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Previous by Date: Subject: Re: [DCHAS-L] Chemical Fume Hood Evaluation Form Date: Thursday, November 20, 2014 1:07:15 PM Author: Debbie M. Decker <dmdecker**At_Symbol_Here**UCDAVIS.EDU> |
Next by Date: Subject: Re: [DCHAS-L] Chemical Fume Hood Evaluation Form Date: Fri, 21 Nov 2014 01:52:12 +0000 Author: Naomi Kelly |
Wayne,
I would never accept a fume hood that has been significantly modified (new
installation, major repair or any repair that would adjust the airflow
volume) without an ASHRAE 110 test, with EHS qualifications.
The EHS qualifications would include:
1. Ensuring an adequate exhaust flow rate. A higher rate is required for
those operations generating a large volume of contaminants, for example I
have one hood that is used with ~20L Acetone with large amounts of dry ice
to freeze specimens for QWBA. Conversely, if the hood can/will only be used
for low volume generating activities, it is possible to pass an ASHRAE 110
at the 4 lpm sulfur hexafluoride generation rate at a lower hood air flow
which is also acceptable. (Note: If this criteria can be met, it is usually
preferable to reduce the hoods annual operating costs - but the scientists
must be made aware of the limitations and the requirement for EHS to buy off
on any other operation generating different air contaminant generation
rates. Communication, training and expectations must be clear.)
2. The ASHRAE 110 test is critical to ensure the hoods are performing as
installed (FYI, they are all designed to standards... with the manufacturers
validation testing performed in pristine conditions.) Experience shows that
as installed hoods have required up to FIVE attempts (with
modifications/repairs made between each) to prove that the hood will indeed
work as reported AND tested by the manufacturer in those pristine
conditions.
3. Add a turbulence intensity performance test to the ASHRAE 110 testing
profile to ensure that you are indeed maintaining proper airflow, but give
yourself, as an EHS professional, room to waive or modify this requirement.
I have run into unacceptable situations where large, flat, or solid lab
apparatuses was placed directly on the bottom of the fume hood's work
surface impairing the air flow and requiring minor to major modifications;
while I have had to modify the performance specification (while still being
able to show adequate containment) for lead radiation shielding that was
required to limit personnel radiation exposures. But, that is why we have
to access and perform our risk assessment. In most cases of unacceptable
laboratory apparatus setup, I have found that that the scientist typically
did not consider the impact upon the airflow or fume hood performance.
Normally I would never endorse anyone on this list and I don't know your
physical location. But, based upon this discussion thread, I would
recommend a consultation with Dale T. Hitchings, of SAFELAB, Inc. located in
Indianapolis, Indiana available at 317-872-6600. (See
http://www.safelab.com.) I have done some pretty extensive research, after
which I had him added him as a new vendor for my current employer. Although
I have not had to use him yet. I have spoken with him on the phone, but I
have never actually met Dale, nor have I used his services up to this point.
But, I think he would be the best and most knowledgeable source to provide
you with advice more sound than mine.
Good Luck,
Bruce
-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of
Wayne Wood
Sent: Thursday, November 20, 2014 8:48 AM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: Re: [DCHAS-L] Chemical Fume Hood Evaluation Form
Thank you for the references and wise advice, Bruce. I agree 100% with your
recommendation about linking periodic evaluations to the designed
performance test - given the variations in face velocity that have been
shown to be acceptable we don't really have a choice.
The question I am wrestling with now is whether factory containment tests
are adequate or whether we have to do field containment tests like ASHRAE
110 at the time of hood commissioning.
W.
-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of
Bruce Van Scoy
Sent: Wednesday, November 19, 2014 6:13 PM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: Re: [DCHAS-L] Chemical Fume Hood Evaluation Form
W.,
I am not familiar with a comprehensive standardized form for the evaluation
of chemical fume hoods.
Some of the better guidance that I have found is available at the two links
listed below.
I would strongly recommend that the designed performance specifications be
specified initially with the periodic evaluations completed to verify that
the hoods are actually performing as designed. My personal experience is
that inadvertent maintenance or user activities have negatively affected the
routine performance requirements, usually due to the maintenance worker or
employee not realizing the impact of seemingly "minor" modifications. I
like using smoke tubes to educate employees on the impacts and results of
these "seemingly minor modifications" with verbal coverage of what needs to
be obtained/maintained. We can't be in every lab all of the time and I've
had good results of laboratory workers recognizing potential hazards and
getting EHS involved when they are not sure based upon these practices, once
they have been educated.
Please see:
http://orf.od.nih.gov/PoliciesAndGuidelines/Bioenvironmental/Documents/SECTI
ON15991CONSTANTVOLUMEJune2007_508.pdf
http://orf.od.nih.gov/PoliciesAndGuidelines/Bioenvironmental/Documents/SECTI
ON15992VARIABLEVOLUMEJune2007_508.pdf
My $0.02 - based upon numerous negative/positive trials and errors over the
years!
Bruce
-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of
Wayne Wood
Sent: Wednesday, November 19, 2014 4:26 PM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: Re: [DCHAS-L] Chemical Fume Hood Evaluation Form
Smart people ask good questions. Good questions, Ralph.
Ralph, I was looking mainly for a basic chemical fume hood evaluation and
inspection checklist which could be used by an EHS technician once or twice
a year but you and Kim Gates, who replied privately, have expanded my
horizon somewhat.
You asked:
What aspect of a fume hood are you interested in evaluating:
- the design of the hood itself
I wasn't thinking of that but Kim got me interested in a commissioning
checklist. It would be hard to do periodic evaluations without data on
commissioning, such as the performance specs at the time of installation.
- its containment?
ASHRAE 110 appears to be the way to go, this is something that would fit
well in a commissioning checklist.
- how it's being used?
Yes, insofar as we would want to identify uses that compromise the hood;s
operation, like clutter and or heat or other turbulence-generating
activities.
- whether it's operating as designed relative to the general ventilation
system in the lab?
That would be more difficult to check. I won't pretend that is something we
systematically follow up on in my institutions; I'm curious to know what
others are doing?
I think that these would require distinct forms?
Yes, and in some cases the persons completing the forms might need different
competencies as well.
W.
- Ralph
Ralph Stuart, CIH, CCHO
Chemical Hygiene Officer
Keene State College
ralph.stuart**At_Symbol_Here**keene.edu
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