Off-duty Mountie dies off B.C.'s Snake Island

[nadwidny]

Before everyone gets all hot and bothered about the CO2 level you have to keep in mind the allowable level in the US is 1000ppm. Had this happened in the US the CO2 level would not have even raised an eyebrow.

Having said that , it is very, very rare to see 700ppm CO2 but having said THAT, since ambient air averages around 350ppm, then there is something going on that there was 700ppm in his tank.

And no, a CO detector will not detect CO2.

 

[Locus]

Before everyone gets all hot and bothered about the CO2 level you have to keep in mind the allowable level in the US is 1000ppm. Had this happened in the US the CO2 level would not have even raised an eyebrow.

The report only lists the abnormally high CO2 levels as one contributing factor to this incident among several. I am unaware of at what levels CO2 in a tank becomes dangerous, and I did not intend to emphasize this factor unduly; it just stood out as the most tangibly wrong thing in the report.

 

[rjk75]

Remember that compressor filters convert CO into CO2 so exhaust or compressor oil burning could cause this.

I thought that the filters "scrub" CO out of the airstream. BRT, are you saying that the compressor is putting that CO2 into the tanks?

 

[Ayisha]

I thought that the filters "scrub" CO out of the airstream. BRT, are you saying that the compressor is putting that CO2 into the tanks?

CO is not mechanically filtered out of the air, but can be chemically converted into CO2. Gaseous CO molecules and gaseous O2 molecules are too similar for simple mechanical filtering. A common way of chemical conversion in the diving industry is with Hopcalite, which in the presence of oxygen in a very dry environment, catalyzes CO into CO2.

 

[rjk75]

CO is not mechanically filtered out of the air, but can be chemically converted into CO2. Gaseous CO molecules and gaseous O2 molecules are too similar for simple mechanical filtering. A common way of chemical conversion in the diving industry is with Hopcalite, which in the presence of oxygen in a very dry environment, catalyzes CO into CO2.

You're telling me that CO2 is being put into the airsupply--how can that be safe?

 

[DandyDon]

You're telling me that CO2 is being put into the airsupply--how can that be safe?

I don't know the details on how efficient those filters are or how much CO2 is produced from an amount of CO. It's just not likely to be a risk. Maximum CO allowed in Canada is 3 ppm, 10 ppm in the US, while as mentioned above - up to 1000 ppm CO2 is allowed in tanks in the US. No way a CO filter producing more CO2 would increase risk. Air averages 397 ppm CO2 but only 0.1 ppm CO. The fact that elevated levels were found is of interest.

 

[Stoo]

Before everyone gets all hot and bothered about the CO2 level you have to keep in mind the allowable level in the US is 1000ppm. Had this happened in the US the CO2 level would not have even raised an eyebrow.

But then there's that pesky Dalton's thing with partial pressures and all that....

 

[nadwidny]

But then there's that pesky Dalton's thing with partial pressures and all that....

Even at 1000ppm that wouldn't be a concern until 40 atm or so.

 

[Locus]

What is the relationship between ml/ml3 and ppm?

 

[nadwidny]

What is the relationship between ml/ml3 and ppm?

I don't think there is anything such thing as an "ml3". That would make it a cubic millilitre which makes no sense. The report should read "ml/m3. Millilitres per cubic metre and ppm are the same.