If you're located in California, the face velocity of the fume hood shall be 100 fpm, average minimum, with no point less than 70 fpm.
Everywhere else, it's performance-oriented. Generally, acceptable face velocity, for a well-designed fume hood installed on an engineered laboratory airflow control system, would be 80-120 fpm. Your institution should have guidance for folks like your air balancer and your certifier so there aren't questions like this.
The testing guidance (ASHRAE 110 or similar) only describe how to do the tests - they don't list out the acceptance criteria. The institution sets the criteria.
80-120 fpm is generally accepted as adequate. Additionally, ASHRAE 110 describes a containment test and a generally accepted criteria would be 4AI1.0 (4 liters/minute of tracer gas released, as-installed, <1 ppm tracer gas detected outside the hood). Hood manufacturers will also provide you their test criteria and operating parameters for the hood.
As the institution, you set the criteria. If 80-120 fpm is acceptable to the institution, then that's what your balancer and certifier should test to. I would suggest 80-120 fpm is a pretty wide range and you might want to narrow that, based on containment and operating parameters. You can find out a lot about hood containment with a smoke pencil and a dish of dry ice and warm water.
Hope this helps,
Debbie M. Decker, CCHO, ACS Fellow
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."
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of Kevin Burns
Sent: Friday, July 31, 2015 7:17 AM
Subject: [DCHAS-L] Fume Hoods
I am currently finding myself in trying to deal with a fume hood problem. We had a mechanical problem that needed to be repaired causing The system to be shut down. Now that the system can be turned back on we need to have an air balancer come in and rebalance the system. After that my certification company would come in to certify that the hoods are maintaining proper CFMs for employees to work in them within the laboratories. The air balancer is in disagreement with the certification vendor. The air balancer says we have to have a policy that our face velocities for each hood must be 100cfm, where the certifiers are indicating that it's between 80 and 120 which that was what my understanding was.
I know this falls under ASHRAE standards, ANSI standards and OSHA standards, can you point me in the right direction of where to get the exact information?
Thank you, any information would greatly be appreciated.
Sent from my iPhone
Previous post | Top of Page | Next post