FAQ’s

What is Local Exhaust Ventilation (LEV)?

LEV is an engineering control system used to reduce workers’ exposure to airborne contaminants such as dust, mist, fume, vapor, or gas. It works by capturing the contaminant at or near the source and removing it safely.

What are the main components of an LEV system?

An LEV system typically consists of:

  • Hood: To capture or contain the hazardous substance at the source.
  • Ducting: To transport the contaminant.
  • Air Cleaner/Filter: To remove contaminants from the air.
  • Air Mover (Fan): To create airflow.
  • Discharge: To safely release the cleaned air.

What types of local exhaust ventilation is there?

There are two primary types of mechanical ventilation systems used in industrial environments:

General Industrial Ventilation (GIV)

GIV systems work by diluting contaminated air with fresh, clean air to reduce the concentration of airborne pollutants or to control heat buildup in hot industrial settings. This method is also referred to as Dilution Ventilation.

Local Exhaust Ventilation (LEV)

LEV systems are designed to capture contaminants directly at or near their source and expel them outside.

Can LEV systems control all hazardous substances?

LEV can control many airborne contaminants, but its effectiveness depends on proper design, maintenance, and suitability for the specific hazard. Other controls may be necessary for some substances or processes.

How do I know what LEV I need?

Extraction is broken down into classes, which are the following:

L – Entry level for softwoods and solid surface material. 99% filter efficiency.

M – Medium hazard for hardwoods, board materials, concrete and brick dust. 99.9% filter efficiency.

H – High hazard for silica dust, asbestos and lead paint. 99.995 filter efficiency.

What factors can affect the performance of an LEV system?

Factors include:

  • Incorrect design or installation
  • Poor maintenance
  • Changes to the process or substances being controlled
  • Blockages or damage to the system components

How do I know if my LEV system is working effectively?

Indicators include:

  • Visual signs (e.g., smoke or mist not being fully captured)
  • Noisy or unusual system operation
  • Airflow indicator devices showing performance issues

Regular monitoring and maintenance results

Is LEV legally required in the workplace?

Yes, under the Control of Substances Hazardous to Health (COSHH) Regulations, employers must ensure the exposure to hazardous substances is adequately controlled. This often involves the use of LEV systems.

What training is required for using LEV systems?

Employees should receive training on how to correctly use the LEV system, understand potential hazards, check basic operation indicators, and report issues promptly. Regular refreshers are recommended.

What does a Thorough Examination and Test (TExT) involve?

The TExT should assess whether the LEV system is effectively controlling exposure to hazardous substances. It includes a performance assessment, inspection of parts (e.g., hoods, ducts, filters), airflow measurement, and checks to ensure compliance with COSHH.

How often should an LEV system be tested?

In the UK, LEV systems should be tested at least every 14 months by a competent person, though certain processes may require more frequent testing, such as certain component replacement. This examination is known as a ‘Thorough Examination and Test’ (TExT).

What are the consequences of failing to maintain or test an LEV system?

Poor LEV performance can lead to health risks for workers. Non-compliance with COSHH can lead to enforcement action by the Health and Safety Executive (HSE), including fines and legal penalties.

Who can carry out a Thorough Examination and Test (TExT)?

The examination should be conducted by a competent person who understands LEV systems and can assess their performance accurately. This includes a knowledge of testing procedures and COSHH regulations.

What documentation should be kept for LEV systems?

Employers must keep:

  • Reports from all Thorough Examinations and Tests
  • Information about the design and commissioning of the LEV system
  • Records of maintenance and repairs

Information on employee exposure assessments (where relevant)