What’s with all the homes in Boston blowing up from gas leaks?

[A930Rocket]

Seems very unusual.

Boston-area gas explosions kill at least 1, injure 13, trigger evacuations, officials say

Boston-area gas explosions kill at least 1, injure 13, trigger evacuations, officials say | Fox News

[Noah930]

Also odd that there is so little news coverage.

[Arizona_928]

I wonder what could fail for this to happen?

I suspect more then a pilot light out and the air compressor kicking on the fridge igniting.

Sounds like a sudden spike in line pressure when they were working on the lines. My first thought was that somebody had hacked into the distribution network to crank up the pressure.

Scary stuff.

[vonsmog]

What is odd is this is in a large area, not close together. There is something not right about it, as around here there is a regulator on the line coming into the house to control pressure changes. So you would have to bypass the regulator or blow them out (don't know if that is possible) for this to happen. Also here if over pressurized then then the extra gas is vented to the outside, so that would have to be removed or blocked off. With over 70 building effected, I think someone is to blame and not an accident.

[billybek]

The regulators are only able to handle a certain amount of pressure on the inlet and make a much lower pressure on the outlet side. Typically for residential about 1/2 psi for the inlet side and 7" of WC on the outlet side. Manifold pressure before the burners is typically around 3" WC for residential equipment +/-.
I would have thought that a spiking inlet pressure would maybe cause leaks through the diaphragm to the atmospheric vent.
Who knows? Maybe ancient equipment in older homes was not able to handle a large change of inlet pressure? Perhaps air had entered the system somewhere and caused these issues? Not sure.

[red-beard]

Originally Posted by madcorgi

Sounds like a sudden spike in line pressure when they were working on the lines. My first thought was that somebody had hacked into the distribution network to crank up the pressure.

Scary stuff.

It is as I suspected. The gas main pressure was too high. The way the regulators work, if the pressure is too high, the relieve the pressure. If it keeps being high, gas will keep going out. Then the gas hits something flammable, like a pilot light, and BOOM!

[red-beard]

Originally Posted by billybek

The regulators are only able to handle a certain amount of pressure on the inlet and make a much lower pressure on the outlet side. Typically for residential about 1/2 psi for the inlet side and 7" of WC on the outlet side. Manifold pressure before the burners is typically around 3" WC for residential equipment +/-.
I would have thought that a spiking inlet pressure would maybe cause leaks through the diaphragm to the atmospheric vent.
Who knows? Maybe ancient equipment in older homes was not able to handle a large change of inlet pressure? Perhaps air had entered the system somewhere and caused these issues? Not sure.

In the US, the inlet pressure is around 2 psig and the outlet pressure is 7-11 inH20.

[carambola]

I was working once in Camden installing a new underground electrical service.
The Operating Engineer doing the digging picked a small gas line, kinked it and then attempted to cover it.
As always, I had to call the gas company to alert them. Turned into a huge scene.
That particular line fed some sort of master regulator, when it senses low pressure the valve opens more increasing pressure in the line.
Luckily the call was made and the request from the OE was ignored.
Was later told that the potential was there to blow a few blocks sky high.
Sounds to me like the same scenario.

[URY914]

We need to outlaw fire.

[A930Rocket]

I remember years ago a guy at work hit a gas line with a backhoe. The sound was amazing.

One more, a guy on a backhoe hit a gas line near my old high school. As I drove by, the firetruck had parked too close and was fully engulfed in flames. DOH!

[URY914]

I was on a project where a gas line was hit by a backhoe. It was scary to say the least.

[widebody911]

Originally Posted by URY914

I was on a project where a gas line was hit by a backhoe. It was scary to say the least.

One of my neighbors pulled that one - he borrowed a backhoe to take out a tree stump and din't get the utilities marked first

[wdfifteen]

Originally Posted by Noah930

Also odd that there is so little news coverage.

The hurricane is grabbing 90% of the attention. I do see a bit about Boston on most every newscast,. CNN only seems to be able to cover one story a day.

[vonsmog]

When I worked for the gas company as summer help while in college, we would work on lines up to 300psi (fed the glass factory) and many times the main lines would have 60psi in them.

[red-beard]

Yanmar Dag - Fire Mountain near Baku Azerbaijan

[sammyg2]

In 1992 a large pipe ruptured at a refinery in Wilmington and released near-pure hydrogen at close to 2000 psig.
I felt and heard the explosion in Placentia, 32 miles away.
Unbelievably no one was killed.

http://community.seattletimes.nwsource.com/archive/?date=19921009&slug=1517659

[billybek]

Someone at work was telling me that in these older towns that the mains are supplying very low pressure gas, around that 7-11" wc figure mentioned before and there are no regulators on the homes inlet. It would seem that a wrong valve was installed and up to 100 psi was sent down the distribution system.
Not sure on the truth of this, just relaying along what was mentioned to me.

[KFC911]

Guess where my neice and family moved to a few years ago....yep . They couldn't go home (hotel), now back in, but no power for a while....every house must be inspected first.

Gimme Flo instead ...

[cstreit]

...and this is the first time this has *ever* happened?

...there were no backups to the regulator?

...no warning that caused an automatic shutoff?

...and 70 houses had the gas leaking long enough to find an ignition source?

Must have been a perfect storm?