possible for reg to blow up underwater?

Discussion in 'Basic Scuba Discussions' started by Spoon, Jun 23, 2005.

  1. Spoon

    Spoon Barangay Pasaway

    # of Dives: 200 - 499
    Location: Philippines
    6,554
    1
    0
    i may just be paranoind of equipment failure now but is it possible for our regs to blow up underwater? does anyone actually know someone that has experienced this? o ring failure? what is the worst case scenario in regards to equipment failure underwater?.
     
  2. SeanQ

    SeanQ Single Diver

    # of Dives: 50 - 99
    Location: Vancouver Island
    1,641
    0
    0
    I doubt a regulator could actually explode during normal use. Sounds like a case for the Mythbusters!

    As for equipment failures, the worst o-ring failure would probably be a tank valve o-ring failure. I've heard that it extraordinarily rare; you are more likely to be hit by a meteorite.

    I really don't know enough about first stage internals to make an accurate guess regarding a mechanical failure.
     
  3. mongoose

    mongoose Single Diver

    # of Dives: 200 - 499
    Location: Denton, TX
    165
    0
    0
    From what I gathered during the course of my instruction, a second stage will generally fail *open* resulting in a free-flow or constant stream of air.

    My intuition (which may or may not be accurate) leads me to think that manufacturers would exhaust every effort to prevent anything like an *explosion* from happening with their products, especially something you wear in your mouth up against your face.

    I would think that worst-case equipment failure would be the failure of the safety device that is positioned between the diver's ears, which is the most important safety device we have. When bad judgement creeps in & makes *that* piece of equipment fail, not much of the other stuff matters.

    Just my 2psi

    --'Goose
     
  4. mxracer19

    mxracer19 Nassau Grouper

    195
    0
    0
    Oh man that reminds me. Yesterday I was sitting in the computer room reading something on here, my cuz was in here playing MLB2005 and the cat was on the floor. He had just gotten 6 CO2 paintball tanks filled. I guess one of them warmed up to a sufficient temp and blew its burst disk. LET ME TELL YOU BROTHA...it scared the heck out of me and the cat took off like a rocket lol. I didn't even see her leave. There was a huge pshhhhh sound and I thought the tank was exploding lol...and I turned and looked and there was a plume of CO2 6 feet high into the room less then 2 feet from my cousins face. :eyebrow: The sound was deafening and it went on for a good minute. I could not imagine a HP Tank blowing its burst disk as the pressures in a co2 tank are probably lower than 3500 psi...

    haha but after it was all over, as the tank warmed up it turned into one giant icecube. It was pretty cool.( ;) )


    -Matt
     
  5. JeffG

    JeffG Giant Squid

    # of Dives: 500 - 999
    Location: Edmonton, Alberta
    10,028
    74
    48
    I'm not sure about regs blowing up, but when you start tech diving you better make sure you O2 clean your mask. When you are deco'n out on 100% you are exhaling ~80% O2 and if you accidentally exhale out of your nose (ie into your mask). When it hits that snot and goo that you spit into your mask.....BOOOOOOOM. Nothing more disturbing than watching your buddies head explode into a pile of goo and watch him sink into oblivion without a head.
     
  6. Spoon

    Spoon Barangay Pasaway

    # of Dives: 200 - 499
    Location: Philippines
    6,554
    1
    0

    you serious???
     
  7. JeffG

    JeffG Giant Squid

    # of Dives: 500 - 999
    Location: Edmonton, Alberta
    10,028
    74
    48
    Is a Mask O2 clean?
     
  8. Rick Inman

    Rick Inman Advisor ScubaBoard Supporter

    9,468
    31
    48
    Actually, without the head your buddy becomes more buoyant and will actually drift up.
    It's why tech divers don't use snorkels. The snorkels aren't O2 clean, and if you try to clear a snorkel with deco gas, it will shoot out fire like a flame thrower and could easily burn your buddy or start a fire on the boat.

    Very dangerous.
     
  9. drbill

    drbill The Lorax for the Kelp Forest

    # of Dives:
    Location: Santa Catalina Island, CA
    20,728
    3,298
    113
    A few years ago while diving in Thailand off Chumphon Pinnacle I had a first stage "blow" on me. I heard a loud pop and air started free-flowing out of the first stage. I checked my gauge and watched the pressure drop rapidly but slow enough to easily get to the surface. We just swapped out reg/tank/BCD on the boat and jumped back in. It was a rental reg and I never found out what the cause was but it was an "interesting" experience.
     
  10. dlegros

    dlegros Divemaster

    # of Dives: 200 - 499
    Location: Birmingham, UK
    252
    0
    0
    You owe me a new keyboard! :)

    Dom
     
  11. jva

    jva Angel Fish

    # of Dives: 200 - 499
    Location: the Netherlands
    42
    0
    0
    Yes, that is what my instructor told me at the time. Guess what happened on my very first open water dive..

    Apparently there was a metal part behind the diaphragm of the (very badly/not serviced?) rental 2nd stage that had come loose and it blocked the valve (from opening)..

    Try with INT->DIN adaptors.. (I mean the ones to make your INT regulator fit on a DIN cylinder)

    First and last time I had to use those I went through three adaptor o-rings and the cylinder valve had not even been fully opened.. I think the effect is more or less the same as a cylinder o-ring failure.. I decided not to try my luck under water..

    Makes you appreciate how nice it is to have your own equipment :D
     
  12. wunat

    wunat Scuba Instructor

    # of Dives: 200 - 499
    Location: Bangkok, Thailand
    983
    0
    16
    I think it is the burst disk on the valve that broke. (Anyone correct me if I am wrong. I am doing my DM right now and it just happens that we were talking about this in our class last night.)

    The burst disk brokes when the tank pressure reaches around 120-140% of the tank's working pressure. My instructor said that divers will hear a explosive-like sound what that happens and air will flow continously.
     
  13. dilligaf368

    dilligaf368 Nassau Grouper

    190
    0
    0
    Come on,,,,That's very inaccurate! O2 is not going to ignite Boogers! That's totally wrong! Oil from somekind of defogger maybe because I don't know what in it but Nasal discarge!!!!!!!!!!!!!
    The "Stories" do grow here! Besides depending on the oil "in the mask" it needs to have something to Ignite the O2. I've done HeO2 in Mk 12 and breathed in through the nose on 100% O2. NO EXPLOSION!
     
  14. crabball

    crabball Guest

    24
    0
    0
    I have personally seen first stage fail underwater. The point of failure is the high pressure seat in the first stage.

    This can happen to a lot of used/ rental/ unserviced reg. Which makes sense to us that dives a lot to get it serviced every year.

    When the failure occur, your first stage will seems like it is free flowing and you will find that most of your air get drained pretty quickly and there is nothing you can do except to turn off the tank valve and ask your buddy for air. There may or may not be a pop sound and the rate of free flow also depends on how bad is the seat broken.

    Not nice to try at all....

    Regards
    Andrew
     
  15. Charlie99

    Charlie99 Orca

    # of Dives: 500 - 999
    Location: Silicon Valley, CA / New Bedford, MA / Kihei, Maui
    7,966
    145
    0
    I doubt a regulator could actually explode during normal use.

    You must have a awful lot of meteorites in the Vancouver area. Yoke o-ring failures are not that uncommon ---- I've seen 5 or 6 fail. Although DIN connections are more reliable, those o-rings have also been known to extrude and fail.

    Although complete and sudden failure of a regulator such that it no longer delivers air is unusual, that sort of failure has happened. It's a good thing to keep in mind as you and your buddy wander further and further apart ;)

    And in spite of your doubt that a regulator could actually explode during normal use, one diver reported on this board an incident where his 1st stage forcibly blew apart into 2 pieces. While failures like this aren't common, they do occur.

    "That'll never happen to me" isn't a very good contingency plan. ;)
     
  16. herman

    herman Divemaster

    # of Dives: 500 - 999
    Location: Raleigh,North Carolina
    8,892
    1,203
    113
    Spoon, Jeff owes me a new BS meter as mine now has a seriously bent needle. :)

    The most likely worse case problem you will have with a reg is a blown LP hose near the first stage. Your air will dump very quickly and short of taking your BC off, there is no way to breath off this escaping air. Not to mention you will no doubt have the pure crap scared out of you when it lets go. The nice part is everyone within a mile of you will know it to so you will have your buddies attention......assuming he can see you in the cloud of bubbles. Blown O-rings do happen but will dump air slower than a LP hose seperation. A failed first stage will cause one or both seconds to free flow which is manageable and a blown HP hose is noisey but actually less of a problem than a blown LP hose.
     
  17. DA Aquamaster

    DA Aquamaster Directional Toast ScubaBoard Supporter

    # of Dives:
    Location: VA and NC
    11,134
    1,185
    113
    In cold water the most common potential failure for a regulator is a first stage freeflow resulting from water freezing in the ambient chamber and preventing the sping or diaphragm from moving back to close the high pressure seat over the high pressure orifice. This can happen even in a completely sealed or environmentally protected reg if the seal fails and/or the alcohol or silicone oil or grease used leaks out.

    In warm water the most likely failure for a first stage is a worn high pressure seat. This almost always begins with a slowly creeping intermediate pressure which, over the course of a minute or two with the reg pressurized but unused, will cause a very slight freeflow as the second stage vents the excess intermediate pressure. These are almost always discovered on the dive boat if you pressurize your reg a few minutes before starting the dive and then listen for a slow leak at the second stage.

    It normally takes a few to several dives for the seat to wear enough to cause a freeflow between breathes in the water so you have to have ignored your reg for several dives or have a rental reg used by an ignorant diver for several dives to encounter this. It will cause an increase in air consumption but not catastophically so, and a normal ascent and safety stop is still easily done.

    The most common failure for a second stage is a worn low pressure seat causing a slight freeflow. This is the most common "problem" noticed by divers as the symptom is the same as with a worn HP seat, so the diagnostic process has to start with the first stage to ensure the IP is stable before blaming the problem on the second stage.

    Most other failures fall into the category of cracked cases, old case o-rings, torn mouthpieces, holed diaphragms, or folded exhaust valves that can cause the reg to breathe a bit wet but generally still allow you to get air from the reg. In any event, it's one of the reasons you have the octopus.

    A second stage failure that results in a failure to deliver air is very rare and is virtually always due to an obstruction (rocks or ice) that prevents the lever from moving enough to open the poppet.

    Hose failures due occur, but they almost always give you ample warning first. An HP hose will start bubbling like an airstone long before it fails. Occassionally if the cover is still perfect, you will get a big blister on one that then also leaks. In the event a knife weilding buddy attacjs you and cuts the hose, there is a restrictor in the first stage HP port that prevents rapid air loss so a normal ascent and even a safety stop will be possible.

    Low pressure hose failures are potentially more serious as LP hoses are designed to flow large amounts so air and a total hose failure can empty a tank in not much more than a minute. But again they virtually always give you signs such as weather checked covers, cuts and leaks near the fittings. Pulling back your hose covers now and then to inspect the area near the metal fittings will usually reveal a cracked or cut cover long before the hose fails. A small stream of bubbles virtually always precedes a major failure by at least several dives, so they should be caught during a bubble check or observed by your dive buddy. So again hose failures are virtually always the result of poor maintence and inattention to the warning signs. If your hose covers are too snug to easily pull back for inspection, get rid of them.

    Tank and valve related failures are also relatively uncommon. I have seen a few tank neck o-rings with minor leaks but I have never seen a catastophic tank neck o-ring failure. For this to occur, it needs to extrude and for that to happen the valve needs to be loose so this occurrence is a poor maintenence issue, not a design problem.

    Similarly, extruded tank valve o-rings are very rare as well and are almost always the result of the yoke or DIN fitting not being tight before the reg is pressurized. If it is too loose it will fail and leak immediately. If however you are in the very narrow range between too loose and just tight enough, it may hold long enough to fail during the dive. But again this is almost always the result of operator error, not the fault of the o-rig or valve/yoke/DIN design.

    The burst disc in the tank valve is designed to burst at 90 to 100 percent of the tank's hydro test pressue. This would be 4500 to 5000 psi for an aluminum 80 so it is very unlikely in normal use. But burst discs do flex with each cycle and they can become weak over time. If left in service long enough they will eventually fail at the normal service pressure. The odds are that this will occur during the tank fill or shortly after the tank is filled. It is very unusual for this to occur during a dive. Out of the water, you will hear a loud pop and a very loud and continuous screeching/whistling sound as the air escapes through the burst disc plug. Underwater you will get lots of bubbles and will need to start an immediate ascent. But this is again a poor maintence issue and if the burst disc assembly is changed every 5 years when the tank is hydro tested, it is extremely unlikely that you will ever see one fail.

    Regs "blowing up" are almost unheard of. Where it can occur is if you are using a non )O2 clean first stage with very high percentages of Nitrox (50%-80% or with pure O2. The dirty first stage provides the fuel but ignition also requires a heat source and in nearly all cases this is supplied by the diver turning the valve on suddenly causing rapid compression and heating in the reg as all the gas in motion comes to a sudden stop. Even then an explosion is extremely unlikely and the most common non O2 clean event is a flash fire in the reg that chars the o-rings and causes a very obvious leak. The diver is often unaware a fire ocuured at all until the reg is dissasembled for service. Turning the valve on slowly with the purge button depressed will prevent the problem even in very dirty second stages so the issue is again poor maintence and operator error.
     
  18. JeffG

    JeffG Giant Squid

    # of Dives: 500 - 999
    Location: Edmonton, Alberta
    10,028
    74
    48
    Thats what you get for learning diving on the internet. Any real tech diver knows that when their buddy has their head blow up, it removes any controls of holding gas in your lungs...so they (the lungs) fill up with liquid, thus losing buoyancy. Not to even mention the catastrophic loss of a person's sinuses and what that does.
     
  19. abitton

    abitton Manta Ray

    # of Dives: 100 - 199
    Location: Montréal, Québec, Canada
    566
    2
    0
    You guys are just mean...

    :D



     
  20. SueMermaid

    SueMermaid Loggerhead Turtle

    # of Dives: 200 - 499
    Location: NJ
    1,955
    1
    0
    I had a HP hose blow on me once, it seemed rather fast, I never had any indication that it was gonna go, it looked okay when I put my gear on. *shrug*

    It was not a big thing, (but it sure was loud, it sounded like a herd of buffalo), just one of those things you have to keep in the back of your mind when you dive.
     

Share This Page