Local Exhaust Ventilation Assessments
Introduction
Thousands of workers contract occupational asthma and other lung diseases each year; many are permanently disabled and unable to work. These conditions develop due of the existence of too much dust, fume or other airborne contaminants, often because of inadequate control measures.
Local exhaust ventilation systems are designed to remove hazardous contaminants from both the operative and working environment; naturally they are only effective when working correctly.
AEC offer occupational hygiene consultants who can provide a thorough examination and test local exhaust ventilation (LEV) systems, in accordance with Health and Safety Executive Guidance Note HSG 258 'Controlling Airborne Contaminants at Work' and as required by Regulation 9 of the COSHH Regulations 2002 (as amended). All AEC occupational hygienists hold the BOHS P601 qualification.
The examination and test will be undertaken in accordance with current regulations and HSE guidance as well as observing good occupational hygiene practices and will include the following:
- Visual examination of the systems and all ancillary equipment.
- Measurements of the system dimensions, face velocities, duct velocities, volume flows and static pressures, including the drilling of test points where required.
- Recording of activities and substances involved.
On completion of the LEV assessment an interpretive report will be produced detailing the findings and conclusions on the performance and effectiveness of the system based on comparisons with recommended performance criteria. Schematic diagrams detailing system layout and measurement locations and, where necessary, recommendations on further work.
Regulations
The legal requirements regarding the control of hazardous substances within the workplace primarily fall under the Control of Substances Hazardous to Health (COSHH) Regulations 2002 and in particular Regulation 7 and Regulation 9.
Regulation 7 is concerned with the 'Prevention or control of exposure to substances hazardous to health'. Regulation 7(1) states: "Every employer shall ensure that the exposure of his employees to substances hazardous to health is either prevented or, where this is not reasonably practicable, adequately controlled."
Regulation 9(1) of COSHH states: "Every employer who provides any control measure to meet the requirements of Regulation 7 shall ensure that, where relevant, it is maintained in an efficient state, in efficient working order, and in good repair and in a clean condition."
Regulation 9(2) of COSHH also states that: "Where engineering controls are provided to meet the requirements of Regulation 7, the employer shall ensure that thorough examinations and tests of those engineering controls are carried out."
For the majority of LEV systems an examination and test should be undertaken at least every 14 months.
Case Study
AEC recently conducted the examination and test of 36 local exhaust ventilation systems within a large manufacturing plant.
In addition to the basic assessment of capture, face and transport velocities, static pressures were recorded. Smoke tubes were utilised to demonstrate the capture of contaminants and identify where improvements were required.
Following on from the initial site visit a number of modifications to the LEV systems have been made, re-tested and now proved to be satisfactory.
