The UK’s Health and Safety Executive (HSE) reminded employers during February that they must protect workers' health by controlling the risks associated with welding fume. The safety body also announced that its current programme of inspections would review health and safety standards across the country, with businesses encouraged to visit HSE’s revised guidance to remind themselves of the changes to control expectations.
The announced inspections follow on from a safety alert that was issued in February 2019 after new evidence from the International Agency for Research on Cancer showed exposure to all welding fume, including mild steel welding fume, can cause cancer .
Welding is a process where two or more parent materials are joined through either heat or pressure, or both, to form a weld. According to guidance from The Welding Institute (TWI), when welding with heat, the parent material can either be used independently or with the presence of a consumable or filler material to produce a weld pool consisting of molten material, which cools to form a weld.
To protect the health of workers, employers must ensure that adequate controls are in place to avoid or reduce exposure to welding fume. John Rowe, head of manufacturing at HSE, says: “Employers and workers should know the risk, plan their work and use the right controls when welding activity is carried out. If they are not, HSE will use enforcement to bring about improvements."
So, what measures can be put in place? Operations Engineer has sifted through the HSE’s guidance to provide a quick overview for employers and employees.
The first step to consider is whether alternative methods to welding can be implemented in order to protect workers from the health risks of inhaling welding fume. Consideration should be taken as to whether exposure can be avoided or reduced by doing the job in a different way. Examples include using alternative joining, cutting or surface preparation methods; reducing the amount of welding altogether; and automating or mechanising the process (by using distance welding, turntables or enclosing the work).
Other examples given by the UK safety body are using clean metals, such as pre-fabrication shaping or better machining, and using materials or a process that generates less fume, such as using metal inert gas welding (an arc welding process), also known as MIG welding, instead of manual metal arc welding (stick welding), also known as MMA welding.
MIG welding is a gas metal arc welding process that uses a continuous solid wire electrode that is heated and fed into the weld pool from a welding gun, according to TWI. The two base materials are melted together which causes them to join. The welding gun also feeds an inert shielding gas alongside the wire electrode, which helps protect the process from airborne contaminants. MMA welding, meanwhile, is a process where the arc is struck between an electrode flux coated metal rod and the workpiece.
LEV & RPE
If workplace welding is unavoidable, then another measure that should be implemented is local exhaust ventilation (LEV) systems for indoor working. According to the HSE guidance, implementing a LEV system will protect the welder, as well as anyone else nearby.
LEV systems work by capturing the emissions (in this instance, fume) at the source. A hood captures the fume and air flow removes the contaminated air from the process by transporting it to a safe emission point or filter.
What is Local Exhaust Ventilation (LEV)?
Video source: HSE
In the UK, there are several manufacturers and suppliers of LEV systems and dust and fume extraction technology. AirBench, for example, offers solutions that fall into product families, including dust extraction, fume extraction, coolant mist extraction, air cleaning, and welding and grinding extraction. The latter includes a range of downdraught benches, cross-draught systems, and modular booths designed for control of dust and fumes from metalworking processes. Typical applications are said to include MIG and TIG welding and steel grinding.
Filtermist is another company in the LEV market. It provides a full turnkey solution for welding fume extraction – from designing and specifying the right fume extraction equipment, to installation, commissioning and ongoing monitoring to ensure the extraction equipment is performing as intended.
Last year it hosted a one-day seminar, led by the Safety & Health Engineering Partnership (SHEP) in conjunction with the HSE, which specifically focussed on controlling exposure to welding fume and metalworking fluids. The seminar included presentations on the health risks from welding and metalworking fluids, as well as practical sessions, including on why it’s important to correctly design and install effective LEV systems.
“LEV is widely recognised as the best way of removing contaminants, including welding fume from workplace air. Composition of fume will vary depending on the type of metal being welded and the welding method used, but can include a range of gases that have all been assigned WELs (workplace exposure limits) – these include carbon dioxide, carbon monoxide and nitrous oxide (see box),” says Andy Hives, director of group UK sales at Filtermist.
|“All substances with WELs are subject to Control of Substances Hazardous to Health (CoSHH) regulations, meaning employers are required to prevent or minimise exposure using effective control measures,” Andy Hives, director of group UK sales at Filtermist|
Hives adds: “There are a lot of benefits to ensuring workplaces benefit from good quality air - not least on the morale and health of staff so they are happy and more productive. That’s not even taking into account days no longer lost due to ill health.”
If adequate fume control cannot be achieved from LEV alone, or if it is not reasonably practicable to provide LEV, workers must also use suitable respiratory protective equipment (RPE). “When you provide RPE for your workers, use an FFP3 disposable mask or half-mask with P3 filter for work of up to an hour; use battery-powered air-fed protective equipment for longer duration work, with a minimum assigned protection factor (APF) of 20; [and] ensure RPE wearers are clean shaven and provide face-fit testing for them,” the HSE guidance states.
Another document, ‘A practical guide to RPE at work’ can be found here. APF, it explains, is a number rating that indicates how much protection that RPE is capable of providing – for example, RPE with an APF of 10 will reduce the wearer’s exposure by at least a factor of 10, if used properly.
LEV will not work for welding activities carried out outdoors, so workers should use suitable RPE to control exposure. Businesses should also provide appropriate personal protective equipment (PPE) for welders and shielding that can protect other workers from eye damage.
The HSE guidance also states that employers must ensure that any controls to protect workers from health risks of welding fume remain effective. For example, a risk assessment might show the need for health surveillance (a system of ongoing health checks).
The final area highlighted revolves around employee training. Workers – both new and old – must be trained properly and understand that fume and dust from welding can cause lung cancer and other lung conditions, if not properly controlled. Training should include, among other things, pre-use checks and doing the job properly, LEV and RPE, and safety risks. The full list can be found here.
Image credit: Filtermist
So, in simple terms, risks to health from welding fume can be controlled by employers and employees by using alternative cold joining techniques, welding in a way that produces less fume and using LEV systems. RPE and PPE should also be used, and control measures and good general ventilation should be maintained. Furthermore, welders need to understand the risks and how to use controls.
Employees and employers alike both have a responsibility to ensure that the risks associated with welding fume are being controlled. Any company carrying out welding activity should heed the HSE’s announcement by ensuring welding activities are being carried out in the safest manner possible. As HSE’s Rowe states: “Everyone should be able to leave work and go home healthy and safe.”
BOX OUT: Workplace exposure limits
According to Breathe Freely, an initiative setup by BOHS (British Occupational Health Society), there is no standard UK welding fume limit. “In the UK, the closest to a general welding fume WEL (workplace exposure limit) is the iron oxide fume limit and the worst case scenario (for stainless steel) is taken as the chromium limit [0.025mg/m3],” its ‘welder factsheet’ states. “The levels of exposure and subsequent risks to health vary depending on what type of welding process is undertaken, the base metal, the composition of the filler rod (core) and flux, any surface contaminants, the work environment, as well as the exposure time (or ‘arcing time’).”
Some welding fume components do, however, have exposure limits, it adds. With this in mind, reproduced below is part of HSE document ‘EH40/2005 Workplace exposure limits - the list of workplace exposure limits for use with the Control of Substances Hazardous to Health Regulations 2002 (as amended)'.