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Thread: How does Air analysis work? Also any contacts to affordable Air analysis in Europe?

  1. #11
    RBW Member iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm's Avatar
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    Re: How does Air analysis work? Also any contacts to affordable Air analysis in Europ

    Just a note of caution before you buy these tubes or a overpriced pump.

    Each tube requires a fixed mass of gas (sample) in order to effect a chemical reaction that stains the chemical in the glass tube against a line marking on the side of the glass tube showing the ppm level.

    The mass of gas is normally achieved by a measured flow rate and time. Some tubes will give a false reading if too much gas is supplied or for too long and each tube has its own specific sample rate and flow.

    For our diving compressors we normally use four tubes.
    Carbon Dioxide, C02,
    Carbon Monoxide CO,
    Water vapour
    Oil vapour.

    Each tube has a shelf life of two years. So for one single test every three or six months, depending on compressor type, using the disposable tubes your going to have more tubes left over and out of date before you finish off each of the packs.

    When using the simple flow meter and stop watch method.

    1. C02 is reactant with a sample flow at 0.2 l/min for 5 minutes or a 1litre sample size when using the 100-3000 ppm tube range

    2. CO is the same sample flow and time when using the 2-300 ppm tube (however be aware some dive shops have been using the CO in Hydrogen tube by mistake)

    3. Water vapour is more complicated as the new HSE guidelines require the maximum water content of air measured at the compressor system outlet to be less than 25Mg/m2
    This requires a 2 l/min flow for 25 minutes. Or a 50 litre by volume FAC sample size.

    4. Oil is the hardest of the lot to achieve a correct sample due to the variance in types of oils used in compressors. You will first have to find the compressor oil you are using before I can give you a flow rate and time.

    The easiest method for sampling is make your own with a small regulator and a simple flow meter, the glass test stain tube can be attached by a simple 1/4 bore rubber tube

    Using a small pressure reducing regulator (like a 1st stage ) with a small 0-5 l/min flow meter and a stop watch to measure time per sample and your done

    A report pad to self certify the air purity and in addition a small SOP standard operating procedure should be signed off before self certification.

    The reason I havenít given the part numbers is that within each gas range there is a number of different tubes, you must first decide your test method, or test machine type before a specific dreager tube part number can be offered. Iain

  2. #12
    RBW Member N Bailey is an unknown quantity at this point N Bailey's Avatar
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    Re: How does Air analysis work? Also any contacts to affordable Air analysis in Europ

    Other gas sampling systems are available from Sub Aqua products in the UK using Kitagawa tubes in the same method as a draeger tube. Or you can contact Aquatron in Glasgow UK they can post you a sample cylinder and send you the results back, there is also Case Chemicals that offer the same serice.

  3. #13
    RBW Member yorkie_chris is an unknown quantity at this point yorkie_chris's Avatar
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    Re: How does Air analysis work? Also any contacts to affordable Air analysis in Europ

    Quote Originally Posted by iain-hsm  View Original Post
    Just a note of caution before you buy these tubes or a overpriced pump.

    Each tube requires a fixed mass of gas (sample) in order to effect a chemical reaction that stains the chemical in the glass tube against a line marking on the side of the glass tube showing the ppm level.

    The mass of gas is normally achieved by a measured flow rate and time. Some tubes will give a false reading if too much gas is supplied or for too long and each tube has its own specific sample rate and flow.

    For our diving compressors we normally use four tubes.
    Carbon Dioxide, C02,
    Carbon Monoxide CO,
    Water vapour
    Oil vapour.

    Each tube has a shelf life of two years. So for one single test every three or six months, depending on compressor type, using the disposable tubes your going to have more tubes left over and out of date before you finish off each of the packs.

    When using the simple flow meter and stop watch method.

    1. C02 is reactant with a sample flow at 0.2 l/min for 5 minutes or a 1litre sample size when using the 100-3000 ppm tube range

    2. CO is the same sample flow and time when using the 2-300 ppm tube (however be aware some dive shops have been using the CO in Hydrogen tube by mistake)

    3. Water vapour is more complicated as the new HSE guidelines require the maximum water content of air measured at the compressor system outlet to be less than 25Mg/m2
    This requires a 2 l/min flow for 25 minutes. Or a 50 litre by volume FAC sample size.

    4. Oil is the hardest of the lot to achieve a correct sample due to the variance in types of oils used in compressors. You will first have to find the compressor oil you are using before I can give you a flow rate and time.

    The easiest method for sampling is make your own with a small regulator and a simple flow meter, the glass test stain tube can be attached by a simple 1/4 bore rubber tube

    Using a small pressure reducing regulator (like a 1st stage ) with a small 0-5 l/min flow meter and a stop watch to measure time per sample and your done

    A report pad to self certify the air purity and in addition a small SOP standard operating procedure should be signed off before self certification.

    The reason I havenít given the part numbers is that within each gas range there is a number of different tubes, you must first decide your test method, or test machine type before a specific dreager tube part number can be offered. Iain
    Mine is using Anderol 500 oil, did not know this changed the oil test!

    None of the people who offer tests mention this.

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    RBW Member CCRWannabe123 is an unknown quantity at this point CCRWannabe123's Avatar
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    Re: How does Air analysis work? Also any contacts to affordable Air analysis in Europ

    It would be great if there was anything like Moisture eye only for oil :)


    Thank you everyone :)

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    RBW Member michael-fisch is on a distinguished road michael-fisch is on a distinguished road michael-fisch's Avatar
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    Re: How does Air analysis work? Also any contacts to affordable Air analysis in Europ

    Quote Originally Posted by CCRWannabe123  View Original Post
    It would be great if there was anything like Moisture eye only for oil :)


    Thank you everyone :)
    If that is what worries you, it's simple enough to let the gas flow through an unused white kleenex for a few minutes, any stains or smell on the kleenex means you have a problem, if it looks good enough that you wouldn't have a problem blowing your nose in it your compressor/filter system doesn't have an oil problem.

    Michael

  6. #16
    RBW Member iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm's Avatar
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    Re: How does Air analysis work? Also any contacts to affordable Air analysis in Europ

    Quote Originally Posted by yorkie_chris  View Original Post
    Mine is using Anderol 500 oil, did not know this changed the oil test!

    None of the people who offer tests mention this.
    We are all kept in the dark of these things, its all part of money making pyramid.
    To sell you inadequate junk products and think only brand label.

    This drive to over test, to over service at inflated price all in the name of safety,
    While working from the kitchen sink out back in the dive shop.
    It's all part of the Safety Testing Demand mantra (a STD) and is bluntly a sop to the masses to make money.

    Using an oil lubricated compressor and oxygen clean service is about as far away from each other. Nitrox, the ultimate in bull you can get away with and make money.

    Clean the cylinders and overcharge the regulator servicing then contaminate them from the compressor it’s more profitable scam than selling the kit new. Over servicing to little too often is the new cash cow.

    As for the air testing itself the dive shop probably don’t yet know, or care. Anyhow 3rd party testing is simply a sop to legislation, for the careless and clueless.

    If you take the same Drager tube, the same pump method and the same volume sample per minute. As an example using three of the popular oils used in scuba compressors.

    The Draeger tube is the 6728371 capable of measuring 0.1 to 1 mg/m3 measuring Oil.
    Now not all oils are the same and if the drive is to produce an oil you can’t detect then it’s possible. Your marketing folk love the Pure Air Purity angle, and the customer clueless as to the cloak.

    First take a mineral based oil for comparison the Drager tube can measure anything comming off the filter tower over the 4.5 microgram level and on the test using the same kit it takes 11 minutes 15 seconds to test

    Next Compair 4000 is an oil designed by my father for Compair, the Drager tube can detect down to 7.5 micrograms and it takes 18 minutes 45 seconds on the pump to test.

    By comparison your Anderol 500, the detection limit is 30 micrograms, and takes one hour and 15 minutes to give an accurate reading.

    Next is the L&W oil, LW 9001 now its getting a bit harder to detect. The Drager tube can only detect oil carryover above the 30 microgram level and it takes 1 hour 52 minutes to detect.

    Finally Ultrachem 800 made exclusively for Bauer. Using the same Drager tube to measure this stuff and it’s not even measusable. No matter how much oil is being pumped into your scuba cylinder or how long you flow your sample air through it, you can be paddling in the stuff and yet it shows zero oil.

    So now you know oils can be made to produce test results you want pinned on the wall.
    Go figure smell the coffee. Iain
    Last edited by iain-hsm; 13th October 2016 at 09:42. Reason: spelling

  7. #17
    RBW Member iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm has a brilliant future iain-hsm's Avatar
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    Re: How does Air analysis work? Also any contacts to affordable Air analysis in Europ

    Double post.

    There is a moisure Eye for water vapour, No dive shop I know hardly uses that either.
    Last edited by iain-hsm; 13th October 2016 at 09:45.

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    RBW Member CCRWannabe123 is an unknown quantity at this point CCRWannabe123's Avatar
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    Re: How does Air analysis work? Also any contacts to affordable Air analysis in Europ

    I plan ti have it at least for water vapour.

    But I am at home user, pumping rebreather bottles, which is not so often. We have a big compressor down at the club which I use for every weekend, however I have a small Coltri at home for my personal use, expeditions and such, so it clocks not so many hours per year, but still I would like to remove at least some doubts about what's pumping

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    Re: How does Air analysis work? Also any contacts to affordable Air analysis in Europ

    Quote Originally Posted by michael-fisch  View Original Post
    If that is what worries you, it's simple enough to let the gas flow through an unused white kleenex for a few minutes, any stains or smell on the kleenex means you have a problem, if it looks good enough that you wouldn't have a problem blowing your nose in it your compressor/filter system doesn't have an oil problem.

    Michael
    Good idea in general for a more substantial oil problem, however is it detailed enough to catch/see the small bits and small oil particles?

    On the first I would guess no, but cannot know as I am not experienced in that part.

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