What Is LEV Testing? What It Covers and Why It Matters
- Nexus Examination
- Jun 26
- 3 min read
If your workplace uses any kind of dust or fume extraction, "LEV testing" is a term that turns up on compliance checklists and insurance paperwork, often without much explanation of what it actually means. Here is a plain explanation of what LEV testing is, what the inspection covers, and why it matters for the people working around the equipment.
What Is LEV Testing?
LEV testing, formally a thorough examination and test (TExT), is a statutory inspection of a local exhaust ventilation system. It checks that the system still captures hazardous dust, fume, mist or vapour at source and controls exposure as intended, by comparing its current performance against the figures it was designed to meet.
In short, it is the formal way of proving the extraction is still doing its job. We carry out LEV examinations across Berkshire and the surrounding counties, and the test is the difference between assuming a system works and knowing it does.
What Is LEV?
LEV stands for local exhaust ventilation. It is an engineered system that captures hazardous airborne substances at the point they are released and carries them safely away, before workers can breathe them in. It is one of the main engineering controls used to manage exposure under COSHH.
A typical system is made up of:
A hood or enclosure that captures the contaminant at source
Ducting that carries the contaminated air away
An air cleaner or filter that removes the contaminant
A fan that drives the airflow through the system
A discharge point that releases cleaned air safely
Often, airflow indicators or gauges so operators can see it is working
This covers a wide range of kit, from a laboratory fume cupboard to a workshop dust extractor or a welding fume arm.
What Does LEV Testing Involve?
The test is far more than a quick look at the fan. A competent person carries out a structured examination against the system's design performance, which usually includes a visual inspection of hoods, ducts, filters and fans, measurements of airflow and capture velocity, and checks on any indicators or alarms.
Where useful, the examiner may use smoke to show whether the hood is actually drawing contaminants in. The findings go into a report that states clearly whether the system passes, and sets out any defects and the action needed to fix them. The HSE's LEV guidance sets the standard this work is measured against.
How Often Is LEV Testing Done, and by Whom?
The test must be carried out by a competent person, with the BOHS P601 qualification widely treated as the industry benchmark. For most systems it is required at least every 14 months, with shorter intervals for higher-risk work, and the records must be kept for at least 5 years.
The 14-month figure is a legal maximum rather than a target, so the right interval for any given system comes from its risk assessment.
Why LEV Testing Matters
A system can look like it is running perfectly while quietly failing to capture contaminants. That is the real risk, because the substances LEV controls are behind serious and often irreversible conditions like occupational asthma, lung disease and cancer, and the harm usually shows up years later.
There is a legal side too. LEV testing is a duty under COSHH, and a missing or failed test can bring HSE enforcement and invalidate insurance. Our thorough examination services exist to confirm, with measured evidence, that a system is still protecting the people who rely on it.
The Bottom Line
LEV testing is the statutory thorough examination and test that proves your extraction still controls exposure at source. It involves a competent person measuring the system against its design performance and reporting clearly on whether it passes.
For most systems it is needed at least every 14 months, and it matters because the alternative is trusting your workers' health to equipment that nobody has checked.
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