Local Exhaust Ventilation (LEV) is part of control equipment use or install in a workplace to gauge the chemical exposures which are hazardous to health. It captures contaminants before it disperses into the working/workroom environment. The pollutants can be in the form of dust, aerosol and other hazardous chemical gas or substances.
It is part of the local regulator’s requirement to control exposures in a workplace to include local exhaust ventilation, water spray, and other airborne chemical removal and containment equipment.
The Local Exhaust Ventilation system has to be checked, tested and examined at a frequent interval to ensure efficiency and functionality. It consists of checking the system’s physical condition, utilising the system, smoke tube tracer test, identifying any obstruction to the air-flow, state of the hood, and inspection of cleaner device and fan’s motor.
Local regulation may stipulate as provision for any control equipment such as LEV to be checked and tested by competent personnel.
The frequency varies by local or country requirements. Other practices/localities have mandated that the system should be checked every 14 months or more frequently if deemed fit by the manufacturer.
A simple routine check needs to be undertaken during the operations of the LEV. Regular checks ensure that performance measurement is being compared against its instalment data, on-going performance, detection of any wear and tear from usage, or any misplaced section of the system. Early detection in the event of a gap or failure in the network can provide speedy diagnosis and action.
How Often Should Local Exhaust Ventilation (LEV) be Checked?
An annual performance testing is undertaken to ensure that the LEV system continues to operate per its initial design to achieve adequate control. The testing should be performed by competent personnel in the operations of the LEV system. The personnel may be appointed as follows:
- Occupational Hygienist or Ventilation Engineer or Outside Contractor (Every 12 month)
*or a shorter period as specified by the designer of the LEV
There are three (3) stages of annual testing, namely Thorough Visual and Structural examination, Technical performance and control effectiveness.
The record or logbook of the said checked has to be retained for a minimum of 5 years. The journal should indicate the initial design, performance monitoring and check for any modification made to the system to show the system’s progress.
A plan for periodic maintenance at regular intervals is an essential aspect of LEV operations. The inspection ensures the operational efficiency of the LEV at least at par with the new instalment. Also, the system is in excellent and working condition. Maintenance schedules depend on the intensity and usage of the course/LEV, which should not be more than 14 months.
A contingency plan or policy must be developed in case of breakdown or power failure and approved by the relevant authority.
The results of the checking/testing have to be recorded and retained for inspection/s by the authority/regulator. The results have to include the design, construction, testing, inspection and examination and maintenance.
A periodic review to be conducted by an independent audit to highlight any discrepancy and action for improvement to be undertaken.
The local exhaust ventilation system’s effectiveness and efficiency depend on its design, regular maintenance, proper usage, and routine inspection of the system.