From:
Charlie Gates <charlie**At_Symbol_Here**GATES.HOUSE>
Subject:
Re: [DCHAS-L] Gas Sensor
Date:
Aug 14, 2026 19:26 UTC
Reply-To:
ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
In-Reply-To:
Re: [DCHAS-L] Gas Sensor
Dear Ruth:
In my old lab at UCSF, we had a room exclusively dedicated to LN2 storage that remained unoccupied. That room had an oxygen sensor (an MSA X5000 with an O2 sensor) which was wired to a strobe light on the outside of the door. I have since moved to a lab in an older building that lacks this installed equipment, though the spaces housing the LN2 dewars are reasonably well ventilated and are occupied.
You may want to talk to your on-site industrial hygienist or safety personnel to see if they have any more specific guidance.
I hope you all have a nice weekend,
Charlie
Hi Ruth,
For natural gas, the sensor is built right into the human olfactory gland. There are mercaptans in the gas that will aid any human in detecting a leak at the ppm level. Action must be taken immediately, humans can quickly become acclimated.
For LN2 it depends on the volume, a few liters should no be a big deal, now if you have 100L or more, and a leak can displace all breathable oxygen, then you might want to consider having a hardwired continuous oxygen monitor installed.
Check with you local fire official, they may provide guidance for cryogens and what volume you would need O2 sensors.
Implementing a good standard operating procedure may be your best practice.
Best,
James
* External Sender - Proceed Cautiously with Links and Attachments. *
Good Afternoon,
Are gas sensors required in chemistry labs with natural gas utilities and/or liquid nitrogen use? If so, what type of sensor is needed? Thank you!
Best,
Ruth Ann Cook Murphy, PhD
Professor of Chemistry
University of Mary Hardin-Baylor
900 College Street
Belton, TX 76513
(254) 295-4542
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