Local exhaust ventilation (LEV) controls airborne contaminants in an engineering workshop
Activities such as welding, soldering, fibre glass repair and painting were performed on work benches throughout a workshop. When performing these activities, the fumes, dust, mist or vapour often rises into the employee’s breathing zone. Initial exposure to these hazards can result in minor discomfort and irritation. However, prolonged exposure can result in serious long term (chronic) illness.
In the past, these hazards had been tackled by the use of respiratory protective equipment (RPE). There are common problems when relying on personal protective devices – the RPE often does not fit; incorrect RPE could be selected; it is often uncomfortable to wear and requires particular attention to maintenance and storage.
Management and employees at the workshop sought a solution which would control the airborne contaminant at its source. To this end, local exhaust ventilation (LEV) ‘arms’ were installed above each work bench. Each LEV arm consists of a capture hood that mounted on a length of flexible ducting which enables the hood to be located at the source of the airborne contaminant. The capture hood also incorporates a gate valve which is closed when the hood is not in operation. Each arm is connected to a fixed ducting system which exhausts the airborne contaminants to a central air-filtering unit located outside the workshop. As a result of the installing the LEV system, RPE is no longer required when performing these activities.
One problem associated with these capture hoods is that they can be difficult to manoeuvre. However, regular maintenance will manage this issue.
Hierarchy of Controls:
- Employees have gained short and long-term health benefits.
- The concentration of a variety of airborne contaminants including fumes, dust, vapour, mist and gasses have been effectively minimised at their source. Employees no longer rely on RPE as the only control method.