DCHAS-L Archives, Mar 20 2014 - Re: [DCHAS-L] Ductless fumehoods or Not.

From: Monona Rossol <actsnyc**At_Symbol_Here**cs.com>
Subject: Re: [DCHAS-L] Ductless fumehoods or Not.
Date: Thu, 20 Mar 2014 09:15:08 -0400
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: 8D112558CD8E61C-1838-2CA51**At_Symbol_Here**webmail-va047.sysops.aol.com
In-Reply-To

I struggled a full hour with my computer guru last night and we finally got it. So how smart was that? He costs $100/hour and I could have bought the standard for $42! But it's the principle of the thing. Besides, we make a lot of money here---at least it seems that way after living most of my life on the edge.

Kim Gates found the Appendix A statement before I did, bless her. It is:

A.8.4.1 Ductless chemical fume hoods that pass air from the hood interior through an adsorption 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.

=E3=80=80

It's nice to see the appendix still has the prohibition, but I also saw that there is no wiggle room in the standard itself, too.

=E3=80=80

8.3.1 Laboratory ventilation systems shall be designed to ensure that chemical fumes, vapors or gases originating from the laboratory shall not be recirculated.

8.3.2 [has rules about replacement fresh air]

=E3=80=80

8.4.1 Air exhausted from chemical fume hoods and other special local exhaut systems shall not be recirculated (See also 8.3.1.)

Note that 8.3.1 only talks about fumes, vapors and gases. Dusts are not covered. I find this a most interesting exclusion. But the A.8.4.1 talks about nuisance vapors and dust. I think this might be something for the NFPA 45 committee to look at for the 2015 standard. Does this mean I can recirculate toxic gases, mists or fumes in a ductless hood? Does this mean that dusts, mists and nanoparticles can be recirculated by laboratory ventilation systems? It could. I usually solve this problem when I write by referring to toxic or flammable contaminants or emissions. Other wise, you really have to say, each time, "gases, vapors, fumes, dusts and mists" to cover all the bases. And maybe even "nanoparticles" for good measure. And the definition of contaminants or emissions could be in the scope to make it iron clad.

=E3=80=80

8.4.2* Energy Exchange Devices [also tightens the noose. by referring again to 8.3.1 and 8.3.2. Then there is one section I will need to do some research on:]

=E3=80=80

8.4.2.2 Devices that could result in recirculation of exhaust air or exhausted contaminants shall not be used unless designed in accordance with section 4:10.1 "Non Laboratory Air," and section 4:10.2 "General Room Exhaust" of ANSI/AIHA Z 9.5 Laboratory Ventilation.

=E3=80=80

I will need to get a look at this ANSI/AIHA standard for the reason that the ACGIH clearly recommends against the heat wheel for Class 4 contaminated air--which clearly applies to fume hood exhaust and may also apply to laboratory air depending on what is done there. I can only hope this standard does the same. Until ACGIH came out with their heat wheel statement, I kept loosing the battle to keep these stupidly designed boondoggles out of the buildings I consulted on. And you can blame LEED.

If anyone out there has a copy of this Z 9.5 standard, I'd love to talk to you.

Monona: Would you post what you find? Thanks. Kevin Dr. Kevin M. Czerwinski, Ph.D. Professor Department of Chemistry University Chemical Hygiene Officer Environmental Health and Safety B150 Science Building University of Wisconsin-Stevens Point 2001 Fourth Avenue Stevens Point, WI 54481 715-346-4154 (Office) 715-340-2216 (Mobile)-- From: Monona Rossol <actsnyc**At_Symbol_Here**CS.COM<mailto:actsnyc**At_Symbol_Here**CS.COM>> Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU<mailto:DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>> Date: Wednesday, March 19, 2014 11:34 AM To: "DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU<mailto:DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>" <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU<mailto:DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>> Subject: Re: [DCHAS-L] Ductless fumehoods or Not. Oh, goody. I think I love you! Many thanks. And when I get time, I'll see if it is in the latest version also. Monona Rossol, M.S., M.F.A., Industrial Hygienist President: Arts, Crafts & Theater Safety, Inc. Safety Officer: Local USA829, IATSE 181 Thompson St., #23 New York, NY 10012 212-777-0062 actsnyc**At_Symbol_Here**cs.com<mailto:actsnyc**At_Symbol_Here**cs.com> www.artscraftstheatersafety.org<http://www.artscraftstheatersafety..org> -----Original Message----- From: Daniel Crowl <crowl**At_Symbol_Here**MTU.EDU<mailto:crowl**At_Symbol_Here**MTU.EDU>> To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU<mailto:DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>> Sent: Wed, Mar 19, 2014 12:22 pm Subject: Re: [DCHAS-L] Ductless fumehoods or Not. Look at this NIH policy document on ductless hoods. It is from 2005. That is where I got the NFPA reference for NFPA 45. It is section 6.4.1. http://www.ors.od.nih.gov/sr/dohs/Documents/DOHS%20Ductless%20Fume%20Hoods%20Review_2007.pdf Dan Crowl Michigan Tech On Tue, Mar 18, 2014 at 4:59 PM, Richard W. Denton <rwdenton3**At_Symbol_Here**gmail.com<mailto:rwdenton3**At_Symbol_Here**gmail.com>> wrote: Hi everyone: I was asked by my department to assist in deciding whether to purchase ductless fumehoods for our undergraduate chemistry labs. We are planning to use these for flammable solvents, and reactions involving HCl and NaOH. These hoods will be used by undergraduates for research also. Any input on the safety issues involved with these equipments versus the regular hoods would be appreciated. -Richard (CHO)

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