San Bruno Pipe Failure NTSB Report

By 803056

Date 01-25-2011 12:42

Excellent link!

Best regards -Al

By joe pirie (***)

Date 01-25-2011 14:56

What a great report. i hope they take this line out of service immediately.
I hope all you welders out there at least glance at this report and realize
how important the quality of the work you do is and why we do NDE inspection
Quite a few people lost their lives in this explosion. Perhaps so calif gas company,
PG&E to name a few will start using CWI or API certified inspectors not just a bunch
of old pipeliners who happen to be there buddies. Perhaps DOT or some other agency needs to
enforce the use of proper qualified personel. How many other time bombs are out there
sorry for the rant but this reallly pisses me off

By dbigkahunna (****)

Date 01-25-2011 18:34

You realize this pipeline was laid in 1956?
The quality of this below typical of what you see in this era of pipe lining.
This was probably radiographed 10% if at that,
And they got their 50 years design service out of it.
You can find a lot to get razzes over but you are way off base here.
If this line had been laid in the 1980's or 90's maybe yes.
And I know for a fact PG&E uses qualified inspectors with CWI's and all their welds are radiographed today on x-country pipelines. And have been that way for over 20 years.
This has more to do with aging infrastructure than lack of inspection in 1956

By joe pirie (***)

Date 01-25-2011 19:28

if you read the report the pipe was not xrayed when installed but when they UT tested
the wall thickness 55 years later it was still acceptable to current code standards. it wasn't
the pipe that failed it was the poor quality of workmanship of the welders. every pipeline i've welded on
or inspected on has been 100% x-ray. I keep close contact with my old rig welder buddies to keep a
line on future work my friend was working for PG & E and i asked him to talk to an inspector to get me a foot
in the door and he told me the inspectors were not CWI. I have welded on numerous so calif gas co projects
for arb, kinder morgan, se pipeline to name a few and their inspectors are not certified by anyone. Just because somebody
is a CWI does not in any way shape or form qualify them to interpet an xray, UT or any other form of NDE testing. I don't
think im off base here at all, and when the truth comes out about the inspection procedures being done on these existing pipelines
comes to light the ****s gonna hit the fan. You got any rr tracks by your house? chances are theres a hi pressure pipeline running
right along side it. How many more people need to die before these pipelines are properly inspected 100% instead of just a certain
percentage.

By Jim Hughes (***)

Date 01-25-2011 19:40

I disagree. I think when you see something like you see in this report, it's not about aging infrastructure it's about lack of inspection by welders and the company that put it in. When I worked for ALCOA, I saw a 800 PSI steam line that had to be cut out and moved, that was built in 1948. It looked like it was welded with E6010 all the way out. You old school guys know what I'm talking about when I say it had a E6010 lased cap. It was done very well from the root out, that weld looked great. Hands were doing it right back then, but like today they had a choice to do it correct or incorrect.

Thanks
Jim

By dbigkahunna (****)

Date 01-26-2011 00:35 Edited 01-26-2011 00:54

The original line was installed in 1946. This segment of line was installed in 1956
The welder who made this weld is dead. Probably the company he worked for is long out of business.
Did this pup section come from the original install in 46? It did not say.
There were not the capabilities to radiograph the welds. NDT was in its infancy. The film was horrible. Most of the NDT was done at the compressor stations because that is where the pressure was in those days. And in 1946 they were lucky if they had a company inspector on site anyway. Most of the men were still in uniform.
This was a pup run. In the old days they took the pups and dropped them in. Dont waste pipe. 1946 or 1956??? Was this war surplus pipe?
They did offset the pipe seams.
This report indicates the initial failure occurred in a girth weld. And looking at how the failure was contained the offset seam welds did what they were designed to do. Stop the failure.
El Paso had one fail outside Belen NM that went for three joints several years ago because the seams were aligned.
All the pipeline companies are facing the pre 70 ERW problem and there are still lap welded pipe and this pipe looks like DSAW. They cannot and the public will not tolerate shutting down these pipelines. Even the technology available today cannot catch some of this and the bad girth welds cannot be dug up and x-rayed. And the smart tools cannot find all the defects.
In this case had a tool been run the problems in the long seams would have been discovered. But the problems in the girth welds would not have been found.
The result of this failure is sad, but the knowledge gained from the analysis is invaluable.
They way you find out how airplanes crash and prevent it from happening is to study airplane crashes.
And to think of all the thousands of miles of pipelines, how rare a catastrophic failure like this.
The fall out of this will result in a lot of work.

By Cumminsguy71 (*****)

Date 01-25-2011 18:46 Edited 01-25-2011 18:49

"A length of welding rod was found fused to the C2 girth weld on the inside of pup 2 as shown in figure 23. The location was approximately 90° counterclockwise of the longitudinal fracture in pup 2."

Wow! Welding back then was a hole different creature than today from what I've learned to date. Can't believe some of the seams and the lengths of the "incomplete fusion".

Figure 7a shows pup 1 and 2 with girth welds C1, C2 and C3, they have three girth welds within approximately 6 feet? Is that normal?

Advise taken Joe, read it cover to cover, learned some new words along the way...many new words actually, but very interesting to see/learn.

By rlitman (***)

Date 01-25-2011 18:06

WOW! Excellent read.
Pages 63 through 68 are truly shocking.

By Blaster (***)

Date 01-25-2011 20:28

Here it says 8 dead: http://en.wikipedia.org/wiki/2010_San_Bruno_pipeline_explosion

By Pickupman (***)

Date 01-25-2011 22:21 Edited 01-25-2011 23:56

After looking at the pictures and reading the report it's a wonder it lasted as long as it did. I can't figure why they had so many short pups in that area. Only thing I can come up with (which it doesnt say) is that there was either a damaged section there, or they had a small change in direction and no way to bend it. Whatever the case the welding sucked. In some places less than 50% penetration!!

By Cumminsguy71 (*****)

Date 01-25-2011 22:48

Here's a link to the article in this months issue of Pipelin & Gas Journal, http://www.pipelineandgasjournal.com/beyond-san-bruno-industry-takes-stock

They had a pretty good write up about this that fits well in this discussion. I know it was a different time back then but I've seen some of those ol' timey welds that looked really good for what they were doing and I have to say, some of the photo's shown in the report were absolutely atrocious.

By dbigkahunna (****)

Date 01-26-2011 00:53

Excellent follow up article.
Covers industry response.
Young person getting into pipeline inspection think Pipeline Integrity Management.
Major bucks to be made in that discipline in the next few years.
Heavy math and RBI quantification.
Where do you concentrate the inspections to mitigated the consequences at the highest risk locations.
There is a tremendous amount of pipelines and a limited amount of $$

By Cumminsguy71 (*****)

Date 01-26-2011 17:48

"Young person getting into pipeline inspection think Pipeline Integrity Management."

I was just talking with a guy this morning that has been very helpful in my pipe welding end of the business and he was telling me about the new government program called "DIMP", Distribution Integrity Management Program. Said they passed it in December, 2009 and all of the utilities have to have it implemented by August as the inspectors will be out in droves checking.

Watching the videos on their website, webcast I think. They showed a map of the hazardous material and gas transmission lines. Can you guys in Texas plant a flower without hitting a pipeline? Looked like somebody poured red noodles over the U.S map and most of them landed on Texas!! LoL!

By MBSims

Date 01-26-2011 17:31

If you look closely at the report, they identified the initiation point as being in the long seam weld that had only 55% penetration from the O.D. The long seams would typically be made with sub arc, but the report mentions "squirt gun" (MIG?) repairs were observed on the ends of some pipe lengths. From the report photos, the lack of penetration was clearly visible on the I.D. portion of the long seam and should have been obvious during installation. It appears to me that this was probably supposed to be welded from both I.D. and O.D. with sub arc and the I.D. pass was not made. I did not see where any of the girth welds were identified as having failed due to weld defects, even though they did not look very good. It is amazing this line lasted so long with only 55% of the intended weld size.

By DaveBoyer (*****)

Date 01-26-2011 03:35

I am surprised that it lasted as long as it did, after seeing all the defects in both pipe and joints.

By Ringo

Date 01-26-2011 15:01

PG&E Faces Demands For More Information After NTSB Reports Defective Welds.
The San Jose Mercury News (1/25, Johnson, Rogers) reports, "PG&E faced growing demands Monday to provide more detailed information about the construction of the San Bruno pipeline that exploded Sept. 9, amid concerns that its shoddy construction might have been replicated under other Bay Area neighborhoods." That was in response to a NTSB report that "revealed 150 defects in welds along the 43-foot section of pipe that exploded, apparently dating to the installation of the pipe in 1956."

The San Francisco Chronicle (1/23, Nalder) reported, "Federal regulators missed at least two chances before the deadly explosion in San Bruno to force Pacific Gas and Electric Co. and other utilities to collect more accurate information on their gas pipes and use better inspection techniques, a Chronicle investigation has found." And "in November, two months after the explosion, the federal Pipeline and Hazardous Materials Safety Administration finally enacted a rule that will force companies to report what inspection techniques they are using on pipelines - an idea the agency first considered in 2003 and then rejected."

By rcwelding (***)

Date 01-26-2011 15:23

Dave I totally agree with you..!! Its pretty amazing that this line stayed active as long as it did..

It makes me feel better about how current lines are going in.. If this thing can last 50yrs we should be in good shape 50yrs from now with the stuff we are building today..!!

RC

By Blaster (***)

Date 01-26-2011 15:28

What pressure level would a pipe like that normally see at peak?

By Cumminsguy71 (*****)

Date 01-26-2011 15:42

The article from P&G J said they were running 375 psig in the San Bruno pipeline but there were some electrical problems a few days before the explosion that got pressures up to 390 psig. I believe it also said something about that pipeline being in a "high consequence area" and federal limits it to 400 psig. It would be interesting to see what kind of pressure it was designed for back in the day. Looks like a bunch of stuff didn't meet code standards back when they were building it, especially on the longitudinal welds.

By rcwelding (***)

Date 01-26-2011 16:48

375psi on how thick of wall 1950s pipe..?? That mite be pushing the envelope just a touch..!! LOL..!!

RC

By Cumminsguy71 (*****)

Date 01-26-2011 17:22 Edited 01-26-2011 17:32

I believe the pipe was .375 wall from the NTSB report. We did a new station using two inch about a year or two ago and it was running 750 psig before the valves where it kicked it down to 60 psig. I believe it was standard wall 2" gas pipe. I just welded it but it was engineered by a guy and Tennessee Gas Pipeline was out there swapping out some parts and they did the testing on it, something like 1300 psi. Was a pretty nervous moment out there when they started to shoot the nitrogen to it. Seems like it came directly off a 24" transmission line a meter, then to the station and then out to the 4" main line for the house's and prison in the area. I know for a fact that the transmission line was running 750 cause I asked but not sure if it dropped down thru TGP's meter before it hit the 2" coming out of the meter house.

By rcwelding (***)

Date 01-26-2011 17:26

Well I guess that's not too bad..!! 50yrs of rust may thin it out a bit in spots though..!! LOL

RC