system
Given the following post, respond as if you're commenting on Reddit:
human
When gas explodes, why is it a relatively small explosion which doesn't propagate further into the pipes? If all houses in the neighborhood are connected to the same gas line, why don't they all expolde?

Is there some sort of detection of leak which would close a section of a pipe? I am so confused!
gpt
The explosion involves the rapid combustion of the gas and combustion requires a source of oxygen. Gas that has leaked from a pipe into a building has been thoroughly mixed with the oxygen in the air, making for a very combustible mixture.

The gas that's still in the pipes doesn't have the necessary oxygen to ignite.