[patcheudor]

What I still don't understand is why the pressure regulators and over pressure valves on the house gas meters didn't kick in? Were the homes involved so old that the meter protections failed or weren't there in the first place? It seems that ultimately you've got to have failsafes at the homes themselves. Without such failsafes, what would stop a bad actor from purposely over pressurizing a residential branch?

[jacquesm]

Those regulators work within a set range of input pressures, and need a certain delta to work properly. Over-pressure them severely and they will simply fail, and most such failures will lead to gas escaping from the regulator body. That is why you will usually find them outside of the premises they protect so they vent into the outdoors rather than into some enclosed space.

As for your bad actor: what would he pressurize your lines with? An air compressor? He'd have to dig up the lines or disconnect them first and gas from the line would likely escape in quantities large enough to discourage such tricks.

Just like in theory you could disconnect the mains from a house and then send a high voltage pulse down the feed lines, in practice pranksters and miscreants tend to avoid doing stuff that might get them killed instead.

[patcheudor]

>What would he pressurize your lines with? An air compressor? He'd have to dig up the lines or disconnect them first and gas from the line would likely escape in quantities large enough to discourage such tricks.

On the gas meter on my house anyway, the underground pipe mates at a valve. It doesn't seem hard or particularly dangerous to shut that valve off, disconnect the meter, connect whatever, then open the valve again.

[jacquesm]

If you leave the valve attached to the mains line then you can access the house lines, usually there is even a special port for this that you could use without disconnecting the mains line that is used for leak inspection (they evacuate the lines and measure the rate of seepage). Once you connect something in the line and you open the valve again all pilot lights will have been extinguished and won't re-light due to safeties.

Anyway, if you want to destroy someone's house there are much quicker, less obvious and easier ways to do so.

[lutorm]

What would those devices do? A pressure regulator is designed to handle a range of input pressures. If the pressure really got 75x higher than the design pressure, the regulators probably just failed.

[sschueller]

Are there really no pressure release valves that will blow out at a certain over pressure? Like a spring release that will give way and release all of the gas outside the house.

[ip26]

Supposedly, old lines like these are low pressure lines to the house. Thus nobody has a pressure regulator in their home. It seems crazy today but these lines are antique, from the days when electrical wire was run by knob-and-tube.

[dsfyu404ed]

Residential gas piping hasn't changed much over the years. Threaded steel pipe from 1910 should be able to hold a couple orders of magnitude more pressure than it should ever see.

The real determining factor is not age but whether the installer was lazy and hand tightened it all (which you can get away with at 1/2psi, but not much more).

[ip26]

If there's no pressure regulator (due to systems being designed that way a hundred years ago), and the pressure spikes, it doesn't matter how the pipes were put together- your pilot lights become blowtorches.

[mikestew]

It does seem odd, and I’m guessing that such protections simply do not exist or the article might have mentioned it. Kinda like running a network with no firewall if you ask me. “I’ll accept whatever comes down the pipe” is a bad idea whether it’s a literal pipe or Ethernet.