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Testing Air Quality

Discussion in 'Compressors, Boosters and Blending Systems' started by Mad_Max, Mar 5, 2007.

  1. Mad_Max

    Mad_Max Angel Fish

    # of Dives: 50 - 99
    Location: On the shores of Lake Ontario @ Kingston, Ontario,
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    Hi All,

    I'm curious how you guys test the quality of the gas for filling tanks?
    What do you test for and at what levels?

    Best Max
     
  2. Surface Tension

    Surface Tension Nassau Grouper

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    There are companies that will do air tests for you. In Florida there is a company Lawrence Factor. They send you an evacuated container under a vacuum and you suck up a sample of your compressor air. Then you send it back to them and they analyze it; for stuff like CO, CO2, hydrocarbons, etc. I think a sample runs about 40 bucks.
     
  3. Mad_Max

    Mad_Max Angel Fish

    # of Dives: 50 - 99
    Location: On the shores of Lake Ontario @ Kingston, Ontario,
    9
    0
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    I was thinking more along the lines of in-house testing equipment?
     
  4. rjack321

    rjack321 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    9,766
    3,911
    113
    Water and CO are the only things you can (practically) test for. Unless you want to buy a GC-MS and get a degree in chemistry to know how to interpret it.
     
  5. WVDiver

    WVDiver Instructor, Scuba

    # of Dives: 500 - 999
    Location: Podunk, WV
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    http://www.lawrence-factor.com/

    I use these guys to do my E grade air tests. Cheap and easy. They send me a container to fill, I send it back and they send me a report.
     
  6. Mad_Max

    Mad_Max Angel Fish

    # of Dives: 50 - 99
    Location: On the shores of Lake Ontario @ Kingston, Ontario,
    9
    0
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    Qualifier: "Please don't interpret my questions as being "smart-***" or "hyper-paranoid". I'm genuinely interested in how the quality of the gas that goes into my tank is tested. What things are tested for, and how often.

    How about CO2 and O2?
    Can you tell me what is used to test water and CO?
    I would have thought that filling stations would be mandated to regularily test the quality of air from their compressors?
     
  7. wedivebc

    wedivebc CCR Instructor ScubaBoard Supporter

    5,373
    1,115
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    CO2 and O2 are the easiest to test for. You can test O2 content the same way you test nitrox. CO2 analyzers are out there and reasonably inexpensive however since these are the most benign components in breathing air they are not the things you should be too concerned about. I would be most concerned about CO and hydrocarbons.
     
  8. rjack321

    rjack321 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    9,766
    3,911
    113
    Water is tested by moisture sensitive strips in a glass holder.

    CO by a variety of commercial analyzers. Mine looks like this:
    http://www.aeromedix.com/?_siteid=a...363cf684a935b63fed818c0ef&action=sku&sku=coex

    O2 by a galvanic cell, same as for nitrox. Its almost impossible to vary this from the inlet air anyway, unless you are continuous blending nitrox.

    CO2 is rarely measured.

    Hydrocarbons, preferably total volatile hydrocarbons, are tested by gas chromatograph. Must be sent to a good lab.

    Fl (and I think PADI) requires gas testing. States/OSHA regulate air quality used for commercial diving but not recreational usage.
     
  9. wedivebc

    wedivebc CCR Instructor ScubaBoard Supporter

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    CO2 is always tested for in breathing air. We actually had a sample fail CSA standards because CO2 was over the 500ppm allowable. It turned out not opening the window when running the compressor (inlet inside dive shop) was the cause but the standard for CSA is 500ppm and Grade E breathing air is 1000ppm we were 725ppm
     
  10. Mad_Max

    Mad_Max Angel Fish

    # of Dives: 50 - 99
    Location: On the shores of Lake Ontario @ Kingston, Ontario,
    9
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    I'm surprised that there doesn't exist a piece of equipment that can test CO2, O2, CO and Humidity?
    Something inline / realtime, that can give the operator realtime feedback as to what goes in the tank? It just seems to make sense to me. A lot of factors can change from the time a sample is taken and sent to a lab and the results are returned. Also, a lot of tanks can be filled in the same amount of time.
    Am I missing something here?
     

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