Exposure to welding fume can be deadly.
Illnesses including occupational asthma, pneumonia, cancer, chronic obstructive pulmonary disease (COPD) and ‘metal fume fever’ are all linked to fume and smoke widely found in facilities where welding and cutting take place.
According to the HSE report into work-related respiratory disease in 2016, COPD alone was attributed to approximately 4000 deaths in the UK in 2014.
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 which have all been assigned WELs (workplace exposure limits) – these include carbon dioxide, carbon monoxide and nitrous oxide.
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.
In the first instance, HSE advises minimising fume as much as possible. Once this has been achieved, Respiratory Protective Equipment (RPE), a Local Exhaust Ventilation (LEV) system or both should be used to reduce exposure to any remaining fume. The HSE website contains more information on factors to consider when deciding which control measures are most appropriate in specific circumstances.
Identifying the most effective extraction method
If extraction is required there are a number of options depending on the customer’s requirements:
Standalone extraction units
Mobile extraction units can be used in workshops where welding takes place in different locations, or fixed position units can be located near to the source of the fume. Mobile units are generally used in applications which do not generate much fume – this could be because welding is an infrequent occurrence, or only carried out for short periods of time.
Generally speaking, fixed position extraction units are able to handle far larger volumes of fume and smoke than mobile units due to higher quality filter media and more filtration stages.
Centralised extraction systems
Centralised systems are ideal for manufacturing facilities which require extraction for a variety of applications. Fume and smoke generated in welding, cutting, grinding, spinning, linishing and polishing can be drawn from numerous pick-up points around the factory and channelled into filtration units through ceiling mounted ducting. This approach is often selected when the layout of the facility is unlikely to be altered.
A number of factors can impact on the performance of an LEV system so it is important the designer considers all aspects of the installation before recommending a specific solution.
Installation and commissioning
Correct installation and commissioning is vital if the fume extraction system is to perform as intended. Specialist engineers will ensure it is operating correctly before signing the job off and a record of the airflow will be made at the time of commissioning. This then acts as a benchmark for future tests, including those required by CoSHH regulations.
Air monitoring ensures control measures are working effectively by analysing the levels of contaminant in samples of air.
Static monitoring can be used to check air quality in a specific area, whilst personal monitoring measures levels of contaminant in the operative’s breathing zone.
If an extraction system has been installed but air monitoring flags a potential issue, the system may not be adequate for the customer’s needs, or there may be an operating issue.
Service and maintenance
One way of helping to ensure air filtration and extraction systems work effectively all the time is to undertake regular routine maintenance. Wear and tear can sometimes affect performance so regular inspections and replacement of worn parts can help to ensure the system is working as intended.
Extraction systems should be designed with a specific airflow requirement in mind, depending on the nature of the application. Airflow should be measured before and after servicing to ensure accurate records are maintained.
CoSHH regulations require all LEV systems to be tested at least once every 14 months by a competent person. LEV test reports should include details of the system’s intended performance, as well as quantitative assessment readings and details of any repairs required.
CoSHH regulations specify that both employers and employees are responsible for ensuring workplace air is clean. Whilst employers are advised to fit effective LEV extraction to minimise exposure to harmful airborne substances, employees are required to use equipment correctly and to report any defects in the LEV system straight away.
Put simply, if the hood of the extraction system is not positioned correctly it will not be able to do its job properly. The HSE website states…
‘In most situations welding fume can be easily seen. If you can see that most of the fume is going up the extractor, then your positioning is about right.’
Airflow indicators and pressure gauges can alert employees to any drop in airflow which can then be investigated to identify the cause of the issue.
More information in regard to system design and hood position can be found here: http://www.hse.gov.uk/welding/fume-extraction-rpe.htm
HSE Health and Work Strategy
Reducing occupational lung disease is one of three core focus areas in the HSE’s current Health and Work Strategy. Find out more by downloading and reading the draft plan.
The HSE website contains a huge amount of information and resources about protecting people from exposure to smoke and fume generated in welding and cutting processes. Please visit hse.gov.uk to find out more, or follow the links below to visit specific pages:
Illness caused by welding fume and gases
Welding fume – reducing the risk
Task specific COSHH guidance for welding, cutting and allied jobs
EH40/2005 Workplace exposure limits
Filtermist’s comprehensive service is designed to protect people from a wide range of airborne contaminants – follow this link to find out about Filtermist’s fume extraction service. Alternatively, please contact our sales team to discuss how we can help you ensure the air in your workplace is clean and safe to breathe.