Analyzer: Nitrox vs. CO

[sambolino44]

I'm not trying to convince String, or anybody, that they need to buy a CO analyzer. It's just something I've been curious about, and I wanted to know what other people think. Thanks to all for your responses.

I think the risk of CO poisoning is low, for the same reason String mentions: there aren't a lot of reports of CO poisoning dive deaths. However, one thing nobody seems to be considering is that, while there may be some record-keeping in regards to deaths, I don't think there's any data at all about how many people get a headache while diving. My point is, there's a wide range between perfectly healthy and dead, and I'd rather not go there. I've gotten a headache while diving before, but who knows what caused it. People get headaches. It doesn't necessarily mean anything. But it does pique my curiosity.

I contend that I am not paranoid! Although I have good reason to be, since everyone is out to get me.

 

[DandyDon]

I've gotten a headache while diving before, but who knows what caused it. People get headaches. It doesn't necessarily mean anything. But it does pique my curiosity.

I understand the feeling. Headaches on dive trips are often caused by skip breathing and/or dehydration - a minor irritation if you don't pass out from one or take a hit from the other. I've never had one but seen others suffer.

Sometime in the last few years I started learning about CO possibilities tho, the risks and some known losses, the lack of prevention common at many destinations, even the lack of postmortem testing and I started looking for better answers. I can see why this has not been well examined on Scubaboard before as one runs into too much old school resistance, defensive crap from pros who don't want to bother, and while finding the info hasn't been easy - it's been rewarding in ways.

Finding a portable analyzer that tests in such very low ranges was a challenge but I found one. I've since learned its weak points and how to avoid them, as well as how to actually test in the field, what bags to use for that model - and the manufacturer has since produced a modified model with appropriate accessories (Pelican box, the best test bag) and software specifically for scuba testing.

While it took me a few trips to work out the kinks, and me wondering if I was wasting time, getting real readings will get your attentions. :shocked2: The first time you get a 5 is a wake-up; getting 17 can be unnerving. Don't let a long string of zeros get to you; it's good practice.

I remember a dive shop trip to Belize once when the first day most of the group got ill after two dives and didn't make the third. I thot they were a bunch of city wusses who didn't adjust to the tropics quickly and shrugged it off at the time. As the days passed, I learned how crappy the local Op was, and at the end of the week learned a bit about air testing from the other Op that supplied the Nitrox but still didn't make too much of it. A few years later, talking over that day with the shop and my home bud, it occurred to me that it was only the air divers who got ill, not the Nitrox users - but that basic difference didn't explain the difference? Now I wonder if the crappy Op realized what had happened, quietly drained his tanks and cleaned his compressor, and how close we came to first day tragedies back then. We'll never know, but - well, hope my feelings make sense.

When I first got my CO analyzer, I loaned to that same shop for their trip to Utila. They forgot they had it until they had another first day of sick divers, then tested, then forced the Op to drain tanks and clean the compressor. After flying that far to dive, you don't want to just quit so you try to make it work - and they did.

I don't know that we'll ever see wide spread monitoring and testing across the sport/industry as DAN is still seemingly avoiding taking up the gauntlet. I wish they would, and they might. I've actually exchanged some communications with their CEO, really nice fellow obviously to take my phone call for starters, and he sounded interested - just not proactive, to my knowledge.

With more and more divers carrying and using CO analyzers tho, then reporting problems here on SB, and now two manufacturers producing new portable units easier for even more to use, some knowledge will be acquired - and hopefully more compressors cleaned up before hits or losses. Hehe, now that DAN's magazine runs ads, I hope to see Analox advertise their new unit there.

We'll never know how many lives this saves, but we will see somethings in the months to come I bet.

 

[sambolino44]

... two manufacturers producing new portable units ...

I know about the Analox, what's the other one?

 

[DandyDon]

Pocket CO modified their unit to make a Scuba unit with a timer in the software as you need to wait three minutes, a special zip lock bag with intake valve so you can fill it and close the tank, along Pelican box as it is sensitive to other vapors,* and a calibration kit. For $199 it's a cheaper choice for a diver Order the Pocket CO SCUBA - Carbon Monoxide Detector and on my last trip it was interesting to compare readings between two different brands onboard - my Pocket CO and another diver's unit: see http://www.scubaboard.com/forums/co...n-adding-analox-clear-inline-co-monitors.html

* I use mine as a pocket monitor on the planes, but once I arrive it goes into the box to humidity, urban vapors, etc.

 

[Soakedlontra]

:crazyeye: Dense discussion! Let's !

 

[jcroy66]

I noticed this issue of the DAN Safety Stop Newsletter has an article titled "When Gas Goes Bad". If you are a DAN member, you can read the article at Alert Diver Online

 

[DandyDon]

From the Fall 2010 issue; I don't think I got mine yet. Maybe I need to go thru my mail stack again. When did yours arrive?

You actually don't have to be a member to read it.

 

[Chris12day]

Nope. Electric compressors with clean intakes are quite capable of producing their own internally.

Please supply reference. Nitrogen, Oxygen, Carbon Dioxide, and the other inert gases in compressed air do not have the ability to be converted into Carbon Monoxide. The chemistry is not there.

Safe Diving

 

[DandyDon]

Please supply reference. Nitrogen, Oxygen, Carbon Dioxide, and the other inert gases in compressed air do not have the ability to be converted into Carbon Monoxide. The chemistry is not there.

Safe Diving

I don't guess that has been explained on this thread, and we've noticed that many Instructors and Dive Operators are not aware, so glad to bring the info over here from one of the other threads...

When a breathing air compressor overheats (higher risk in high ambient heat tropical areas) and the temperature in any of the stages exceeds the autoignition temperature of the lubricant oil one will get pyrolysis or dieseling of the compressor oil with production of carbon monoxide. If there is no catalyst (Hopcalite) in the purifier to convert the toxic CO produced to less toxic CO2, or if the catalyst is excessively moist as the cartridge end-of-service life has been reached the CO will pass directly into the cascade or individual tanks.

The term was first used in a paper by Dr. Claire Austin, an industrial hygienist, who has done work on compressed breathing air quality for divers and fire fighters.
Carbon monoxide and water vapor contamination of c... [J Toxicol Environ Health. 1997] - PubMed result

Since the publication of her paper and further research on the frequency of CO contamination in compressed breathing air all US fire service compressors are now required to have inline CO monitors installed as of 2008.

Interesting that inline monitors are required for Firefighter compressors but not for ours even tho we take our tanks to several atmospheres.

Also see http://www.scubaboard.com/forums/5562940-post40.html

and http://www.scubaboard.com/forums/5556759-post36.html

and maybe http://www.scubaboard.com/forums/5565319-post39.html

Air intake can be a problem to be sure, but the compressors and make their own.

 

[jcroy66]

DD, I haven't gotten the paper copy yet - the link was in the email newsletter I got this weekend. By the way, thank you for all the info you provide on this topic. Both a CO monitor and an O2 monitor are on this year's wish list for Santa.