Analyzing tanks for CO?

[mainedvr]

Received my CooToo today analyzed 8 tanks no CO, very happy From what I have seen, read and heard I know CO issues on the whole are rare but now I can at least rest assured that I can test for it. I asked this in another thread but do you need to bump test it for CO just as you would calibrate it for O2. We test our four gas units at work everytime we use it and its good for the shift. Was wondering if you do bump test it can someone recommend a source for bump gas

 

[archer1960]

Interesting note: I dove tonight. Myself and one other diver had gotten fills at one local shop, and the third diver had gotten fills at a different shop. Mine and the other diver that got fills at the same shop both registered 1ppm and I thought perhaps my cootwo was reading incorrectly as I do trust their fill station. 3rd divers tank then read 0ppm and I went back to my tank and sure enough 1ppm for CO.

I'm the one that posted above about my shop often showing 1 -2 ppm, and I see the same thing. Open air and tanks filled elsewhere usually show 0.

 

[kelemvor]

10ppm is the limit, 5ppm recommended, many of us go with 3ppm as a max

I go with 0.

 

[tbone1004]

I go with 0.

you can't unless you are getting pure O2 or Helium. Ambient air contains CO, small amounts of it, less than 1ppm in most places, but if your fill station is in a populated urban area, it's going to be closer to 1ppm, maybe 2ppm depending on where you are. In the Keys, you have limited traffic, and lot's of wind and fresh air, so yours is going to be lower than the fill stations at say Northeast Scuba Supply, Dive Right in Scuba, Add Helium, etc. that are in populated urban areas you can only get so remote with the intakes and prefiltering only does so much... If you have the cootwo set to not show tenths, then yeah it may read 0, but if it is showing tenths, then it won't show 0ppm unless it is an O2 bottle

 

[kelemvor]

you can't unless you are getting pure O2 or Helium. Ambient air contains CO, small amounts of it, less than 1ppm in most places, but if your fill station is in a populated urban area, it's going to be closer to 1ppm, maybe 2ppm depending on where you are. In the Keys, you have limited traffic, and lot's of wind and fresh air, so yours is going to be lower than the fill stations at say Northeast Scuba Supply, Dive Right in Scuba, Add Helium, etc. that are in populated urban areas you can only get so remote with the intakes and prefiltering only does so much... If you have the cootwo set to not show tenths, then yeah it may read 0, but if it is showing tenths, then it won't show 0ppm unless it is an O2 bottle

Interesting, I didn't realize I could change the setting. I'll do that, just because I think it will be interesting. I'll probably still go with <1 = OK.

 

[nadwidny]

you can't unless you are getting pure O2 or Helium. Ambient air contains CO, small amounts of it, less than 1ppm in most places, but if your fill station is in a populated urban area, it's going to be closer to 1ppm, maybe 2ppm depending on where you are.

No. Normal atmospheric air, even in populated urban areas doesn't contain 1-2ppm ambient CO. I can show you a few thousand scans from compressors in urban areas using no filtration (other than for moisture and particulates) to demonstrate that fact (our instruments' official level of detection is 0.75ppm but we can see down to 0.2ppm).

 

[nadwidny]

Interesting, I didn't realize I could change the setting. I'll do that, just because I think it will be interesting. I'll probably still go with <1 = OK.

I doubt any handheld analyzer would be at all accurate at anything more than +/- 1ppm so setting it for 10ths really wouldn't mean anything.

 

[tbone1004]

No. Normal atmospheric air, even in populated urban areas doesn't contain 1-2ppm ambient CO. I can show you a few thousand scans from compressors in urban areas using no filtration (other than for moisture and particulates) to demonstrate that fact (our instruments' official level of detection is 0.75ppm but we can see down to 0.2ppm).

maybe in Alberta, but the WHO would beg to differ for major cities in the US....

 

[67macoshark]

Was wondering if you do bump test it can someone recommend a source for bump gas

I've picked up more than a couple of lp72's from garage sales over the last couple of years. One set was doubled up and last filled sometime around 1965, and had 1500psi still in it. Fortunately (for me) is has 20ppm of CO. I have another single lp72 that had 1200psi when I got it. That one was filled sometime in the 70's, and it has 10ppm of CO. I am set for bump gas for a while.
They both tasted a little like a Lucky Strike, or maybe a Camel (non-filter).

Here are the 2 sources linked on the cootoo support forum.
Disposable Calibration Gas, Function Testing Gas, EPA Protocol Gas Calibration Gas Cylinders
Calibration Gas Buy from Cross

 

[kafkaland]

I'd be more curious to know how often CO is found.

I have rejected tanks twice that had more than 3ppm CO in them. Until I got my COO2 which gives me the CO reading while I check O2 on my Nitrox, I had no idea that this would actually be an issue.