+ Reply to Thread
Page 1 of 2 1 2 LastLast
Results 1 to 10 of 18

Thread: Final DOT Report on Exploding Cylinder in FL

  1. #1
    RBW Member whynot? will become famous soon enough whynot? will become famous soon enough whynot? will become famous soon enough whynot? will become famous soon enough whynot?'s Avatar
    Join Date
    May 2006
    Location
    CA, NY
    Posts
    609
    MK15.5, MK25

    Final DOT Report on Exploding Cylinder in FL

    From those of us filling scuba tanks... this is the final DOT report on an incident that happened in FL back on September 11, 2011. Long document but worth the read if you handle scuba tanks, with graphics and pictures of the tank and first stage.

    http://www.phmsa.dot.gov/staticfiles/PHMSA/DownloadableFiles/Files/Press%20Release%20Files/11287051_Scuba_Cylinder_Final_Report.pdf

  2. #2
    Cognitive surrender TopLeft is an unknown quantity at this point TopLeft's Avatar
    Join Date
    Oct 2009
    Location
    Columbus, Ohio
    Posts
    441
    Evolution+

    Evolution

    Re: Final DOT Report on Exploding Cylinder in FL

    You call 632 pages a "long document"?! LOL

    Appreciate the link though. I'm quite curious...

  3. #3
    RBW Member decostanza is an unknown quantity at this point decostanza's Avatar
    Join Date
    Aug 2012
    Location
    fly-over country
    Posts
    53
    rEvoIII Ti

    Re: Final DOT Report on Exploding Cylinder in FL

    an interesting read...thanks for posting the link

  4. #4
    RBW Member rjack will become famous soon enough rjack will become famous soon enough rjack will become famous soon enough rjack's Avatar
    Join Date
    Jan 2007
    Location
    Seattle
    Posts
    408
    Meg

    Re: Final DOT Report on Exploding Cylinder in FL

    Quote Originally Posted by TopLeft  View Original Post
    You call 632 pages a "long document"?! LOL

    Appreciate the link though. I'm quite curious...
    It's most an appendix of photos.


    I recall this has been a speculated frictional O2 fire for a long time.

  5. #5

    Re: Final DOT Report on Exploding Cylinder in FL

    Anyone wanna post a little summary? Downloading a pdf with 632 pages on my allready stuffed cell phone is a no-go :-!

    Sent fra min GT-I9505 via Tapatalk

  6. #6
    RBW Member Gl1tchie is an unknown quantity at this point Gl1tchie's Avatar
    Join Date
    Sep 2015
    Location
    Perth, Western Australia
    Posts
    53
    JJ

    Re: Final DOT Report on Exploding Cylinder in FL

    Wow, after all that:

    "The mechanism of ignition which resulted in the explosion was undetermined"

  7. #7
    RBW Member rjack will become famous soon enough rjack will become famous soon enough rjack will become famous soon enough rjack's Avatar
    Join Date
    Jan 2007
    Location
    Seattle
    Posts
    408
    Meg

    Re: Final DOT Report on Exploding Cylinder in FL

    From report:
    A 6061 ali cylinder
    O2 cleaned, Genesis DIN valve
    Dive rite regulator attached

    Fire started at the valve thread interface.
    Fire did not progress upwards into the valve or valve seat.
    Outside of the valve and the attached regulator are completely charred while the insides of both are undamaged
    Fire melted the cylinder thread-crown area as pressure in the cylinder soared
    Burst disk did not rupture so pressure never exceeded 5000psi
    Crack started at the crown in the now weakened aluminum
    Crack split open side of cylinder as gas (from fire inside) expanded
    No evidence of O2 incompatible lubricants anywhere.
    About 12 different sources of ignition discussed and most are not possible
    ~6 different possible ignition mechanisms remain and they were unable to conclusively decide which started the failure

    From me:
    Friction between loose valve and aluminum threads ignited the aluminum and the now weakened aluminum failed.

  8. #8
    RBW Member whynot? will become famous soon enough whynot? will become famous soon enough whynot? will become famous soon enough whynot? will become famous soon enough whynot?'s Avatar
    Join Date
    May 2006
    Location
    CA, NY
    Posts
    609
    MK15.5, MK25

    Re: Final DOT Report on Exploding Cylinder in FL

    I believe there are few missing parts to the event that aren't covered in the report, and more than likely contributed to the explosion. A few of which:

    What was the force the operator used when opening the valve (did he do it slowly to avoid any possibility of adiabatic expansion - heat?)

    What type of lube (if at all) was used in the first stage and on the tank valve o-ring? Were they both clean and current?

    What was the % of O2 in the tank at the time? Did the operator VERIFY this?

    .....

    But the take away should be that as owners and operators of compressed gas cylinders we ABSOLUTELY MUST follow cleaning, inspections, and best practices for handling gases, especially those with higher FO2 percentages.
    Only the guy who owned the tank will know what the history of the tank was, how it was filled (and what with), and how he cracked the valve open. And I'll bet the full story wasn't conveyed to the DOT for this report. I'm not trying to knock the guy but rather saying there are details about what led up to this situation that more than likely weren't mentioned nor made it in this report. Therefore no conclusive decision could be made as to the reason for the event.

    It should also give us pause when we go to have our O2 tanks filled at a shop. The guy (or lady) who is there to fill your tanks has zero clue about how you've handled it. It may have every disco inspection sticker in the world on it saying it's so clean the Queen would drink her favorite hooch out of it. But to the person filling your tank, it's a potential bomb. So when they question you about it being current, clean and up to date, maybe give them a little slack instead of the "tude" I see some jackasses giving as if they are entitled to have it filled with some exotic gas from Kolob. If I was filling tanks at a shop, I'd be nervous filling some stranger's O2 tank as well. A smile and understanding of why they ask certain questions can go a long way...
    Last edited by whynot?; 18th October 2016 at 17:28.

  9. #9
    RBW Member rjack will become famous soon enough rjack will become famous soon enough rjack will become famous soon enough rjack's Avatar
    Join Date
    Jan 2007
    Location
    Seattle
    Posts
    408
    Meg

    Re: Final DOT Report on Exploding Cylinder in FL

    Quote Originally Posted by whynot?  View Original Post
    I believe there are few missing parts to the event that aren't covered in the report, and more than likely contributed to the explosion. A few of which:

    What was the force the operator used when opening the valve (did he do it slowly to avoid any possibility of adiabatic expansion - heat?)

    What type of lube (if at all) was used in the first stage and on the tank valve o-ring? Were they both clean and current?

    What was the % of O2 in the tank at the time? Did the operator VERIFY this?

    The valve was closed at the time of the explosion and fire. He was not opening the valve and the interior of the valve (and attached regulator) was unburnt. The fire started on the exterior of the valve near the bottom (inside end) of the valve-tank thread junction. It spread upwards into the tank neck and downwards into the cylinder from there.


    Silicon or other incompatible lubricants were not found anywhere


    It was marked as a deco gas and contained 100%. They called out that the cylinder was not properly labeled to US DOT specifications with a hazard placard. But the lack thereof was not diagnostic.


    Quote Originally Posted by whynot?  View Original Post

    But the take away should be that as owners and operators of compressed gas cylinders we ABSOLUTELY MUST follow cleaning, inspections, and best practices for handling gases, especially those with higher FO2 percentages.

    This is all true. But contamination was not what started this fire. Not wrenching the valve onto the cylinder allowed it to rotate slightly while under pressure (its not hard to do). The friction of the valve on the aluminum neck threads then started an aluminum-O2 fire.


    Something similar happened to the diver in North Carolina when he knocked an ali O2 scuba cylinder over in his garage and it ignited.
    Last edited by rjack; 18th October 2016 at 17:45.

  10. #10
    RBW Member Pat O'Brien is an unknown quantity at this point Pat O'Brien's Avatar
    Join Date
    Apr 2014
    Location
    Indianapolis
    Posts
    40
    Hollis Prism2

    Re: Final DOT Report on Exploding Cylinder in FL

    Wow over 600 pages and to end the report with the below statement.




    8. The ignition of the fire that led to an explosion originated within the threaded section of the
    cylinder neck opening. The actual mechanism of ignition could not be determined.

+ Reply to Thread
Page 1 of 2 1 2 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts