What is LEV?
Understanding Local Exhaust Ventilation (LEV)
Local Exhaust Ventilation (LEV) is an engineering control system designed to remove hazardous dusts, fumes, vapours, mists and gases from the workplace before they can be inhaled by employees.
Unlike general ventilation, which dilutes contaminants throughout a building, an LEV system captures airborne contaminants at their source, helping to protect workers, improve indoor air quality and support compliance with UK health and safety legislation.
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At A-Mac Environmental, we specialise in the design, installation, testing and maintenance of bespoke LEV systems for businesses throughout Scotland, helping organisations create safer and healthier working environments.
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What Does LEV Stand For?
LEV stands for Local Exhaust Ventilation.
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The purpose of an LEV system is simple:
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Capture harmful airborne contaminants before they spread into the workplace.
By removing hazardous substances at source, LEV helps reduce employee exposure and creates a cleaner, safer working environment.
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How Does an LEV System Work?
Although every system is different, most LEV systems operate using the same four key components.
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1. Hood or Capture Device
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The hood, extraction arm or enclosure is positioned as close as possible to the source of the contaminant.
Its job is to capture hazardous dust, fumes or vapours before they enter the breathing zone.
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2. Ductwork
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Once captured, contaminated air travels through a ducting system to the filtration equipment.
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Correct duct sizing and airflow are essential for maintaining efficient extraction.
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3. Air Cleaner or Filter
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Depending on the contaminant being removed, the air passes through suitable filtration equipment, such as:
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Cartridge filters
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Bag filters
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HEPA filters
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Activated carbon filters
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Cyclone separators
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The filtration system removes harmful particles before the air is discharged or, where appropriate, recirculated.
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4. Fan
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The extraction fan creates the airflow needed to move contaminated air through the entire LEV system.
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Correct fan selection is vital to ensure the system performs efficiently and maintains adequate capture velocities.
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What Can LEV Remove?
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LEV systems can control a wide variety of hazardous airborne contaminants, including:
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Welding fumes
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Wood dust
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Flour dust
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Metal dust
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Silica dust
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Oil mist
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Vehicle exhaust emissions
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Paint and solvent vapours
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Chemical fumes
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Smoke
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Laboratory contaminants
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Pharmaceutical powders
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Plastic and composite dust
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Every application requires a system specifically designed for the type of contaminant being generated.
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Why is LEV Important?
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Exposure to airborne contaminants can lead to serious health problems over time, including respiratory diseases, occupational asthma and other long-term illnesses.
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A properly designed LEV system helps businesses:
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Protect employee health
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Improve workplace air quality
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Reduce exposure to hazardous substances
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Improve housekeeping by reducing dust build-up
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Protect machinery and equipment
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Improve productivity and employee comfort
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Support compliance with COSHH Regulations
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Reduce the risk of HSE enforcement action
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Which Industries Use LEV?
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Local Exhaust Ventilation is used across a wide range of industries, including:
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If your workplace generates airborne contaminants, an LEV system may be one of the most effective methods of controlling exposure.
Is LEV a Legal Requirement?
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Under the Control of Substances Hazardous to Health (COSHH) Regulations, employers have a legal duty to prevent or adequately control employee exposure to hazardous substances.
Where hazardous dusts, fumes, vapours or gases cannot be eliminated, Local Exhaust Ventilation is often the preferred engineering control.
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A properly designed, maintained and tested LEV system plays an important role in helping businesses meet their legal responsibilities.
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Does an LEV System Need Testing?
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Yes.
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Most LEV systems require a Thorough Examination and Test (TExT) at least every 14 months, although some systems require more frequent testing depending on the substances being controlled.
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Regular testing helps ensure the system:
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Continues to perform effectively
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Maintains adequate airflow
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Captures contaminants efficiently
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Protects employees
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Remains compliant with COSHH requirements​
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A-Mac Environmental provides professional LEV testing and certification carried out by qualified P601 engineers.
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How A-Mac Environmental Can Help
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We provide complete LEV solutions throughout Scotland, including:
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Repairs and system upgrades
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Air quality improvements
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Whether you require a new extraction system or need to improve an existing installation, our experienced engineers can recommend the most effective solution for your business.
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Frequently Asked Questions
What is the difference between LEV and general ventilation?
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General ventilation dilutes airborne contaminants throughout a building by introducing fresh air and removing stale air. LEV captures hazardous substances directly at the point where they are produced, preventing them from spreading through the workplace.
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Does every business need an LEV system?
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Not every workplace requires LEV. However, if your processes generate hazardous dust, fumes, vapours, smoke or mists, you should assess whether LEV is needed as part of your COSHH risk assessment.
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How often should LEV systems be tested?
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Most systems require a Thorough Examination and Test every 14 months, although certain high-risk applications may require more frequent inspections.
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Can an existing LEV system be upgraded?
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Yes. Many older systems can be improved by upgrading fans, filters, ductwork or capture devices to improve efficiency and meet current operational requirements.
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Who can carry out LEV testing?
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LEV testing should be completed by a competent person with the appropriate knowledge, training and experience. A-Mac Environmental's qualified P601 engineers carry out Thorough Examination and Test (TExT) inspections in accordance with current HSE guidance.
Whether you're installing a new LEV system, upgrading an existing installation or arranging a Thorough Examination and Test, A-Mac Environmental can help.
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Contact our experienced team today to discuss your workplace, improve air quality and ensure your business remains compliant with COSHH Regulations.