How do fume hoods work?

With a fume cabinet, air is sucked from the laboratory, around the researcher and into the front of the hood by a fan. It is then expelled out of the laboratory building (ducted fume cabinets) or made safe through filtration and fed back into the room (re-circulating fume cabinets).

Most fume cabinets are known as constant air volume (CAV) hoods. CAV hoods draw a constant volume or amount of air all of the time.

Disadvantages of CAV hoods

The rising cost of energy costs means that CAV fume cabinets can be exceptionally costly to run. Also, Constant Air Volume hoods do not react quickly to airflow upsets inside the fume cabinet or within the environment where they are situated. As their purpose is containment and protection, this can be a serious problem.

Attributes of the best fume cupboard

•           Capture and contain the spread of dangerous gasses and materials
•           Be ergonomically designed so that they are easy for workers to use
•           Conform to high safety standards
•           Have a good energy efficiency rating

See How to buy fume hoods for more information.

Fume cupboard controls

Most fume cupboards or fume cabinets come with a control panel. Typically, these controls:

Warn the operator of low air flow.

Warn the operator of too large an opening at the front of the unit. These are sometimes known as a "high sash" alarm. Having too larger gap can cause the air velocity drop and thus reduce the efficiency of the unit.

Allow the user to switch the extract fan on or off.

Allow the user to switch the internal light on or off.

Fume cupboards

FUME CUPBOARDS

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How do fume hoods work?

Disadvantages of CAV hoods

Attributes of the best fume cupboard

Fume cupboard controls