QUOTE: We are looking to renovate a Genetics teaching lab that has the students using ethyl ether to put fruit flies asleep. This is a common method of doing this, put certainly has its drawbacks when you consider the ventilation strategy (ether vapor is very heavy).
I'm wondering if anyone has been successful in having 12-14 student stations using this chemical in a teaching setting (on the bench) and keeping the exposures and smell down? Keeping in mind that fruit flies will get sucked up into local exhaust if they are too close!-
In addition to floor level exhaust diffusers, what else would you recommend and how many air exchanges for the room? END QUOTE
Aw geez. Guys. Can we please not think this way? A vapor at room temperature, even a REALLY heavy one like mercury, will diffuse in all directions. It's why we can sample the air above a drain to determine if mercury was spilled in it. When ethyl ether evaporates, it takes so many calories that the vapor is cold and dense. It is not at room temp, and will go down -- for a very short distance before it attains room temperature and now it diffuses in all directions with the objective of filling the room to an even concentration.
The ONLY place for local exhaust ventilation is as near to the source as you can get it. Once it gets loose in the lab, the only control is the number of air exchanges in the room to slowly reduce the concentration. And since ASHRAE has unfortunately gotten into the ACGIH territory of industrial ventilation, most labs do not have adequate dilution ventilation for any open bench work.. Those rates are dependent on the TLVs, evaporation rates and other physical constants for the chemicals used on the open benches, not some ASHRAE lab standard rate set to make building owners happy by saving energy and designers happy by making their lives simple -- wrong, but simple.
Well --- l probably did no good thing here, but at least I feel better. And now I'm going to remind you that one of the art buildings I worked on which is full of ventilation systems for open processes won the AIA Committee on the Environment (COTE) award and I got a design award from the Boston Society of Architects for my work on Duke Hall at James Madison U, both in 2016. I'm not just flapping my lip here.
Here's the formula:
403 = volume of pt at STP
cfm/pt = 403 x 106 x SG x ER SG = specific gravity
MW x TLV ER = evaporation rate in pints/minute
MW= molecular weight
TLV= Threshold Limit Value
Figure out the how much ethyl ether could be used by the 12/14 students at one time, get the physical data for the ethyl ether and run the numbers. Then figure that students are not workers and the TLV is not protective enough and raise the rate by about 10 times
Then figure out what other folly you may intend to do on open benches and see what kind of dilution ventilation would be needed for each. Betcha when you are done, you will select a better fruit-fly murder weapon.
Monona
-----Original Message-----
From: Margaret Rakas <mrakas**At_Symbol_Here**SMITH.EDU>
To: DCHAS-L <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Sent: Wed, Feb 5, 2020 5:55 am
Subject: Re: [DCHAS-L] ether for anesthetizing fruit flies
Monona-
I think this is a situation where the various federal agencies may have varying points of view, some of them quite in opposition to the other. I also wonder if the EPA folks were aware of regulations promulgated by USDA and other agencies involved in animal research, and/or how the question was posed.
If you're killing flies, or rats, or garden slugs because they are pests- invading your home/office/workplace then yes I agree that a registered pesticide is what is legal and required.
But these fruit flies-or genetically modified rodents, or zebra fish used in research-are not being destroyed because they are pests- they are being euthanized for study. The means of euthanasia must not only inflict minimal to no pain (generally), it must also not affect the property being studied, whether that's neural development, the effect of various viral vectors carrying gene modifying units, or whatever. I can=E2=80™t imagine that a registered pesticide used expressly to euthanize animals for scientific research would be in compliance with either requirement. Moreover, if the institution received research funding from USDA or other related agencies, it would be in violation of federal animal welfare regulations.
So- my two cents on the original question is, we use "fly nap" in a fume hood. That's a combination of triethyamine, methanol and isopropyl alcohol-still flammable, maybe somewhat less so than ether, but I may suggest to our folks they try triethylamine by itself or the device w/alka-seltzer tablets. Ether just seems like more trouble than it's worth when there are less hazardous substances..
Good luck with this project (can you at least have them add a fume hood or 2 if they insist on sticking with diethyl ether?)
Margaret
Sent from my iPhone
On Feb 4, 2020, at 9:33 PM, Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**lists.princeton.edu> wrote:
=EF=BB=BF
oooow. How interesting. The natural history museums also commonly use inert gases or chemicals that are oxygen scavengers for killing critters in containers.
However, we recently posed the issue of these practices to the EPA pest people, and found that as soon as you intend to kill a critter, you need to be using a pesticide registered for the purpose. So I suggest you use one of the products mentioned on this thread registered for the purpose.
It's not a good practice to teach students to break the law, however small the offence.
Monona
-----Original Message-----
From: Jeff <jtenney46**At_Symbol_Here**ATT.NET>
To: DCHAS-L <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Sent: Tue, Feb 4, 2020 9:09 pm
Subject: Re: [DCHAS-L] ether for anesthetizing fruit flies
Finn Scientific has a Carbon Dioxide Drosophila Anesthetizer.. Uses an alka-seltzer tablet.
Sent from
Mail for Windows 10
Hi everyone,
We are looking to renovate a Genetics teaching lab that has the students using ethyl ether to put fruit flies asleep. This is a common method of doing this, put certainly has its drawbacks when you consider the ventilation strategy (ether vapor is very heavy).
I'm wondering if anyone has been successful in having 12-14 student stations using this chemical in a teaching setting (on the bench) and keeping the exposures and smell down? Keeping in mind that fruit flies will get sucked up into local exhaust if they are too close!-
In addition to floor level exhaust diffusers, what else would you recommend and how many air exchanges for the room?
Thanks!
Ellen
P.S. I'm pushing for CO2, but may not get what I want.
Ellen Sweet
Laboratory Ventilation Specialist
Department of Environmental Health and Safety, Cornell University
American Chemical Society, Division of Chemical Health and Safety
315-730-8896
---
For more information about the DCHAS-L e-mail list, contact the Divisional membership chair at
membership**At_Symbol_Here**dchas.org
Follow us on Twitter **At_Symbol_Here**acsdchas
