We always used the ASHRAE 110 face velocity test as the primary annual hood
recertification. We run several tests using the tracer gas testing from
ASHRAE 110 but found that it rarely if ever showed us anything different
from the face velocity testing. (By that I mean we got too high a tracer gas
reading wherever we go too low a face velocity reading.) SO we decided many
years ago to use the tracer gas testing only in those rare cases where the
face velocity testing gave us strange readings (strange in that we could not
explain what we were seeing).

In general we found that hoods "failed" either test due to being overcrowded
(see "Why Don't We Just Put It in the Hood?": Issues with Degrading Hood
Effectiveness Due to Equipment Placement, ACS J. Chemical Health & Safety,
Jan, 2020) or due to being starved of supply air. Both were easily
identified by face velocity testing.

I recognize this is a position that many safety professionals do not support
but I remain convinced the need for routine tracer gas testing is
unnecessary in most cases.

Richard Palluzi
PE, CSP,FAIChE

Pilot plant and laboratory consulting, safety, design, reviews, and training
www.linkedin.com/in/richardppalluzillc/

Richard P Palluzi LLC
72 Summit Drive
Basking Ridge, NJ 07920
rpalluzi**At_Symbol_Here**verizon.net
908-285-3782

-----Original Message-----
From: ACS Division of Chemical Health and Safety On
Behalf Of Chainani, Edward Torres
Sent: Friday, November 12, 2021 10:33 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: Re: [DCHAS-L] SF6 fume hood certification

The search for a suitable alternative to sulfur hexafluoride was the cover
story of the 1st quarter 2021 issue of The NEBB Professional:

https://nebb.org/the-nebb-professional/

The article, "The Future of Fume Hood Testing: Implementing a Suitable
Alternative to Sulfur Hexafluoride", mentioned that an ASHRAE Technical
Committee sponsored a project that began in March 2017 and was tasked with
finding a replacement tracer gas. Isopropyl alcohol was mentioned as a
possible replacement. So there may be a change in ASHRAE 110 on the
horizon.

I learned from discussion with two fume hood testing professionals that the
major SF6 measuring instrument is no longer being manufactured or no longer
being supported, and certified testers are in a holding pattern and waiting
for the new standard and the potentially new equipment requirements that
could go with a change in tracer gas.

Regards,
Ed

Edward Chainani, Ph.D.
Assisitant Director for Safety
The Grainger College of Engineering Office of Safety University of Illinois
Urbana-Champaign
1308 W Green St
Urbana, IL 61801
Phone: (217)244-5594
Email: echaina2**At_Symbol_Here**illinois.edu
Web: http://officeofsafety.engineering.illinois.edu/

"Safety is a dynamic non-event; we have to work very hard so nothing will
happen." -James Reason

-----Original Message-----
From: ACS Division of Chemical Health and Safety On
Behalf Of Ralph Stuart
Sent: Friday, November 12, 2021 6:45 AM
To: DCHAS-L**At_Symbol_Here**Princeton.EDU
Subject: [DCHAS-L] SF6 fume hood certification

With COP 26 finishing up, those of us involved in assessing fume hood
performance are thinking (again) about the use of SF6 as a tracer gas in
fume hood evaluations (SF6 has 22,800 times the greenhouse gas potential of
CO2). With this in mind, I have a couple of questions for the list:

1. Have CHAS members investigated alternatives to testing every fume hood
using the ASHRAE 110 tracer gas test as written, using SF6 as the tracer
gas?

2. Has anyone changed their fume hood acceptance protocol to try to reduce
the amount of such tests that are conducted for climate impact mitigation
purposes?

3. Has anyone calculated the relative climate impact of doing a
commissioning test of a hood using SF6 relative to the lifetime climate
impact of the energy required by that hood?

My personal opinion is that the test as written was designed to address
specific design challenges associated with fume hoods when the standard was
written in 1985. And it is based on a rather stilted scenario (a single user
in a specific location with chemistry which is properly located in the
hood). In my experience, essentially all hood installations since 1990 were
designed and specified to pass that test and so additional 110 tests seldom
generate actionable information. I am curious if other CHAS members have
other experiences with this test?

Thanks for any information about these questions.

- Ralph

Ralph Stuart, CIH, CCHO
Environmental Safety Manager
Keene State College
603 358-2859

ralph.stuart**At_Symbol_Here**keene.edu

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