From: Stephen Stepenuck <sstepenuck**At_Symbol_Here**>
Subject: Re: [DCHAS-L] Tragic Asphyxiation
Date: Wed, 3 Oct 2018 00:37:05 -0400
Reply-To: ACS Division of Chemical Health and Safety <DCHAS-L**At_Symbol_Here**PRINCETON.EDU>
Message-ID: D7D9B7AB.3F2B6%sstepenuck**At_Symbol_Here**
In-Reply-To <1764CC49-9649-4D58-ADD5-0F6F8ED20F77**At_Symbol_Here**>

I once worked in a nuclear plant, parts of which had a carbon dioxide fire
suppression system. As part of our training we were told that if that
particular alarm went off, we had I think something on the order of
seconds to exit that room or area, or you would be sacrificed in the
attempt to save the plant. Later, in academe, our Biology Dept. got such
a system as part of an undergrad lab upgrade. I always felt [?no offense
to former colleagues?] that faculty, never mind students, never got
sufficient training or refreshers to have enough respect for that sleeping
giant with which they lived every day. Maybe there were monitors, alarms,
and inspections of which I was unaware, but my impression was that there
had been precious little training to deal with a full discharge, let alone
what symptoms to look for that might be associated with a leak.
If you have or are planning to have such a system, please include regular
training for everyone?students, janitorial staff, and faculty, who might
be in that room or those rooms.

Steve Stepenuck, Faculty ret.

You wrote:

>I don1t doubt the lethality of carbon dioxide at elevated concentrations
>but I take issue with the describing CO2 as an asphyxiant. Unlike
>nitrogen which functions as a displacer of oxygen, CO2 at elevated
>partial pressure has a direct effect on human physiology. Concentration
>in excess of 10% v/v are immediately dangerous to life. I recall some
>authorities reporting pretty near instantaneous incapacity (possibly due
>to heart failure) at 20% v/v In brewing/baking industries where operators
>have leant into vats/dough bins and been unable to assist themselves. (I
>would add that in these last incidents the concentrations were estimated
>post mortem).
>However I can report that in my student days, whilst making home brewed
>beer and leaning on the lid of the brew bin I was exposed to a puff of
>fermentation gas which I can best describe as an explosion in my nasal
>passages like being kicked in the face with a violent recoil. That was a
>learning moment.
>Post graduation I developed a range of IR analyzers, one of which was
>used in saturation diving. At depth, the gas mix in the bell is heliox
>and the CO2 concentration is strictly monitored to maintain a very low
>At face value one might assume partial pressure should not exceed 500 Pa.
>However the risk of stratification is very much higher at the extreme
>pressures (especially as balance is predominately helium) and alarm
>action levels may be set at much lower levels.
>Perhaps someone can advise the physiological pathways that elevated
>partial pressure of CO2 adversely influences the body, even when the
>oxygen partial pressure is maintained at normal levels.
>James Osprey C Phys
>Novatech Analytical Solutions Inc.
>+1 514 378 9076
>Sent from my iPhone
>> On Oct 2, 2018, at 5:59 PM, DCHAS Membership Chair
>> wrote:
>> From: eugene_ngai**At_Symbol_Here**
>> Subject: Tragic Asphyxiation
>> A lot of discussion recently on Liquid Nitrogen safety. Here is a
>>tragic example of asphyxiation
>> 180904000834
>> Eugene Ngai
>> Chemically Speaking LLC
>> ---
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