gas lines set 70 houses on fire simultaneously in Massachusetts, live now.

[Otis11 + 551]

On 9/13/2018 at 11:08 PM, Jan van Eck said:

I have no solution, or at least no obvious solution, for such a line over-pressure event.  Gas in the home is quite low pressure, just a few psi.  I have to think that those mains are running at several hundred psi. How you figure out how to make that failure-proof is not obvious. 

Why would these systems not have redundant valves and PRV?

I would expect that anywhere there's a designed pressure change or a spec break they would have at minimum a PRV or some secondary protective device. Anything less is engineering negligence. If they had them and they're not working, that's operational negligence.

Either way - this should not be accepted as normal. I'm reserving final judgement until we get more information, but unless there are extenuating circumstances, I would suspect some one failed to adequately do their job. 

[Jan van Eck + 7,558]

18 minutes ago, Otis11 said:

Why would these systems not have redundant valves and PRV?

I would expect that anywhere there's a designed pressure change or a spec break they would have at minimum a PRV or some secondary protective device. Anything less is engineering negligence. If they had them and they're not working, that's operational negligence.

Either way - this should not be accepted as normal. I'm reserving final judgement until we get more information, but unless there are extenuating circumstances, I would suspect some one failed to adequately do their job. 

You are likely right.  The company, Columbia Gas, apparently has this history of problems.  As is typical, sloppy management leads to field problems, it is always the same dismal story.  

And I agree, you would think this would be set up to be idiot-proofed, that it would shut off before an over-pressure could take place.  Obviously, whatever that design was, it did not work.