carbon monoxide in tanks - cozumel

[redacted]

I sometimes use Nitrox, but do not own an O2 analyzer. I depend on the fill station to have one available for my use. I consider this part of the bargain, and so do they. Why couldn't this same agreement be used when I want to do a CO analysis on air/gas I buy from the same fill station? This service would certainly be helpful in deciding which facility to use. I also think this approach would be the easiest to implement.

Having said that, fair dues to you who already own a CO detector.

Couv

That is the way I'm thinking it should work.

So Dive Palancar and its associated resorts are off my list until they get some CO monitoring equipment. I think I will continue to take my chances with other ops that have no past history of any problems. CoCo View has been off my list for quite a while now. It is silly for divers to have to spend almost $300 each rather than the ops covering the cost for under $1000.

If none install CO monitoring. I'll just take my chances with those with a clean record. Once tjhey have had a problem like CoCo View and Dive Palancar, I'm done with them until they install a credible safeguard.

 

[DandyDon]

Think I'm going to get one of those as well, I checked and they ship down under for any antipodeans who are interested.

Dave

The calibration can be done with any 100ppm cal gas I suppose. There are additional instructions than those that come on the supplied can so save the leaflet too, but I suppose the instructions can be shared.

I sometimes use Nitrox, but do not own an O2 analyzer. I depend on the fill station to have one available for my use. I consider this part of the bargain, and so do they. Why couldn't this same agreement be used when I want to do a CO analysis on air/gas I buy from the same fill station? This service would certainly be helpful in deciding which facility to use. I also think this approach would be the easiest to implement.

Having said that, fair dues to you who already own a CO detector.

Couv

A reasonable attitude, altho not not one to count on. But then I did buy my own Nitrox analyzer because I did not like the models sometimes offered by some of the stations.

That is the way I'm thinking it should work.

So Dive Palancar and its associated resorts are off my list until they get some CO monitoring equipment. I think I will continue to take my chances with other ops that have no past history of any problems. CoCo View has been off my list for quite a while now. It is silly for divers to have to spend almost $300 each rather than the ops covering the cost for under $1000.

If none install CO monitoring. I'll just take my chances with those with a clean record. Once tjhey have had a problem like CoCo View and Dive Palancar, I'm done with them until they install a credible safeguard.

And often I am the only one on the boat who knows his air is safe, or how marginal it is - like last week. I just don't see much to change until more divers are willing to spend $200 to be sure. One analyzer can be used by more than one diver of course, but at 5 minutes or so per tank - not too many.

In the CALA at least, hardly any will have CO monitors and we just don't know who will screw up next, how many will be injured, or dead - until more of the divers stand up to them.

 

[vladimir]

The 3-5% stat comes from the following article.

Carbon Monoxide tester for scuba and firefighting

What the author is saying is that of all samples tested, 3-5% fail the Grade E standard (MAX of 10 ppm of CO). It does not necessarily follow that one will experience symptoms 3-5% of the time. Symptoms will depend on the length and depth of the dive with the contaminated air, as well as the weight of the diver, breathing rate, whether they are a smoker, etc.

But it does not inspire a lot of confidence in the dive industry when 3-5% of the samples sent in for testing are "failing" the Grade E standard for Scuba air.

This is a shocking statistic. At the bottom of the range, it means that I have a 97% chance of breathing clean air on a given dive. After 2 dives, .97 x .97 = 94%. After 23 dives I have, more likely than not, breathed contaminated air!

 

[ktomlinson]

I just ordered a CO test kit last week, and reading all the instances of CO injuries and deaths on scubaboard is one of the main reasons I did. $200 is a hell of a deal if it saves my life, or even gives me a little peace of mind.

 

[redacted]

The 3-5% stat comes from the following article.

Carbon Monoxide tester for scuba and firefighting

What the author is saying is that of all samples tested, 3-5% fail the Grade E standard (MAX of 10 ppm of CO). It does not necessarily follow that one will experience symptoms 3-5% of the time. Symptoms will depend on the length and depth of the dive with the contaminated air, as well as the weight of the diver, breathing rate, whether they are a smoker, etc.

But it does not inspire a lot of confidence in the dive industry when 3-5% of the samples sent in for testing are "failing" the Grade E standard for Scuba air.

And, as I recall, the smoker will have an advantage over the non-smoker as their system seems to tolerate the carboxihemoglobin better.

 

[JonKranhouse]

It will be gratifying if CO monitors show up EVERYWHERE - maybe that will help change the alarming 60% spike in dive fatalities:

Dive deaths reported by DAN in 2007 spiked 60% from 2006, hitting a 30-year peak. This was the worst year-to-year % jump in 20-years. This is from DAN’s 2008 report, published in 2009, RE 2007 fatalities (page 8):

This 2007 spike in dive fatalities coincides with the beginning of the "Be A Diver" marketing campaign, which of course could mean nothing and just be a statistical anomaly.

I believe that a lackadaisical attitude for safety increases dive deaths. But that's mere opinion, not hard data, so make up your own minds. Can anyone cite the very first time that the "Diving is as safe as bowling" claim was made?

For extra credit:
(A) Cite the source data that was used to make the bowling claim.
(B) Characterize the reliability of that source data that was used to make the bowling claim.
(C) What data-sets were excluded to make the bowling claim.

My complete earlier post RE claims of dive safety is here, which includes clues for answering the "extra-credit" questions.

 

[DandyDon]

This is a shocking statistic. At the bottom of the range, it means that I have a 97% chance of breathing clean air on a given dive. After 2 dives, .97 x .97 = 94%. After 23 dives I have, more likely than not, breathed contaminated air!

Uh yep. Aren't you glad you've been lucky enough to have it only mildly tainted so far? True, 5ppm like I was reading last week on boats is not much even if I were get down to 130 ft where it's like 25ppm, but it shouldn't be there at all. Remember this part of that article...

"First is the overuse of the compressor system's inlet filter," says Laughlin. "You can think of the air filter as a big sponge, soaking up the contaminants. If you run with a filter too long, you get what we call 'breakthrough' and it's just like squeezing that sponge. All the contaminants come right out into the compressed air.​

That's when it gets really bad! Ever play "Russian roulette"...?

I just ordered a CO test kit last week, and reading all the instances of CO injuries and deaths on scubaboard is one of the main reasons I did. $200 is a hell of a deal if it saves my life, or even gives me a little peace of mind.

You know, part of me wants to find a bad tank and say I told you so last year! And I would damn sure make my findings known to others diving as well as the Op, then get out what rescue gear I have to help those who still dive as some would still I think.

Then I'll test the tanks of those hit, and fight anyone who tries to keep me from getting them to the American consulate.

Part of me wants to never find anything over 5ppm and just feel assured that I can dive without a CO hit, hopefully not anywhere close - altho every tank is different.

Mostly I hope more Ops see more divers testing their tanks and get the clue: if they don't want trouble, they need to be responsible.

And, as I recall, the smoker will have an advantage over the non-smoker as their system seems to tolerate the carboxihemoglobin better.

No, it hits smokers harder.

 

[swamp diver]

Well! I just got off of the phone after speaking with a representative of CanarySense.com. They are an autherized retailer for BW Technologies analyzers. Here is what I have learned thus far:
1) Bw Technologies is a Canadian based subsidiary of Honeywell.
2) They recommend that you calibrate your unit with a 100 ppm CO gas (which they will gladly sell to you at a cost of $140).
3) Oh, and by-the-way, you will need a regulator to hook up to that bottle of calibration gas!... Uh, that's another $150!.... See where this is going yet? :depressed:
4) Now the analyzer itself will set you back $265. It is, however, calibrated at the time you receive it. So (as the rep was quick to point out!), you can deffer the cost of regulator and calibration gas for a "few months" if you so desire.... Bottom line: You will be out those costs eventually!
5) They have no adapters/methods for testing directly from a SCUBA tank. Therefore, you are relegated to purging gas into a Zip-lock bag, or what ever alternative method you can come up with!
6) When it is all said and done, you will have forked out $550 for the analyzer and equipment to calibrate it!

Wow!!! Seems steep to me! Surely there is a more "palatable" approach to this problem! Much as I am in favor of testing my tanks, I know I would have a hard time dropping that sort of money on a single gas analyzer!

I think if you do a little more digging you will see that this is a worst case scenario and that the cost of purchasing a ToxiRae 3 with equivalent supply of calibration gas is identical to the Pocket CO and you will have a far superior monitor that is calibrated at 10 ppm CO rather than 100 ppm which will give poor accuracy when trying to measure CO contamination in the < 10 ppm range.

Here's how:

ToxiRae 3

ToxiRae 3 $150 from a distributor in Utah according to Scared Silly

0.5 lpm regulator for 17 L tank $96
GASCO - 72-MFV/17 Mini Valve and Flow Meter


17 litres 10 ppm CO/balance air $45 (this will provide 34 calibrations or fewer calibrations and a supply of bump gas for verifying the accuracy each day before use)
GASCO Non-Reactive Single & Two Gas Mixtures - Carbon Monoxide

Flow restrictor for BCD lp hose $31
BC Connector for Gas Analysis [GA-BC-Flow] - $30.45 : Tech Diving Limited, a subsidiary of Scuba Training and Technology Inc.

Total $322


Pocket CO

Unit with only 3 calibrations and no bump gas potential to verify accuracy $199
Calibration gas for 3 additional years done 3x per year $120

Total $319


Other properties to consider:

1) Analysis time

Time to take a reading known as T90 or time to reach 90 % of true concentration

ToxiRae 3 : 15 seconds
BWT Gas Alert Extreme : 30 seconds
Pocket CO : 3 minutes in bag

If one needs to check multiple tanks the ToxiRae 3 is the way to go due to its very fast sensor

2) Calibration gas concentration

With the ToxiRae 3 and BWT Gas Alert Extreme one can change the calibration gas concentration from 5 ppm to 50 ppm. In order to have high accuracy in the 0 to 10 ppm range these detectors must be calibrated at 10 ppm not 100 ppm as found with the Pocket CO.

3) Water-resistance

Both the ToxiRae 3 and BW Tech units are splash proof and will withstand immersion to one metre for one minute.

The Pocket CO has no IP rating and is not splash proof as the air intake ports communicate directly with the printed circuit board and battery. If this unit falls in salt water it will be ruined.

4) Cross-reacting gases

Each unit will react to NO, H2, and H2S and give false positive ratings. The Pocket CO reacts to far more cross-reacting gases which is a problem if one is challenging a fill station owner yet the contaminant is simply NO and not CO.


Given the cost of ownership over 4 years is the same between the Pocket CO and ToxiRae 3 the latter is a better value especially considering one will also have 22 litres of calibration gas remaining for daily bump checks.


For Canadians the calgas, regulator, and portables can be purchased from
Concept Controls Ask for Dave at the Mississauga office.

While the 10 ppm CO calgas may not be listed it is a stock product from Gasco.

 

[Doc Harry]

Unfortunately, every single variation of CO detectors have some inherent cost problem.

1. You can buy a disposable analyzer for $150-$250 that you throw away every 3 years and buy a new one.

2. You can buy an analyzer that requires factory calibration periodically at a price. But why is one sensor so good that it only requires calibration every year while others require quarterly calibration?

3. You can buy an analyzer that you can calibrate yourself (use 10 ppm calibration gas, not 100 ppm cal gas, to ensure your analyzer is linear at low CO levels).

Anyway you look at it, you're going to be spending $$$. There is no easy solution.

My perspective:

1. What makes one cheap analyzer so good that it requires calibration only annually, while other expensive analyzers require quarterly calibration? Sounds fishy to me, I don't think I can trust an analyzer that hasn't been calibrated in 11 months.

2. As far as my breathing gas is concerned, I want to know without any doubts. How can you trust an analyzer that hasn't been calibrated in a year?

3. I prefer to lay out the $$$ up front and calibrate my own analyzer every 3-6 months. That way I KNOW for sure that my analyzer is both ACCURATE and PRECISE. After the initial layout in cash, you've going to spend only $20 every 3 to 5 years for the calibration gas, and $100-$150 for a new sensor every 3-4 years.

 

[swamp diver]

The 3-5% stat comes from the following article.

Carbon Monoxide tester for scuba and firefighting

What the author is saying is that of all samples tested, 3-5% fail the Grade E standard (MAX of 10 ppm of CO). It does not necessarily follow that one will experience symptoms 3-5% of the time. Symptoms will depend on the length and depth of the dive with the contaminated air, as well as the weight of the diver, breathing rate, whether they are a smoker, etc.

But it does not inspire a lot of confidence in the dive industry when 3-5% of the samples sent in for testing are "failing" the Grade E standard for Scuba air.

Also generally if the shop fails the test on CO they are notified by the lab and one would hope they take corrective action such that the diver never is exposed to any carbon monoxide.

The real problem is those shops which are not testing. Well over half the shops offshore never send a compressed air sample in for testing. If there is CO in the breathing air the fill station operator or the diver will never know it. This is one major advantage to only patronizing those shops which do have quarterly air quality testing. While a quarterly test tells the diver nothing about CO contamination other than on the day that the compressor was sampled, one would hope that if there was a recurrent problem with CO production, for example from a compressor which overheats while under load, one of those quarterly tests would identify it.

Two years ago while in Roatan we surveyed a dozen dive shops many of which were PADI 5 star resorts and only 3 had a current air test certificate. Seventy-five percent were not testing at all. One shop actually had two years worth of tests on the Net (since removed) and one could see that in the winter when ambient temperatures were cooler the CO concentration was < 1 ppm or same as ambient. During the summer months though the CO would rise to 8 ppm and this was clearly evident on the test reports. There were three compressors in a small room with no mechanical ventilation and the compressors were a model known for overheating.

PADI could easily require its PADI-affiliated fill stations to install a $1000 CO monitor. DAN could produce a set of guidelines for safe compressor installation and operation, however this would require them to acknowlege the air quality elephant in the room problem in the first place.

If industry doesn't step up to the plate to make sure the quality of our compressed air, something so integral to this sport, is safe then the lawyers eventually will.