There are many different measures that can be implemented to control exposure to hazardous substances. Inevitably, some are more effective than others and it is possible to develop a list of measures in order of priority – a “Hierarchy of Control”.
Those measures towards the top of the hierarchy are normally considered to be most preferable.
In principle, anyone considering control 2 techniques should start at the top of the list, considering each option in turn and deciding whether it is feasible.
The hierarchy is a useful tool, but it must be remembered that in most cases more than one measure will need to be implemented to properly control exposure.
Redesign the job or eliminate a substance so that the hazard is removed.
- Design the job so there is less hot work, e.g. Using CAD/3D design techniques.
- Buy in raw materials with edge profiles already cut.
- ensure surface coatings are removed prior to welding
Replace the metal or welding technique with a less hazardous one.
- Use a welding technique that produces less fume.
- For arc welding use the lowest current and voltage applicable.
- Optimise your shielding gas.
3. Engineering controls
Use work equipment or other measures to reduce exposure.
- Use suitable local exhaust ventilation (LEV) to remove the fume at source.
- Use a turntable to enable welding in a position where the fume rises away from the face (in addition to LEV).
- Ensure adequate room ventilation
4. Management and administrative controls
These are all about identifying and implementing the procedures you need to reduce exposure.
- Introduce a dedicated area for welding.
- Control access to working area.
- Minimise the work carried out in enclosed or confined spaces.
- Implement a maintenance and test regime for LEV systems.
5. Personal protective equipment
Masks, eye protections, gloves etc.
- Wear a battery powered respirator with a welding visor or helmet if the fume cannot be controlled in other ways.
- Ensure other workers in the area are not exposed to the fume.
- Where respirators are being used ensure that they are properly fitted, used and maintained.
Air monitoring and measurement may be needed where there is a serious risk to health from the inhalation of welding fume and the likely exposure level of the welders to the fume is not known, e.g. during the manual metal arc (MMA) welding of stainless steel.
Monitoring may also be needed to help confirm that the control measures in use are working correctly, as a deterioration or failure of engineering controls could result in welders being exposed to high levels of fume.
Under the Control of Substances Hazardous to Health (COSHH) system, an initial exploratory exposure monitoring exercise may be needed to reach an accurate judgement about the risk to health. The results will then influence the assessment of how well control measures for the welding fume are working. The investigation will also need to look at other factors that can influence exposure on the day, such as the production rate setting the amount of welding work needed. These things will influence the personal results of the survey for exposure to welding fume.