The object of an LEV system is to control the emission of such substances to the atmosphere as close as possible to the point of source, thereby preventing release into the workplace. To be effective, LEV must initially be well designed and constructed. Over time, the performance of systems can deteriorate due to wear, blockage or damage. Thus, regular inspection and testing is critical to ensure that control of exposure remains adequate.
The Control of Substances Hazardous to Health (COSHH) Regulations require employers to assess and control the exposure of their workforce to hazardous materials. COSHH Regulation 9 requires that where local extract exhaust ventilation plant is used to control exposure to substances hazardous to health, a thorough examination and test be undertaken at least once every 14 months to ensure that it remains in good working order, or more frequently in some specific cases.
Local Exhaust Ventilations Systems should be examined and checked following guidelines in HS(G) 258 ‘Controlling of Contaminants at Work’. The guidance provides advice to employees and others who operate, service and maintain local exhaust ventilation (LEV) systems. The aim is to ensure that LEV systems which are intended to control substances hazardous to health, including biological agents, continue to operate as originally intended. In order to work a system should effectively capture released hazardous substances, remove them from the workplace and safely dispose of them. The health of people indoors and outside is then protected.
LEV Monitoring Techniques
SOCOTEC employ a number of techniques to check LEV systems. This will include flow checks using specialist anemometers, pitot tubes and smoke tests, pressure measurements and visual examinations. The ductwork in larger systems will need to be fitted with access points for the equipment. If these are not already in place, SOCOTEC staff can install them where it is possible to do so safely.
Exposure Monitoring of Staff
HSE guidance also suggests that staff who are protected by the LEV may also need monitoring to confirm the effectiveness of the system at controlling exposure to a substance hazardous to health. SOCOTEC’s Occupational Hygienists can monitor individual staff members and the general atmosphere for most hazardous materials.
Emissions to Atmosphere
For some processes there may be regulations requiring the monitoring of the final exhaust from the system into the environment. SOCOTEC has specialist MCERTS accredited staff who can undertake this work and provide reports to provide reassurance to the enforcing authorities.