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For decades, industrial workplaces across the UK relied on a relatively simple philosophy when it came to air quality. Bosses believed if enough air was moved throughout a building, any contaminants would eventually disperse.
Large wall-mounted fans, roof vents and open doors were considered adequate methods of maintaining a safe environment in factories, workshops and production facilities. However, this left employees exposed to potentially harmful substances.
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Today, this haphazard approach no longer satisfies either best practice or legal expectations. The evolution of workplace air quality standards reflects a deeper understanding of how airborne contaminants behave and affect human health. Modern employers must provide ventilation, and also demonstrate that harmful dust, fumes, mists and vapours are being effectively controlled so workers don’t inhale them.
At the centre of this shift, HSG258 is the Health and Safety Executive’s definitive guidance on Local Exhaust Ventilation (LEV), representing a move away from broad dilution strategies towards targeted control measures to protect the workers at the point where hazardous substances are generated.
For health and safety professionals, workshop managers, production leaders and industrial employers, understanding this transition is essential for protecting staff, maintaining compliance and reducing legal risks.
Historically, general ventilation was widely used throughout British industry from the early 19th century. Fresh air entered through windows and vents, while mechanical fans pushed out contaminated air elsewhere in the building. This approach was known as dilution ventilation.
In some situations, it still has a place, as it can improve comfort, regulate temperature and reduce background concentrations of lower-risk emissions. However, its limitations become apparent when dealing with hazardous substances generated by manufacturing processes, as workers inhale the air before contaminants disperse.
A cloud of welding fumes, a plume of chemical vapours, or fine dust from cutting operations travels through the immediate breathing space long before the air reaches a distant extraction point. Even if the overall room concentration is eventually reduced, exposure has already occurred.
Controlling Airborne Contaminants at Work: A Guide to Local Exhaust Ventilation is published by the Health and Safety Executive as practical guidance for employers operating systems. Although HSG258 itself is guidance rather than legislation, it carries significant authority, as it provides the benchmark inspectors use when assessing compliance with the Control of Substances Hazardous to Health Regulations (COSHH).
Employers have a legal duty to adequately control employee exposure to hazardous substances. Companies must demonstrate that their systems effectively capture airborne contaminants at source and perform as intended throughout their operational life.
Modern industrial processes frequently generate fine particulate matter capable of remaining airborne for prolonged periods. Sanding, cutting, grinding, polishing, material transfer and finishing operations all have the potential to release contaminants. Effective dust extraction systems are designed to address this challenge directly.
They improve workplace air quality by capturing and filtering fine particles before they spread through the wider environment. Rather than allowing dust to circulate freely and relying on dilution, the system intercepts particles close to their source. This approach offers significantly greater protection for employees while helping organisations meet their regulatory responsibilities.
Designed to improve cleanliness as well as safety, the systems trap fine dust and release cleaned air through carefully controlled discharge arrangements. As industrial understanding has evolved, extraction has been recognised as a critical health protection strategy.
The breathing zone refers to the area immediately surrounding a worker’s nose and mouth where inhalation occurs. This space determines actual exposure. General ventilation rarely protects the breathing zone effectively because contaminants generated during work pass directly through it before becoming diluted.
Fine particulates, often invisible to the naked eye, can remain suspended at head height for extended periods. Air currents generated by movement, machinery, or temperature differences can keep the particles circulating unpredictably throughout the workspace.
A distant extraction fan may eventually remove some contaminants, but it can’t reliably intercept them before exposure occurs. The health consequences associated with prolonged inhalation have driven increasingly robust guidance.
Occupational asthma remains a serious concern across multiple sectors. Exposure to respirable crystalline silica has been linked to silicosis and irreversible lung damage. Metal fumes, wood dust and chemical aerosols can all contribute to chronic respiratory disease. Many of these conditions develop gradually, often becoming apparent only after years of repeated exposure. Preventing contaminants from entering the breathing zone in the first place is the most effective strategy available.
General ventilation improves the overall environment by introducing fresh air and diluting pollutants throughout a large area. It can help where emissions are low-level or widely dispersed.
LEV systems, by contrast, target the source of contamination before pollutants spread. They capture hazardous substances immediately where they are generated through the use of hoods, ducting, filters and extraction fans – generally more efficient at controlling specific hazards associated with activities such as welding, paint spraying, woodworking, plastics processing and chemical handling.
In some workplaces, both methods operate together to create the safest possible environment. However, where more hazardous emissions are generated, companies increasingly favour LEV methods.
COSHH Regulation 9 requires employers to maintain LEV systems and ensure they undergo Thorough Examination and Testing, commonly known as TExT, at suitable intervals. This examination must be carried out by a competent person at least every 14 months for most systems.
TExT goes far beyond a visual inspection. It assesses airflow performance against commissioning data, evaluates the condition of hoods, ductwork, filters and fans, and determines whether the system continues to control exposure effectively. Written reports documenting findings must be retained for a minimum of five years.
HSG258 also expects organisations to undertake routine checks between formal examinations. Operators should verify airflow indicators, inspect visible components and identify defects before systems are used.
An ageing wall fan with no performance records, or an extraction hood that has never been tested, represents more than a maintenance concern. During an HSE inspection, it may expose the organisation to significant legal liability.
The journey from warehouse wall fans to sophisticated LEV systems reflects a broader evolution in attitudes towards worker health. HSG258 provides the framework for businesses across the UK.
Ultimately, modern air quality standards represent an investment in the wellbeing and long-term health of the people who keep British industry moving.
AirBench Ltd are the UK’s leading manufacturer of downdraught benches and cross draught extraction systems. We have more than 10,000 extraction systems in service in the UK and overseas. Along with our range of coolant mist filters and air cleaning systems, we are actively helping businesses across many industries solve their workplace dust and fume issues.
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If you’d like to try an AirBench product for FREE simply book a demo and we’ll bring one to you.