Date: Fri, 20 Nov 2009 10:24:58 -0500
Reply-To: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: Ray Ryan <RRyan**At_Symbol_Here**FLOWSCIENCES.COM>
Subject: Re: Hoods
In-Reply-To: A<4B056E830200002900015FD1**At_Symbol_Here**>
You state that you feel that the flow gauges are more reliable; what are
they measuring??
Has anyone actually used an anemometer to measure the face velocity on
these hoods??
It sounds to me that since all the hoods are experiencing the same
'problem' that the exhaust of the HVAC system may be the culprit.

Ray Ryan

President & CEO
Flow Sciences, Inc. 
corporate office 800-849-3429 
corporate fax    910-763-1220 
2025 Mercantile Drive
Leland, NC 28451 

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-----Original Message-----
From: DCHAS-L Discussion List [mailto:DCHAS-L**At_Symbol_Here**] On Behalf Of
Edward Senkbeil
Sent: Thursday, November 19, 2009 4:13 PM
To: DCHAS-L**At_Symbol_Here**LIST.UVM.EDU
Subject: [DCHAS-L] Hoods

The hoods (about 5 years old) in all our undergraduate chemistry labs
are equipped with alarms which supposedly should go off with improper
air flow.  However many will continually alarm if the sash is pulled up
by more than one third the way (below where sash has a normal catch
about half way up).

Is there any law / regulation which states that we must have the alarms
working if they are part of the original equipment?  All the hoods have
flow gauges on them which are functioning, but we have been unable to
get all the alarms to work properly.  We are told it would be very
expensive to get them all functioning.  They become a problem in large
student labs since they continually go off, and are distracting both
faculty and students.

We have considered disarming the alarm, but are concerned about any
regulations we might be violating.
Students are beginning to not pay attention to the flow gauges, but just
automatically hit the mute button on the alarms.  We believe the flow
gauges are a more accurate reflection of any problems.

Any comments or suggestions welcome.

Ed Senkbeil, Ph.D.
Chemistry Department
Salisbury University

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