Carbon Monoxide Detectors?

[BDSC]

My point is that in the same way that we take for granted that we need to test O2 content in Nitrox ourselves, a time will come where testing for CO will be as commonplace.

I think you are probably right. I'm not sure that I can see each diver going out and buying some device to test with but I could see a resort offering a tester that folks could use if they wanted. As usual, time will tell.

 

[MRadke]

I doubt that I will buy one. We can't keep sensors in a very expensive fire service device, I can't imagine relying on any of the inexpensive units. If you do consider one, make sure that it fails in a CO present mode. It may cost you a dive but at least it won't give you a false sense of security.

 

[Lobzilla]

If you ask (and continue to ask) the dive destination you are headed to if they monitor CO at the source (the air compressor), eventually everyone will put a CO monitor on their air compressors. Of course, most folks won't even ask for a basic air quality test.

I agree with Wookie that testing for CO is the responsibility of the filling station. They should have an in-line CO tester right at the compressor, like they have a O2 tester for you to sign your nitrox tanks out.

The pre-dive gas analysis is to prevent grabbing the wrong tank rather than assuring the basic quality of the gas.

If you do not trust the fill station to pump breathable gas you should also test for Hydrocarbons and moisture - or just walk away.

 

[DandyDon]

Testing for CO may well be the responsibility of the filling station, but that just doesn't work.

I have never tested a tank for carbon monoxide and probably never will. While I realize that it is possible that a tank could become contaminated, the chances of that happening is so remote that it's a risk I'm willing to take. At some point I think a person has to decide where to draw the line in trying to mitigate their risk in diving.

We really do not know, and DAN admits, how many drownings were caused by CO, how many not fatal hits are dismissed as having other causes, and certainly how many "travelers flu" cases were sub clinical CO close calls. Attitudes like your are common across the scuba sport which is why we are not testing tanks on a wide scale and learning just how common this is - and preventing accidents.

I have survived many things that could have killed me and will take more risks whether I leave home or not, but when affordable technology is available - the options become more appealing.

If you ask (and continue to ask) the dive destination you are headed to if they monitor CO at the source (the air compressor), eventually everyone will put a CO monitor on their air compressors. Of course, most folks won't even ask for a basic air quality test.

Nice idea that fails in too many ways. Compressor owners are wise to install and maintain CO monitors to ensure quality and protect their business but few do, and there will always be those who don't - or screw up. I stopped asking for test results when I saw that most don't test, but then learned that of those who do test - they usually do so while the compressor is cool and the filter new, rather than hot and just before filter change. Besides, things can be great one day and fail the next.

I think you are probably right. I'm not sure that I can see each diver going out and buying some device to test with but I could see a resort offering a tester that folks could use if they wanted. As usual, time will tell.

We are a long, long ways from that. The Analox portable CO analyzer can be obtained for less than $300, the sensor is good for more than 2 years, the sensor price just dropped to $158, and calibration costs are coming down soon. There are some things that every buddy pair should own, but my home bud is not into diving as much so I own the O2 and CO testers.

It can get boring checking tank after tank but getting nothing but zeros. Don't fall for that false security as you never know what's next. You probably won't forget your first time to get a reading tho. Then when we had to turn a boat because we got 11, 14, and 17 ppm on our tanks, the other two divers were glad to have dodged the bullet - but didn't want to post about it.

 

[BDSC]

Then when we had to turn a boat because we got 11, 14, and 17 ppm on our tanks, the other two divers were glad to have dodged the bullet - but didn't want to post about it.

So at what levels would CO in a tank be dangerous? Of course a level of zero would be ideal but those numbers seem kinda low to be dangerous unless the effects of breathing it during diving multiplies the effects.

 

[bleeb]

Testing for CO may well be the responsibility of the filling station, but that just doesn't work.

We really do not know, and DAN admits, how many drownings were caused by CO, how many not fatal hits are dismissed as having other causes, and certainly how many "travelers flu" cases were sub clinical CO close calls. Attitudes like your are common across the scuba sport which is why we are not testing tanks on a wide scale and learning just how common this is - and preventing accidents.

IIRC someone recently re-posted somewhere here on SB the regularly republished observation from a US test lab that when agencies used to required regular testing, a surprisingly large fraction had significant CO. Does anyone remember what fraction, and did they actually fail the CO requirement? Also, somewhere in the distant past, someone had actually posted a link or reference to the original report. If anyone remembers the post or the link, it might be helpful to repost it here, thanks.

 

[bleeb]

So at what levels would CO in a tank be dangerous? Of course a level of zero would be ideal but those numbers seem kinda low to be dangerous unless the effects of breathing it during diving multiplies the effects.

IIRC, CO multiplies with absolute pressure, so at 100 fsw, that 17 ppm has an effect close to but not quite like 76 ppm on the surface. Interestingly, because at depth useful amounts of O2 can be carried dissolved in blood plasma, people can apparently survive breathing significant amounts of CO at depth, even though their hemoglobin has stopped working. Supposedly they only pass out as they start to ascend.

 

[DandyDon]

So at what levels would CO in a tank be dangerous? Of course a level of zero would be ideal but those numbers seem kinda low to be dangerous unless the effects of breathing it during diving multiplies the effects.

Last update I know of: Government accepted limits for scuba air...

Canada's diving CO spec for air is 5 ppm

USA with its CGA Grade E is 10 ppm

Australia is 10 ppm

Britain has the tightest CO spec at 3 ppm.
http://www.hse.gov.uk/PUBNS/dvis9.pdf

Rest of Europe is 15 ppm

Most of the diving world - not controlled

Yes, the effect is greatly increased at depth, and worse. CO binds to the blood so that on ascent when PPO decreases, PPCO doesn't.

 

[BDSC]

You know it would probably be quite interesting to see what numbers you would come up with if you went to a place like Cozumel where there are numerous dive operations and just randomly tested CO levels in tanks.

 

[DandyDon]

You know it would probably be quite interesting to see what numbers you would come up with if you went to a place like Cozumel where there are numerous dive operations and just randomly tested CO levels in tanks.

Sure, it'd be interesting if they cared enough to do that too. My first CO analyzer didn't show anything until it found at least 5 ppm, and the first time that happened was a New Mexico compressor, electric, running outdoors in dry desert air - but probably just starting to partially burn it's own lubricating oil. I ruined that one, replaced it, and the new one starts at 3 I think. I'd seen a lot of 5s & 7s but nothing happened when I reported those.