Oooo - I'm all atwitter - a fume hood question!
In California, 100 fpm is the minimum average face velocity with no point less than 70 fpm (8CCR5154.1). Modern well-engineered fume hoods contain just dandy at 80 to 120 fpm. Over about 125 fpm, there's too much turbulence for good capture and less than 80 fpm doesn't contain well, either. At my campus, we've standardized on vertical-rising sashes and 100 fpm at an 18" sash height.
Hope this helps,
Debbie M. Decker, CCHO, ACS Fellow
Immediate Past Chair, Division of Chemical Health and Safety
University of California, Davis
Birkett's hypothesis: "Any chemical reaction
that proceeds smoothly under normal conditions,
can proceed violently in the presence of an idiot."
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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