From: Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**LISTS.PRINCETON.EDU>
Subject: Re: [DCHAS-L] ether for anesthetizing fruit flies
Date: Thu, 6 Feb 2020 17:52:32 +0000
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: 439515222.428655.1581011552360**At_Symbol_Here**
In-Reply-To <66E3C074-2886-41A1-BAAB-6B3ED1427F74**At_Symbol_Here**>

That's the problem I wrote about.  HVAC people usually can't do this or don't do it well.  And the problems with doing it right are legion.  For example, someone suggested a slot vent at the back of each bench.  In order to draw the length of the bench, they are going to need a somewhere between 1000 and 2000 fi/m slot face velocities and either partial enclosure at the back of the table or three slots to accommodate the diffusion by evaporation of solvents on the bench.  We are already into a lot of custom metal work and sight line problems for the instructor in the class.

So these slots have to draw a lot of air, and with 12 to 14 students in the room that will be gassing fruit flies, even if you branch duct 6 slot hoods together and have a centerline velocity of 3000 f/m in the duct to cut down on diameter, you are looking at finding a chase to the roof for two ducts that are probably 20 inches in diameter or more.  Add that to the fume hood ducts that also need to go to the roof and you have a major chase design issue.  Say nothing about energy cost for heating and cooling.

And in my other email, I provided the basic formula for doing it by dilution ventilation and that also requires a lot of air and energy.  

A laboratory in which there is bench work CANNOT be designed until the users tell the designers exactly what they intend to do on those benches and with what chemicals.  There is no ASHRAE lab one-size-fits all as soon as bench work is done.  And using solvents of any kind on open benches is going to be expensive.  Fine with me --- I get paid for working out a good hood for the proposed work and the specs for the engineers who do the system.  

But clearly, if you can kill critters other ways and don't do it, you sure aren't part of the green revolution.


-----Original Message-----
From: Stuart, Ralph <Ralph.Stuart**At_Symbol_Here**KEENE.EDU>
Sent: Thu, Feb 6, 2020 7:59 am
Subject: Re: [DCHAS-L] ether for anesthetizing fruit flies

> >Avoid using hazardous chemicals for such a task.
While this is a reasonable response, as has been demonstrated by the many posts about the disadvantages of ethyl ether and possible alternatives, I know that this particular teaching lab has been doing this work with ethyl ether for at least 40 years. The use of ethyl ether has been discussed by many generations of lab instructors with many generations of EHS professionals (including me).

The fact that the use of ether persists suggests that it would be prudent to design the lab ventilation system to manage ether. Even if the next generation of lab instructors decide to move to a different agent, it's possible that the one after that will return to ether. There are few EHS staff that have the authority to force specific changes on managers of lab processes.

- Ralph

Ralph Stuart, CIH, CCHO
Environmental Safety Manager
Keene State College
603 358-2859


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