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Laboratory Hoods

Testing Requirements

Laboratory hoods used to prevent harmful exposures are required to be tested or retested:

  • Annually, at a minimum
  • Whenever there is a "FAILED" sticker
  • Whenever a laboratory hood has been modified
  • Whenever the exhaust duct system connected to a hood has been modified (if needed)
  • Whenever the hood has been relocated
  • Fume Hood Usage

Observation of the laboratory hood environment, maintenance, and work practices can provide an indication of proper exposure control performance. For example, if the sash of the hood is left open during operation of the research activity, the hood is likely to reduce its functional effectiveness.

Laboratory fume hood performance can also be compromised by the following factors:

  • Equipment blocking airflow to slots in baffle
  • Equipment placed within 6 inches from the plane of hood face
  • Hood sash or panels not replaced after equipment setup completed
  • Cross drafts - can be due to ventilation supply ducts or blowers/exhaust related to nearby equipment
  • Worker leaning into the hood
  • Leaks in exhaust ducting
  • Turning off the hood fan during actual hood use

Fume Hood Testing

All fume hood testing is performed by a safety representative. The test performed is a quantitative evaluation - face velocity measurement. The following is a belief description of its procedures.

  • Test air flow when the sash at the 18 inches height and fully opened
  • Calculate average face velocity from both 18 inches and fully opened
  • If average face velocity is greater than or equal to 100 fpm, with a minimum of 70 fpm at any point, the unit has PASSED
  • If the unit FAILED the quantitative evaluation:
    • A safety representative will place a "FAILED" sticker on the hood.
    • Laboratory personnel are to call the phone number listed on the sticker for maintenance IMMEDIATELY. [NOTE: It is not good safety practice to perform work in a hood with a failed sticker.]
    • After any repair or maintenance, click HERE to email request a fume hood retest before beginning to work in the hood.

Biological Safety Cabinet

The HSC Safety Department does not test this type of hood. However, the hood needs to be recertified every year. In order to recertify your biological safety cabinets contact your vendor of choice.

  • NSF accredited field certifiers for biological safety cabinets can be found at the following link:

    Class II Biosafety Cabinet Field Certifier Accreditation Program
  • Two vendors that often do this certification for West Virginia University:

    Russell F. Petroski
    Filtech Inc.
    Phone: (412) 461-1400

    ENV Services Inc.
    Hatfield, PA
    Phone: 1-800-883-3681