Local exhaust ventilation - preventative maintenance

Guidance for employers on how to reduce employee exposure to airborne contaminants by maintaining effective local exhaust ventilation (LEV) systems.

Legal Duties

Under the Occupational Health and Safety Act 2004, employers must, so far as is reasonably practicable:

  • provide and maintain for employees a working environment that is safe and without risks to health
  • provide or maintain plant or systems of work that are safe and without risks to health

Under the Occupational Health and Safety Regulations 2017, employers must ensure that any particular risk control, such as LEV, is properly installed (if applicable), used and maintained.

LEV System

An LEV system typically includes a capture hood, ducting, a filter that cleans air and collects dust, an air mover or fan, and a discharge point.

The LEV is designed to capture airborne contaminants, such as:

  • dust (for example, wood dust)
  • fumes (for example, welding fume)
  • vapour (for example, chemical vapour)
  • gas (for example, toxic gas)
  • mist (for example, chemical spray mist)

An LEV system poorly maintained will result in ineffective capture of these airborne contaminants.

Health risks

If a LEV system is poorly maintained, it increases the potential health risks associated with exposure to excessive levels of airborne contaminants.

Health risks include:

  • respiratory irritation
  • central nervous system depression
  • asthma
  • lung diseases and cancer

Refer to the safety data sheet (SDS) for the product to determine specific health effects associated with exposure to airborne contaminants.

Preventative maintenance of LEV

Reduce employee exposure to airborne contaminants by using an effective and properly maintained LEV system.

Regularly maintain the LEV system:

  • Check for signs of damage or deterioration to:
    • capture hoods
    • ducting
    • air cleaners
    • dust collectors
    • fans
    • connections
  • Inspect and clean any contaminant build-up like dust and overspray.
  • Test the unit’s effectiveness using smoke tubes or an anemometer.
  • Check for any drop in pressure across the filter (bags) where appropriate. Where it is practicable, install a direct reading device to measure the pressure drop across the filters.
  • Remove any waste from collection units.
  • Change filters as required.

The frequency of a preventative maintenance program depends on the rate of work and manufacturer’s recommendations.

Annual LEV maintenance

The LEV system requires annual maintenance by a competent person who has the necessary skills and knowledge in maintaining the LEV.

A competent person should:

  • check the operation of the system
  • test the airflow
  • inspect the fan and motor for:
    • noise or vibration
    • integrity and security of fixings
    • cleanliness
    • need to lubricate or grease
  • inspect:
    • belts, bearings and pulleys for tension
    • alignment
    • safety guards
    • wear and tear
  • check duct work for cleanliness, damage or holes and secure connections
  • check electricals (there may also be an automatic sensor operation and time delay system)
  • check other plant associated with the LEV system

Keep preventative maintenance and inspection records for the life of the LEV unit. The records should include any actions required and should be signed and dated by the person performing the inspection and maintenance.