Date: Wed, 15 Aug 2007 08:42:03 -0400
Reply-To: ILPI <support**At_Symbol_Here**ILPI.COM>
Sender: DCHAS-L Discussion List <DCHAS-L**At_Symbol_Here**LIST.UVM.EDU>
From: ILPI <support**At_Symbol_Here**ILPI.COM>
Subject: Re: Carbon Monoxide Detector
In-Reply-To: <46C2DCB0.50801**At_Symbol_Here**>

Chemical/detectors of any sort can be prone to false positives with 
interfering substances.

This OSHA doc reports that 1,000 ppm hydrogen was falsely reported as 
40 ppm CO by one detector.  A malfunctioning lead-acid battery in an 
enclosed space could easily cause that (or a higher) concentration: 
(Section 1.6 Interferences).

Of course, interferences will be specific to the type of sensor unit.

Another possibility to be on alert for is the pump itself.  While 
sump pumps are generally oilless in design, any pump that has oil is 
a potential source of CO.  The oil degrades/burns over time.  This is 
why OSHA and other bodies require air purification panels and/or CO 
detectors one air compressor respirator systems.

Finally, I would suspect that the battery unit was making some sort 
of nasty smell.  It is not uncommon for folks who smell an unfamiliar 
smell (that they believe to be from a Deadly Chemical) to react with 
symptoms such as fatigue, palpitations etc.  I once had a student 
have a panic attack on my office floor after he smelled something 
funny in the lab.

Carbon monoxide is, of course odorless....

Rob Toreki

PS: Please note that my phone and postal address info has changed. 
Our company has moved from Lexington, KY to Sewell, NJ effective 

>One of my colleagues and I received a call today from one of the 
>fire chiefs in our County regarding high carbon monoxide  readings 
>in an enclosed space. This unto itself would not be a problem, 
>simply  ventilating and turning off the CO producing device should 
>suffice to eliminate the source. There was no active device to 
>produce the CO, no actively running fuel burning device anywhere to 
>be found. Upon further inspection, it was observed that the CO 
>reading increased when the instrument was near the sump-pump, and 
>that the battery in the back-up for the pump was without water and 
>that most of the plate area in the lead-acid battery were exposed 
>without electrolyte. A small amount of heat was observed, but the 
>battery was not on fire. The CO readings dropped in the space once 
>the battery unit was removed from the basement. The occupant of the 
>building complained of fatigue and was treated at the scene.
>The meter used for the analysis was a MSA 5 Star, which uses a 
>electronic sensor, for measuring CO. Unfortunately, wetted pH paper 
>on the tip of the meter input  was not used, which would make this a 
>simple determination. I suspect that the battery had lost nearly all 
>of its water, and was possibly vaporizing the sulfuric acid, what 
>surprised me was the  false CO reading and that the patient's 
>symptoms mimic those of CO poisoning.
>Have others in our very knowledgeable group observed anything 
>similar to this scenario?
>Jay Toigo
>Eastern Pennsylvania

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