Hi Bruce, I had to comment on you term "no potential for exposure". There are materials and operations for which even a properly functioning fume hood will not achieve "no exposure" I would love to find criteria that could be reasonably applied to help the prudent person decide when to work in a lab fume hood and when to work in a glove box... Anyone know of one? Thanks, -Russ Russell.Vernon**At_Symbol_Here**UCR.edu Sent from my iPhone On Oct 6, 2011, at 5:06 AM, "Bruce Van Scoy"
wrote: Before I opt to purchase yet another standard, would you please specify the benefit of this standard as compared to installed/as-built performance testing, e.g., ASHRAE Standard 110-1995 "Method of Testing Performance of Laboratory Fume Hoods" using SF6 at 4LPM? If I can effectively prove that we are controlling all exposures at a lesser flow rate, is that acceptable under the 25 cfm/ft2 minimum found within the ANSI standard? I really don't care which standard is applied as long as I can defend in court that employees have no potential for exposure. Is that still acceptable? Please advise, thank you. BruceV -----Original Message----- From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**MED.CORNELL.EDU] On Behalf Of Mary Ellen A Scott Sent: Wednesday, October 05, 2011 11:13 AM To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU Subject: Re: [DCHAS-L] There is no "new" ANSI minimum hood flow rate Is there any note on a flow monitor for a fume hood being required now, even on older fume hoods? On Tue, Oct 4, 2011 at 11:45 PM, wrote: As the current chair of the ANSI-AIHA Z9.5 subcommittee, I am hoping to use this forum to counter some erroneous information that has been circulating about the forthcoming standard. Whether the information was outright or egregiously misleading or just audience misinterpretation doesn't really matter. I received a report recently about "an especially large group (of interested parties) at the Labs 21 conference...and hearing people talking about "the new ANSI flow level" as though we had erased one number and wrote in another." For the record, I feel obliged to add something to the vacuum created by the slow consensus publishing process. The standard revision replaces the 25 cfm/ft2 of work surface minimum flow rate with performance oriented language (which may more cautiously assign minimum flows for floor-mounted hoods with much larger interior volumes). The standard revision refers to studies and European experience where flow rates less than what would have been possible at 25 cfm/ft2 have reportedly been used (thus far) with success. The standard revision is steadfast in the actual requirements section (the left-hand column) and offers no room for placing energy conservation ahead of safety. Without copying verbatim and getting AIHA upset with me, let me just say that the bottom line is this; designers and owners must choose CAV hood flow rates and VAV hood minimum flow rates which prevent hazardous concentrations of contaminants in the laboratory fume hood. An extensive right-hand column goes into some detail describing and defining potential hazardous concentrations. I do regret that the revised standard hasn't been published yet. As we all know, (information) vacuums get filled. It would have been a lot easier to control what filled this particular vacuum if we all could be reading and interpreting the same text. Unfortunately, publication appears to be out a few more months. In the mean time, if you hear someone mention the "new ANSI minimum hood flow rate," politely correct them and assure them that in some cases, applying the revised standard could in fact raise the minimum (from 25 cfm/ft2). It will be fair to say as well that environmental performance and sustainability IS not entirely outside the scope of this standard any more. The subcommittee hopes that where appropriate, an equally safe but smaller carbon footprint may now be possible so long as safety isn't compromised. I encourage those with a role in laboratory ventilation management to purchase the standard once it's finally ready and volunteer to help make the next revision even better. Thank you, Steve Crooks, MS, CIH, CSP Chair, ANSI/AIHA Z9.5 20##. scrooks**At_Symbol_Here**ppeppro.com -- Mary Ellen Scott, PhD. Safety Specialist II Case Western Reserve University EHS - Environmental Health and Safety Service Building 1st Floor Rm 113 2220 Circle Dr. Cleveland, OH 44106-7227 216-368-6077 216-368-2236 (Fax) maryellen.scott**At_Symbol_Here**case.edu "There is no science without fancy and no art without fact" - Vladimir Nabokov (1899-1977)
Previous post | Top of Page | Next post