LEV Ventilation Explained: How It Keeps Workplaces Safe and Compliant

If your business generates dust, fumes, vapours, or mist, you’re legally required to protect your employees from breathing in harmful substances. One of the most effective ways to do that is through LEV ventilation.

At DevineAir, we understand that keeping workplaces safe isn’t just about ticking boxes. It’s about protecting your people and ensuring compliance without disrupting production. 

In this article, we’ll explain what LEV ventilation is, how it works, and why regular testing is essential for every UK employer.

What is LEV ventilation?

LEV stands for Local Exhaust Ventilation. It is a control system designed to capture airborne contaminants at their source before they can spread into the workspace or be inhaled by employees.

It’s commonly used in industries like:

• Engineering and manufacturing (welding, grinding, metalwork)
• Woodworking (dust extraction)
• Laboratories and healthcare (chemical fumes, biohazards)
• Construction (silica and cement dust)
• Printing and paint spraying (solvent vapours)

Instead of relying on general room ventilation, LEV systems work right where the hazard starts, at the process or workstation.

How LEV ventilation works

A typical LEV system has five key components:

1. Hood or capture device – positioned close to the source to collect the contaminant (for example, an extraction arm or fume hood).
2. Ducting – carries contaminated air away from the source.
3. Air cleaner or filter unit – removes hazardous particles, dust, or vapours from the air.
4. Fan – moves the air through the system.
5. Exhaust outlet – safely discharges cleaned air or filtered contaminants.

When designed and maintained correctly, LEV systems remove contaminants before they reach the breathing zone, protecting your staff’s lungs and keeping you compliant with UK health and safety law.

Why LEV ventilation is essential

1. Legal compliance

Under the Control of Substances Hazardous to Health Regulations (COSHH), employers must prevent or control exposure to harmful substances. LEV is one of the most effective engineering controls available, and when used properly, it can help you meet your COSHH duties.

According to the Health and Safety Executive (HSE), failure to maintain and test LEV systems can lead to enforcement action, fines, and even prosecution. You can read more in the HSE’s official guidance on COSHH and LEV testing.

2. Protecting employee health

Breathing in harmful dusts or fumes can cause serious, sometimes irreversible diseases, including asthma, COPD, lung cancer, and silicosis. These conditions develop over time, so employers often underestimate the risk. LEV ventilation provides consistent, reliable protection against long-term exposure.

3. Reducing costs and downtime

Poor air quality doesn’t just harm health. It clogs filters, damages equipment, and increases maintenance costs. A well-designed and well-maintained LEV system keeps your operation cleaner, reduces absenteeism, and improves overall productivity.

LEV testing and inspection – what’s required?

Under Regulation 9 of COSHH, LEV systems must be thoroughly examined and tested at least once every 14 months (or more often for high-risk processes).

During an LEV test, an engineer will:

• Check airflow and capture efficiency.
• Inspect filters, ducts, and hoods.
• Measure static pressure and velocity.
• Verify system performance against design standards.
• Provide a written report and any recommendations for corrective action.

You’re legally required to keep these LEV reports for at least five years and make them available to inspectors or employees upon request.

Signs your LEV system might not be working properly

Even if your LEV looks fine from the outside, performance can degrade over time. Here are a few warning signs to watch out for:

• Dust or fumes are visible in the air around the process.
• Workers report headaches, coughing, or irritation.
• Extraction arms or hoods are losing suction or making unusual noises.
• Blocked filters or buildup inside ducts.
• No recent records of testing or maintenance.

If you notice any of these, it’s time to book an inspection. A faulty or untested system can quickly put staff health at risk.

Common LEV mistakes employers make

1. Not testing regularly – Skipping annual testing is one of the biggest compliance gaps.
   
2. Relying on general ventilation – Room fans or open doors don’t control contaminants at the source.
   
3. Moving hoods or ducts – Even slight changes can drastically reduce effectiveness.
   
4. Ignoring user training – Employees should understand how to use and check LEV equipment.
   
5. Not recording maintenance – Without clear records, you can’t prove compliance with the HSE.

Small oversights can lead to big issues — from poor air quality to legal enforcement.

Best practice for maintaining your LEV ventilation system

To get the best performance and longest life from your LEV system:

• Schedule regular maintenance and filter changes.
• Keep hoods and ducts clean and correctly positioned.
• Ensure all employees know how to use the system correctly.
• Keep an LEV logbook with test results, airflow readings, and service dates.
• Work only with qualified, accredited LEV engineers for testing and certification.

Why LEV testing should only be done by professionals

LEV testing requires specialist knowledge, instruments, and understanding of airflow dynamics and contaminant behaviour. Professional engineers can identify hidden performance issues, test against the right standards, and provide corrective recommendations that keep you compliant and safe.

Working with an accredited testing provider like DevineAir ensures every test meets HSE and COSHH requirements, and every report is valid for inspection.

How DevineAir can help

At DevineAir, we know how crucial it is to keep every workplace safe, compliant, and protected from hidden air quality risks. Our specialists carry out LEV ventilation testing and inspection in line with COSHH Regulation 9 and HSG258 standards, ensuring your systems work efficiently and meet every legal requirement. 

We provide clear results, expert advice, and practical solutions to fix any issues quickly, helping you maintain clean air, healthy staff, and peace of mind with full compliance.

Alongside LEV testing, we also offer a full range of environmental and health & safety services, including breathing air quality testing, indoor air quality assessments, noise and vibration monitoring, cleanroom validation, and lux level assessments.

With DevineAir, you’re not just meeting regulations. You’re creating a safer, healthier environment for your team. Get in touch today to arrange your next LEV ventilation test or discuss a tailored compliance plan for your business.