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Local Exhaust Ventilation (LEV)

Guidance on LEV engineering controls for airborne hazards in the workplace

Across different industries, different jobs involve work processes that create dusts and fumes. While these substances are often hazardous to human health – asthma, lung scaring and cancer – awareness of the problem remains limited.

The most effective engineering control method to carry away airborne contaminants at source, before they can be breathed in, is by using Local Exhaust Ventilation (LEV), often called extraction or fume control. It is vital that you understand how LEV works to ensure that you have the right equipment and know how to use it properly.

Safety Standards

If hazards such as fumes, vapours or dusts are created by your processes, you have a legal responsibility under the

  • Health and Safety at Work etc Act 1974 (HSW)¹
  • Control of Substances Hazardous to Health Regulations 2002 (COSHH)²
  • Management of Health and Safety at Work Regulations 1999 (MHSWR)³

There are also provisions for employers in safety data sheets under REACH (see paragraphs 82-86).

If you are using a substance that could form an explosive atmosphere, you must consider your responsibilities under the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR).

MHSWR and COSHH require a level of 'competence' which applies to whoever:

  • Designs or selects control measures;
  • Checks, tests, and maintains control measures.
  • Operatives must have sufficient training, knowledge, and experience of using LEV equipment.


If work produces dust (eg flour dust in bakeries), mist (eg paint mist from spraying), fume (eg from welding), gas (eg carbon monoxide from furnaces), or vapour (eg solvents from painting), there may be a risk to health of your employees. Depending on the type and degree of exposure, breathing in substances can cause:

  • Occupational Asthma
  • Occupational Alveolitis
  • Pneumoconiosis
  • Silicosis
  • Lung Cancer
  • Chronic Obstructive Pulmonary Disease (COPD)

Employers are often unaware that:

  • their employees are being over-exposed to hazardous substances or that existing controls are inadequate.
  • sources of exposure are missed.
  • are over-optimistic about the effectiveness of controls.
  • existing controls have deteriorated.
  • controls are not used correctly.

Evaluating the hierarchy of control is a good first step in establishing how to lower dust and fume exposure.

While hazards will not be eliminated, engineering control measures such as LEV, can help to reduce workers' exposure to airborne contaminants by capturing them right at the source and transporting it to a safe emission point or to a filter/scrubber.

LEV protects everyone in the workplace, while respiratory protective equipment (RPE) only protects the person wearing it. For optimum protection, use LEV engineering controls in conjunction with Respiratory Protection Equipment (RPE)

LEV Equipment

LEV systems capture the hazardous substance at source and it is carried away in a ducted air stream generated by a fan and filtered by one of several methods depending on the substance.

A typical LEV system will have:

  • Hood(s) – to collect airborne contaminants at, or near, where they are created (the source).
  • Ducts – to carry the airborne contaminants away from the process.
  • Air Cleaner – to filter and clean the extracted air.
  • Fan – which must be the right size and type to deliver sufficient 'suck' to the hood.
  • Discharge– for safe release of cleaned, extracted air into the atmosphere.
  • Collection Bin – dislodged dusts from the filter falls into a collection bin which, when full, is to be taken away and emptied.

The LEV system chosen should be fit for purpose and capable of adequately controlling exposure.


Correct Product Selection

Buying the right LEV equipment is a critical step. Some employers buy LEV equipment to find that it doesn't work. That's because the wrong type has been purchased or because it hasn't been installed or maintained properly.

We partner with leading LEV manufacturers and installation teams and through our site surveys, we can recommend the best product solutions tailored to your workplace and application needs.

Contact us on: 01482 383288 or email


Advice and Support

To help you comply to health and safety law and to avoid expensive mistakes, we can offer site surveys, advice on product specification and selection, training, and on-going service and maintenance.

Site Surveys

To ensure that you choose the right LEV solution for your workplace and/or application, you can arrange for one of our safety experts to visit conduct a site survey.

Training in the use of LEV

It is vital to ensure that all operators and supervisors understand how LEV works and receive adequate training in the correct use. Training records must be kept up to date to show this.

Service and Maintenance

According to Regulations 9 of the COSHH Regulations, it is a legal requirement that employers thoroughly test and inspect their LEV systems every 14 months via a Thorough Examination and Test (TExT) Reports to ensure good working order and provides the necessary protection.

Consisting of a visual inspection, examination and testing of technical performance and checking the system is fit for its intended purpose, Arco Professional Safety Services can provide an LEV testing and inspection service and supply a report and recommendations on the findings.

Contact us on 01482 383288 or email

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