Analyzer: Nitrox vs. CO

[DandyDon]

bleeb see this lengthy post

While CO itself might be odorless, it is the product of incomplete combustion. This, with a reasonably high degree of probability, means that other junk such as incompletely burned gas or oil exhaust will also be present. These would be likely to have a detectable odor, assuming the concentration is high enough.

If that was a viable theory, we might not have 2,000 deaths in the US a year. Ok only 500 are accidental, but the other 1500 found it appealing for suicide. BTW, the 17 ppm tanks I found on my last trip had no odor.

 

[String]

Interesting. I can understand why somebody might say, "I wouldn't get one; I don't think it's necessary." But to elevate that to "You shouldn't get one; you're being paranoid" is, well, I guess I just don't understand why somebody would say that. What do you care what I do with my money?

When its a choice between something (o2) and useless (co) and the only deciding factor is a paranoia level its an issue.

For one thing, every Nitrox fill station I've ever gotten fills at (that's only a few places) has an O2 analyzer, and has me observe, or perform, the calibration and analysis.

OK so you trust their battery, trust their cell, trust their calibration? Have you asked to see the paperwork showing when the cell was last changed and the 2 point linearity check on it at regular intervals? Never checked before a dive on a busy boat in case someone has swapped labels (it does happen, they do fall off and helpful people stick the wrong one back on)?

I've never seen a CO analyzer anywhere.

There's a reason for that. For the same reason you dont see people wheeling round full scale gas chromatography equipment - its not needed.

I don't understand the negative, "You're being paranoid and stupid." vibe I get from some of these responses.

How hard is it to understand? People are being paranoid and stupid. But as above, paranoia and fear really do boost sales. Lead people into think there is a problem, just like this they'll never ask for evidence showing there is one but buy a "solution" anyway.

 

[String]

From my brief research, I've gotten conflicting answers to the question of should you be able to smell anything in SCUBA air, and if so, is that necessarily bad.

A very well maintained compressor with an untainted intake should have absolutely no smell or taste what-so-ever.

However, some do due to the exhaust being in the wrong place, filters needing changing or not packed correctly, leaks and so on. Moored dayboats with compressors are particularly bad for this. They moor, on days with no wind their own engine exhausts don't blow away from the boat and get sucked back in. With good filters they'll remove MOST of this but often still leave a slight smell.

Ultimately its up to you how bad the gas you're prepared to breathe actually is. Its not a black and white thing.

I think CO may be more common than is commonly realized, it is recognized as one of the more common "failure modes"

If its a common problem again where are the incidents? We're talking tiny amounts here. Just because its a common failure mode doesn't mean its the most life threatening problem. The statistics simply fail to back this up. Not always but a large CO content is very often supplied with an oily,plasticy smell and taste too as its produced by the oxidation of hydrocarbons.

Oh, yeah, String, what's HSE? Do you mean the UK's Health and Safety Executive?

Yes

 

[String]

bleeb see this lengthy post

If that was a viable theory, we might not have 2,000 deaths in the US a year. Ok only 500 are accidental, but the other 1500 found it appealing for suicide. BTW, the 17 ppm tanks I found on my last trip had no odor.

2000 deaths a year due to undetected carbon monoxide in DIVING equipment. Please supply these statistics.

The mechanisms for formation are COMPLETELY different on land vs a diving compressor. So remote you can't compare them. On land it is produced by DELIBERATELY burning stuff.

If you're that desperate to back up your baseless argument you're in big trouble.

 

[DandyDon]

2000 deaths a year due to undetected carbon monoxide in DIVING equipment. Please supply these statistics.

The mechanisms for formation are COMPLETELY different on land vs a diving compressor. So remote you can't compare them. On land it is produced by DELIBERATELY burning stuff.

If you're that desperate to back up your baseless argument you're in big trouble.

Are you that desperate that you insist on quoting me out of context? My indicated post was to address a misconception about CO in general only. Why are you so defensive as to twist my words? I see that you avoided the lengthy post given to answer your whining on the other thread indicated.

bleeb see this lengthy post

While CO itself might be odorless, it is the product of incomplete combustion. This, with a reasonably high degree of probability, means that other junk such as incompletely burned gas or oil exhaust will also be present. These would be likely to have a detectable odor, assuming the concentration is high enough.

If that was a viable theory, we might not have 2,000 deaths in the US a year. Ok only 500 are accidental, but the other 1500 found it appealing for suicide. BTW, the 17 ppm tanks I found on my last trip had no odor.

There is a direct comparison tho, still...

On land, 500/year die of accidental CO poisoning in the US with odor not being sufficient enough to alert sufficiently.

For diving, serious risks start at much lower CO concentrations, therefore any possible odors could be missed at much lower rates.​

I understand that you are a trained & experienced dive pro, and that's at the core of the problem here when your type rejects affordable technological improvements to improve diver safety.

I don't guess you have ever tested tanks for CO, have you?

How would you feel if someone demonstrated their portable CO analyzer on your tank and it read say 50 ppm? How deep would you dive it? We know that such happens a few times a year, just not how many for sure as the local authorities in much of the diving world lack the ability to test the and dead divers' bodies, if they would admit to the findings.

Eh, it's pretty evident that you are not interested in this safety improvement and we will just have to work around you.

 

[bleeb]

bleeb see this lengthy post

Thanks for the information. A few questions came to mind as I was reading it, and I'm wondering if anyone out there has any additional information, comments or corrections.

Outside of Canada and the US, it does not sound like compressors are routinely quantitatively tested for CO (i.e. in a certified lab using analytic chemistry equipment like a mass spec). In industrialised parts of Europe and Asia, it seemed like only field testing was going on, and used colour-change type detection. Isn't this type of testing both much less accurate and generally also significantly less reliable? It also wasn't clear if testing for CO was routinely scheduled, although it didn't sound like it was. If any of these are reasonably true, this would imply the lack of data is not from lack of cases. The articles referenced in the post seem to date from 2005 at the latest. Have regulations or common practice changed significantly since then with regards to CO testing and monitoring in Europe or Asia?

It was also noted that only 15% of dive fatalities in the mid 90s were tested for CO. I'm inferring these were mostly from industrialised North America, and that most of the fatalities in question would have been professionally examined by a government pathologist. Anyone know what post mortem examination protocols are/were in Europe or Asia, and whether North American protocols (or even common practice) have significantly changed since the 90s in regards to CO testing? It seems medical bureaucracies change even slower than other bureaucracies, so it would again be nice to know how consistently people are checking for the problem even after the fact, or whether the lack of cases is from no one looking for them.

 

[String]

Outside of Canada and the US, it does not sound like compressors are routinely quantitatively tested for CO (i.e. in a certified lab using analytic chemistry equipment like a mass spec).

Completely incorrect. Every single country in europe has to do it by law on a weekly or monthly basis and the test results have to be displayed clearly next to the fill. Australasia is the same.
Egypt is the same.
I dont know of a single country where it ISNT mandatory.

 

[String]

I see that you avoided the lengthy post given to answer your whining on the other thread indicated.

Ive replied to every thread. Why do you consistently avoid providing ANY evidence what so ever to back up your claim about these "hidden" incidents or any evidence what so ever about even ONE happening?

I understand that you are a trained & experienced dive pro, and that's at the core of the problem here when your type rejects affordable technological improvements to improve diver safety.

Laughable. All it proves is you appear to have no idea what you're talking about. If there were incidents, if there were corpses piling up, if people were losing diving due to illness id notice and it would affect me a lot. However they aren't. Anywhere in the world. You've been asked repeatedly to supply facts, evidence and supporting material to back up your claims and you have failed to do so.

I don't guess you have ever tested tanks for CO, have you?

No. Ive also never put my breathing gas through a mass spectrometer, my drinking water through a full bacterial analysis and i don't get all my food screened before eating. All for the same reason, there is nothing out there in terms of real world incidents and events that suggest that there is any reason what-so-ever to actually do this.

How would you feel if someone demonstrated their portable CO analyzer on your tank and it read say 50 ppm?

If they want to dive it, its up to them. You wont get a 50ppm hit from any properly maintained compressor on odourless gas. In any gas as with any contaminated gas problems, if you feel ill underwater abort immediately. Standard procedure and not an issue. I dont need a random sensor to tell me to get out of the water.

just not how many for sure as the local authorities in much of the diving world lack the ability to test the and dead divers' bodies,

Really? And im sure you have documentary evidence to back up yet another fanciful claim proving that blood and other tests are not performed on sudden death incidents. Or are you yet again inventing things with nothing to back it up? Come on, PROVE the point for once rather than just making claims.

if they would admit to the findings.

Oh so its all some conspiracy theory cover up. PROVE the point or stop making unfounded allegations.

Eh, it's pretty evident that you are not interested in this safety improvement and we will just have to work around you.

Yes of course. I have no interest in safety. I routinely bury students bodies in shallow graves in the desert and lie about it. I mean why would safety matter at all for me in my job? What does it matter to me if 200 students die a year? i just need to dig a bigger hole. No problem.

Laughable insulting comment. Now lets have some EVIDENCE to back up your claims. What about actually trying to prove there is a safety need for this for once by providing some sort of evidence rather than accusing people with experience who think you're talking rubbish of having no interest in safety?

 

[DandyDon]

Originally Posted by bleeb View Post
Outside of Canada and the US, it does not sound like compressors are routinely quantitatively tested for CO (i.e. in a certified lab using analytic chemistry equipment like a mass spec).

Bleeb, why don't you ask on that thread where Swamp Diver posted. I just linked the single post for you, but you can click the thread title in upper right corner to see all of it, still reply to it, or here is the link to the thread: http://www.scubaboard.com/forums/red-sea/352814-inline-co-monitors-sharm-el-sheikh.html

Completely incorrect. Every single country in europe has to do it by law on a weekly or monthly basis and the test results have to be displayed clearly next to the fill. Australasia is the same.
Egypt is the same.
I dont know of a single country where it ISNT mandatory.

He was referencing the "antiquated colorimetric devices (Drager tube technology) where testing is done on-site and the results typically remain on paper with the compressor operator." Even in the countries that do test, with the old color tests over there, or lab tests over here, it's old news typically based on loaded testing done on cool compressors at start-up with fresh filters vs the inline Clear units that monitor in real time. Personal tank testing with portable units pick up on those omissions.

There are many countries that do not require any testing even tho you apparently not been to them. Most by be the more appropriate word.

Ive replied to every thread. Why do you consistently avoid providing ANY evidence what so ever to back up your claim about these "hidden" incidents or any evidence what so ever about even ONE happening?

Nope, not true at all. Your whining was well answered by that referenced post on http://www.scubaboard.com/forums/red-sea/352814-inline-co-monitors-sharm-el-sheikh.html#post5556759 where you seemed to have stuffed it.

Really? And im sure you have documentary evidence to back up yet another fanciful claim proving that blood and other tests are not performed on sudden death incidents. Or are you yet again inventing things with nothing to back it up? Come on, PROVE the point for once rather than just making claims.

Done! (yawn) See that post/thread referenced.

I'm not going to get into all of your word twisting mixed with some truths.

What about actually trying to prove there is a safety need for this for once by providing some sort of evidence rather than accusing people with experience who think you're talking rubbish of having no interest in safety?

Done! (yawn) See that post/thread referenced.

On the other hand, if you were to state that scuba is generally managed safely to the extent that there are relatively few deaths and serious injuries, therefore the CO hits must be a smaller number, then that would be true. If you are happy with that gamble, your call. The only way to monitor a compressor is in real time tho, and the only way to know is you own personal test, but for you who don't care much - cool.

 

[swamp diver]

Completely incorrect. Every single country in europe has to do it by law on a weekly or monthly basis and the test results have to be displayed clearly next to the fill. Australasia is the same.
Egypt is the same.
I dont know of a single country where it ISNT mandatory.

Before you prattle on any further you might want to review the facts on compressed breathing air standards from around the globe. There is no country in the world which requires monthly let alone weekly laboratory testing for compressed breathing air either in the dive industry or fire service.

Up until 2009 PADI had a global breathing air standard which required quarterly testing to the US's CGA G7.1 Grade E standard. PADI no longer specifies any testing frequency and simply defers to the local authority having jurisdiction which as another poster has stated does not exist in most tropical dive areas.

In Britain they follow the European EN 12021 plus the Health and Safety Executive's (HSE) DVIS 9 which is in addition to the Euro 12021 and requires quarterly (that's every 3 months) sampling. Of note Britain now has the tightest CO specification for recreational diving set at 3 ppm. This specification was reviewed by the HSE in 2009 and given CO's high respiratory toxicity the spec was lowered from the EN12021 specification's 15 ppm (currently under review) to 3 ppm.
www.hse.gov.uk/pubns/dvis9.pdf

For the rest of Europe they follow CEN 12021 which does not specify a sampling frequency but most countries require biannual (that's every 6 months) testing.

Australia's AS/NZS 2299.1 is a commercial dive standard which does not apply to recreational diving however the local state authorities have incorporated this into regulations for recreational diving. The required sampling interval is once every 6 months in 2299.1

Here in Canada we have no recreational dive standard regarding compressed breathing air and traditionally have deferred to the training agencies. Now that PADI has withdrawn its air quality guideline worldwide there is essentially no requirement to test air anywhere in the world where a local standard does not exist to supercede the withdrawn PADI quarterly requirement. On the commercial side here in Canada testing is required every 6 months by an accredited third party laboratory.

For places like Mexico or Egypt in the past the training agencies specified quarterly testing to the CGA Grade E standard (PADI and NAUI) and they sometimes enforced this (it certainly was not law), however that safety net is now gone. While many shops have continued to sample quarterly and send their samples typically to the accredited laboratories Trace Analytics or LF in the USA many fill stations have stopped testing altogether. This very significant negative change to PADI's compressed air policy on a global basis greatly weakens the protection the recreational diver once had against potentially contaminated air and makes the introduction of Analox's carbon monoxide diver self-protection device even more important for the traveling recreational diver who may end up at a fill station where the air testing frequency has declined or ceased altogether.

There is no jurisdiction in the world therefore that requires any type of lab testing for dive air more frequently than once every 3 months. Quarterly tests only prove that the compressor at the time of the test was producing clean air. In between these tests, whatever the frequency, if the diver wants to truly ensure the air is CO-free the use of a portable CO monitor will give peace of mind. I'd suggest you allow divers to make up their own minds on this important decision based solely on the facts rather than what appears to be mostly hyperbole and opinion.

Not sure if you are famaliar with Dr. Gavin Anthony, a British exercise physiologist at QinitiQ, and consultant to the HSE the the British Royal Navy? He wrote a good basic article article in 2008 on the risks of CO in compressed dive air attached below.

For a peer-reviewed treatment on the subject of air contamination including carbon monoxide have a look at the excellent article by Dr. Ian Millar, the head of hyperbarics at The Alfred Hospital in Melbourne. The full article including a description of a New Zealand CO fatality can be downloaded at the bottom of this link.
Rubicon Research Repository: Item 123456789/7964

I'd suggest you read these references in order to improve the signal to noise ratio in this thread.