Bad weld caused San Bruno pipeline explosion?

I am looking at this piece of pipe:

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and the clean end suggests to me that the entire weld failed. What do our resident pipe weldors say? Steve? Private?

Reply to
Ignoramus1469
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Maybe they cut it to remove it?

Engineman

Reply to
engineman

Looks like it blew open in the center and the vibration busted the joint weld

I am the Sword of my Family and the Shield of my Nation. If sent, I will crush everything you have built, burn everything you love, and kill every one of you. (Hebrew quote)

Reply to
Gunner Asch

============ While in one sense the disaster may indeed be the result of a bad weld [no inspection? no x-ray?], in the larger sense, the disaster was the easily foreseen outcome of the complete failure to criminally prosecute the accountable directors, officers, cadre management, and mid level supervisors for reckless endangerment and/or negligent homicide for prior disasters.

Fines and jury awards against the legal fiction of "the corporation" have little or no impact on the behaviors/actions of the people that run the corporations, but significant individual/personal fines and especially prison time, even short 30-90 day jail sentences, make a deep and lasting impression and reinforce the concept that actions [and omissions] have consequences. Huge salaries and bonuses should come complete with large amounts of [strict] accountability.

-- Unka George (George McDuffee) .............................. The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953).

Reply to
F. George McDuffee

It does look like a bad weld... would love to see some sharp high resolution photos of all this.

However, I don't buy the bit about the 'gas line exploding'. How would it explode? There is little if any oxygen mixed in with the gas, and no ignition source.

I think it happened something like this:

The line developed a small leak for whatever reason, and over time gas accumulated in some adjacent area like a storm drain.[1] Did I hear correctly that it was windy that day? That certainly could have helped mix in some air. Once said mixture found an ignition source the pipe section was probably then broken and ejected up through the street along with tons of other debris in the explosion. From then on was the large fireball being fed from the now severed high volume gas line....

It will be interesting to see the the investigation results...

Erik

[1] TV reports I saw mentioned area residents had been smelling gas for some time.
Reply to
Erik

Surprises me that steel pipes are still used.

Reply to
User

Natural gas is lighter than air. So no collecting in a storm drain.

=20 Dan

Reply to
dcaster

Maybe they cut it to remove it?

Engineman

Well, to start with, my computer says site has moved or does not exist or piffled into oblivion. I do not know if the line had an incident while being worked on, or just sitting there, decaying normally.

The whole weld does not need to fail to produce catastrophic results. A small failure can produce big results. Entire welds do not fail at the same time. There starts a failure in one place, and then it could spread along the whole weld, such as lateral tearing from shifting earth. If the weld was that bad throughout its length, it would have never made it past testing, and that includes the ultrasound and relatively primitive testing methods that predate X rays. If they had even done a NDT, (non-destructive testing) test and pressurized the pipeline to more than 100% of working pressure it would have all cut loose at that time.

From what I can state from 36 years of welding is this:

You have a pipeline in the ground that is nearly as old as I am (pipeline 50 years, me 62), that much corrosion, that many years of shifting under California earthquake activity, that many years of tie-ins (look it up) and repairs, and it blows up.

It's like someone looking at a car with 300,000 miles on it and saying, "Gollee, what could be the problem? It wuz running good yestiddy."

Pipelines are like anything else. They have a lifespan. To get excited that one that is fifty years old failed is not listening to the first few years of the report (at least the one I saw) "Half century pipeline explodes.

And that is even incorrect when you technically define what an "explosion" is versus brissance or conflagration.

But it makes much better press to say the word "EXPLOSION".

"BOO!"

Pipelines are like freezplugs in cars. They last for a while, but eventually they corrode even with the finest of antifreeze and the most meticulous of care. And when they fail, it causes everything to come to a halt.

It's just like you and me. Stuff gets old, and it wears out. It's that simple.

Steve

Reply to
Steve B

Cost. It is a simple risk vs. benefit equation that companies run, but when you factor in human nature you can see the immediate dangers inherant:

Steel is relatively cheap and plentiful, and can be made to virtually any bursting strength required. Company says, "Using steel, we build it faster, cheaper, and start raking in the bucks quicker."

Looking at the risks is difficult, cause you always have the, "it'll never happen to me, I'm too good at what I do, so why even think about a catastrophic failure too much! You wanna freak out the public and ruin the project??"

When you look at how much money the people who built the system have made from it, the money the people running the system make from it now, versus the money paid out in damages, you'll see why rust-prone steel is such a steal.

Reply to
TinLizziedl

It also looks like a thin wall pipe. Pipe welders out there ?

Running close to the surface ??? and Garden/lawn chemicals may have eaten the outside in. Ground water a problem ?

Reported smelling for days before - maybe hydrogen in the pipe that softened the steel into a sponge. Internal destruction from gases.

Mart> >

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Reply to
Martin H. Eastburn

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That's it, always blame the welder! ;)

The failure may not be in the weld, so much as adjacent to the weld. All buttwelds must be at least the same thickness as the pipe at the minimum. There may not be a maximum reinforcement (amount of weld above pipe surface) given. The goal is to always have the base material fail before the weld fails. This is why welding rods and wires all exceed their advertised tensile strengths and why most welders will choose a rod or wire that is advertised as at least as stong as the steel of the pipe, usually stronger. Welds thicker than base material means the base rusts and bursts before the weld does. The other end of that pipe that's still in the hole may have a beautiful buttweld still on it.

We welders have also learned a lot in the 50 some-odd years since that pipeline was laid in there, I hope.

Reply to
TinLizziedl

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>

ah. finally got it to come up. Could you get any farther away than that?

I can't even tell what kind of car that is.

Steve

Reply to
Steve B

Probably no tie-ins on this one, it appears that it is/was a high pressure transmission line, not a distribution line. Something around

600 PSI I believe?
Reply to
Pete C.

Indeed. The NTSB has very good metallurgical expertise on staff and on call; little escapes them. Until then, guess away.

But so what if it is 50 year old. Is it time to tear down that bridge nearby, or the slightly older one in Brooklyn?

That would be ..interesting... as this is/was a transmission line, not a distribution one. The methyl mercaptan is injected post-transmission.

As for the remark about steel pipe.... Given the 1000-2000 psi line pressure; you were expecting what instead of [likely] Sked 3000 steel; maybe PVC?

(My experiences is in liquid petroleum product, not gas, pipelines; but both go boom when you have a bad day.....)

Reply to
David Lesher

I'm going to stick my neck out and predict .................

fingers to forehead .................

metal fatigue ................ metal failure .............. corrosion .................. age ............................ substrate shifting ................ movement from overhead traffic, either directly overhead or nearby .................... Venus in Scorpio.

Let me know how I did.

Steve

Reply to
Steve B

========== The news as it trickles out seems to be getting worse and worse.

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NTSB investigators are looking to determine why a 40-foot section of pipe that was blown into the air by the original explosion appears to have been cut at some earlier point and rewelded in segments.

{Coincidentally, much of the PG&E data appears to have been "lost."}

Despite numerous reports that people in the neighborhood had reported the smell of gas in the days before Thursday's explosion, officials from Pacific Gas and Electric Co., which operates the 30-inch-diameter, high-pressure pipe, said Saturday that so far they have discovered no evidence that they received any calls.

A look into company records has found "no confirmed calls by residents in the vicinity within nine days" of the explosion, PG&E President Chris Johns said at a news conference. The utility also has no record of any construction work being done in the area by PG&E crews in the days before the blast.

-- Unka George (George McDuffee) .............................. The past is a foreign country; they do things differently there. L. P. Hartley (1895-1972), British author. The Go-Between, Prologue (1953).

Reply to
F. George McDuffee

"F. George McDuffee" wrote

BTW, does anyone know the operating pressure of those lines?

Interesting .........

Citizen, "We called in and reported gas. I'm 67 years old and have smelled gas before."

PGE, "Yes, but can you PROVE it?"

Bet they tightened up security after that Erin Brockovich thing.

Steve

Reply to
Steve B

1000psi, 30". The photo showed one end of the pipe (thrown many feet from the crater by the explosion) with one end as if it had been cut cleanly perpendicular to the pipe (a factory end, if you wish); the other end was harder to see in the photo, but looked torn and mangled.

The gas wasn't required to be odorized, and PG&E hasn't confirmed whether it was or not. 1000PSI bursting will create quite the mess even if the pipeline had been charged with air.

scott

Reply to
Scott Lurndal

It's 3/8". (.375).

It's a transmission line, not a distribution feeder, so it was buried deeply.

scott

Reply to
Scott Lurndal

54 years ago, when this line was installed, they were used.

scott

Reply to
Scott Lurndal

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