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Subject:
Re: [DCHAS-L] Oxygen Sensor
Date:
Aug 29, 2012 01:23 UTC
Author:
Barbara Wiehe <bjwiehe**At_Symbol_Here**OWU.EDU>
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Subject:
Re: [DCHAS-L] Oxygen Sensor
Date:
Aug 29, 2012 03:50 UTC
Author:
Smith, George S. <george.smith**At_Symbol_Here**THERMOFISHER.COM>
From:
Emily Reiter <eareiter**At_Symbol_Here**ALASKA.EDU>
Subject:
Re: [DCHAS-L] Oxygen Sensor
Date:
Aug 29, 2012 02:23 UTC
Reply-To:
DCHAS-L
In-Reply-To:
One of the reasons that liquid nitrogen is an asphyxiation hazard is
that it has an approximately 700-1 expansion factor. This means
that one liter of liquid nitrogen becomes 700 liters of gas.
Therefore, a small spill can quickly displace the air in a room. It
does not have a significant density difference from atmospheric air
(which is already about 80% nitrogen), so it will not collect on the
floor or rise to the ceiling. Sensors should be placed at
approximately the level of people in the room--if users are usually
standing, then the sensors should be placed at "head" height.
Emily
We did a quick calculation to
convince our researchers not
to put dewars of LN2 in their vehicles--a small (3 L) dewar, if
spilled, can easily displace the air in an average sedan to below
15%, which means almost instant asphyxiation and a vehicle crash.
It's nice to give facts beyond "you're not supposed to."
On 8/29/2012 9:23 AM, Barbara Wiehe
wrote:
Thank you for your responses.
Neal, fair enough put the red flags away...I was thinking scuba
but it isn't going to fly with anyone here to go to that extent.
I appreciate getting feedback from your perspectives rather than
push back from others.
Barb
--
-----------------------------------
Emily Reiter
Lab Coordinator/Safety Coordinator
Dept of Chemistry and Biochemistry
University of Alaska Fairbanks
192 Reichardt Bldg (907) 474-6748
