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 Fume Hoods

Fume Hoods

A fume hood is a typical local ventilation device, designed to vent out the hazardous chemical fumes and vapors. A per OSHA, "the fume hood is often the primary control device for protecting laboratory workers when working with flammable and/or toxic chemicals". The ventilation system of fume hoods is separate from the building's HVAC system, and hence, hazardous fumes and vapors are not recirculated into the building.

It is important to understand how fume hoods work, and follow safe working practices, to ensure adequate protection from hazardous chemical fumes. The front panel of the fume hood is called a Sash, which can slide up and down, to give adequate access to the fume hood bench. Certain precautions must be taken before using the fume hood, and even while using the fume hood.

Pre-use Checks:

  • The fume hood must be switched ON before use.
  • Keep the sash opened at a standard operating level, in line with the arrows indicated on the hood.
  • Check the airflow indicator installed on the hood, to make sure that airflow is within the required range, i.e. 60 – 100 fpm (feet per minute).

Precautions while using the Fume Hood:

  • Use appropriate PPE even while working with chemicals on fume hood.
  • Never enter your head in the plane of the fume hood.
  • Keep the fume hood sash at a level below your face.
  • Keep all the working material in the hood at least six inches inside from the sash opening.
  • Keep the large working equipment elevated at least two inches off the fume hood base.
  • Keep the sash closed when not working in the hood.

Housekeeping and Maintenance of Fume Hoods:

  • Do not store chemicals permanently inside the fume hoods.
  • The fume hood workbench should be clear enough for work to be carried out hassle free and safely.
  • Exhaust slots at the back of the hood should be kept clear all the time.
  • The fume hoods with airflow level below the required range should be tagged "Out of Service" and reported for repair and maintenance.
  • The fume hoods must be inspected regularly as per the prescribed frequency, and the inspection history must be displayed on each fume hood.