations the inclusion of a gas filter in the Adflo respirator adds an additional large surface of carbon granules on which a further reduction of ozone takes place.

Q: What are nitrogen gases?
A: Nitrogen dioxide and nitric oxide are examples of nitrogen gases that are formed when you weld with high amperage and high temperatures. Nitrous gases are formed by a reaction in the air between nitrogen and oxygen and are very dangerous to inhale in large concentrations, e.g. when welding in confined, poorly ventilated areas. We always recommend Fresh-air C in such cases.