Local Exhaust Ventilation systems play a pivotal role in building healthier, cleaner workspaces across corporate and industrial environments. Therefore, it is imperative for workspaces to maintain their LEV systems, ensuring health and safety compliance.
World Day for Safety and Health at Work brings attention to policies, procedures, and reporting. All of that matters, and it plays a role in setting the right framework. On-site, though, exposure is rarely controlled by documentation alone. It comes down to something more practical. Whether contaminants are actually being captured before they reach the breathing zone.
That is where the gap usually sits, and where LEV becomes critical.
Health and Safety Compliance by Law
The Control of Substances Hazardous to Health Regulations place a legal duty on employers to assess risks and apply appropriate control measures. LEV is one of those measures.
That duty does not end at installation, and systems must continue to perform as intended.
Under COSHH Regulation 9, LEV systems must undergo a Thorough Examination and Test at least every 14 months. HSG258 expands on this by setting expectations around performance and condition.
In practice, compliance is not achieved by having a system in place. It is achieved when exposure is controlled during normal operations, not just at the point of inspection.
How Exposure Actually Occurs
Airborne contaminants are not always visible. Dust, fumes, mists and vapours can all be present without obvious signs. Here is a quick guide on the different kinds of extraction methods and how it captures different contaminants.
Even materials that are generally considered low risk, such as wood dust or food particulates, can become harmful with repeated exposure. Workers often rely on what they can see or smell. That is not always a reliable indicator.
On-site, this is where assumptions tend to form. If nothing is visible, it is assumed to be under control. That may not always be the case.
Why Exposure Is Often Missed
One of the more consistent issues is that exposure is underestimated.
Systems degrade gradually. Ductwork builds up material. Hood positions shift slightly. Processes change over time. These changes are not always reflected in how the system is set up.
Many systems we assess are not fundamentally flawed. They have simply moved away from their original design conditions.
That does not always present as a failure. It presents as reduced effectiveness, which is harder to identify without assessment.
LEV vs General Ventilation
General ventilation supports overall air quality, but it does not replace source control.
HSE guidance suggests fresh air supply rates should typically fall within a defined range per occupant. That supports dilution within a space.
Therefore, a LEV is more specialised. It is intended to capture contaminants at source before they disperse.
There is a tendency to rely on fans or increased airflow where LEV performance is reduced. In practice, that approach does not address the source of exposure.
What We See During LEV Assessments
Many systems do not fail outright; sometimes, they drift. Airflow readings may still appear acceptable on paper. At the hood level, capture can be reduced. This is where compliance starts to become uncertain.
We often see systems that technically meet specifications but do not fully control exposure under real working conditions.
While air velocity readings are useful, they are not the full picture. Observation matters more than one thinks. How the system behaves during operation is often more telling than the figures recorded.
What to Consider for World Day for Safety and Health at Work
World Day for Safety and Health at Work is useful in that it brings attention back to workplace risk and prompts a review of existing controls. That in itself is valuable.
In the context of LEV, though, the more useful question is not just whether a system is in place, but whether it is still doing what it was originally designed to do.
Sometimes, it is worth stepping back and looking at the system as it is being used today, rather than how it was designed to operate initially. That tends to give a more accurate view of whether exposure is actually being controlled.
If there is any uncertainty around performance, it is usually worth reviewing the system in the context of current working conditions and process demands. Arrange a site survey or discuss your compliance requirements if you need a clearer understanding of how your LEV system is performing in practice.