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Thread: Manufacturer's WARNING - AMSORB

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    Manufacturer's WARNING - AMSORB

    Team,

    I wanted to share this post from the Inspiration list by Martin Parker earlier today.

    ************************************************** **********

    If you can't be bothered to read the whole mail, here's the message: - AMSORB MUST NOT BE USED IN DIVING SCRUBBERS



    As you all know the only CO2 absorbent currently tested and approved by APD is Sofnolime 797. ( Why did we concentrate on that? - because QinetiQ told us it was good and all our tests have concentrated on it)

    But, we are in the process of extending our trials and investigating other materials -but don't hold your breath for the results as these tests take time.

    But, if we discover any shockers that information will be released immediately.


    We recently tested AMSORB and although the tests aren't completed, it has become obvious that AMSORB MUST NOT BE USED IN ANY diving REBREATHER. ( our testing is limited to the diving application).

    AMSORB is a CO2 absorbent used in anaesthesia machines. It's made by Armstrong Medical - The manufacturer's state it must not be used in Closed Circuit Anaesthesia machines and the material loses it's capability when it becomes wet but I'm sure that all users would read the data sheet.

    The manufacturer's website is here:
    http://www.armstrongmedical.net/products/amsorb/amsorb-main.htm

    It looks like slug pellets, it's packing density isn't good. An Inspiration canister takes about 2.5kg of 797, we could only get 2.2kg of AMSORB in. (so you are giving up quite a bit of absorbency capability before you start). It's claim to fame is that it doesn't have any Sodium Hydroxide in it. My understanding is that NaOH (there's about 4% in 797) acts as a catalyst to the main reaction so without this, the reaction is slower to start which makes it wholy unsuitable for our application.

    The test conditions were the standard European Standard test conditions:
    4C, 40RMV, 1.6lpm CO2, depth 100m.
    CO2 and breathing machine are started on the surface and gas monitored externally on a fast response (calibrated) analyser for the whole descent and then the depth is held constant until we've seen enough - usually between 2- 5.0kPa PCO2. The sample line is inserted in the breathing hose prior to the mouthpiece.

    CO2 started coming through straight away. It goes past 0.5kPa PCO2 very quickly.
    1.6 lpm CO2 is seen as an average rate. IF the diver worked harder then he would get significant levels of CO2 coming through the scrubber immediately!

    Worryingly - the material just doesn't get hot. 797 gets hot and then cools rapidly as the reaction is finished. AMSORB get's warmish then dies but retains some heat which makes the Scrubber monitor appear as though the scrubber is working. We ran the test to 4.0kPa PCO2 and the scrubber monitor still hadn't reached it's warning levels - which is extremely dangerous. With the 797 the first scrubber warning is prior to 0.5kPa PCO2 and the 2nd warning prior to 1.0kPA PCO2.

    THE APD SCRUBBER MONITOR DOES NOT WORK WITH AMSORB.

    AMSORB DOES NOT ABSORB CO2 FAST ENOUGH FOR DIVING APPLICATIONS.

    If you have any further questions please contact me direct.

    Please feel free to forward this message where you see fit.

    Best regards


    Martin Parker
    Managing Director
    Ambient Pressure Diving Ltd
    MartinParker@apdiving.com
    www.apdiving.com
    Tel: +44 (0)1326 563834
    Fax: +44 (0)1326 565945





  2. #2
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    Re: Manufacturer's WARNING - AMSORB

    Quote Originally Posted by diverklondike  View Original Post
    Team,

    I wanted to share this post from the Inspiration list by Martin Parker earlier today.

    ************************************************** **********

    If you can't be bothered to read the whole mail, here's the message: - AMSORB MUST NOT BE USED IN DIVING SCRUBBERS



    As you all know the only CO2 absorbent currently tested and approved by APD is Sofnolime 797. ( Why did we concentrate on that? - because QinetiQ told us it was good and all our tests have concentrated on it)

    But, we are in the process of extending our trials and investigating other materials -but don't hold your breath for the results as these tests take time.

    But, if we discover any shockers that information will be released immediately.


    We recently tested AMSORB and although the tests aren't completed, it has become obvious that AMSORB MUST NOT BE USED IN ANY diving REBREATHER. ( our testing is limited to the diving application).

    AMSORB is a CO2 absorbent used in anaesthesia machines. It's made by Armstrong Medical - The manufacturer's state it must not be used in Closed Circuit Anaesthesia machines and the material loses it's capability when it becomes wet but I'm sure that all users would read the data sheet.

    The manufacturer's website is here:
    http://www.armstrongmedical.net/products/amsorb/amsorb-main.htm

    It looks like slug pellets, it's packing density isn't good. An Inspiration canister takes about 2.5kg of 797, we could only get 2.2kg of AMSORB in. (so you are giving up quite a bit of absorbency capability before you start). It's claim to fame is that it doesn't have any Sodium Hydroxide in it. My understanding is that NaOH (there's about 4% in 797) acts as a catalyst to the main reaction so without this, the reaction is slower to start which makes it wholy unsuitable for our application.

    The test conditions were the standard European Standard test conditions:
    4C, 40RMV, 1.6lpm CO2, depth 100m.
    CO2 and breathing machine are started on the surface and gas monitored externally on a fast response (calibrated) analyser for the whole descent and then the depth is held constant until we've seen enough - usually between 2- 5.0kPa PCO2. The sample line is inserted in the breathing hose prior to the mouthpiece.

    CO2 started coming through straight away. It goes past 0.5kPa PCO2 very quickly.
    1.6 lpm CO2 is seen as an average rate. IF the diver worked harder then he would get significant levels of CO2 coming through the scrubber immediately!

    Worryingly - the material just doesn't get hot. 797 gets hot and then cools rapidly as the reaction is finished. AMSORB get's warmish then dies but retains some heat which makes the Scrubber monitor appear as though the scrubber is working. We ran the test to 4.0kPa PCO2 and the scrubber monitor still hadn't reached it's warning levels - which is extremely dangerous. With the 797 the first scrubber warning is prior to 0.5kPa PCO2 and the 2nd warning prior to 1.0kPA PCO2.

    THE APD SCRUBBER MONITOR DOES NOT WORK WITH AMSORB.

    AMSORB DOES NOT ABSORB CO2 FAST ENOUGH FOR DIVING APPLICATIONS.

    If you have any further questions please contact me direct.

    Please feel free to forward this message where you see fit.

    Best regards


    Martin Parker

    Managing Director
    Ambient Pressure Diving Ltd
    MartinParker@apdiving.com
    www.apdiving.com
    Tel: +44 (0)1326 563834
    Fax: +44 (0)1326 565945





    I guess the testing was in response to this fatality..

    http://www.rebreatherworld.com/showthread.php?t=11796
    Joe Radomski
    CCR Trimix Instructor Trainer
    ANDI Instructor Trainer Director #10

    All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.

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    Re: Manufacturer's WARNING - AMSORB

    Thanks for passing on the warning, Mark.

    Joe, good call in the original accident thread.
    Quote Originally Posted by jradomski  View Original Post
    Interesting..

    That sorb lacks naoh so it will be less reactive (slower chemical reaction) than conventional sodalime..

    I don't think it would function that well at depth..

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    Re: Manufacturer's WARNING - AMSORB

    As you all know the only CO2 absorbent currently tested and approved by APD is Sofnolime 797. ( Why did we concentrate on that? - because

    I think Dräger Divesorb is tested too for Inspo

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    Re: Manufacturer's WARNING - AMSORB

    Quote Originally Posted by IN468  View Original Post
    I think Dräger Divesorb is tested too for Inspo
    Seen as that message comes from Martin Parker - I wouldnt have thought so unless some one else tests it?

  6. #6
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    Re: Manufacturer's WARNING - AMSORB

    Quote Originally Posted by schford  View Original Post
    Seen as that message comes from Martin Parker - I wouldnt have thought so unless some one else tests it?
    I woundn't discount it.. Martin has never said other sorbs couldn't be used but that other have never been tested with the inspiration and the duration and performance is unknown.. We all know most other sorbs should work since the chemical makeup is very similiar.. The sorb in question is missing the chemical thats VERY reactive, instead in concentrates on the less caustic but slower reacting chemical.. Off hand I don't rember the reactivity difference but if I rember correctly naoh is more than an order of magnitude more reactive.. it generates ALOT OF HEAT! Most of the scrubber heat is generated by this reaction..

    Older sorbs used to have KOH as well and thats very reactive also but its not good for you if ingested..
    Joe Radomski
    CCR Trimix Instructor Trainer
    ANDI Instructor Trainer Director #10

    All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated.

  7. #7
    RBW Member Joe Botz is an unknown quantity at this point Joe Botz's Avatar
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    Re: Manufacturer's WARNING - AMSORB

    I wonder how the Bara Lyme that I've been using for the past five years, that I procure from the Hospital I work at would rate. I don't "steal said" I get the lyme that is technically months short of its expiration date.

    I've never had any problems with said product,nor any CO2 issues.

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