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OT: Mystery solved...It's not thieves breaking in. It's .......

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  • OT: Mystery solved...It's not thieves breaking in. It's .......

    The door to the equipment room for the building where the welding shop is located is on the outside in the breezeway. In the past several months, the door has been found forced open several times with some damage to the locks and hinges. School officials thought it was someone breaking in to steal the copper pipe or possibly a homeless person looking for a warm place to stay. They installed a security camera to monitor the activity around the door. There was already an alarm system on the door.

    Early yesterday morning, the alarms went off. The replay of the video showed the double doors swinging open violently, but no other activity. An inspection of the room showed another set of double doors was buckled outward and the upper part of a concrete block wall was cracked and displaced about an inch. It was obvious something very bad had happened in the room.

    An inspection of the gas line for the hot water boiler revealed a very small gas leak. The boiler is on a timer, so it's off all night, and comes on early. Apparently enough gas had been collecting in the room to cause minor explosions when the boiler lit off.

    The thing that puzzles me is why the explosions were so small. It seems like a 15 by 20-foot room with a twelve-foot ceiling filled with a combustible mixture of gas would do a LOT more damage.
    Any products mentioned in my posts have been endorsed by their manufacturer.

  • #2
    Absolutely amazing. I know a guy that, after he had his kitchen remodeled, would occasionally find the cabinet doors open. It drove him and the contractor nuts trying to figure it out. They too were convinced that somebody was messing with them. Finally somebody noticed the faintest odor of natural gas. The stove connection was leaking and the gas would build up and occasionally ignite, opening the doors but no fire. It just goes to show that if you live long enough that eventually you will see the impossible, TWICE! You must be living right as you are so fortunate that nobody was injured or killed.
    Take care, Mike
    Last edited by mf205i; 04-09-2013, 12:16 PM.

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    • #3
      The furnace in my old house always lit off with a bang and the door to the furnace room would shutter.

      I have a very small leak on the valve before my water heater right now. I have been putting it off for awhile now but I think I should get to replacing that valve.
      Andy

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      • #4
        Some years ago the juvenile court building in Ottawa blew up, killing the night watchman.

        A small gas explosion in the furnace blew the furnace door open. The gas supply pipe had a vertical leg within the arc of the door swing and this was ruptured.

        The safety system shut down for fifteen minutes and then attempted a re-light.

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        • #5
          ..and yet again one more reason for me to not get a gas line to my house, ever. Though gas heating or cooking is quite rare in residential homes around here, but still.

          One just wonders why there is no leak detectors installed in the rooms that have the gas lines?
          Amount of experience is in direct proportion to the value of broken equipment.

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          • #6
            One of the worst gas explosion disasters occurred in 1937 in New London, Texas:

            http://www.youtube.com/watch?v=aKt01p3DJRw
            Cheers,
            Gary

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            • #7
              When I replaced my central heat/AC unit 3 years ago, the service tech asked me, "Did you know you have a gas leak here?"
              Uhhhh ....NO.
              But, come to think of it, I had been smelling the faintest whiff of gas for about 10 years before the replacement.
              OOPS....
              Lucky I don't smoke.
              Last edited by KiddZimaHater; 04-09-2013, 11:51 AM.

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              • #8
                Some things you just can't make up.

                I was working on changing the road deck in a large tunnel once and another guy grabbed me and took me over to his machine, a trailer-mounted drill-rig weighing about 750kg. We both stood and watched the threads unscrew as the drill was turning and cutting. The drill was turning clockwise, half a tonne of weight on it and the thread was 1.25" BSP right-hand thread, standard on all the equipment. It un-screwed under load right in front of us, we stopped the machine, lifted the drill, screwed the drill back on by hand half a dozen turns until it seated then set it drilling again and watched it very slowly un-screw again whilst it was cutting. You could see the jack-legs start to wobble as it lifted the weight of the machine.

                I adjusted the engine RPM and the phenomenon went away. Tried to re-produce it so I could get some video (D'oh!) but couldn't make it happen again.

                My only guess was that the slight wobble in the bit was making machine wobble and the male thread 'walk' up the flanks of the female thread at just the right rpm. I dunno. People don't believe either of us when we tell them and I doubt I would accept it from someone if I heard it myself had I not witnessed it with my own eyes.
                Peter - novice home machinist, modern motorcycle enthusiast.

                Denford Viceroy 280 Synchro (11 x 24)
                Herbert 0V adapted to R8 by 'Sir John'.
                Monarch 10EE 1942

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                • #9
                  Originally posted by Jaakko Fagerlund View Post
                  ..and yet again one more reason for me to not get a gas line to my house, ever. Though gas heating or cooking is quite rare in residential homes around here, but still.

                  One just wonders why there is no leak detectors installed in the rooms that have the gas lines?
                  Personally I love using gas for cooking and heating water. As to the risks, I have no doubt I exceed the risks of a gas explosion killing me every time I drive whether in my truck or on the motorcycle. Anedcotally, I would guess that the risks of being killed or hurt in a gas explosion are far less than the risks of being killed on the street, here in S. Florida anyway. Given that gas has an odor-ant, mercaptan, to warn of leaks and that the odor of mercaptan mixed in gas is detectable to the human olfactory system at concentrations far less than the flammable range, small leaks are detectable far sooner than when they are a hazard. Certainly there are instances where gas could collect undetected in areas not frequented by humans and that does pose an increased risk.
                  Electric appliances also have risks and an electrical hazard is far less detectable prior to injury/death than gas. We all use it regardless of it's inherent risks, without a thought, every day.
                  However that risk can be mitigated to a great extent with adequate ventilation and detection systems. For me, any many others, using gas in a no brainier for convenience, efficiency, cost and safety, just as electricity is something I wouldn't want to be without.

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                  • #10
                    Originally posted by Jaakko Fagerlund View Post
                    ..and yet again one more reason for me to not get a gas line to my house, ever. Though gas heating or cooking is quite rare in residential homes around here, but still.

                    One just wonders why there is no leak detectors installed in the rooms that have the gas lines?
                    I do wonder that myself. I know they are on boats. And I have seen the sensors they are only like $50~70 quanity 1 (raw sensor, mind you, not an alarm)

                    Still, seems worth it to me.

                    My last house, the furance would often 'fawoof' when lighting up.. And sometimes a loud bang.

                    I think the reason why there was 'so little damage' in the OP story is that not very much of the volume of the building was at the right mixture range for combustion before it ignites. (Indeed, with very still air it might not mix right period, both too rich and lean will prevent combustion)
                    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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                    • #11
                      Gas-fired cookers and central heating is the norm in many UK towns and cities. You don't see buildings blowing up on a regular basis, but then we don't get any real earthquakes either.
                      Peter - novice home machinist, modern motorcycle enthusiast.

                      Denford Viceroy 280 Synchro (11 x 24)
                      Herbert 0V adapted to R8 by 'Sir John'.
                      Monarch 10EE 1942

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                      • #12
                        when you think of all the masses involved it's actually pretty safe stuff.


                        good post WM

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                        • #13
                          I have friends that built a new cabin in the mountains. After having the cabin for only a few years, the propane built up in it and exploded, destroying the entire cabin. The explosive force moved a neighbor's cabin 10" sideways (knocked loose from the foundation). My friends still own the naked foundation. Investigators seemed to think there was a bad propane regulator, but it kinda disappeared.

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                          • #14
                            Originally posted by firbikrhd1 View Post
                            Given that gas has an odor-ant, mercaptan, to warn of leaks and that the odor of mercaptan mixed in gas is detectable to the human olfactory system at concentrations far less than the flammable range, small leaks are detectable far sooner than when they are a hazard.
                            Except for those who don't smell it. Google it. As we get older our sense of smell typically declines and I've seen mentioned where over half of people 60 and older can't smell a gas leak.

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                            • #15
                              Originally posted by Mike Nash View Post
                              Except for those who don't smell it. Google it. As we get older our sense of smell typically declines and I've seen mentioned where over half of people 60 and older can't smell a gas leak.
                              Yep, that would be me...
                              Weston Bye - Author, The Mechatronist column, Digital Machinist magazine
                              ~Practitioner of the Electromechanical Arts~

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