A collection of the off-line responses I've received in response to my inquiry yesterday (which should have been entitled "Fume Hood Sills" rather than "Fume Hood Sashes"). I agree with those who suggest it is a lab design as well as a user training issue. Unfortunately, it's hard to apply 21st century design practice to a 1970 building (which had several budget cuts during the design phase without a corresponding decrease in square footage)... Thanks to everyone who responded. - Ralph From: "Hadden, Susan [PRDUS]"
Date: July 11, 2006 5:11:39 PM EDT Subject: RE: [DCHAS-L] Fume hood sashes I work at a large pharma R&D site. I was a Discovery chemist for many years before joining the Safety department. In my experience, most chemists do not understand how their fume hoods work. (I know I did not.) A couple of articles in JCHAS about computational fluid dynamics a few years ago were very helpful to me and I have shared them with those chemists of ours who expressed interest. So, I think ignorance is the biggest reason coupled with wanting to the "get the job done" attitude. == From: Pat Ceas Date: July 11, 2006 5:14:13 PM EDT Subject: Re: [DCHAS-L] Fume hood sashes It is pure ignorance. They can not remove the air foils!! It is an integral part of the hood, and a serious safety issue since it will affect containment. Pat Ceas Chemical Hygiene Officer St. Olaf College Northfield, MN 55057 == From: Date: July 11, 2006 5:25:49 PM EDT Subject: FW: [DCHAS-L] Fume hood sashes I think this situation would be a good opportunity to do some research: I would be interested in seeing the results of an ASHRAE 110 test (including tracer gas) on some of these hoods with and again without the airfoils. I suspect that the hoods that pass with the airfoils in place might not pass with the airfoils removed. It would also be instructive to look at smoke introduced into the hoods; I suspect the turbulence will be visible without the airfoil. I think the removal of the airfoils shows ignorance on the part of the users. We include a good bit of information on hoods as part of our lab safety seminar, and our lab safety specialist discusses (and demonstrates) hood problems when she tests the hoods and does audits. Our people tend to strap cylinders beside the hoods. This means that the airfoils stay in place, the cylinders do not obstruct air flow into the hoods, and people have more room to work safely in the hoods. We don't have a lot of unauthorized modifications to hoods by lab personnel. Al Alton Simpson, CHMM, NRCC-CHO Director, Environmental Health and Safety The University of Memphis 216 Browning Hall Memphis, TN 38152-3340 (901) 678-4672 fax (901) 678-4673 == From: "matt" Date: July 11, 2006 6:00:21 PM EDT Subject: RE: [DCHAS-L] Fume hood sashes The laboratory fume hood is a piece of safety equipment. Users need to be trained in the correct use, maintenance, and testing of this equipment just like any other type of safety equipment. Modifications of any safety equipment by users to suit their convenience must never be allowed since these compromise the protective factors of the safety equipment. A quick trip through the Fischer safety catalogue should identify suitable cylinder stands and a few feet of flexible 1/8" stainless tubing will allow the lines to fit under the airfoil. Matt Schneider == From: John Nail Date: July 11, 2006 9:29:07 PM EDT Subject: Re: [DCHAS-L] Fume hood sashes Ignorance on the part of the user. He/She needs to use a gas in the hood and seeks the most convenient way of attaching the cylinder clamp. On new lab and lab remodels, it would be a good idea to design in a way to attach one or two tank clamps without removing the front air foils. At least be thankful that the occupants are securing the tanks! I found two unsecured He tanks in a reception room a few weeks ago. John John Nail Associate Professor and Department Chair Chemistry Department Oklahoma City University == From: "Peter Zavon" Date: July 11, 2006 10:24:33 PM EDT Subject: RE: [DCHAS-L] Fume hood sashes I would put it down to ignorance. Attaching a cylinder in front of a hood is like having a second person standing there all the time. It will have a severely adverse impact on the air flow patterns into the hood. In years gone by, the incidence of foil removal was not nearly so great. So I suspect something else has changed. Peter Zavon, CIH Penfield, NY PZAVON**At_Symbol_Here**Rochester.rr.com == From: Joe Passante Date: July 12, 2006 9:23:16 AM EDT Subject: Re: [DCHAS-L] Fume hood sashes Our new construction at Penn includes locations in the lab where cylinders can be secured and connected to copper tubing which feeds an inert specialty gas valve on the hood. That coupled with a vacuum pump cabinet frees up a lot of space in front of the hood. Modifying fume hoods is not a great idea. Air foils smooth out turbulent flow or back flow out of the hood. -- Joseph R Passante, CIH, CHO Industrial Hygiene Manager Environmental Health & Radiation Safety University of Pennsylvania 215.746-6550 215-898-0140 (F) 215-651-0554 (M) == From: Jennifer Minogue Date: July 12, 2006 10:05:42 AM EDT Subject: Re: [DCHAS-L] Fume hood sashes Re removal of air foils 1. Ignorance of the users tops the lists. Most wouldn't know what an airfoil is much less what it does. 2. Bad lab design - no place to put the cylinders next to the fume hood. This really bugs me because they end up in the aisle space. Why not make an alcove? Why this feeling that every piece of wall space needs a bench, cupboards, or desk. This is why garbage cans end up as tripping hazards - no one made space for them when the labs were designed. Cheers -- Jennifer Minogue Biosafety Officer Environmental Health and Safety University of Guelph Guelph, Ontario N1G 2W1 Canada Voice 519-824-4120-x53190 Fax 519-824-0364 == From: "Michael Kleinman" Date: July 12, 2006 12:44:04 PM EDT Subject: RE: [DCHAS-L] Fume hood sashes Aren't most fume hoods operated with the sash open such that the flow is regulated to a nominal flow depending on the type of use? Also it is required (at least in CA) to chain cylinders at the top and the bottom. Mike Kleinman == From: "William Parks" Date: July 11, 2006 6:07:51 PM EDT Subject: Fume Hood Sashes Possibly just ignorance..........and yet..........................the sashes were not posted do not use????? The lab supervisor notified???? A written report made to the CHO?????? I did all three.......and the success rate was 100%. As a staff industrial hygienist, once was all it took. Bill Parks R.P.I.H. CHEMPHYXX 877/402-6609 479/685-9343 == From: "Victor Neuman" Date: July 12, 2006 1:52:55 AM EDT To: rstuart**At_Symbol_Here**UVM.EDU, DCHAS-L**At_Symbol_Here**LIST.UVM.EDU Subject: RE: Fume hood sashes Except for those few fume hoods which are designed to operate without an airfoil, 80%+ of fume hoods work really badly with their airfoil removed. After testing hundreds of fume hoods both ways, removing the airfoil is a good way to make your fume hood leak. Best Regards, Victor Neuman Professional Engineer Cell: (619) 865-8235
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