[GOPJ]

The utility's inlet pressures were so low, and dropping, that soon the distribution system pressures would be below atmospheric pressure. Air could then flow into the gas pipelines. Typically, back-flow valves stop that. Since many of the furnaces were old and converted from prior fuels (oil, coal), proper valving was a big problem. Oxygen in natural pipelines is incredibly dangerous. Whole city blocks could be destroyed in an air/gas explosion.

Worth reading ping...

[kjam22]

Politicians think they can shutdown or throttle back natural gas production and use solar or wind..... with the idea of then kicking natural gas on at the coldest days when most needed.... so stupid. Anyone who has worked in NG operations knows when it is down in cold weather it takes time and a lot of extra manpower to get it back up. Dumb dumb politicians talking and legislating stupidly

[rktman]

Differential pressures in gas systems IS a thing.