Frequency of thorough examination and
test of Local Exhaust Ventilation (LEV) plant
The maximum time between tests of LEV systems is set down in COSHH and for most systems this is 14 months (see the exceptions below). * In practice, this is normally taken to mean annually. If wear and tear on the LEV system is liable to mean that the system effectiveness will degrade between tests then thorough examinations and tests should be more frequent.
* Source text: Health & Safety Executive - Controlling airborne contaminants at work: A guide to Local Exhaust Ventilation (LEV) - HSG258
# Source table: Health & Safety Executive - Control of substances hazardous to health - HSE L5, (Section 4, page 90)