Date: Sat, 28 Aug 2010 14:33:12 -0400
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From: Don Abramowitz <dabramow**At_Symbol_Here**BRYNMAWR.EDU>
Subject: Re: Hoods failing annual calibration
In-Reply-To: <6AD6E0EF87C9E14E97A1A3DB9181A3B33ECFA41E**At_Symbol_Here**usvfmbx02>
< div style='font-family: Times New Roman; font-size: 12pt; color: #000000' >Pat,

You raise an interesting question, and thus far, replies have focused on restoring the hood to its performance criteria.  Seems you are asking more about whether and how one would evaluate the potential exp osures to hood users who may have been inadvertently exposed to chemicals a s a result of  having been operating a hood outside of its intended pe rformance specs.

Seems there's an ethical component here about discl osure to users, and a technical question of assessing the potential exposur es that may have occurred.  Both are difficult questions, and they req uire a lot of specific information about the particular circumstances invol ved.  

It would be difficult to correlate face velocity w ith exposure.  A 40% drop in face velocity does not mean 40% more expo sure.  You'd probably need to do some sort of simulation to attempt to model the exposures. 

It's also important to consider what ma terials were handled in the hood.  If you were working with relatively low-toxicity-but-irritating or odorous materials (something like acetic ac id comes to mind), and no one noticed any effects or odors, you might concl ude there was little or no impact.   At the other end of the spec trum, biological monitoring and/or medical evaluation/surveillance could be indicated for highly toxic substances that tend to bio-accumulate.  C hances are your particular circumstances fall somewhere in between, and all you can do is try make thoughtful decisions based on the information and i ndividuals involved. 

                   & nbsp;                       Don

Donald Abramowitz
Environmental Health & ; Safety Officer
Bryn Mawr College
Bryn Mawr, PA

I work in a GMP laboratory in the medical device ind ustry.  A member of our metrology team questioned me today as to what we would do in event one of our chemical fume hoods did not meet one or mor e of its annual qualification events, for example if the hood did not meet its face velocity requirement during the annual test.  We do have monitors on our hoods, but occasionally they have been found to be faulty.


According to our work instructions, any "ins trument=" which does not meet any of its qualification events must h ave an impact assessment done.  Usually this relates to the impact the failure may have had on the results of tests that were done using the instrument.  But in this case we would be talking abou t a safety impact assessment rather than focusing on the results of tests.& nbsp; The metrology member also mentioned to me that we should, according t o our work instruction, have a usage log for each hood so that a proper impact assessment could be done. 


My thoughts are this:

I would not call a chemical fume hood an "in strument=" and therefore would not consider it subject to the previo usly mentioned work instruction

I have never heard of any facility having a usage lo gbook for chemical fume hoods


BUT=E2=80=A6 the question I really want to ask the g roup is this:  in the event a hood fails any of its annual calibration events, what do you do?   Do you speak to people who have been u sing the hood, prepare an impact assessment, etc.?



Pat Peifer

Health, Safety and Training Team Leader

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