Ronda Cross Tank CO Test cause of Death

[DandyDon]

Just a little perspective on this point. If the analyzer is rated at 1-50, a reading of 1900 means nothing more than it is above 50. It is not reliable beyond that and the true reading could be much lower (or much higher) than 1900. Obviously, no matter what the real reading is, it is a lot. But in terms of the plausibility of getting that much CO into a tank, this reading should be viewed suspiciously. The only thing we can conclude is that it is somewhere above 50. It is probably substantially higher, but does that mean it is 100, 1000, 2000? We just don't know and the reason instruments are rated is to let us know the range in which they can reliably be operated. It is a mistake to attach any precision to a reading that is out of range - especially so far.

I'm certainly curious. I checked the EII CO site, data sheet, and manual - all of which list 2 digit displays and 1-50 ppm range, but my unit has a 3 digit display. I think that the sensor is actually capable of measuring higher than 50 ppm but it's more accurate in the low range - which is part of the reason for its costs. When I first got interested in CO tank testing, I then hoped to use a $25 home monitor - but those sensors work in higher ranges, slower response times, etc. So the info furnished to us retail consumers on the EII CO tells what we need to know in safe operations, but there may well be a lot more to the story not published to us. It just might be a 2000 ppm max sensor, and the display just might be able to add a 4th digit in extreme case. I am trying to ask around and fine out.

 

[mdax]

I've had a CO monitor for over 2 years now and test every tank I dive. The only reading that has concerned me was in mexico (believe it was 10 or 11ppm) but that doesn't change the fact that I test EVERY tank I dive...Even tanks from the shop where my wife works, which has written, specific maintenance schedules.
CO analyzers are just too cheap to risk the consequences, you can even rent them for vacations!
You can get these for around $300
Or Rent for a trip for $45 for 2 weeks!

All divers should test their tanks for proper oxygen content as well as the presence of co! Spread the word!

 

[Johnoly]

However, without sidetracking the discussion too much, can anyone explain what a compressor oil flash is? (just curious)

Compressor flash over can not be seen since it occurs inside the compression cylinder. Cylinders are lubricated by oil to make them slide. There are many different types of oil from synthetic with a high temp to a mineral or even a vegetable oil that has a very low temp ~100 degrees. {Yes, I've seen remote compressors run with vegetable oil, because they were out of spec oil} CO is generated from lubricating oils getting so hot that they actually ignite (combust) and partially burn. The incomplete burning results in extremely high levels of CO. Since a temperature range for a flashover is so tight, it regularly happens that flashover can occur for just 1,3, 5, 10 minutes of a compressor running for a 30 minute fill. This very short amount of flashover time is enough to significantly raise CO ppm to unacceptable or deadly levels. In addition, so many outside factors like air temp, cooling lines, intake position, a fan, dirty heat fins, and numerous others, that it is next to impossible to visually look at a compressor and try to determine if it's pumping CO. The only way to look for CO is to test with an analyzer.

 

[nimoh]

Compressor flash over can not be seen since it occurs inside the compression cylinder. Cylinders are lubricated by oil to make them slide. There are many different types of oil from synthetic with a high temp to a mineral or even a vegetable oil that has a very low temp ~100 degrees. {Yes, I've seen remote compressors run with vegetable oil, because they were out of spec oil} CO is generated from lubricating oils getting so hot that they actually ignite (combust) and partially burn. The incomplete burning results in extremely high levels of CO. Since a temperature range for a flashover is so tight, it regularly happens that flashover can occur for just 1,3, 5, 10 minutes of a compressor running for a 30 minute fill. This very short amount of flashover time is enough to significantly raise CO ppm to unacceptable or deadly levels. In addition, so many outside factors like air temp, cooling lines, intake position, a fan, dirty heat fins, and numerous others, that it is next to impossible to visually look at a compressor and try to determine if it's pumping CO. The only way to look for CO is to test with an analyzer.

thanks for the explanation. Based on my (limited) understanding of gas filling, this is the single biggest reason to test your tanks for CO. It seems that (except when filled from a bank) it can affect a single tank in a batch of fills, and can happen without the operator knowing.

 

[Dive-aholic]

This is certainly interesting. I have no idea what the pictured document is exactly or what it says. A translation would be nice...

It doesn't say anything about carbon monoxide so I'm not sure why it's even attached here. It states it is the evidence sheet for tank number 1. It provides the date, whose authority it falls under, and an itemization of the gear along with it. Then it states its location. That is it.

---------- Post added December 13th, 2012 at 11:33 AM ----------

However, without sidetracking the discussion too much, can anyone explain what a compressor oil flash is? (just curious)

What actually happens is the compressor can get too hot if it is run under less than ideal conditions or too long. This is one reason I only run my compressor from 6am-8am or 8pm-10pm in the summer. In the winter I will run it during the day as long as it's below 80 degrees out, but not for more than 2.5 hours. If the compressor begins to run above a certain temperature it will inactivate the hopcalite in the filter. The hopcalite is what binds with carbon monoxide and converts it to carbon dioxide, which is much safer. As long as the temperature stays elevated CO will keep passing right through the filter stack and into the tanks or banks. Running a compressor during the hottest part of the day or for too long increases the chances of this happening. Even when I'm running it during cooler months I still have a fan blowing air on the compressor coils to keep air circulating outside the compressor and keeping them cool. I've been doing this for over a year and have yet to find any carbon monoxide in any of my tanks.

 

[DandyDon]

thanks for the explanation. Based on my (limited) understanding of gas filling, this is the single biggest reason to test your tanks for CO. It seems that (except when filled from a bank) it can affect a single tank in a batch of fills, and can happen without the operator knowing.

It's certainly a risk and blows away the theory that electric compressors are safe, and yeah, there be a lot of change in a run - just because some tanks in a run are ok does not mean that the others are.

 

[Patti Analox]

Divers,

The cell used in the EII CO has a max specified range of 1000 (and will actually probably go higher), so as the level of CO the cell is exposed to increases the the signal from the cell will rise accordingly. Essentially, the only limit to the measurement electronics is the fact that the display only goes up to 1999ppm. Once the measurement goes past this the display will just show '1' (as it does on the video) to indicate that the display is over range. So that's why the unit displayed the values that it did when it was exposed to the gas.

The reason why we only specify a range of 50ppm is that is what the unit is calibrated on and the higher level of measurement you then go to the accuracy will degrade. But in reality once you get over a few ppm you wouldn't really want to use that gas anyway, so being able to measure much higher levels of CO accurately is irrelevant.

Hope this helps and highlights just how wrong a tank of diving air can go.

 

[nimoh]

It doesn't say anything about carbon monoxide so I'm not sure why it's even attached here. It states it is the evidence sheet for tank number 1. It provides the date, whose authority it falls under, and an itemization of the gear along with it. Then it states its location. That is it.

---------- Post added December 13th, 2012 at 11:33 AM ----------



What actually happens is the compressor can get too hot if it is run under less than ideal conditions or too long. This is one reason I only run my compressor from 6am-8am or 8pm-10pm in the summer. In the winter I will run it during the day as long as it's below 80 degrees out, but not for more than 2.5 hours. If the compressor begins to run above a certain temperature it will inactivate the hopcalite in the filter. The hopcalite is what binds with carbon monoxide and converts it to carbon dioxide, which is much safer. As long as the temperature stays elevated CO will keep passing right through the filter stack and into the tanks or banks. Running a compressor during the hottest part of the day or for too long increases the chances of this happening. Even when I'm running it during cooler months I still have a fan blowing air on the compressor coils to keep air circulating outside the compressor and keeping them cool. I've been doing this for over a year and have yet to find any carbon monoxide in any of my tanks.

good to know. The hottest part of the day where I get my tanks filled is currently about 30 degrees Fahrenheit

 

[cabodetails]

Well if you check the Padi Web Site They are not there as a PADI shop and never will be again.
As far as the Case in Cabo San Lucas it is an open case according to the Canadian Consular Agent the case is still on going. You just make your self look bad by posting things you have no idea about.

ok, johnzdiver , lets look at what you are trying to achieve, you start off your profile life by asking a innocent question about diving in cabo san lucas, then you reply saying how much of a great experience you had with BAJA DIVE and divemaster CARLOS. then you promptly reply that the manta boat from manta cabo san lucas was indeed the boat that sunk, then when the unfortunate accident occurred this year, you were very quick to put sunshines name all over your replies, ..... see any pattern?....
then yesterday, you show up again, 9 months after the accident, with a very bad, uneducated, and even illegal video (if the case is still open, you made yourself liable for defamation) showing the BAJA DIVE divemaster CARLOS BRETHERTON DIAZ de SANDI doing the official test on "a tank", as he was the self appointed representative to test the tanks, are you still following the pattern here?
from what we see, the dive community in cabo in general is a very friendly and happy community. this very sad accident effected a lot of people, but trying to pass the blame onto a shop and / or individuals just to make them look bad, is a very low act.
also, just because the shop in question is not on the padi webpage, doesn't mean it was expelled or suspended, if you actually look on the page of expelled and suspended members and shops, you won't see the shops name there. because they were never expelled or suspended.
so BAJA DIVE owner Devor Sherman, or dive master Carlos........ or whoever...... acting like you are, will not increase your business.

 

[DandyDon]

Divers,

The cell used in the EII CO has a max specified range of 1000 (and will actually probably go higher), so as the level of CO the cell is exposed to increases the the signal from the cell will rise accordingly. Essentially, the only limit to the measurement electronics is the fact that the display only goes up to 1999ppm. Once the measurement goes past this the display will just show '1' (as it does on the video) to indicate that the display is over range. So that's why the unit displayed the values that it did when it was exposed to the gas.

The reason why we only specify a range of 50ppm is that is what the unit is calibrated on and the higher level of measurement you then go to the accuracy will degrade. But in reality once you get over a few ppm you wouldn't really want to use that gas anyway, so being able to measure much higher levels of CO accurately is irrelevant.

Hope this helps and highlights just how wrong a tank of diving air can go.

Thanks for explaining. Makes sense.