From: "Glode, Andy" <andy.glode**At_Symbol_Here**UNH.EDU>
Subject: Re: [DCHAS-L] Operating a fume hood w/Sash Height 15 inches max...
Date: Fri, 16 Nov 2018 21:41:34 +0000
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: d5596c62b8e841eeacea554051d461c6**At_Symbol_Here**

If the hood passed ASHRAE 110 at 15" and it has a working face velocity monitor/alarm, then I see no problem. The sash should be used as low as possible to best protect workers anyway, so I wouldn't worry about it being restricted to 15". If you are concerned about people using it with the sash above 15", then you should consider lowering the sash stop (if it has one) to 15", rather than relying on tape or a sign.


Regarding the acid use, if they will dissolve rocks in hot acid, make sure the hood interior/duct/fan are compatible. We've had some hoods and ducts get eaten alive by acid vapor deposition. Dissolving rocks in acid is straightforward, but the hazards are acute: our geologists use hot hydrochloric, HF, and perchloric. Of course you'd need plastic duct and hood, and a good wash down system for perchloric. And you won't get many years out of a steel hood with galvy or stainless duct if they are digesting rocks with HCl.


Good luck!

Andy Glode





From: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU> On Behalf Of Margaret Rakas
Sent: Friday, November 16, 2018 12:12 PM
Subject: [DCHAS-L] Operating a fume hood w/Sash Height 15 inches max...


Caution - External Email



I wanted to check whether there are any health and safety concerns or any 'lessons learned' that would preclude using a continuous volume fume hood with a maximum sash height of 15 inches (rather than 18) if it passed ASHRAE 110 testing and had an average face velocity between 80-120 fpm.  We would train users regarding why the sash has to be at the 15 inches and there would be a sticker indicating maximum sash height.  It  is the sole fume hood in a lab, and would be used for mixing aqueous acidic solutions and dissolving rocks rather than complicated organic chemistry setups...I realize manufacturer's specifications are likely 18 inches (this is an old fume hood, probably from the 1980's) so looking up documentation on this is probably not going to be possible and might not be helpful, anyway.


A renovation several years ago turns out to have futzed the ventilation in this room; we're planning another renovation in the next year or so, but in the meantime it would be great to be able to use this fume hood if there are no regulations/guidance which would indicate it should not be used.


Many thanks,



Margaret A. Rakas, Ph.D.
Manager, Inventory & Regulatory Affairs
Clark Science Center
413-585-3877 (p)

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