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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