In the UK, regulations known as the Control of Substances Hazardous to Health (COSHH) require that control measures are regularly maintained and tested to ensure their effectiveness.
These measures include not only hardware such as Local Exhaust Ventilation (LEV) and Respiratory Protective Equipment (RPE), but also safe systems of work and proper supervision.
To make sure your control measures are effective, you need to ensure that they are:
- Maintained in an efficient state
- In efficient working order
- In good repair and clean condition
When it comes to welding fumes, you can assess control by observing how well the LEV captures the fume.
For TIG welding, where there is little visible fume, you may need to use a dust lamp. If arc welding produces UV radiation that can’t be observed without eye protection, you can video the process for a qualitative fume assessment.
The performance of Local Exhaust Ventilation (LEV) can be tested by comparing its capture velocity to the range of 0.5m/s to 1m/s, as described in the HSE guidance on controlling airborne contaminants at work (PDF).
When there are draughts interfering with the flow of air into the hood, higher-capture velocities may be necessary. However, capture velocity measurement is not appropriate for testing on-torch extraction. In this case, the total volumetric flow can be checked against the manufacturer’s recommendations in the user manual.
To judge the performance of LEV, you should consider its effectiveness in capturing any welding fume, rather than relying solely on airflow measurements.
You must also thoroughly examine and test LEV (PDF) at least every 14 months.
When using Respiratory Protective Equipment (RPE), you should inspect it thoroughly before each use. For reusable RPE, keep a record of your regular examinations, maintenance, repairs, and testing where appropriate. The HSE publication on Respiratory Protective Equipment at work (PDF) provides further guidance on this.
