LEV Testing is the process of thoroughly inspecting and evaluating a local exhaust ventilation system against the commissioning report’s performance, industry standards, and HSE guidelines. It includes airflow and pressure measurements, as well as checks on the effectiveness of contamination exposure control. All equipment, including hoods, filters and ducts, is also subject to additional inspections. According to the HSE, 12,000 lung disease deaths each year are estimated to be linked to past exposures at work. This has led to increasingly stringent guidelines and statutory requirements for Local Exhaust Ventilation. HSE published the third edition of HSG258 in 2017.

How often do I need LEV testing?

LEV systems must be tested every 14 months. This is a legal requirement under COSHH regulations and applies to all forms of extraction systems. Testing must be performed by a competent person in accordance with HSE standards, particularly HSG258.

What equipment is required to perform an LEV test?

Equipment includes: Manometer, pitot tube, hotwire anemometer, rotating vane anemometer, rotation sensor, Tyndall Beam Lamp, smoke generator, LEV test labels, clearance time labels, and capture distance labels.

Why is it so important for companies to ensure their LEV systems are tested by a competent person at least once every 14 months?

COSHH regulations require regular LEV testing, and some applications demand testing more frequently. HSE can prosecute companies for non-compliance. The cost of regular testing is minor compared to the consequences of regulatory fines.

Presumably, employers should be doing everything they can to provide a safe and clean working environment?

Yes. Under the Health and Safety at Work etc Act 1974, employers must ensure the safety and welfare of their employees. A clean workplace improves safety, reduces illness, boosts morale, and maintains product quality.

COSHH regulations have been in place for more than 30 years now – do all manufacturers realise that regular LEV testing is a legal requirement?

Not all do. Some assume installation is enough without routine maintenance. This indicates a lack of awareness. The HSE sends regular bulletins to improve compliance awareness.

What is the main reason for companies requesting LEV Testing?

Requests are usually split between legal compliance and employee complaints about air quality — both highlight the importance of regular testing.

Why is it important for LEV systems to be tested regularly?

Regular tests identify airflow or performance issues, like blocked filters or damaged ducting. This ensures the system is functioning as intended and protects employee health.

What other factors can affect the performance of an LEV System?

Operator interference and poor filter maintenance are common issues. Employees might switch off systems to reduce noise. Regular servicing is crucial to catch such problems early.

The HSE states that LEV Testing must be carried out by a ‘competent person’ - why is this so important?

Experienced testers can identify risks beyond the basic test scope. For example, ATEX directives may require additional safety measures like explosion relief panels, which might be overlooked by untrained personnel.

What does the HSE mean by ‘competent’?

Competency involves a combination of training, experience, skills, and knowledge to safely perform tasks. Attitude and physical ability also play a role.

How can Filtermist prove its LEV Engineers are competent?

All engineers hold BOHS qualifications: P600, P601, and many also hold P602 and P604. They also bring over 20 years of field experience.

What does a HSE compliant LEV test report look like?

It includes test details, system photos, performance data, recommendations, pass/fail status, inspector statements, safety documents, and follow-up schedules.

How long does an LEV test take to carry out?

It varies by system complexity and accessibility. Initial visits take longer due to risk assessments and documentation, while follow-ups are quicker if no setup has changed.

Does the LEV test interrupt production?

Usually not. Testing is designed to work around your schedule, including evenings or weekends if needed.

Is cost another reason why people put off regular LEV testing?

Yes. Some small businesses see it as avoidable, but the cost per employee is minimal compared to potential fines or health risks.

Filtermist is known for its oil mist extraction systems – do you only provide LEV Testing for oil mist filters?

No. Filtermist tests all types of LEV systems including those for dust, fumes, smoke, and VOCs — regardless of brand.

In conclusion, why is it so important for anyone with an LEV system to have them regularly tested?

To protect workers from airborne contaminants and to avoid legal action from HSE.

What is an LEV System?

Q: What is an LEV system?

Local Exhaust Ventilation (LEV) systems capture, contain and treat air contaminated with oil mist, fume, smoke and dust at source before it can spread. LEV systems typically include a hood, ducting, a filter, a fan, and a discharge mechanism.

LEV is short for Local Exhaust Ventilation. HSE publication HSG258 ‘Controlling Airborne Contaminants at Work’ describes LEV as follows:

‘LEV is an engineering control system to reduce exposures to airborne contaminants such as dust, mist, fume, vapour or gas in a workplace. Most systems, but not all, have the following:

Hood: This is where the contaminant cloud enters the LEV.
Ducting: This conducts air and the contaminant from the hood to the discharge point.
Air cleaner or arrestor: This filters or cleans the extracted air. Not all systems need air cleaning.
Air mover: The ‘engine’ that powers the extraction system, usually a fan.
Discharge: This releases the extracted air to a safe place.

The exact configuration of an LEV system will differ depending on the type of extraction unit used, the manufacturing application it is being used on, the location of the system, how many pick up points are needed and other factors.

A Filtermist centrifugal oil mist filter includes the following:

Hood: In Filtermist installations this is the machine tool enclosure on enclosed machines. Open machines may use fish tail capture hoods, but the HSE recommends that all machining applications are enclosed as much as possible for the most effective extraction.
Ducting: A short length of ducting is fitted between the machine tool extraction point and the flange of the Filtermist unit.
Air cleaner or arrestor: This is the Filtermist unit itself.
Air mover: Filtermist’s FX and S Series units include an internal perforated drum with specially designed vanes which rotate at high speed to draw contaminated air into the unit.
Discharge: Clean air is discharged through the diaphragm at the top of the unit. An Afterfilter can be fitted if additional filtration is required. High Efficiency Afterfilters are fitted as standard on all UK installations.

Larger, centralised LEV extraction systems often look similar to this:

Multiple capture hoods to pick up contaminated air from different processes throughout the production facility.
The air is drawn through ducting and into the ‘air cleaner’ – in this case, a dust collector with internal cartridge filters.
A large fan acts as the air mover.
Clean air is discharged to atmosphere.

As you can see, LEV systems can vary massively. From single stand-alone filter units located directly on a CNC machine tool that clean the air on one machine and recirculate it back into the machine shop, to large-scale multi-pick up point systems that feed into one large filter unit and exhaust to atmosphere.

Our team of LEV extraction system experts can specify, design, install, commission and maintain systems for a diverse array of contaminant types, applications and industries. Contact our team now to find out more.