Mary Ellen, Listen to Kay. This is one way to use a makeup unit to fix the problem that we talked abut. And diffusing it through the ceiling tiles is a good method of distributing the additional make up air. This is not rocket science. If they want to fix this, they can in short order.

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: Rita Kay Calhoun <r.calhoun**At_Symbol_Here**MOREHEADSTATE.EDU>
To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>

Sent: Mon, Apr 29, 2013 12:08 pm
Subject: Re: [DCHAS-L] Chemistry Fume Hood Experience

Mary Ellen,

When they built our new labs they discovered that the amount of supply air coming through the diffusers (or whatever they're called) was insufficient. The solution was to replace many of the ceiling tiles with open grate type tiles and pump supply air into the ceiling space. This has solved that problem. By the way, we didn't have alarm problems; we had "air flow from the hoods into the room" problems. It was noticed when we were doing a Cu/S experiment. You can always count on SO₂ to let you know when it's not where it's supposed to be. The most interesting part was that the display still read 100lfm, even when the flow was 100lfm into the lab!

Kay

From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of Mary Ellen A Scott
Sent: Monday, April 29, 2013 10:47 AM
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
Subject: Re: [DCHAS-L] Chemistry Fume Hood Experience

The biggest issue we have is supply air or lack there of. At least all are VAV hoods go into alarm so much that the students just put paper in the MUTE button. We seem to have created a cry wolf situation.