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HSE guidance on controlling welding risks

Guidance from the HSE. www.hse.gov.uk

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http://www.hse.gov.uk/welding/index.htm?utm_source=govdelivery&utm_medium=email&utm_campaign=Welding&utm_term=riskmanagement&utm_content=updatedguidance-nov19

Controlling the risks from welding

 

If welding is part of your work activity, you must carry out a risk assessment to identify what measures are required to control the risks from exposure to welding fume.

 

  • Regular welders will weld for most of their shift and carry out different types of welding and other associated activities in the same day, depending on the requirements of their job. Their exposure to welding fume will be regular and of a significant duration or high intensity. They will require adequate controls to protect them from the risk of developing occupational lung diseases.

 

  • Sporadic welders will carry out welding infrequently when it is incidental to their main manufacturing operation. Engineered fume controls will not normally be expected for occasional welding carried out less than once each week and lasting less than 1 hour. In these situations, ensure that respiratory protective equipment (RPE) and good general ventilation is provided to control exposure to welding fume. But, you must also consider the protection of others nearby and ensure the general ventilation is effective at removing and dispersing the welding fume. 
    • For example, a car mechanic wearing RPE with good general ventilation in the workplace, carrying out an occasional short welding job on a car with a broken exhaust support bracket, would meet the minimum requirement for compliance.

Without controls in place, workers will be exposed to welding fume. This video shows typical fume emissions arising from MIG welding.

Your assessment should consider factors such as the:

welding process, volume of work and level of fume generated

  • size of the component being welded
  • metal being welded (mild steel, stainless etc)
  • consumable being used in the welding process

When reducing exposure to any hazardous substance, the principles of control are based on a prioritised approach. You should consider eliminating welding where possible by using cold joining techniques with:

mechanical fasteners (bolts, rivets etc.), or

  • adhesives (such techniques are under continuous development)

If you cannot eliminate welding, consider:

reducing the amount of welding

  • using a consumable that produces less fume
  • using a welding process that produces less fume
  • making sure the metal has been properly cleaned and prepared
  • automating or mechanising the process or job
  • using other engineering controls such as LEV

LEV for the most common types of manual welding processes

The most effective way to reduce welding fume is to capture it at source, protecting the welder and preventing fume spreading.

To adequately control exposure to welding fume you should use suitable LEV where possible. These may vary depending on the welding activity.

On-torch extraction

On-torch extraction can be very effective for MIG welding, and you should assess if it is useful for your task. Modern, bespoke, high-efficiency welding guns with built in on-torch extraction can provide really good control.

Extracted benches

Extracted benches are a good choice for medium and smaller welding jobs that can be brought over to the bench. When welding larger articles, extracted booths large enough to house the workpiece with it mounted on a turntable to ensure the fume is drawn towards the extraction at the back of the booth can be suitable. This video shows an extracted bench.

Movable LEV

Movable LEV units with swing-arm hoods rely on workers correctly placing hoods and moving the hood as they work. Some tasks require bespoke hoods.

The videos above illustrate what good control looks like when LEV is used to control exposure. The BOHS Selector Tool will help you select the right LEV for your workplace.

When LEV discharges within the work area, the discharged air must be filtered to reduce the particulates to a negligible concentration (defined within paragraph 52 of HSE's Enforcement Management Model).

Extracted air discharged outside the work area should leave the building at a high enough level to ensure it will be dispersed. Environmental legislation may also apply.

The HSE publication Controlling airborne contaminants at work PDF  gives guidance on planning, designing, commissioning and testing effective LEV.

The COSHH essentials sheet WL3 Welding Fume Control PDF gives more guidance.

Respiratory protective equipment (RPE)

If you cannot achieve adequate control from LEV alone, or it is not reasonably practicable to provide LEV, you must provide your workers with suitable respiratory protective equipment (RPE). Also consider any other workers exposed to the welding fume, taking account of the level of general ventilation provided and excluding unprotected people from welding areas.

Welder in capture zone
This photo shows although the welder is working in the capture zone, there remains residual risk in the form of uncaptured particulate and therefore additional RPE would be required.

You cannot rely on LEV to effectively capture welding fume at outdoor operations. So, for any welding outdoors, you must provide suitable RPE and consider the protection of others nearby.

A powered air respirator or a supplied air respirator which combines respiratory, eye and face protection, with an APF of at least 20, is the best option for arc welders. Otherwise, if tight-fitting RPE is used, it can become uncomfortable to wear, leading to workers loosening or removing the RPE.

For work not expected to exceed one hour, a FFP3 tight-fitting disposable mask or re-usable half-mask with a P3 filter may be adequate to protect against particulates if the wearer is clean shaven, but these particulate filters will not protect workers from welding gases contained in the fume.

RPE must be suitable for each wearer. Face fit testing for devices with a tight-fitting face seal will ensure the equipment selected is suitable for each worker.

You should have an RPE management programme which includes:

suitable face-fit testing

  • a stock of spare parts for example, batteries and filters  
  • clean storage of RPE when not in use
  • compatibility with other personal protective equipment (PPE) you have provided for the task, for example a welding visor

The HSE publication Respiratory protective equipment at work PDF gives more guidance.

Other workers in the area

Workers operating automated or mechanised welding machines or other workers nearby are unlikely to need RPE if:

effective general ventilation provides rapid fume clearance and a through draught to ensure that fume generated from welding is dispersed and removed.  In most welding workshops mechanical general ventilation will be required because natural ventilation from open doors and windows is not sufficient to disperse the fume generated from the work tasks

they can see fumes generated, but are working far enough away that they are not near any fume generated and there is no haze of fume lingering in the air

It may not be possible to have an LEV system in robotic cells capable of capturing all the fume. So how far away the operators can work becomes one of the main factors in deciding whether mechanical general ventilation is needed. Mechanical general ventilation uses fans mounted in the ceiling or high up on a wall to extract the air in the room and draw in clean air to disperse airborne contaminants.

Resistance spot welding

 

Resistance spot welding produces much less fume than other welding processes like MIG welding. Good general ventilation is usually sufficient to remove welding fume from low intensity resistance spot welding processes where the welding is on clean uncoated metal. Eye protection is required to safeguard against splatter. COSHH Essentials sheet WL3 PDF gives more advice on fume control.

 

Prevention of arc-eye using welding curtains

 

The purpose of a welding curtain or screen is to protect passers-by and nearby workers from the welding arc light.

 

Flame-retardant, heavy canvas screens are very common, but many people prefer to be able to see if someone is welding inside. This means that many screens are made of 'semi-transparent' plastic. These semi-transparent screens allow you to see enough to know that someone is welding, but the material filters out the harmful parts of the light. If there is no need to see the person welding or for screening in between welding bays, darker or opaque screens and curtains should be used.

 

Welding curtains and screens should conform to the British Standard BS EN ISO 25980 or at least offer the same level of protection as this standard. Some welding equipment suppliers may refer to this as EN ISO 25980.

 

The standard does not specify any particular colour, it just requires the curtain to attain certain levels of performance. This means that suitable curtains may be available in a variety of colours and levels of 'darkness'. A reputable supplier should be able to confirm if a curtain conforms to the British Standard. At the moment, HSE is not aware of any clear welding curtains that conform to BS EN ISO 25980.

 

Personal protective equipment (PPE)

 

Prevent exposure to direct and reflected ultraviolet (UV) light and infrared rays by wearing protective clothing and using welding screens. If possible, use dark-coloured wall coating to reduce reflections.

 

To protect against splatter when welding, wear appropriate clothing that covers arms and legs, and use suitable gloves. Wear goggles when chipping slag or wire brushing welds during preparation or finishing off work.

 

Specific eye protection including filters for welding operatives (to prevent arc eye) should conform to relevant British and European standards. There are standards covering impact resistance, auto-darkening welding filters and fixed filters. Reputable welding equipment suppliers will be able to help you make the correct choice.

 

 

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