Policies & Procedures

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FUME HOOD TESTING CRITERIA

Class A Fume hoods - High Toxic Hazard
Class B Fume hoods - Moderate Toxic Hazard

Fume hood shall be in normal operation with the usual the usual amount of equipment in the hood. Testing shall be performed with the sash in the full open position and hood baffles in the normal position.

For Class A fume hoods, the average face velocity should be maintained at 125fpm
For Class B fume hoods, the average face velocity should be maintained at 100fpm

The average face velocity shall not be less than 100fpm with hood in normal operating condition for Class A, and not less than 85fpm for Class B

No reverse gas flow shall be observed during the use of the chemical smoke test. This refers to the outward flow towards the face of the hood.

Face velocity should not exceed 250fpm at any point on the face for both Class A and Class B fume hoods.

Establish and indicate the operating range for monitoring devices. Mark on fume hood.

Ensure exhaust duct is functioning properly, and adjust total exhaust air volume to manufacturers specifications where applicable.

Ensure proper working of fan blades and housing.

Adjust hood baffles and fan drives etc to provide required face velocity.

Ensure proper condition and operation of baffles, sash, counter balance and service fixtures like water, gas, air, lights etc. Sash must move freely and smoothly and stay in a stationary position when required.

Ensure low flow alarm is functional.

Duct and/or filters must be in proper working condition with no blockages.

Fume hoods must operate at minimum noise level

On fulfilling the above criteria a certification label must be affixed to the fume hood with the following information: -

Name of testing organization
Name and signature of person performing testing
Hood application and limitations e.g. perchloric acid
Average and minimum face velocity
Measured exhaust air volume and static pressure
Acceptable range of monitoring device
Date of testing.