What is an LEV system

The COSHH regulations state that employers must provide a safe working environment for their employees. A COSHH assessment looks at the hazardous substances in the workplace and examines the measures that could be put into place to control them. Local Exhaust Ventilation (LEV) systems are a type of engineering control that control the hazardous substance at source. These are useful because they remove the substance from the workplace and therefore protect not only the worker using the LEV system but also all of the other people in the area. Over time, the performance of a local Exhaust Ventilation System can deteriorate due to blockages, damage and wear. It is a legal requirement through COSHH Regulation 9, that employers that use LEV systems to control hazardous substances must arrange for LEV testing to be carried out at least once in every 14 months (for most hazards).

LEV Testing of ductwork

Background to LEV Testing

Every year thousands of people develop diseases from breathing in dust, fumes and other hazards while at work. The HSE estimates that twelve thousand deaths each year are caused by past exposure to hazardous substances.The health and safety at work ACT 1974 requires employers to provide and maintain working conditions that are safe and without risk to health of employees so far as is reasonably practicable. COSHH expands on this duty and requires employers to prevent their workers’ exposure to hazardous substances or, where this is not reasonably practical, to ensure adequate control.

Local Exhaust Ventilation (LEV), often referred to as dust and fume extraction, is designed to ensure this adequate control and takes the dust or gas hazard in the air away from the employee and removes it from the work place.
The HSE state that around a 100,000 work places in the UK use LEVs to control the risks of 2.6 million workers. 40,000 of these companies have their LEV tested regularly, leaving 1.6 million workers at risk and 60,000 companies open to potential prosecution.

Who should carry out LEV Testing

The Management of Health and Safety at Work Regulations 1999 require that an employer must ensure that the person carrying out the LEV Testing is competent. The best way to guarantee this competency is to ensure that the person undertaking the test has passed BOHS Proficiency Module P601 “Initial appraisal and thorough examination and testing of local exhaust ventilation systems”

Synergy’s Testing Service

Our P601 qualified staff will check that your LEVs are still performing as intended and ensure that your company complies with COSHH Regulation 9. If your LEV systems are not performing as required we will tell you what’s wrong and prioritize the remedial work that needs to be done to correct it.

Our LEV testing service offers three main stages.

Stage 1 – A visual examination to check that the LEV system is clean, in good repair and working.

This may include:

a check for damage, wear and tear
Internal duct examinations
checks that the air cleaning device is working correctly
inspection of the filter material
checks that display devices (such as pressure gauges) work correctly.
check of water flow and sumps for wet scrubbers
check that system alarms work correctly
a check of the fan that serves the system
A check of effectiveness – e.g. dust in and around the LEV hood

Stage 2 – Measurements to test if the technical performance of the LEV system continues to be effective.

This may include:

Gas velocity measurements at the hood faces, branch ducts and main ducts
a measure of the static pressure behind each hood, in the ducting, across the air cleaner and fan.
a check of the fan speed
a check of the direction of the fan
check of the make-up air supply
check of the alarms by simulating failure
a measure of the air temperature
a test of the cleaner performance
a comparison of the volume flow rate against the design spec.

Stage 3 – An assessment of the control effectiveness of the LEV system.

This may include:

observation of the processes and sources
assessment of how well exposure is controlled
smoke tests to check if the operator’s breathing zone is affected
smoke test to assess leakage in the system.
lamp tests to check for the escape of dust or mist
observation of the operator’s working pattern.

LEV Testing reminder

As part of our service we can remind you that your systems are due for inspection. We can do this free of charge and provide discounts for contracts covering a number of visits.


Local Exhaust Ventilation (LEV) workplace fume and dust extraction.
Frequently asked questions about LEVs.
HSG 258 – “Controlling Airborne Contaminants at Work”.


Call us today on: 01782 614236 or email us at: info@synergy-environmental.co.uk