At UNR we specified many years ago that face velocities be tested at a sash opening of 16.” We are looking for an average face velocity of 100 fpm but will pass a hood with a face velocity as low as 80 fpm. If the face velocity is over between 150 – 200 fpm the hood can still be used but we have the air flow adjusted, and over 200 fpm we don’t allow use of the hood until the air flow has been adjusted. All of this assumes an acceptable a visual smoke test as well.
Assistant Director, Laboratory Safety
Environmental Health and Safety Dept., MS 328
University of Nevada, Reno 89557
Office Phone: 775-327-5196
Cell Phone: 775-843-2113
By a quick show of hands, what face velocity do all of you consider as an acceptable velocity for certifying standard chemical fume hoods in academic and research labs? OSHA is pretty vague on the issue (must provide adequate ventilation [1910.1450(e)(3)(iii)]). Appendix A (non-mandatory) references Prudent Practices, where 80-100 is standard, up to 120 is okay for high hazard (no containment benefit proven) and 60fpm may be okay for low flow, specially designed hoods.
Before getting into too much detail, I am curious as to what all of you are considering as passing at 18in sash height, and what you are considering as failing.
Brandon S. Chance, M.S., CCHO
Associate Director of Environmental Health and Safety
Office of Risk Management
Southern Methodist University
PO Box 750231 | Dallas, TX 75275-0231
T) 214.768.2430 | M) 469-978-8664
"… our job in safety is to make the task happen, SAFELY; not to interfere with the work…” Neal Langerman
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