• Welcome to ScubaBoard


  1. Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

    Benefits of registering include

    • Ability to post and comment on topics and discussions.
    • A Free photo gallery to share your dive photos with the world.
    • You can make this box go away

    Joining is quick and easy. Login or Register now by clicking on the button

Sensorcon 20% discounts thru April 25

Discussion in 'Computers, Gauges, Watches & Analyzers' started by DandyDon, Apr 5, 2018.

  1. divinh

    divinh ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 100 - 199
    Location: San Francisco
    1,026
    526
    It seems like, with awareness of CO, divers would speak with their wallets and avoid filling stations that don't have CO monitors. The filling stations that don't use monitors will eventually lose business and either adopt or go out of business. Diver awareness seems key to getting filling stations to adopt.

    The reason I'm on this thread in the first place is because I wanted to pay for a tester and I bought one, the Sensorcon. Now, there's uncertainty with its effectiveness as a tool for divers. It's why I sought for clarity on testing methodology. If the Sensorcon can't test directly within a pressurized air stream, can it test with a pocket of captured air? Or will only top-of-the-line suffice, in which case, why not only buy inline monitors with auto shutoffs, as in your case? Was cost an issue? If cost is an issue for divers, then will a Sensorcon suffice? Are there regulatory standards for CO testers that all testers must meet? And regarding the price difference between a low-end vs a high-end, the more expensive cost means more features, but not necessarily less safety? (For example, regulators have a large range in pricing, but the most cheap ones will serve a diver, provided it has passed industry standards.)

    Given that not all dive ops have monitors yet, what can a diver do if he/she is going on a liveaboard where air is provided by only one filling station? Bring his/her own tester? Fine. Now, what's a safe tester to use without breaking the bank?
     
    Last edited: May 2, 2018
    Jay likes this.
  2. DandyDon

    DandyDon Old men ought to be explorers ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: One kilometer high on the Texas Central Plains
    50,472
    5,582
    Well, a monitor is something on all the time, like an inline monitor for a compressor.

    For a tank tester, there are several choices now - some better and more expensive than others. The Sensorcon in a ziplock may not be as accurate as the pricier models, but I think it'll be close enough to alert you to possible dangers. Just make sure it reads zero in clean air and a few digits when you blow on it. If tank test show a 3, consider complaining and maybe canceling, but after all it took to get you onto the liveaboard - it'd probably take more to get you to cancel. If a tank test reads a 30, bail.

    I started with the Pocket CO, but wouldn't suggest it to anyone - too many problems. Color changing stickers are okay for a vehicle, but not enough for tank tests.
     
    Last edited: May 2, 2018
    divinh likes this.
  3. divinh

    divinh ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 100 - 199
    Location: San Francisco
    1,026
    526
    Thanks for the correction in the distinction between monitor and tester and providing a sensible methodology. Previous post edited for correct terminology.
     
    Jay and DandyDon like this.
  4. Jay

    Jay Need to dive more!

    # of Dives: 100 - 199
    Location: Melbourne, OZ.
    994
    566
    A question about in-line monitors (with auto-shut offs). DAN AP last week emailed about their campaign re CO - link: DAN Divers Alert Network Asia-Pacific : Membership and Insurance for Scuba Divers (Yes, @DandyDon they heard you before you wrote your post!!). In their text they say "CO contamination usually arises from impurities in the air taken into the compressor or from contaminants generated by the compressor itself." The quote seems to imply the compressor might introduce CO directly into its tank aside from the air intake. This seems wrong to me, and is possibly just a sloppy sentence.

    They also fail to specifically mention in-line monitors, although they do say "Regularly check the quality of the air: this can be done by using detector tubes and other non-reusable devices, or with electronic analysers. Alternatively, and required in some regions, air testing by accredited laboratories can be done."

    As per DandyDon below, wouldn't the smartest campaign simply be for us divers to insist / only get fills from places with in-line monitors (with auto-shut offs) and where all Operators need to maintain and furnish tank testers??
    From DAN AP's email - link is in first sentence above.

    Screen Shot 2018-05-04 at 12.32.09 pm.png
     
  5. DandyDon

    DandyDon Old men ought to be explorers ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: One kilometer high on the Texas Central Plains
    50,472
    5,582
    Oh, I have mentioned DAN before. Once years ago I even called to ask what they could do about the CO risk, tried asking for the Chairman, and was amazed that he took my call - and agreed with my remarks, verbally at least. That one has long since retired, I think.

    Nope, not a mistake. Overheated compressors can partially burn their own lubricating oil adding CO.

    Nice idea but not likely. Test your tanks, let them know you're testing, complain if you even find a small amount, whine & gripe because they don't do more.
     
  6. Dan

    Dan ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: Lake Jackson, Texas
    7,168
    4,701
    I think this sersorcon is good enough for testing / monitoring CO level to be below OSHA PEL of 50 ppm, the limit of CO concentration in the breathing air for human to breathe for 8 hours, Chemical Sampling Information | Carbon Monoxide | Occupational Safety and Health Administration

    I carry the setup below after reading @DandyDon post on CO long time ago.

    640362B0-0CC5-42EC-B9CD-DB786D7D5F72.jpeg

    Just checked the hotel room CO level by pumping the rubber bulb several time. CO level went up from 1 to 5 ppm and level off there (an order of magnitude lower than the OSHA PEL). I’ll check my tanks tomorrow.

    As you can see in the setup (above), down stream of the rubber bulb has a T fitting to vent off the over pressure (as your hand squeezing the bulb) and there is a one-way check valve to insure the air going from the tube onto the sensor, not the other way around (sucking outside air near the sensor and tube fitting, which would be diluting the air flowing onto the sensor). The pumping frequency is 1-2 seconds over a 15-20 second period to provide a sufficient sample for the Inspector’s sensor.
     
    Last edited: May 4, 2018
    DandyDon likes this.
  7. Jay

    Jay Need to dive more!

    # of Dives: 100 - 199
    Location: Melbourne, OZ.
    994
    566
    (But) Wouldn't that burnt lubricating oil be adding the contaminant CO via the air-intake? (or am I miss-understanding the mechanics of a typical compressor - in which case an in-line monitor would not be picking up CO via this source).

    Don't forget those are 1ATM :)
     
  8. Dan

    Dan ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 500 - 999
    Location: Lake Jackson, Texas
    7,168
    4,701
    If compressor is like piston engine, using several oil-lubricated metal-ring seals that form thin film on the cylinder cavity and the air in the compressed cylinder gets too hot, as the piston sliding up & down the cylinder, compressing the air, to the point of incomplete combustion of the oil, the product of the incomplete combustion is CO.

    The Sensorcon CO sensor reads accurately at / very near 1ATM. That’s why the kit comes with a T fitting (circled in red in the close up picture, below), where most of the sample gas from the rubber bulb is mostly vent out as you squeeze the bulb.

    3CA98A5D-BFB2-45CC-A540-2E42F08D8838.jpeg
     
    Jay likes this.
  9. DandyDon

    DandyDon Old men ought to be explorers ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: One kilometer high on the Texas Central Plains
    50,472
    5,582
    Yes, I think we overlooked flow rate pressure affecting the Sensorcon readings. If you drop the unit into a gallon ziplock, then fill the bag from the tank, you should get a good reading. However directing tank gas into the unit seems to give false positive readings. Still a good, economical choice, but not under any pressure.
     
  10. DavidFL

    DavidFL Wide-eyed nube in the Pub ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Orlando, FL
    522
    565
    I bought a Sensorcon during the earlier part of this thread using the discount. Followed the other conversation in the thread about testing under a flow from a tank and experienced similar results using the dome from my DIY El-Cheapo O2 analyzer. I subsequently bought a Cootwo, but i'm keeping the Sensorcon. Have learned a lot about the CO I'm exposing myself to on my bike rides on the highway shoulder, and plan to keep the Sensorcon on all the time in live-aboard staterooms and some hotel rooms. I will use the Cootwo for tanks, but the Sensorcon and plastic bag method as a backup.
     
    DandyDon likes this.

Share This Page