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CNG explosion and fire on a trash truck Investigation

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  • CNG explosion and fire on a trash truck Investigation


    I am a lawyer and investigating a CNG explosion and fire on a Mac/Hyal trash truck utilizing an Agility CNG delivery system. We have reason to believe a hose failure contributed to the accident and also believe there may be other similar accidents and possible recalls. I am very new to this area and I am having trouble finding information. If anyone can point me in a good direction regarding similar accidents or general incident data about CNG/hoses/pressure relief devices that would be much appreciated.

    Thank you,

  • #2
    Welcome to CNGchat Wapner!

    There was a non-profit "Clean Vehicle Education Foundation" which up until a year ago or so investigated such incidents and wrote up reports on each. They are now part of NGV America but I don't see all of the reports online any more.

    You might want to contact NGV America for follow-up. They are having their annual conference in a couple of weeks in Denver. I will be there too.

    John Mitton


    • #3
      Parts of comments included with the news link below about the 26 Jan 2016 incident:

      It is obvious in this video that the fuel tank did NOT explode. All CNG fuel tanks have pressure relief valves which open and vent their contents once the pressure exceeds safe limits. Roasting a sealed bottle of CNG will definitely cause it to vent, at some point.

      You can see the vapor cloud of expelled CNG surrounding the truck. Once the mixture of oxygen (from air), and CNG was at just the right ratio, the vapor cloud ignited. The force of this explosion is still notable, but it isn't like the bottle itself blew up.

      Investigators in Hamilton, NJ have determined that a faulty battery compartment started the electrical fire


      • #4
        Here is a photo of a refuse truck that is less than 2 years old which was fully engulfed in fire - cause not stated. Saddle mounted CNG tank shows delamination of fibers from the heat.



        • #5
          as i understand it one of the most important things to prevent catastrophic failure of a CNG cylinder is to give the safety valves the opportunity to function, often times the only way this can occur is if they reach a certain temperature

          if the fire department comes along before the safety valves reach critical temp and the fire department starts spraying water on the valves they will never reach the required temp for a safe release of the pressurized gas leading to catastrophic failure of the cylinder

          Perhaps this type of failure is the result of poor training on part of the fire department, know when and how to put out a fire involving a CNG vehicle.

          The last thing the fire department wants to do is to not do its job but in this case less IS more, give the valves the opportunity to work, once they start to vent then think about putting out the fire..


          • #6
            OP . . . . just from your comment I can tell you do NOT understand CNG fuel delivery system. There are NOT hoses for CNG fuel. STAINLESS STEEL bent tubing that carry the 3,600 psi CNG fuel is utilized EVERYWHERE in the CNG fuel system. Stainless steel tubing from the fill nozzle to the tank, then outgoing stainless steel tubing along the frame of vehicle to regulator up near the engine where pressure is reduced to individual stainless steel tubes running to each cylinder fuel injector.

            Highly UNlikely that there are whole slew of other trash trucks with problems. CNG in USA is simply the SAFEST system on the road today.

            Consider that all OTR trucks have diesel saddle tanks with absolutely no protection at all. Any T-bone accident or harsh accident with a diesel truck will result in giant fireball of burning diesel as it splashes everywhere on impact and ignites. See video of truck crashing in CA tunnel where it caused LOTS of problems for every vehicle in the tunnel at the time.

            For the above particular truck fire with CNG, investigate EXACTLY what happened in that incident as to ROOT CAUSE of any CNG leakage. Plus the high probability that Fire Department were NOT properly trained how to battle CNG fire.


            • #7
              Republic Services yard in Corvallis OR had this curbside collection truck with overhead tank package damage from a collision. It was likely when service started 3 years ago that low-hanging cable TV wires in neighborhoods were at risk. But the damage to this tank frame on top of the truck - having a height of 16 ft - seems to have happened due to an impact with an under crossing or overhead bridge. Compare with intact tank unit on next truck in the lineup:




              • #8
                well the legal limit is 13.6 ft so it would seem that they forgot to higher the bridges LOL. more likely driver forgot to put the arms down or it could be that someone ordered a tall truck but hitting any overhead obstruction is ultimately the drivers fault as he should how high truck is and be watching for overhead obstructions


                • #9
                  Analysis of an article posted by Betsy Lillian in NGTNews December 10, 2018 titled CNG Truck Fire Under Investigation in Kansas City, KS

                  The Dec 7 2018 (Pearl Harbor day) incident involved a two-year-old CNG garbage truck operated by Deffenbaugh Industries, a Waste Management company. Lisa Disbrow, spokesperson for Waste Management of Kansas Inc., explained that there was no explosion and that the truck was CNG-powered. The root cause is still under investigation. It was servicing a customer at the time - a Phillips 66 gas station (no CNG at this station).


                  A tweet, shown in the article, by Terry Zeigler, KCKPD Chief, attributes fire to propane fuel (in fact, a CNG-fueled truck); misspells Fairfax as Faifax; says truck had just taken on fuel at Phillips 66 at 2701 FAIRFAX, KANSAS CITY, KS ( shows closest CNG fuel available 2 mi away at CNG@Work 401 KINDLEBERGER RD KANSAS CITY KS), and that there were no injuries. Further investigation may show that, as happens several times annually for these waste haulers, the fire may have started in the rubbish load. Usual procedure is to call the fire dept and find a clear parking lot and dump the load.



                  • #10
                    I dont understand why we dont have a dump valve plumbed into the open port for prds and run down the side of the truck in say a 1 inch stainless tube to a large ball valve with a lock pin like a fire extinguisher after a accident or the start of a fire the driver or ems could pull the pin and dump the gas before the tanks got anywhere near being a problem it would take just a few min to get rid of the gas with large tubes and valve. this would also work for cars and light trucks too. all discharges should be aimed upward and not under the vehicle including cars. this is add to not instead of prds
                    Last edited by cowboy; 12-23-2018, 10:08 AM.