LEV Testing: Why Regular Checks Are Critical for Workplace Safety

If your workplace produces dust, fumes, vapours, or mist, LEV testing is not optional; it’s essential. In the UK and Northern Ireland, LEV testing is a legal requirement under COSHH, designed to ensure your ventilation system continues to protect workers from harmful substances.

Too often, business owners think that once an LEV system is installed, the job is done. But just like any piece of machinery, LEV systems wear down, filters clog, fans fail, and performance drops. Without routine testing, you may believe your employees are safe when in fact they’re being exposed to dangerous contaminants every single day.

At DevineAir, we help businesses ensure their ventilation system runs efficiently, keeping the workplace safe and your team protected at all times.

What is LEV and How Does it Work?

Local Exhaust Ventilation (LEV) is an engineered system that captures airborne contaminants at their source and removes them from the workplace air. Rather than relying on general room ventilation, LEV is designed to prevent hazardous substances from entering a worker’s breathing zone.

An LEV system usually includes:

• Hood or capture device – positioned close to the source of dust, fume, or mist.
• Ducting – carries the contaminated air away.
• Fan – creates the airflow needed to pull contaminants in.
• Filter or collector – removes harmful particles before clean air is released.

Without proper testing, each of these components can fail silently, leaving workers exposed without anyone noticing.

Why is LEV Testing Legally Required?

LEV systems are covered by the Control of Substances Hazardous to Health Regulations 2002 (COSHH). Specifically, Regulation 9 requires every employer to:

• Ensure LEV systems are maintained in efficient working order.
• Carry out a “thorough examination and test” at least once every 14 months.
• Keep records of tests and any repairs for a minimum of five years.

Failure to comply can lead to HSE or HSENI enforcement notices, fines, or prosecution of directors in serious cases.

The Benefits of Regular LEV Testing

For many business owners, LEV testing feels like just another compliance task. But in reality, regular LEV testing offers far more than ticking a legal box. It protects your people, your reputation, and your bottom line.

Here’s why it’s one of the smartest investments you can make:

1. Protects employee health and well-being

Your staff are your most valuable asset. A properly tested LEV system means they aren’t breathing in harmful dusts, fumes, vapours, or mists every day. That means:

• Fewer cases of occupational asthma, lung damage, or skin and eye irritation.
• Lower risk of long-term diseases like COPD, cancer, or silicosis.
• Staff who feel safe and valued tend to boost morale and loyalty.

2. Reduces absence and lost productivity

Illness caused by poor air quality can lead to repeated staff absence or even permanent incapacity. LEV testing prevents hidden risks from escalating, keeping your workforce healthy and your operations running smoothly.

3. Ensures compliance and avoids costly fines

In the UK and Northern Ireland, LEV testing is legally required under COSHH. Failing to comply can result in enforcement notices, substantial fines, or even the prosecution of company directors. Regular testing is your insurance against legal and financial consequences.

4. Extends the life of your LEV system

Unchecked faults, such as clogged filters, leaking ducts, or worn-out fans, can significantly shorten the life of your system. Regular testing identifies these issues early, allowing for small, low-cost fixes that prevent major breakdowns or full replacements.

5. Saves money in the long run

Testing costs are predictable and budget-friendly. The cost of ignoring problems can be ten times higher. Regular LEV testing keeps your system efficient and cost-effective.

6. Provides clear documentation for audits and insurance

An LEV test report is your proof that you’ve met your duty of care. If there’s ever a workplace inspection, insurance claim, or employee grievance, your records show you’ve done everything required to protect staff.

7. Improves business reputation and trust

Today’s employees, contractors, and clients care about workplace safety. Demonstrating that you invest in regular LEV testing shows that you prioritise health, safety, and compliance.

8. Peace of mind for you as an employer

As a business owner, you carry the responsibility. LEV testing means you don’t have to second-guess whether your extraction is working. It gives you confidence that your workplace is safe, compliant, and under control.

Health Risks of Poor LEV Systems

LEV testing isn’t just about compliance. It’s about protecting health. The HSE reports around 12,000 deaths every year in the UK due to occupational exposure to harmful dusts, fumes, and chemicals.

Common health issues linked to inadequate LEV include:

• Occupational asthma – triggered by flour dust, isocyanates (from paint spraying), or wood dust.
• Lung scarring (silicosis) – from inhaling respirable crystalline silica (RCS) in construction.
• COPD and emphysema – from long-term dust or fume exposure.
• Cancers – nasal cancer from hardwood dust, lung cancer from welding fume.
  

Untested LEV means invisible contaminants can accumulate and damage health long before symptoms appear.

What does an LEV test involve?

A proper, thorough examination and test (TExT) must be carried out by a competent person (ideally BOHS P601 certified).

During the test, the engineer will:

• Inspect hoods, ducts, and fans for damage, blockages, or poor design.
• Measure airflow, capture velocity, and static pressure.
• Check that hoods are positioned and labelled correctly.
• Perform smoke or airflow indicator tests.
• Assess filter condition and efficiency.
• Verify that alarms, gauges, and warning devices are functioning properly.

The engineer will then provide a written LEV report, which should include:

• Test results with data.
• Photos and diagrams.
• Clear pass/fail outcomes.
• Remedial actions needed.

This report serves as proof of compliance and must be retained for a minimum of five years.

How Often Should LEV Systems Be Tested?

• Standard requirement: At least every 14 months.
• CoSHH schedule 4 allows for more frequent testing frequencies under certain conditions, e.g. Every 6 months or even monthly
• Laboratory fume cupboards: At least every 14 months, but often tested more regularly.
• After installation or modification: Commissioning must be carried out before use.
• After repairs or filter replacement: System should be re-tested.

Put simply, whenever your LEV system changes, it must be checked to ensure it continues to protect workers effectively.

Common problems found during LEV testing

Some of the most frequent issues identified during tests include:

• Clogged filters are reducing airflow.
• Damaged ductwork is causing leaks.
• Fans running in reverse after maintenance.
• Hoods are positioned incorrectly or not used properly.
• Warning devices switched off or ignored.

Each of these problems can render the system almost useless, even though it appears to be functioning properly.

Business Risks of Ignoring LEV Testing

Beyond health risks, failing to test LEV regularly can have major business consequences:

• Fines and legal action – for non-compliance with COSHH.
• Insurance invalidation – if a claim arises and no records exist.
• Production downtime – if HSE/HSENI issues a prohibition notice.
• Staff absence and turnover – ill health increases costs and lowers morale.
• Reputational damage – unsafe working conditions damage your brand.

The costs of testing are small compared to the risks of not testing.

Who Can Carry Out LEV Testing?

The law is clear: LEV testing must be carried out by a competent person. But what does “competent” actually mean in practice?

Too often, businesses assume that anyone who understands ventilation can carry out a test, but that’s not the case. COSHH Regulation 9 requires a thorough examination and test (TExT), which demands specialist knowledge of airflow dynamics, contaminant control, and system design.

What to look for in a competent tester

• Independence – Choose a provider who isn’t just trying to sell you a new system. Independent specialists provide unbiased results and clear guidance, without recommending unnecessary replacements.
  
• Formal qualifications – Look for engineers with BOHS (British Occupational Hygiene Society) P601 or higher. This qualification proves they have been trained specifically in LEV testing and can interpret results correctly.
  
• Sector-specific experience – Different industries face different hazards. 

• Practical testing ability – A competent person won’t just take a few airflow readings. They’ll thoroughly inspect hoods, ductwork, filters, and control systems, and explain whether your system meets legal and health requirements.
  
• Clear reporting – The test report should be easy to understand, with photos, diagrams, test data, and specific actions you need to take. Vague or overly technical reports won’t protect you if HSE or HSENI asks questions.
  

Protecting People, Protecting Business

LEV systems only protect workers if they are properly maintained and regularly tested. LEV testing is crucial for safeguarding health, mitigating business risks, and providing peace of mind. 

At DevineAir, we provide expert LEV testing, design, and maintenance across the UK and Ireland. With over 20 years of experience, our qualified consultants deliver clear reports, practical advice, and trusted solutions tailored to your industry.

If your next LEV test is due or you’re unsure whether your system is working as it should, contact DevineAir today. We’ll help you stay compliant, protect your employees, and keep your business running smoothly and safely.