HSG 258 is the guide produced by the Health & Safety Executive that covers the design, use and testing of local exhaust ventilation systems. LEV are used to control gas, vapour, dust, fume and mist exposure in workplace air. The object of an LEV system is to control the emission of harmful substances to the atmosphere as close as possible to the point of source, thereby preventing release into the workplace.
Care must be taken to ensure that individual LEV are effective in controlling sources of exposure and continue to perform correctly after installation. Accurate testing is required to quantify air velocity and pressure, along with visualisation using smoke capture trials.
We have extensive practical experience of occupational exposure monitoring to make informed interpretation of the LEV performance data for valid pass/ fail of LEV systems. Envirotest conduct fume cupboard testing, stack height suitability and log book generation.