RE: Hood Face Velocity

["Reif, Ronald H." <rreif@doeal.gov>]

Chuck-
I'm not sure what your state requirements are, but I offer the following
references:
1) ANSI - Laboratory Ventilation, Z9.5, 1996 (703-849-8888)
2) OSHA - 29CFR1910.1450 Occupational Exposures to Hazardous Chemicals
in Laboratories
3) ACGIH - Industrial Ventilation Manual, 22nd Edition (703-849-8888)

The above references will give performance criteria for lab fume hoods.
I believe that the ANSI standard gives a range of face velocities
(80-120 FPM), with no individual grid point velocity less than 25% of
the average face velocity.

I'm not sure about the units "LFM", as face velocities are generally
characterized in feet per minute (FPM).  Additionally, the "125" needs
to be further defined by your regulator (i.e., average velocity across
hood face, minimum value at any point, etc.).

Rather than expressing a specification standard, it may be more prudent
for your regulator to specify a performance standard (i.e., no loss of
airborne contaminants outside of fume hood).

These opinions are my and not that of my employer.

Ron Reif, CHP, CIH, CSP
rreif@doeal.gov
>----------
>From: 	Chuck Pickering[SMTP:CPICKERING%engr-serv.usc.edu@internet.al.gov]
>Sent: 	Friday, November 07, 1997 9:40 AM
>To: 	Multiple recipients of list
>Subject: 	Hood Face Velocity
>
>Our License requires fume hood face velocities to be greater than 125 
>LFM. In researching this number I have seen different figures quoted. 
>Does anyone have any input on this or know of any guidance on what 
>the velocity should be. Thanks.
>
>Chuck Pickering
>University of Southern California
>(213) 342-2200
>cpickering@engr-serv.usc.edu
>