Local Exhaust Ventilation (LEV) Thorough Examination and Testing (TExT)

What is local exhaust ventilation (LEV)?

LEV is an engineering control system to reduce exposure to airborne contaminants such as dust, mist, fume, vapour or gas in a workplace.

HSG258 Controlling airborne contaminants at work – A guide to local exhaust ventilation (LEV) (third edition, published 2017) provides guidance on designing, commissioning and testing effective LEV.

Figure 1- Below shows the common elements of a simple LEV system (Source HSE; HSG 258).

Hood: This is where the contaminant cloud enters the LEV examples include capture hoods, canopy hoods over a hot process or spay booths.

Ducting: This moves the air and contaminant from the hood to the exhaust discharge point.

Air cleaner/Filter: This filters or cleans the contaminated air. Not all systems require these. 

Air Mover/Fan: The ‘engine’ that provides the power to move the contaminated air.

Discharge: The is the point extracted air is returned to the workplace or to a safe place.

Why do I need LEV?

The HSE identified that in 2018/19 1.4 million workers suffered from work related ill health. Workers contract occupational lung diseases such as occupational asthma and silicosis. Many people die or are permanently disabled by these conditions and are unable to work.

People develop these diseases because they breath in too much contaminated air and control measures do not work well enough. Common industries affected included woodworking, bakeries, engineering and metal working, car body paint spraying and pharmaceutical.

LEV is there to control the clouds of contaminated air before people breathe them in.

However, before using LEV employers must have considered other control options such as eliminating the source of contaminant or substituting the material for something safer. Spending lots of money on an LEV system isn’t always the correct solution. 

An occupational hygienist can advise you further on this.

What is a statutory thorough examination and test (TExT)?

A thorough examination and test is a detailed and systematic examination sufficient to make sure that the LEV can continue to perform as intended by design and will contribute to the adequate control of exposure.

At Armstrong Environmental Ltd. undertaking an thorough examination and test of the sites LEV system/s would follow a clear set of objectives, which would include:

• Testing the engineering controls as per the duty within COSHH Regulation 9 and ensure it ‘is maintained in an efficient state, in efficient working order, in good repair and in a clean condition”.

• Undertake a 3 stage examination and testing of each LEV system as defined by HSG258.
  • Stage 1: Thorough visual and structural examination;
  • Stage 2: Review technical performance;
  • Stage 3: Assess control effectiveness.

• Provision a comprehensive report which includes a decision on the effectiveness of each system (Satisfactory/Unsatisfactory/Not determined).

• Provision of an initial priority assessment outlining any recommendations including timescales for re-testing.

Frequency of thorough examination and test

The maximum time between tests of LEV systems is set down in COSHH and for the majority of systems this is 14 months. Our testers would typically recommend a re-test in 12 months giving you a 2-month window of opportunity to get the testing undertaken again.

More frequent testing may also be recommended if it is anticipated that the system effectiveness will degrade between tests.

COSHH schedule 4 lists the intervals for TExT for certain processes such as grinding and polishing metal in a room for more than 12 hours per week or casting process.

The test report needs keeping for at least five years.

What information do we need from you prior to a thorough examination and test?

• We need to agree safe working procedures – the lev examiner must know the risks from the system under test.

• Ideally we’d like to see copies of any of the following documents for each system:
  • Commissioning Reports;
  • User Manuals;
  • Log Books/Service Records (Including details of filter changes or saturation tests where applicable)
  • Previous Thorough Examination and Test Reports;
  • Air Sampling Reports.
  • DSEAR Risk Assessments (Sugar, coal, wood, grain, certain metals & many synthetic organic chemicals have the potential to explode)
  • COSHH Risk Assessments – these will confirm the hazardous substances under control for each system and is the cornerstone of the LEV test.

Legal Requirements?

The Health and Safety at Work etc Act 1974 (the HSW Act) is the primary document which defines the duties employers have to themselves, their employees and others. Employers that use the LEV, designers, installers and companies that undertake testing on it are also bound by duties and responsibilities under the HSW Act. Consequently, it is not just the owner of the LEV system that has responsibilities.

The Control of Substances Hazardous to Health Regulations (COSHH) 2002 (as amended) requires that:

• Regulation 6: Employers should not carry out work that is liable to expose employees to substances hazardous to health until a suitable and sufficient assessment of the risk has been undertaken
• Regulation 7: Every employer shall ensure that the exposure of employees to substances hazardous to health is either prevented or controlled.
• Regulation 8: Employees should make full and proper use of any control measures and report any defects as soon as possible.
• Regulation 9: Every employer who provides any control measure shall ensure they are maintained in an efficient state, in effecieint working order, in good repair and in a clean condition. In addition the LEV should undertake a thorough examination and test every 14 months or as required by column 2 of the Schedule.
• Regulation 10: Employers are required to monitor exposure of employees to ensure the LEV systems continue to provide adequate control.- determined by the risk assessment.

If an employer is using a substance that could form an explosive atmosphere they must consider the responsibilities under the Dangerous Substances and Explosive Atmospheres Regulations 2002 (DSEAR).