Date: Fri, 29 Apr 2005 14:08:18 -0400
Reply-To: Ralph Stuart <rstuart**At_Symbol_Here**>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Ralph Stuart <rstuart**At_Symbol_Here**>
Subject: Replies to Ductless fume hoods policy?

Based on the responses summarized below, I think that my conservative
inclination with regard to ductless fume hoods is generally shared,
although it sounds like there are some potential uses out there. I
think that
Monona Rossol's suggestion of collecting more data (and submitting a
paper to the CHAS Journal) is a good one.

Thanks to everyone who replied.

- Ralph

Subject: FW: Ductless fume hoods policy?
Date: Thu, 28 Apr 2005 13:17:02 -0400
From: "Reinhardt, Peter \(Environment Health and Safety\)"

I think a ductless fume hood would be OK only when
handling fine particles and turbulence is not permissible. -- Pete

Date: Thu, 28 Apr 2005 12:33:40 -0500
From: Alton Simpson 
Organization: The University of Memphis

Our Chemical Hygiene Plan says, "Ductless hoods are considered
unsuitable for materials other than nuisance vapors and dusts which
do not present fire or toxicity hazards."  Our radiation safety
committee, however, does allow approved ductless hoods equipped with
carbon filter for use in I-125 labeling.


Alton Simpson, CHMM
Director, Environmental Health and Safety
The University of Memphis

Date:         Thu, 28 Apr 2005 13:34:44 -0400
From: "Wawzyniecki Jr, Stefan" 
Subject: Re: Ductless fume hoods policy?

We do not allow them for the following reasons:

1. No way of enforcing the "no more than 50cc of a solvent" dispensing rule

2. Solvents such as methylene chloride are not captured efficiently

3. Usually a maintenance program for scheduled replacement of the
filters is not established and / or followed

4.  Departments may use the excuse that they can't afford replacement
filters,  and Facilities will claim that replacements don't come out
of their budget either.

5. Monitoring of the exhaust is usually not done, and it is an added
cost as well.

-Stefan Wawzyniecki

Date: Thu, 28 Apr 2005
From: "David D Lee" 

Inquiring minds?  Or someone who's looking for a way around the
current policy?  Why not just use a normally exhausted lab hood in
the first place?  Or are they trying to avoid the expense of
installing one?  I'm just curious. Personally, I have no use for
ductless hoods.

David D. Lee, MIS, CIH, CSP
Safety Specialist
University of Nevada, Reno
EH&S Dept/MS 328
Reno, NV 89557

Date: Thu, 28 Apr 2005 14:03:58 -0400
From: "Margaret Rakas" 
Subject: Re: [DCHAS-L] Ductless fume hoods policy?

I have, and would, fight tooth and nail against having them.  First,
charcoal filters will preferentially absorb and desorb various
solvents; you can't quite know what you're capturing and what you
aren't.  And manufacturer change-out recommendations?  Forget it,
they aren't going to touch that issue and you're flying blind.
Lastly, when has anyone ever bought a hood (other than hopefully a
perchloric acid hood) to just use for one or two chemicals?  Even if
the intentions are there and pure at the beginning, suddenly an idea
takes off and whoosh!  So my only policy (which might not help much)
is "Let's find a better way to do this."  I would be very  interested
in the results if anyone has done vapor absorption and/or air
sampling for these types of devices; data would be extremely helpful
in establishing policies but I haven't found any.

The above are my personal opinions only.


Margaret A. Rakas, Ph.D.
Manager, Inventory & Regulatory Affairs
Clark Science Center
Smith College

Date: Thu, 28 Apr 2005 14:04:08 -0400
From: "Haugen, Bob" 

SEFA 1 is beginning to look at this area, but most people who design
hoods, like me, use a slightly modified saying:
"Keep your friends close, and give your enemies ductless fume hoods."

Dr. Bob Haugen

From: "George H. Wahl, Jr." 
Subject: Re: Ductless fume hoods policy?


Our new teaching labs have them on the desk top, as well as "normal"
6-8' hoods along one wall.  Since we're also using "Micro Scale" we
have no policy of which I'm aware.   I'm copying our Lab Director to
see if she has ever stated a "policy" on the matter.

Any suggestions of folks I might harass to get a few more speakers on
"Teaching Safety" for DC mtg?  We're looking for folks who are trying
new approaches; or may have recently done an evaluation of what they
have been doing.  Could also be some new software, or applications of
software to Safety instruction.

Just digging!


From: Robert R Mako 
Date: Thu, 28 Apr 2005 15:30:29 -0700

We also avoid them, but have used them based on need, capture efficiency,
filter life, and ability to establish a reliable PM process.

Bob Mako, CIH, CSP
EHS Manager
Goleta, CA

From: Harry J. Elston
Date: Thu, 28 Apr 2005


Talk with Lou DiBerardinis at MIT.  I was a complete anti-ductless
guy not so long ago, but after speaking with Lou and Doug Walters, I
can see some useful applications.  His e-mail is:  louDiB**At_Symbol_Here**



Harry J. Elston, Ph.D., CIH
Principal - Midwest Chemical Safety

Editor, Chemical Health & Safety

From: "Bob Peck" 
Subject: RE: [DCHAS-L] Ductless fume hoods policy?
Date: Thu, 28 Apr 2005 22:08:05 -0500

Unless you are using an absorbent bed with a service life indicator
specific to the liquid/vapor being used, a ductless hood should only be
used for dusts that don't sublime.  Use of any volatile material with
this type hood should be gauged by room air changes, with the
understanding that you are contaminating the run air by the process you
run.  That is generally a very bad idea from a personnel exposure point
of view!

Bob Peck
Eagle's Rest Consulting Services, LLC

Date: Fri, 29 Apr 2005 12:17:27 -0400
From: mark.kidd**At_Symbol_Here**
Subject: Re: Ductless fume hoods policy?

In NFPA 45, "Fire Protection for Laboratories Using Chemicals," A.6.4.1:

"Ductless laboratory hoods that pass air from the hood interior
through an absorption filter and then discharge the air into the
laboratory are only applicable for use with nuisance vapors and dusts
that do not present a fire or toxicity hazard."

I think acetone pouring would not be allowed in a ductless fumehood.

Mark Kidd
Chemical Hygiene Officer
Savannah River National Laboratory
Telephone:   803.725.4576
Fax:  803.725.1660
Email:  mark.kidd**At_Symbol_Here**

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