LEV Testing Explained — Dust & Fume Extraction Duties for Trade Businesses (2026)

What Is LEV?

Local Exhaust Ventilation is an engineering control that captures dust, fume, mist or vapour at the point where it's generated — before it reaches the worker's breathing zone. Instead of relying on a mask to filter contaminated air, LEV removes the contaminant from the air in the first place. A typical system has a hood or capture point near the source, ducting, an air mover (fan) and a filter or collector.

You'll already be using LEV in some form if you have any of the following:

• On-tool dust extraction for cutting, grinding, chasing or sanding — capturing respirable crystalline silica from concrete and stone, or wood dust from timber
• Welding fume extraction — fume arms, on-torch extraction or downdraught benches
• Spray booth extraction for paint and isocyanate mist
• Soldering fume arms for rosin/colophony fume on the bench
• Woodworking dust extraction systems — fixed ducted extraction serving saws, planers and sanders in a workshop

Why LEV Matters — COSHH and the Hierarchy of Control

The Control of Substances Hazardous to Health Regulations 2002 (COSHH) require that exposure to hazardous substances is either prevented or, where that isn't reasonably practicable, adequately controlled. Crucially, COSHH sets out a hierarchy of control. Engineering controls like LEV sit near the top of that hierarchy — above respiratory protective equipment (RPE). The law expects you to control the contaminant at source first, and to use RPE only as an additional last layer where LEV alone can't bring exposure down far enough.

In other words, you can't just hand out masks and call it controlled. A dust mask is the last line of defence, not the first. If a job realistically needs extraction and you skip it, you're not meeting your COSHH duty even if everyone is wearing RPE.

This matters because the substances common in the trades are genuinely dangerous:

• Respirable crystalline silica (RCS) — released when cutting, grinding or drilling concrete, stone, brick and mortar. It causes silicosis, lung cancer and COPD. It's the focus of the HSE's "Dust Kills" campaign.
• Wood dust — both hardwood and softwood dust can cause occupational asthma, and hardwood dust is linked to a rare nasal cancer. It has a workplace exposure limit, and LEV on woodworking machinery is the standard control.
• Welding fume — now a major HSE enforcement focus. The HSE's position is that all welding fume, including from mild steel, can cause cancer. Suitable controls are required for all indoor welding, and for outdoor welding where reasonably practicable. RPE alone is not enough indoors.

The Key Legal Duty — Thorough Examination & Test Every 14 Months

This is the part most trades miss. Under COSHH Regulation 9, any LEV provided to control exposure must be maintained in an efficient state, in efficient working order, in good repair and in a clean condition. As part of that, LEV must undergo a Thorough Examination and Test (TExT) at least once every 14 months by a competent person.

The 14-month interval is the legal maximum for most systems. In practice, the overwhelming majority of businesses test annually, which keeps you comfortably inside the limit and makes scheduling easy to remember. Some processes — such as certain high-risk operations listed in COSHH Schedule 4 — require more frequent testing.

You must keep the TExT records for at least 5 years. These records prove you've met your duty and are exactly what an HSE inspector will ask to see. If you can't produce them, you can't demonstrate the LEV is actually working — and an unproven control is treated as no control.

What Does a TExT Actually Involve?

A Thorough Examination and Test is not just a quick look. A competent LEV tester carries out three stages:

• Thorough visual and structural examination: checking hoods, ducting, the fan, filters and the overall condition of the system for damage, wear, leaks or blockages.
• Measurement and testing of technical performance: measuring airflow, capture velocity at the hood, face velocity, duct transport velocity and static pressures — and comparing them against the values the system was designed to achieve.
• Assessment of control effectiveness: confirming the LEV is actually capturing the contaminant in use, not just moving air, often using smoke or dust-lamp techniques.

The tester then issues a report with a clear outcome for each part of the system — typically a pass, or a remedial outcome flagging what needs fixing. If anything fails, the report tells you what to repair to bring the system back into effective working order. Keep this report on file; it's part of your 5-year record.

Your Day-to-Day LEV Duties

The 14-month TExT is the headline duty, but it's only one piece. Between tests, you're responsible for keeping the system working and used correctly:

• Use it properly: the LEV only works if it's switched on, positioned correctly and used the way it was designed to be. A fume arm parked two feet from the weld captures nothing.
• Maintain it: follow the manufacturer's maintenance schedule, keep ducting clear, and replace or clean filters before they choke airflow.
• Train operators: workers need to understand why the LEV matters, how to set it up, and what good capture looks like.
• Carry out regular user checks: simple daily or weekly checks — is the fan running, is the indicator gauge in the green, are hoods undamaged, is there obvious dust escape?
• Replace filters and consumables: a blocked filter quietly kills extraction performance long before the next TExT is due.

Summary of LEV Duties

Practical Examples for Trades

On-Tool Extraction for Silica and Wood Dust

For cutting, grinding, chasing and sanding, the standard control is on-tool extraction connected to an M-class or H-class dust extractor. M-class is the minimum for wood dust and many construction dusts; H-class is preferred for the most hazardous dusts. The extractor pulls dust straight off the tool through a shrouded guard or sanding pad before it reaches the air. These on-tool extractors are LEV, so they fall under the same examine-and-test duty — don't assume a portable vac is exempt.

On-tool extraction rarely captures 100% of the dust on its own, which is why RCS work usually still needs RPE as an additional layer. That's the hierarchy in action: extraction first, mask as backup — and the mask must be face-fit tested to be relied on.

Welding Fume Extraction

Since the HSE tightened its stance on welding fume, indoor welding needs effective fume control — typically on-torch extraction or a movable extraction arm capturing fume at source. General workshop ventilation is not a substitute. For outdoor welding, suitable controls are needed where reasonably practicable, and RPE is used where extraction can't be applied. Any fixed welding fume extraction is LEV and needs the 14-month TExT.

Spray Booths and Soldering

Spray booths used for paint, lacquer and especially two-pack isocyanate products are LEV and a classic high-risk process — isocyanate spraying often requires more frequent examination and air-fed RPE. Bench soldering fume arms capturing rosin/colophony fume are LEV too. In every case the principle is the same: capture at source, examine and test on schedule, keep the records.

For more on the related controls, see how LEV connects with your wider COSHH assessments, your RPE and face-fit testing programme, and your dust control measures on site — these duties overlap and an inspector will look at them together.

Why It Matters — Enforcement and Occupational Disease

This isn't paperwork for its own sake. Occupational lung disease is one of the biggest causes of work-related death in the UK, and the construction and manufacturing trades carry much of that burden. Silica-related disease alone is estimated to cause hundreds of deaths a year, which is why the HSE runs the "Dust Kills" and silica campaigns and inspects dust controls heavily on site visits.

The HSE actively enforces LEV requirements. Inspectors check that suitable extraction is in place, that it's being used, and — critically — that you can produce a current TExT report and the records to back it up. Failure to control exposure or to test your LEV can lead to improvement and prohibition notices, fees for intervention, and prosecution. Beyond the legal risk, a worker who develops silicosis, occupational asthma or cancer from exposure you could have controlled is the outcome the whole regime exists to prevent.

The practical takeaway is simple: if your work generates dust, fume or mist, put proper extraction in, use it, maintain it, and book the Thorough Examination and Test before 14 months are up. Keep the report. It protects your team and it protects your business.