Know About Local Exhaust Ventilation(LEV)

Local exhaust ventilation (LEV) is a ventilation system that takes out any dust, mist, gas, vapor or fumes in the air, hence preventing the persons from inhaling the fumes. It is an engineering controlled system capable of preventing airborne contamination which may be harmful for the health. Local exhaust ventilation is used in many areas like laboratories and industrial premises to protect people working from hazardous chemicals. Enclosed hoods or chemical fume hoods vapor or particle generation during pouring operations which involves highly corrosive or reactive chemicals are removed with this system.

To effectively remove pollutants from the workplace and to dispose them off in a safe manner, local exhaust ventilation systems must be maintained in a good working condition. The thorough testing and examination of LEV plants must be carried out for least every 14 months and even more frequently for specific processes.

When applying local exhaust ventilation to a specific problem, there are several basic principles that should be implemented. They are:

• The source of contaminants should be enclosed as completely as practicable.
• Adequate air velocity should be used for capturing of contaminant.
• The contaminant should be kept out of the worker's breathing zone.
• Adequate make-up air must be provided.
• The exhaust air must be discharged away from air inlet systems

If any damage occurs to the LEV, employees must always report so that it can be repaired immediately. The majority of LEV systems need a complete examination and test annually to ensure it still works well and protects employees. More rigorous COSHH testing is required for some high hazard processes.