What Is an LEV System? A Simple Guide to Clean Air at Work

Every workplace has invisible risks, and the air your team breathes is one of the biggest. Dust, fumes, vapours, and mists can all accumulate without your notice — leading to long-term health problems and potential legal issues. An LEV System (Local Exhaust Ventilation System) is designed to stop that from happening. By controlling airborne contaminants in the workplace, it protects your staff, maintain compliance, and create a safer, more productive environment.

If you run a workshop, factory or even a small garage, you already have some kind of extraction in place. But is it actually protecting your team the way it should? Understanding what an LEV System is, how it works, and why proper testing matters can make the difference between a safe, compliant business

At DevineAir, we ensure that businesses provide a safe work environment for their teams. We are composed of trained and highly qualified consultants. 

What exactly is an LEV System?

An LEV System is essentially a workplace’s built-in safety net for the air we breathe. Think of it as a targeted ventilation system. Instead of simply circulating air like a fan, it captures hazardous substances at the point where they’re released.

A standard system is made up of several key parts:

• Hood or capture device – This is placed as close as possible to the hazard (e.g. a canopy over a cooker, an extraction arm above a welding bench, or a downdraft table for sanding). The closer the hood, the better the capture.
  
• Ductwork – Sealed pipes transport the contaminated air away. Poorly maintained ducts can reduce airflow and allow contaminants to leak back into the room.
  
• Filter or air cleaner – Depending on the process, this may be a fabric filter, a HEPA filter, or an activated carbon unit designed to catch fine particles or absorb harmful vapours.
  
• Fan or air mover – The “engine” of the system that creates the suction needed to pull contaminants through the ductwork.
  
• Discharge point – Where the cleaned or filtered air is released safely, either outside the building or back into the workplace if recirculation is approved.
  

The principle is simple but powerful: stop contaminants from spreading before anyone can inhale them. Without an LEV System, airborne hazards quickly mix into the general atmosphere, exposing everyone on site.

Why an LEV System matters for business and home owners

Protecting health

Exposure to airborne hazards isn’t always obvious. Workers may not notice irritation straight away, but over time these exposures can lead to serious illnesses such as:

• Occupational asthma
• Chronic obstructive pulmonary disease (COPD)
• Silicosis from stone, concrete or wood dust
• Lung cancer linked to welding fumes
• Skin and eye irritation from solvent vapours
  

According to the Health and Safety Executive (HSE), thousands of workers in the UK still fall ill each year from exposure to substances that could have been controlled with an effective LEV System.

Staying compliant

In both Great Britain and Northern Ireland, the law is clear. Under the Control of Substances Hazardous to Health Regulations (COSHH), employers are required to prevent or control exposure to hazardous substances. If your main control measure is an LEV System, then you are legally required to maintain and test it at least once every 14 months (HSENI guidance).

Business advantages

It’s not just about compliance; a reliable LEV System supports your business, too.

• Staff stay healthier and take fewer sick days.
• Customers and clients see you take safety seriously.
• Insurance and audits go smoothly when records are in order.
• Well-maintained systems use less energy and avoid costly breakdowns.
  

What is LEV Testing?

To keep your LEV System effective, it must undergo LEV Testing, also called a Thorough Examination and Test (TExT). This isn’t a quick look with a torch. It’s a detailed inspection conducted by a competent person with the necessary training and equipment.

During testing, the engineer will:

• Measure airflow rates at hoods and ducts to check that capture is sufficient.
• Inspect ductwork for leaks, corrosion, or blockages.
• Check filters and cleaners for damage or saturation.
• Confirm gauges, indicators, and alarms are working properly.
• Compare the results against the original commissioning data to ensure the system continues to perform as designed.
  

At the end, you receive a written report that documents test results, system performance, and any identified defects. You must keep these reports for at least five years in case HSE or HSENI asks to see them.

How to keep your LEV System working

Design and installation

A good LEV System starts with proper design. Each process — from welding and soldering to flour dust handling — needs a system built for that hazard. Off-the-shelf solutions often fail because they’re not tailored to the job.

Commissioning

When installed, the system must be commissioned to prove it achieves the intended airflow and capture. These figures become the baseline for all future LEV Testing.

Training staff

Operators should be trained to:

• Position hoods properly.
• Recognise airflow indicators.
• Carry out simple daily checks.
  

Maintenance

Routine tasks like cleaning ducts, replacing filters, and servicing fans prevent problems from building up. Poor maintenance is one of the main reasons systems fail testing.

Testing

Finally, book a competent person to carry out LEV Testing at least once every 14 months. In high-risk sectors, more frequent checks may be required.

Keep Your Workplace Safe with the Right LEV System

An LEV System isn’t just another piece of workplace equipment. It’s a safeguard for your staff, your reputation, and your compliance with UK law. Poor ventilation can lead to serious health problems, downtime, and even legal penalties. 

At DevineAir, we are a team of experts in LEV system testing, design, consultancy, and maintenance, making sure your system works exactly as it should. Beyond LEV, we also offer a wide range of environmental services, including air quality assessments, noise assessments, cleanroom testing, hand/arm vibration monitoring, and lux level assessments, all tailored to keep you fully compliant and your people safe. 

If you’re ready to improve your air quality and compliance, get in touch with DevineAir today.