Local Exhaust Ventilation (LEV)

What is local exhaust ventilation (LEV)?

Why do I need to examine and test my local exhaust ventilation (LEV) system?

Who can examine and test a local exhaust ventilation (LEV) system?

What standards or guidance should be followed by the person undertaking the examination and testing of the local exhaust ventilation (LEV) system?

What does the examination and testing of the local exhaust ventilation (LEV) system involve?

What should my LEV report contain?

How long do I need to keep my report on the examination and testing of my local exhaust ventilation system(s)? What format should I keep it in?

How much does the LEV examination and testing cost?

What else do I need to do to look after my local exhaust ventilation system?

Where can I find out more about local exhaust ventilation?

Local exhaust ventilation (LEV) is a method of reducing workers' exposure to potentially harmful substances generated by the work process. The release of the substances is controlled at, or close to the point of release reducing the potential for the substance to be released.

A typical local exhaust ventilation system will extract air using a hood, partial enclosure or other opening and transport the contaminated air away from the workplace, cleaning it and then discharging it either outside or back into the workplace.

Local exhaust ventilation (LEV) can be used to control a wide range of substances including gases and vapours, fume and solids.

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In the UK the Control of Substances Hazardous to Health (COSHH) Regulations, 2002 require that thorough examination and testing of local exhaust ventilation plant is carried out at least once 14 months and in some instances (e.g. shot blasting units, grinding extracts), at shorter intervals.

The Control of Lead at Work Regulations 2002 (CLAW) have similar requirements for examination and testing of local exhaust ventilation plant.

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In the UK the law specifies that the person undertaking the examination and testing must be competent to do so (The Management of Health and Safety at Work Regulations 1999). In its publication HSG258 "Controlling airborne contaminants at work. A guide to local exhaust ventilation (LEV)" the Health and Safety Executive lists four qualifications as being suitable:

• Diploma of Professional Competence in Occupational Hygiene (Dip Occ Hyg)
  
  
• Certificate of Operational Competence in Occupational Hygiene (Cert Occ Hyg)
  
  
• BOHS Proficiency Module P601 "Initial appraisal and thorough examination and testing of local exhaust ventilation systems"
  
  
• BOHS Proficiency Module P602 "Basic design principles of local exhaust ventilation systems"
  
  

Environmental Evaluation has trained and qualified occupational hygienists who can undertake thorough examination and testing of LEV systems based in all of our UK offices. All LEV projects are managed by personnel holding either the BOHS Certificate of Operational Competence in Occupational Hygiene (Cert. Occ. Hyg.) or the Diploma of Professional Competence in Occupational Hygiene (Dip Occ Hyg).

For details of our occupational hygiene team and qualifications please click here.

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Many organisations undertaking examination and testing are still working to guidance note HS(G) 54 which has been superseded. The latest guidance on the examination and testing of local exhaust ventilation is given in the Health and Safety Executive's publication HSG258 "Controlling airborne contaminants at work. A guide to local exhaust ventilation (LEV)".

It is essential to ensure that work is being undertaken by trained staff who are familiar with this guidance.

Environmental Evaluation's occupational hygiene team are fully conversant with the requirements of HSG 258.

A company specialising in the provision of services such as the examination and testing of local exhaust ventilation systems is likely to have a quality management system registered to ISO 9001 and will have or be working towards UKAS accreditation to ISO 17020.


For details of Environmental Evaluation's accreditations please click here.

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The thorough examination and testing of a local exhaust ventilation (LEV) system will involve three stages:

1. A thorough visual examination,
2. Measuring technical performance,
3. Assessment of the LEV system's control effectiveness.

Stage 1. The thorough examination: will include the inspection of the following

• condition of captor hoods;
• ductwork;
• filter / air cleaning equipment including monitors and alarms.

Stage 2. Measuring technical performance could include measurement of:

• static pressure;
• duct transport velocity;
• temperature;
• face and/or capture velocities;
• pressure drop across fans / filters.

Stage 3. Assessment of the LEV system's control effectiveness will include:

• visual observations of processes and contaminant sources;
• effectiveness of LEV at controlling operator's exposure;
• smoke testing to visualise air movement and contaminant capture;
• dust lamp tests, if appropriate;
• observations of operator's interaction with the LEV system.

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LEV examination and test reports produced by Environmental Evaluation follow a HSE approved format and include measurement test data, schematic diagrams of the LEV systems, an assessment on the control effectiveness of the system and any recommendations for remedial requirements detailed in a prioritised action plan. Local exhaust ventilation design advice can also be provided to ensure that effective control is achieved.

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Records of all tests should be kept for at least five years.

There is no prescribed format for keeping your report but it should be accessible, some employers keep the records in paper format, others prefer electronic storage. Environmental Evaluation offers an online document storage facility where PDF copies of reports can be accessed via a secure log in.

For more information about this service please visit www.elocate.co.uk and click on the "Health and Safety" link.

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The cost of the examination and testing will depend on several factors, including:

• the size and complexity of the system(s);
• the availability of existing drawings / diagrams;
• the presence of suitable test points.

Environmental Evaluation will be pleased to provide a firm and fixed quotation for the examination and testing.

To obtain a quotation for the examination and testing of your local exhaust ventilation system(s), use our online form or print, fill in and fax back an enquiry form.

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A visual check of the equipment should be carried out by maintenance staff at least once a week. Employees using the LEV system must report any defects as soon as they are noticed. Thorough examination and testing of the LEV system, undertaken by suitably qualified personnel, are required at least once every fourteen months (more frequently for certain processes or where particular toxic substances are used). The fourteen month cycle allows for seasonal variations in the performance of the equipment, but this is a maximum, not a minimum, interval between tests. Records of all tests should be kept for at least five years.

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The Health and Safety Executive provides guidance for both employers and employees:

• Clearing the air. A simple guide to buying and using local exhaust ventilation (LEV)
  Leaflet INDG 408  
  
  
• Time to clear the air! A workers' pocket guide to using local exhaust ventilation (LEV)
  Leaflet INDG 409  
  
  

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