Local Exhaust Ventilation (LEV)

What is LEV?

LEV is a ventilation system that takes dusts, mists, gases, vapour, fumes or microorganisms out of the air so that they can’t be breathed in.
Properly designed LEV will:

  • collect the air that contains the contaminants;
  • make sure they are contained and taken away from people;
  • clean the air (if necessary) and get rid of the contaminants safely.

In order to protect the worker:

  • it needs to be the right type for the job;
  • it needs installing properly in the first place;
  • it needs regular checking and maintenance throughout the year;
  • it needs testing thoroughly at least once every year;
  • if moved, it must be checked to make sure it still works;
  • it needs an indicator to show it’s working properly;
  • the worker needs to check that it works properly every time it is used;
  • the worker must use it properly.

What Users of LEV Need to Know and Do

What workers should know before using LEV:

  • the harmful nature of the substances in use;
  • how exposure may occur;
  • how the LEV system works;
  • methods of working that get the best out of the LEV;
  • how to check the LEV is working;
  • the consequences of the LEV failing; and
  • what to do if something goes wrong.

Workers must carry out the following checks each time they use LEV :

  • Does the indicator show the LEV is working properly?
  • Are there any signs it is not working properly, like odours escaping from the hood or lack of air movement?
  • Are there any unusual noises or vibration coming from it?
  • Has it been thoroughly tested, with a ‘tested’ label that is within date?
  • Have you told your Lab Manager about anything you think may be wrong?

Types of LEV in SLS

In SLS the most common types or LEV are:

  • chemical fume hoods (sometimes called fume cupboards);
  • microbiological safety cabinets;
  • movable extract ducts in Dark Rooms.

Fume Hoods

  • Fume hoods are thoroughly examined and tested, annually by an external, specialist contractor. This is timetabled and coordinated by Estates & Buildings.
  • Users are required to carry out a visual check in accordance with the official Pre-Use Checks notice before using a fume hood. This notice must be clearly posted on every fume hood. Pre-use checks must be recorded in the user's lab book.
  • Lab Managers are reposnsible for ensuring a recorded monthly check is carried out. This must be recorded on the official LEV Recorded Monthly Check label posted on each hood.
  • Any faults/failures should be immediately reported to the Lab Manager who will then report to E&B.
  • Workers must receive training before using a fume hood for the first time.
  • The sash must always be kept as low as possible.
  • The sash must be fully lowered when the fume hood is not in use.
  • SOP for basic fume hood operation
  • Safety Clearance Certificate for chemical fume hoods
  • Signs for vented chemical storage cabinets beneath fume hood

Microbiological Safety Cabinets (MSCs)

Other LEV

  • Other LEV is formally examined and tested annually by Safety Services.
  • LEV must be registered with Safety Services to ensure it is included in the annual program. Email Martin Rollo to register new LEV.
  • Users must do a visual check before each use. Pre-use checks must be recorded in the user's lab book.
  • Official monthly checks may be required depending upon the type of LEV.
  • Any faults/failures must be immediately reported to the Lab Manager.
  • Workers must receive training before using LEV for the first time. The nature and extent of the training will depend upon the type of LEV and to what extent the user has to check and/or operate it.

HSE Guidance