Local Exhaust Ventilation (LEV) Testing

Thousands of workers contract occupational asthma and other lung diseases each year. Many people die or are permanently disabled by these conditions and are unable to work. People develop these diseases because they breathe in too much dust, fume or other airborne contaminants at work, often because control measures do not work well enough. The most common industries affected although by no means limited to, include woodworking, welding, paint-spraying, stonemasonry, engineering and foundry work.


Local Exhaust Ventilation (or LEVs) are engineering control systems designed to control / reduce airborne contaminant exposure of personnel / employees. They can range from small & simple to large & complex systems.


For the UK, under CoSHH reg 9, it is statutory for employers / LEV owners that thorough examination & testing is carried out at least once every 14months (or more frequently - CoSHH Schedule 4). Furthermore the employer / LEV owner must ensure to ensure all controls are maintained in an efficient state, an efficient working order, good repair & in a clean condition.

For ROI, the Safety, Health and Welfare at Work Act 2005 requires the employer to manage health and safety in the workplace,
and to prevent and reduce risks to health and safety, through the provision of safe systems of work by completing a risk assessment and putting controls in place.

HSG 258 “controlling airborne contaminants at work. A guide to LEV” outlines the roles and responsibilities concerning LEV. Thorough examination and testing must be carried out by competent persons. ¬†Free copy here

The equivalent document for ROI containing almost identical themes to HSG258 but with a few differences also. E.g. a lower recommended value for wood dust duct transport velocities.  Free copy here


DevineAir Limited consultants are P601 & p602 qualified and can provide LEV testing services & deliver reports to the criteria laid out in HSG258.
This will include:

1.Thorough visual and structural examination (including function checks on components, where applicable)
2.Technical measurement of performance:

a.Face velocities;
b.Static & differential pressures
c.Duct velocities
d.Volumetric flows
e.Air temperatures

Other / optional tests may include

i.Air monitoring (occupational & emissions)
ii.HEPA filter testing
iii.Noise monitoring
iv.Microbiological sampling
vi.Water Quality
vii.Enclosure smoke clearance testing

3.Assessment of the control effectiveness

a.Observations of employee / LEV interactions
b.Smoke testing
c.Dust lamp scans

4.Reporting to HSG258 criteria & marking systems with test labels





New systems, undocumented LEV systems where there is no user manual or logbook & any system where there have been changes in process, workplace layout, the equipment creating the source or any other change in the LEV system itself will require commissioning / initial testing. DevineAir Limited has a wealth of experience in benchmarking new, prototype, client modified / built and existing undocumented LEV systems.