From: Monona Rossol <0000030664c37427-dmarc-request**At_Symbol_Here**LISTS.PRINCETON.EDU>
Subject: Re: [DCHAS-L] Fume Hood Ducting
Date: Mon, 16 Oct 2017 13:26:29 -0400
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: 15f2638f974-c08-29f04**At_Symbol_Here**webjas-vaa010.srv.aolmail.net


Maintaining the pumps sounds like a way to fix the problem if these pumps are the only source of  oily substances.  It might be that some of you work with processes that involve heating of a high molecular weight hydrocarbon oils, fatty acids or similar substances.  And I have the same concern for generation of particulates of certain sizes.


If you are only doing processes that generate gas and vapor contaminants that don't recondense into mists or liquid in ductwork and no particulates that require higher transport velocities, the HVAC kind of engineering I see should suffice.  

The principle here is that the fan and the ductwork must be designed to fit the nature of the contaminants.  There is no one-size-fits-all.  In fact, I'd really like a peek at your centrifugal fans.  I'm betting they are energy-efficient ones with airfoil blades rather than the less efficient fans with backward inclined blades that clean themselves of contaminants.  And if I'm right, you people with the oil leaks should get up on the roof and make sure there isn't oil deposition and a potential fire hazard at or near the fans. 


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   www.artscraftstheatersafety.org

 


-----Original Message-----
From: Stephen M. Elwood <selwood**At_Symbol_Here**PRINCETON.EDU>
To: DCHAS-L <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Sent: Mon, Oct 16, 2017 7:24 am
Subject: Re: [DCHAS-L] Fume Hood Ducting

Not adding anything new here, except to concur with the point made by Jim on use and maintenance of oil =E2=80=98mist' separators and filters on vacuum pump  exhaust.

We have been dealing with this very same issue in our engineering buildings and believe we have a consensus on the source - poorly maintained vacuum pumps.

In some cases the filters had not been installed or had been removed.  In most other cases the filters had not been properly maintained.

There is also the issue of responsibility for periodic maintenance of pump exhaust filtration; researchers feel it is a building maintenance responsibility and the facility groups the opposite.

Stephen Elwood
Associate Director

On Oct 12, 2017, at 5:33 PM, Jim Doughty <jdoughty**At_Symbol_Here**MIT.EDU> wrote:

As a further note I would ask if your researchers are using oil most filters, and if so are they being maintained? The most common we have,BOC Edwards, need to be periodically drained (there is drain plug in the side). If the oil reaches a certain level the oil most will blow by the filter and not filter at all. 

Jim

Sent from my iPhone

On Oct 12, 2017, at 5:29 PM, Jim Doughty <jdoughty**At_Symbol_Here**MIT.EDU> wrote:

Hello,

We experienced this in our Chemistry Department; however, we believed it to be from vacuum pumps and the likely culprit were those pumps that had hard connections to their exhaust duct. A better setup is to insert the vacuum pump hose into the duct and let room air flush the duct out continuously. Hard connections are frequently made unintentionally when some tries to figure out how to keep the hose from falling out of the duct and then duct tapes over the whole thing or similar. This was particularly noteable in our labs with a high glove box density.

Hope that helps.

Jim Doughty
MIT

Sent from my iPhone

On Oct 12, 2017, at 4:46 PM, Elizabeth Brubaker <ebrubaker**At_Symbol_Here**MURRAYSTATE.EDU> wrote:

Has anyone experienced accumulation of oil (perhaps mineral oil from a heated oil bath?) in fume hood duct work? Is this reasonable or even possible? Could a sufficient amount remain in the system for it to condense out in the ducts when the exhaust fans were turned off for an extended period?

--
Beth Brubaker
Laboratory/Safety/Waste Coordinator
Murray State University Department of Chemistry
2226 Jesse D. Jones Hall
Murray, KY  42071-3300
(270) 809-6390
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