Chris Eastwood, R&D Engineering Manager at Air Control Industries, charts the evolution of dust removal in the workplace and looks at LEV (Local Exhaust Ventilation) 's role in controlling dust.
The World Trade Center twin towers in New York City collapsed on 9/11/2001, transforming much of the building's mass into dense dust clouds that settled on the streets and within buildings throughout Lower Manhattan.
About 80–90% of the settled dust was a highly alkaline mixture of crushed concrete, gypsum, and synthetic vitreous fibres. High dust concentrations were inhaled by rescue and clean-up teams, office workers and residents, causing chronic adverse health effects.
This tragic event had an impact on many subject matters & affected so many people, but it also marked a period of raised awareness of the dangers of respiratory dust.
As well as a recognition of dust hazards in the US, the early 2000s showed that global dust awareness was increasing. In the UK, the Control of Substances Hazardous to Health (COSHH) 2002 Regulations were established to protect workers from exposure to hazardous materials. Directive 2004/37/EC was introduced in Europe to protect workers from health & safety risks related to carcinogens, mutations or substances toxic to reproduction at work. In 2005, EH40 was published by the Health & Safety Executive (HSE) to provide workplace exposure limits for various hazardous substances.
Since then, momentum has continued to build, primarily driven by the HSE & the emphasis on dust removal in the workplace. Thankfully, this has produced an increased awareness to prioritise dust control management.
Today, the big focus of the HSE is controlling dust at the source using Local Exhaust Ventilation (LEV). LEV systems have three primary purposes:
LEV systems range from dust extraction systems to welding fume extraction arms, ventilated preparation benches and exhaust extraction units. Essentially any LEV system will consist of a hood, duct(s), an air cleaner /filter, a fan and a discharge.
Repeatable processes on automated production lines are often easier to manage from a dust control perspective due to their controlled nature of input, environment & output. The challenges for effective LEV often arise where operations take place outside or are very variable.
LEV control at source is always the correct approach, & should be used at all times. However, installing a personnel cleaning booth can often remove any additional dust that remains on clothing or personnel. JetBlack Safety offers an LEV-compliant walk-in booth that extracts and collects dust in a high-efficiency particulate air (HEPA) H14-filtered unit.
LEV technology has moved on considerably since the first extractor fans and dust collectors were invented. Lower workplace exposure limits have driven the development of improved systems that can collect & retain finer particles in more intelligent and efficient ways.
Today's LEV systems also incorporate more performance monitoring and safety features. For example, LEV systems have visual indicators to prove they are working correctly and within operating parameters. Additionally, more safeguards against human error are being built into the latest systems. So, a fan might be designed to speed up as a filter gets blocked, maintaining consistent performance. Or an LEV system might prevent user operation or entry if a dangerous situation occurs; an example is insufficient airflow if a filter remains unchanged. These essential features ensure that LEV systems never become a potential safety risk.
Looking forwards, we all hope to see a continuation of better workplace practices, as the message about the importance of dust control 'filters' through organisations, from health & safety professionals and factory managers to the people who encounter dust at work.
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