I agree with all that Harry has said. We used ductless hoods extensively when weighing particulate actives. We never used them when solvents were involved. Period. Bob Alaimo -----Original Message----- From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**LIST.UVM.EDU] On Behalf Of Harry Elston Sent: Saturday, July 07, 2007 10:54 AM To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU Subject: Re: [DCHAS-L] Ductless Fume Hood - need information Generally speaking, Melissa, I am not a big fan of "ductless hoods" primarily for the reason that Jim Kaufman mentions in his post, "...when used properly." Ductless hoods rely on filtration technology to remove contaminants that are generated in the hood, be they an acid vapor, solvent vapors or particulate. The problem that I've run into the most regarding ductless technology is user discipline. When used in a research environment researchers tend to focus on research instead of safe use of engineered systems like hoods. For example, a researcher will substitute solvents in a hood without giving a second thought that the absorbing material (i.e. filter) has a higher affinity for the new solvent than the old, and therefore release some portion of the previously filtered material. If you want a hard-core chemistry example, think "ion-exchange chromotography." It's the same principle. The other problem is going to be who is going to monitor the system to ensure that the filters are still working? Will it be you? Do you have the right training and technology to do that? What will be the filtration change-out schedule? How do you know that whatever you pick will be safe and effective? Are you going to perform periodic air monitoring to ensure that the filters are still working? Jim Kaufman is absolutely correct that ductless technology can be a good substitute for ducted hoods with the all important caveat - when used properly. Ducted hoods, when working correctly are much more "chemist-proof" and generally speaking provide fewer headaches (figuratively and literally) for the user or supervisor. Harry > ------------------------------------------------------------------- >In a message dated 7/6/2007 3:39:20 P.M. Eastern Daylight Time, >melissa**At_Symbol_Here**melgetz.com writes: > >I have been asked to look into using a portable, ductless fume hood, and a >ductless chemical storage cabinet for the chem lab. >Do you have any experience with ductless systems? If so, please share your >opinions, suggestions on which ones to get or not get, etc. Which filters >should we buy? Do we really need a filter for organic materials? >Do you know how often the filters would need to be replaced? >The ductless fume hood is for regular chemistry classroom use. The chemical >storage cabinet will be in a room separate from the classroom and will hold >chemicals for chem., bio, and other science classes. >If you need more clarifying information, please ask. >Thank you in advance for helping out with this decision making process. >Sincerely, >Melissa Getz >_Melissa**At_Symbol_Here**melgetz.com_ (mailto:Melissa**At_Symbol_Here**melgetz.com) > > ----------------------------------------------------------------- > > >James A. Kaufman, Ph.D. >President/CEO > >Laboratory Safety Institute (LSI) > > >Safety in Science and Science Education >192 Worcester Road, Natick, MA 01760 >508-647-1900 Fax: 508-647-0062 Cell: 508-574-6264 >Email: jimkaufman**At_Symbol_Here**labsafety.org >Web Site: _http://www.labsafety.org_ (http://www.labsafety.org/) > >Making Health, Safety and the Environment an Integral >and Important Part of Education, Work and Life. > >************************************* > > > >************************************** See what's free at http://www.aol.com. +++++++++++++++++++++++++++++++++++ Harry J. Elston, Ph.D., CIH Principal - Midwest Chemical Safety www.midwestchemsafety.com helston**At_Symbol_Here**midwestchemsafety.com 217.971.6047 Editor, Chemical Health & Safety www.elsevier.com/locate/chs http://membership.acs.org/c/chas/ "When a committee is in charge, no one is in charge." Elston's management axiom #3
Previous post | Top of Page | Next post