Local exhaust ventilation (LEV) is a method of extracting fumes and airborne contaminants from ambient air, cleaning the air and making it safe to breathe. Contaminants such as dust and fumes are a common workplace hazard in industries ranging from bakeries to paint shops.
The 1974 Health and Safety at Work Act made it a legal obligation that employers should maintain a healthy working environment for their employees. This means that any business using a LEV system has to ensure that all of the equipment is regularly examined and tested, usually at 14 month intervals, to ensure its effective operation and safety.
Employers are required to control hazardous substances under the provisions of the 2002 Control of Substances Hazardous to Health (COSHH) Regulations. This means that the employer has to first identify all potential health hazards, and carry out a risk assessment to decide how to prevent or minimise them. He or she is obliged to install control measures, such as LEV, to reduce these hazards and to ensure the controls are used correctly and adequately maintained.
All employees must be provided with the correct training information and instruction on how to operate any control procedures and how to monitor the hazards. There must also be a contingency plan in place to deal with any emergencies.
All LEV equipment should be tested at 14 months or fewer intervals by a competent person. Depending on the industrial process, some LEV systems have to be checked every six months. This means that the tests cannot be carried out by the employer themself or their staff. The employers and staff need to cooperate fully with the visiting examiner.
This examiner has to be supplied with the LEV system user manual (provided by the system’s installer), and all details of maintenance and checks that have been carried out by the staff and recorded in the system’s logbook. The logbook should also be supplied to the examiner. These workplace checks need to be recorded in a commissioning report.
Relevant staff tests should include pressure and airflow measurements and checks on the effectiveness of system controls.
The examiner will carry out a thorough examination of the system, components such as hoods, ducts and filters. They will measure the system’s technical performance criteria and make recommendations for repair or replacement of parts in the event that the system does not operate correctly.
Once the testing is complete, the examiner attaches a “tested” label to all of the parts in question. The label should include their name and the scheduled date of the next test. They will write a report of the test that includes an action plan for future repairs and maintenance.
Sometimes the examiner may attach a red, “fail”, label to some parts. This means that the part has to be repaired or replaced. As this process is underway, the employer must provide extra protection for employees. Such measures may include extra protective clothing or breathing apparatus.