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  Local Exhaust Ventilation
Local Exhaust Ventilation (LEV) is an engineering control system used to reduce exposure to airborne contaminants such as dust, mist, fume, vapour or gas in a workplace.
Within the manufacturing industries, methods of production and handling of substances and materials may involve the release of hazardous substances into the air. This has the potential to expose employees in the workplace to hazardous substances with the possibility of ill health, either soon after or in the years following exposure. As an employer, it is your responsibility to ensure that adequate control measures are in place and maintained, ensuring that exposure is reduced to levels as low as is reasonably practicable. In many cases, LEV is the solution. It is a commonly used control measure that aims to capture the pollutant at source. As it is a control measure, this LEV must be regularly inspected and tested in accordance with the new HS(G) 258 guidance.
In accordance with the HS(G) 258, it is required that the persons examining LEV systems are fully competent to the BOHS (British Occupation Hygiene Society) proficiency P601 course, which can be provided by Envirocare. The new guidance (HSG258) requires thorough examination and testing as stated in Regulation 9 of the COSHH Regulations. For most systems, the maximum time between tests is no longer than 14 months. But certain LEV systems, require more frequent inspection.
According to the new guidance, the examination and test procedure and methods are similar to the original commissioning exercise of the system, with visual testing and technical measurement methods.
The three vital key stages involved in completing a thorough examination and test are as follows:
Stage 1 - A thorough visual examination to verify that the LEV is in efficient working order, in good repair and in a clean condition. Examples of the procedures include:
- Thorough external examination of all parts of the system for damage, wear and tear.
- Checks that any filter cleaning devices (shake-down, reverse or pulsed jet) work correctly.
- Checks that monitors and alerts/alarms, e.g. for returned air, are functioning.
Stage 2 - Measuring and examining the technical performance to check its conformity with the commissioning date. Examples of the procedures include:
- Measuring the air velocities at suitable test points as indicated in the system documentation. This includes hood faces, branch ducts and the main duct
- Checking the fan speed, motor speed and electrical power consumption
- Testing alarms, by simulating a failure, and the alarms’ ability to detect the failure
Stage 3 - Assessment to check that the control of worker exposure is adequate. Examples of the procedures include:
- Challenge tests, using smoke, with the process running, to check for some leakage, eddying and breathing zone encroachments. (Examiners warn employees and management that testing is undertaken to ensure smoke alarms are not activated)
- Dust lamp tests with the process running to check for escape or dust or mist
- Observation of the way operators work, whether they are using the methods specified and whether these methods are suitable
A key requirement of HS(G) 258 involves attaching a label to each part of the system once the examination has confirmed it has been checked and is up to standard. If part of the system does not conform to the standards, a red ‘Fail’ label should be attached instead to indicate attention is required.
Envirocare provides comprehensive, informative reports for LEV testing.
To view a sample report of LEV, click here
These example reports are tasters of the type of report that you would receive following commissioning of such testing work at your premises. As you can see it includes the requirements of the regulations and guidance for thorough testing and assessment to help you in gathering information to control your risks. They include plenty of useful information in the discussion and recommendations to help provide you with cost effective solutions to your problem areas.
For further information about our LEV services please contact our Health & Safety Manager, Andrea Beswick.
For contact details click here.
‘I’d like to comment on the much improved proposed layout for our LEV records. The way the data is now being presented is in a far more concise and logical manner, making it far more understandable for myself when trying to make direct comparisons with previous years, and producing action list for all relevant managers’.
Lee Mason CMIOSH, Health & Safety Manager, Scientific Games International, Leeds
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