Laboratory designers install fume hoods to ensure the safety of researchers, but fume hoods must be annually inspected to maintain researchers and other lab staff aren’t being overly exposed to toxic chemicals and tracer gasses. This testing is not usually used for biological safety hoods, as ASHRAE 110 testing inspects for chemicals and toxins rather than pathogens.
The ASHRAE 110 test is generally used to inspect fume hoods in the factory, but these procedures can also be used for testing hoods once installed.
Fume hood testing is the law, and most labs use testing standardized by ASHRAE, the Association of the Society of Heating, Refrigerating, and Air-Conditioning Engineers. The ASHRAE 110 protocol is a three-part test which measures face velocity, flow visualization, and trace gas performance. Each of the three categories receives a rating of “good, fair, poor, or fail.”
ASHRAE 110 testing doesn’t prescribe a level of performance or safety that a fume hood should meet, but it offers a uniform testing standard that occupational safety organizations can use in the adoption of fume hood safety standards.
Face velocity measures the speed at which air enters fume hood openings. Different fume hoods have different specifications for face velocity. Testers compare face velocity with manufacturer’s specifications to ensure a fume hood is meeting safety guidelines. Different safety organizations also provide safety standards for face velocity. For example, the Occupational Safety and Health Administration recommends that air flow into and within the hood should not be turbulent.
Flow visualization measures how air flows within the fume hood. Smoke is used to visualize where and if air is escaping from a fume hood. The smoke assists in finding leaks, cracks or other areas in which air may be escaping the fume hood. If smoke escapes from the front of a fume hood, the hood fails the flow visualization test.
The ASHRAE 110 fume tests for leaks inside the hood. A mannequin is placed in different spots around the fume hood for five minutes at a time, as the sash is opened and closed. The test uses a probe attached to the mannequin to measure how many parts per million of tracer gas escape.
Fume hoods are a critical component of lab safety. When the fume hood leaks, dangerous fumes and chemicals can escape creating a potential hazard. Fume hood inspections are the law, and ASHRAE 110 fume hood test standardizes the way these critical safety components can be inspected. In addition to regular testing, OSHA also encourages laboratory staff to create and implement measures for the proper usage of fume hoods.