Permanent MOD markings on tanks

[rongoodman]

You should consider checking for CO2 as well because the better and proper filtering systems would convert any CO from the compressor into CO2.

How do you check for CO2 in your tank?

[a64pilot]

You should consider checking for CO2 as well because the better and proper filtering systems would convert any CO from the compressor into CO2.

How do you check for CO2 in your tank?

CO2 cells do exist, one RB manufacturer monitors CO2, but I haven't seen a CO2 tester for tanks. I thought though that the "better" filtering systems absorbed CO2, I wasn't aware they could convert CO into CO2?

[tursiops]

CO2 cells do exist, one RB manufacturer monitors CO2, but I haven't seen a CO2 tester for tanks. I thought though that the "better" filtering systems absorbed CO2, I wasn't aware they could convert CO into CO2?

The Liberty Mutual site ( http://www.libertymutualgroup.com/om...=1138364693273 ) says the following:

"Carbon Monoxide (CO) Contamination
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CO (a colorless, odorless gas) ranks as the most dangerous compressed air contaminant. Headaches, dizziness, unconsciousness and death can result from exposure to elevated CO levels. High-pressure compressors are often equipped with a catalyst which converts CO into much less toxic CO2. Both CGA G-7.1 Grades D and E (the most widely recognized SCBA air quality grades) list a 10 ppm maximum CO content. If a good air supply and a properly functioning, efficient compressor are in use, CO levels will be less than 1 ppm. Detectable CO levels above 1 - 2.5 ppm are abnormal and require further investigation.

Carbon Dioxide (CO2) Contamination
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Normal CO2 levels in outdoor air (i.e. 200 - 400 ppm) or indoor air (i.e. 500 - 2,500 ppm) are not considered hazardous. However, compressed air with CO2 levels that are within the "indoor air range" can create problems in SCBA applications. Some compressors are equipped with filters to reduce CO2 levels. CGA G-7.1 lists a 1,000 ppm maximum for Grade D and a 500 ppm maximum for Grade E air. High CO2 levels in SCBA tanks can produce many of the same symptoms as CO poisoning (see above). In addition, high CO2 levels increase breathing rates, which shorten SCBA usage time. One of the most common causes of SCBA air quality failures is excessive CO2 content."

But it seems a bit counter-intuitive to convert a gas that is hard to monitor (CO2) into a gas that is easy to monitor (CO).

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[a64pilot]

I knew an automobile Cat converted CO to CO2, but that takes really high temps, I didn't know it was done in a breathing gas compressor, wonder if it's a platinum type of cat, and how it works?

[gianaameri]

How do you check for CO2 in your tank?

I use a CO2 Monitor ( http://www.temc.it/en/diving/de-ox-b...oxide-analyzer )

Same sensor I have used in my rebreather for CO2 inhale side detection.

[gianaameri]

CO2 cells do exist, one RB manufacturer monitors CO2, but I haven't seen a CO2 tester for tanks. I thought though that the "better" filtering systems absorbed CO2, I wasn't aware they could convert CO into CO2?

I use these filters for my compressor: http://www.lawrence-factor.com/Purifiers/Hyper.asp

They contain Monoxycon ( http://www.lawrence-factor.com/Libra.../Monoxycon.pdf ) which oxydises CO into CO2.

This is a good article on compressors/filtration: http://scuba.club.anu.edu.au/gear/co...rs_Article.pdf