Date: Thu, 1 Jun 2006 11:07:48 -0400
Reply-To: Mark Tinsley <mtinsley**At_Symbol_Here**LASARCHITECT.COM>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Mark Tinsley <mtinsley**At_Symbol_Here**LASARCHITECT.COM>
Subject: Re: Hood Sash question
Comments: To: Debbie Decker

You asked: Has anyone out there [here on this list ;~)] prohibited horizontal sashes or have justifiable pros for having them? Horizontal sashes, under certain situations, can offer operating cost (energy) savings. They follow the same model as some of the newly advertised 'Low Flow' fume hoods. The low flow fume hoods fall into two categories, each offering lower energy costs: those that lower the face velocity, and those that maintain the face velocity (at or near 100 FPM) but limit the opening area. Horizontal sash fume hoods (or combination sash) fall under the latter category, that is they can offer energy savings by limiting the open face area of the hood when used in this way. Keep in mind that anyone reaching for operating cost savings by using any volume reduction technology, such as variable-volume fume hoods or either category of 'low flow' hood, must judge the situation carefully, as the driver for exhaust volume for most labs with hoods is the air change rate, which is a function of the lab volume and exhaust function (hoods, canopies, snorkels) density. You can invest a great deal of money in these technologies, only to find that you cannot lower the exhaust volume (and save energy) because you would be breaching the required air change rate (occupied or unoccupied) that has been determined for the lab (or the cooling load, which may drive the low exhaust volume limit). Complicated, but it is a lab-to-lab judgement. -----Original Message----- From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**LIST.UVM.EDU] On Behalf Of Debbie Decker Sent: Wednesday, May 31, 2006 7:18 PM To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU Subject: Re: [DCHAS-L] Hood Sash question Kerry: I have successfully (mostly) banned horizontal sliding sashes in favor of vertical rising sashes. I use the following reasons: The researchers will never work with their arms around the horizontal sash - they will shove the sash out of the way and work directly in front of the diethyl death they have burbling away, with nothing between them and their goop but air. A vertical rising sash prevents researchers from diving head-first into their hoods. With the sash at 18", they bonk their heads on the sash and figure out a different way to work without climbing into the hood . The combo sashes are marketed as providing energy savings because they limit the hood opening. The combo sashes are also more expensive. A vertical rising sash, set at 18" with limits on lab airchange rate, a variable air volume lab airflow control system and good sash management (pull the thing down when not in use) can achieve similar levels of energy savings. Since you're not located in California, you can take advantage of energy savings using the lower flow fume hoods - 80 fpm or so. My project managers and design professionals have bought into the vertical sashes and the researchers understand that the vertical sash can protect them. I haven't had much resistance. Hope this helps, Debbie ------------------ Debbie M. Decker, Campus Chemical Hygiene Officer Environmental Health and Safety University of California, Davis 1 Shields Ave. Davis, CA 95616 (530)754-7964/(530)752-4527 (FAX) dmdecker**At_Symbol_Here** Co-Conspirator to Make the World A Better Place -- Visit and join the conspiracy -----Original Message---- From: "Kerry Smith" Date: May 30, 2006 6:25:24 PM EDT (CA) Subject: Hood Sash question We are selecting hoods for several lab remodels. The architects have already specified combination horizontal/vertical sashes. My experience with hood users has given me a less than positive desire for horizontal sashes. Has anyone out there [here on this list ;~)] prohibited horizontal sashes or have justifiable pros for having them. Thanks Kerry J. Smith, CIH Senior Industrial Hygienist BYU Risk Management & Safety Dept. T 801-422-2943 F 801-422-0711

Previous post   |  Top of Page   |   Next post

The content of this page reflects the personal opinion(s) of the author(s) only, not the American Chemical Society, ILPI, Safety Emporium, or any other party. Use of any information on this page is at the reader's own risk. Unauthorized reproduction of these materials is prohibited. Send questions/comments about the archive to
The maintenance and hosting of the DCHAS-L archive is provided through the generous support of Safety Emporium.