[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.