From: James Saccardo <James.Saccardo**At_Symbol_Here**CSI.CUNY.EDU>
Subject: Re: [DCHAS-L] NMR Ventilation ?
Date: Mon, 10 Aug 2015 18:07:14 +0000
Reply-To: DCHAS-L <DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU>
Message-ID: f110f624200d4f52b573905b787fc351**At_Symbol_Here**MBOX-02.FLAS.CSI.CUNY.EDU
In-Reply-To <1109037139E1524980CF9CBEB247661883AD4657**At_Symbol_Here**>

Have you done any calculations with maximum volume of cryogen your 400MHz can hold against the ventilation rate in the 1500cuft space? How will the emergency ventilation be activated when/if needed?

You guys are thinking of an emergency condition where all of the cryogenic liquid let's go at once. Most facilities have a hard wired oxygen sensor monitoring the area to alert occupants to the absence of adequate O2 levels and to evacuate. During normal evaporation of N2, 6 ACH is sufficient to handle the emission from a 400mHz unit. The standard is having the hard wired oxygen monitor.

Another problem I see in these types of facilities with regard to ventilation is the heat load thrown off by the magnet, console, pumps, and He recovery unit. All of those electronics do produce quite a bit of heat and the temps in the room can soar to above 80F during normal operations. Something you should also consider.

-----Original Message-----
From: DCHAS-L Discussion List [mailto:dchas-l**At_Symbol_Here**] On Behalf Of Wilhelm, Monique
Sent: Sunday, August 09, 2015 3:36 PM
Subject: [DCHAS-L] NMR Ventilation ?

Hello Everyone,

I am looking for advice for installation for a new 400 MHz NMR. Our faculty and EHS people (from another campus) cannot seem to agree about the ventilation for cryogen safety. Does anyone have any ideas what best practices are for a 400 MHz? The EHS people are not agreeing with Bruker's recommendations.

Is emergency exhaust or a quench pipe more reasonable for a small space on a 400 MHz system? I am worried that having the quench pipe for the He would not be sufficient to protect against any N2 accumulations. Is there a "best practice" for a NMR in its own small space (approx. 1500 cu ft)?

I appreciate any advice that can be provided.

Thank you,
Monique Wilhelm
Laboratory Supervisor/Adjunct Lecturer/Chem Club Co-Advisor Department of Chemistry & Biochemistry University of Michigan-Flint Flint, MI 48502

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