Barb,
Liquid nirogen if exposed to the atmosphere will natually become nitrogen gas which in an enclosed space can act as a simple asphyxiant by displacing oxygen from the breathing atmosphere. There are OSHA regulations about the oxygen content in enclosed spaces, and monitoring the concentraion of oxygen in such a setting is a good safety measure. I'll leave it to others in the group to list the actual OSHA regulations, but as an old USAFR Flight Surgeon who had to deal with issues of hypoxia, in general effects begin to be seen at O2 concentrations of 18% or less, significant effects at 12% or less, and potential ftalities at 6% or less.
ALan
Alan H. Hallzz, M.D.
Date: Wed, 29 Aug 2012 10:01:08 -0400
From: bjwiehe**At_Symbol_Here**OWU.EDU
Subject: [DCHAS-L] Oxygen Sensor
To: DCHAS-L**At_Symbol_Here**MED.CORNELL.EDU
We are installing an Oxygen Sensor in a room using Liquid Nitrogen. Question, why do you mount it in the room where loss of Oxygen would be present? What type of training should the technician have overseeing the monitor?(ie respirator fit)
Barb Wiehe
