Major PG&E gas line ruptures during test (blow'd a crater in alfalfa field near town of Weedpatch)

SFGate.com ^ | 10/24/11 | Jaxon Van Derbeken

[HiTech RedNeck]

I was in a village in the Chicago area about twenty years ago when flooding from a heavy rain apparently undermined a large gas main downtown. Fortunately no fire, but the gas could be smelled all over town.

When I was looking for a house to buy in the same geographic area in 1998, I noticed one fairly nice house on the market had an odd gas odor near the garage. I asked the area gas company, Northern Illinois Gas, about it. They came with a sniffer and found a leak at the area, and even said it was due to old copper line corroding from the inside from sulfur containing gas, but didn’t seem to want to do anything more. Well when I learned the gas line belonged to the gas company and couldn’t be replaced by a property owner, I got incensed and called Northern Illinois Gas again. I said they knew their gas lines were corroding like this and they just let them sit. I said this would keep me from buying the house, especially if I could do nothing about it, and let the selling real estate agent know too. Well, Northern Illinois Gas got busy and dug up the yard and replaced the pipe, but by then other more suitable houses were on my short list.

[Greysard]

Interesting way to test. Overpressure, stand back and see what blows.

You can do X-rays and ultrasound until you are blue in the face, but in the end the real pressure is the only test that is conclusive.

Imagine that instead of testing the pipe this way they'd send a robot into the pipe. The robot would have returned fuzzy pictures and engineers would then tell their bosses "Well, we think this spot here and that spot there are kinda weak..." One option is to spend $100K on digging and repairs of a pipe that may be good enough for a few more years. Another option is to declare it safe and do nothing. Can you imagine what the management would do?

But now the pipe is all blown up and there is no debate. That's why it is safer to test.

[Mr. Jazzy]

Not sure if it is common practice to have residential structures built over a transmission line of that size. Transmission lines like this usually have ROW cleared for everything except surface agricultural use. 34” line is not your average street to house line.

[easternsky]

Weedpatch has quite a History during depression era, read the other day it is now 100% hispanic population.

[Diver Dave]

Back in the 80's I worked on a 42" gas line up in E. Washington. The gas line came from Canada and traversed through Northern Idaho, Washington, Oregon and into California. The contractor was PGT (Pacific Gas Transmission) a subsid of PG&E.

The pipe we installed was buried alongside an existing 30" line. The pipe we installed was seamless pipe. All welds were x-rayed. The pipe also had a vinyl coating on the pipe and each joint was coated prior to burial.

Whether this is truth or fantasy, we were told that a condition of the sale of the Canadian Gas stated that the gas could not be sold to any business that was in competition with a Canadian business. Don't know how that could have been monitored.

Here's a pic of that pipeline in Eastern Washington...

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[CarryaBigStick]

Just a stone’s throw from Pumpkin Center...seriously. :)

[ken21]

ut oh!

[jimnm]

I read in an engineering publication that the water test is what the state regulators want, not x-rays or ultrasound. It’s going to take them a long time to test all their line.

[al baby]

All of it but we would rather reward failure in this country and laziness

[GladesGuru]

“Is that near Bugtussle?

Nah. It’s over near Chigger Ridge.”

That is Chigroe Ridge to you, Cracker!

Signed,
The Obamoids of AmeriKa

[TaMoDee]

They are doing it along the line at almost the same time.
They just got done in my area last week. They do not do it one section at a time. They leap frog and will complete the tests and whatever repairs in a few weeks. Doing the test one section at a time would cost them BIG bucks. The idea is to get it over with and start gas transmission as quickly as possible.

[JRandomFreeper]

Just a stone’s throw from Pumpkin Center.

I did bury my father-in-law in Punkin' Hollar, Oklahoma, on the reservation, up near Talaquah.

You have to wonder where these names come from. Does someone wake up and say "I'm going to get blind drunk and name towns and natural features today!"

/johnny

[JRandomFreeper]

So, what did they find out?

a) Testing with air pressure instead of gas is less destructive, and b) there's a problem near Weedpatch. Wherever that is. A state would be nice.

Upshot is that no-one died, the gas company completed their tests and repairs are probably underway.

Beats the heck out of a live test in January.

/johnny

[Jack Hydrazine]

How do you say Weedpatch in Spanish?

[JRandomFreeper]

Interesting way to test. Overpressure, stand back and see what blows.

That's the exact way that the local gas company tests houses when they re-connect gas.

In the field case, as well as home cases, air is used as the test medium.

How would you do it differently? and why?

/johnny

[RLM]

Weedpatch, and Pumpkin Center, are a few miles south of Bakersfield, CA.

[MichaelP]

Weedpatch, Ca...You couldn't make that up!

Mike

[IMR 4350]

They probably ran what's called a “PIG” through it first to find out if there was any corrosion pitting or gas cutting which makes it look like it is being eaten by worms.

If the pipe passes that test, meaning the pitting or cutting isn't too bad, then the pipe is pressure tested.

Testing to the pressure that it will be used is useless, you have to overpressure to make sure it holds. It didn't.

[IMR 4350]

In most cases the pressure test is done with water so you don't get a violent explosion.

It will blow, but it's a short quick blow because the pressure drops instantly with water, unlike a gas which blows and keeps blowing until the pressure bleeds off.