NTSB finds fusion weld variances in pipe from San Bruno blast

Nick Snow
OGJ Washington Editor

WASHINGTON, DC, Dec. 15 -- US National Transportation Safety Board investigators have initially found longitudinal weld variations in pipe recovered following the Sept. 9 explosion on a San Bruno, Calif., natural gas gathering system, NTSB announced.

NTSB emphasized that its investigation is still in its early stages and more information needs to be developed before it reaches a conclusion about what caused the accident, which killed eight people. It noted that metallurgical examination of the pipe includes technical experts from the US Pipeline and Hazardous Materials Safety Administration, the California Public Utilities Commission, and pipeline owner Pacific Gas & Electric Co.

NTSB said PG&E survey sheets and charts for where the pipe ruptured indicate that the line was constructed of 30-in. seamless steel pipe (AP15L Grade X42) with a 0.375-in. thick wall. Initial evidence also shows that the pipeline in the blast area was constructed, at least in part, with seam-welded pipe, it added.

“Investigators found that while the longitudinal seams on some of the pipe segments were fusion-welded from both inside and outside the pipe, some were fusion-welded only from the outside of the pipe,” NTSB said. “In order to understand this variance, investigators are in the process of researching pipe welding standards and practices in effect at the time the pipeline was installed in 1956.”

Outer surfaces of the ruptured pipe’s segments examined by NTSB revealed no evidence of external corrosion, it added. “No dents, gouges, or other physical indications consistent with excavation damages were observed. Additionally, no physical evidence suggests that a preexisting leak occurred in the ruptured pipe pieces,” it said.

Ongoing activity
NTSB said laboratory work is continuing to analyze chemical composition and test mechanical properties of samples taken from the ruptured pipe’s pieces, and evaluation of the accident site’s environment is proceeding. “Other areas that investigators are examining include pipeline control and operations, regulation and oversight, human performance, survival factors, and pipeline maintenance and records,” it indicated.

PG&E said in a response that while NTSB’s update noted a discrepancy in the local natural gas distribution company’s records on the type of pipe which was installed, “at not time did the pressure in the pipe exceed the maximum allowable operating pressure nor did the discrepancy impact the required maintenance and inspection protocols.”

The company nevertheless has launched an exhaustive, system-wide check of its pipeline records to confirm their accuracy and correct any discrepancies, it added.

The Interstate Natural Gas Association of American said in a statement that NTSB’s update demonstrates that the board is taking a methodical and commendable approach in its investigation. “At the same time, we believe that the pipeline industry and federal, state, and local officials cannot sit idly by,” it continued.

“We can better address the issue of damage by third parties such as excavators, the leading cause of fatalities and injuries associated with pipeline accidents,” said INGAA, whose members are primarily interstate gas pipelines. “Local officials need to make better land-use decisions about development near pipelines. And the pipeline industry should keep investing in technology that can reduce risk,” INGAA said.

Contact Nick Snow at nicks@pennwell.com.

Related Articles

Lukoil lets contract for Uzbekistan gas processing plant

02/13/2015 Russia’s OAO Lukoil has let a contract to a consortium headed by South Korea’s Hyundai Engineering Co. Ltd., Seoul, for the construction of its lon...

Horn Petroleum to reduce Puntland exploration program

02/13/2015 Horn Petroleum Corp., Vancouver, BC, will reduce its presence in Bosaso, Puntland (Somalia), and will “refrain from any operational activity and as...

Partners submit Johan Sverdrup development plan

02/13/2015 Partners Statoil ASA, Lundin Petroleum AB, Petoro, Det Norske Oljeselskap ASA, and Maersk Oil have submitted a plan for development and operation (...

MARKET WATCH: NYMEX crude oil price jumps more than $2/bbl

02/13/2015 Crude oil prices on the New York market jumped by more than $2/bbl Feb. 12 to settle above $51/bbl, which analysts attributed to more oil and gas c...

Apache’s 2015 capital budget less than half of last year’s $8.5 billion

02/12/2015 Apache Corp., Houston, plans a capital budget of $3.6-4 billion in 2015, with $2.1-2.3 billion directed toward onshore North America and $1.5-1.7 b...

Alaska LNG project partners file resource reports with FERC

02/12/2015 A series of draft environmental and socioeconomic reports for the Alaska LNG project have been submitted to the US Federal Energy Regulatory Commis...

Total reduces budget by 10% to $23-24 billion

02/12/2015 Total SA plans to lower its organic investments to $23-24 billion in 2015 from $26.4 billion in 2014 by reducing spending in brownfield development...

TransCanada challenges EPA’s comments on Keystone XL SEIS

02/11/2015 TransCanada Corp. responded to the Feb. 2 comment letter from the US Environmental Protection Agency on the US Department of State’s final suppleme...

PNR cuts capital spending nearly in half

02/11/2015 Pioneer Natural Resources Co. (PNR), Dallas, plans to spend $1.85 billion in 2015 following a fourth quarter in which the company reported a net in...
White Papers

Transforming the Oil and Gas Industry with EPPM

With budgets in the billions, timelines spanning years, and life cycles extending over decades, oil an...
Sponsored by

Asset Decommissioning in Oil & Gas: Transforming Business

Asset intensive organizations like Oil and Gas have their own industry specific challenges when it com...
Sponsored by

Squeezing the Green: How to Cut Petroleum Downstream Costs and Optimize Processing Efficiencies with Enterprise Project Portfolio Management Solutions

As the downstream petroleum industry grapples with change in every sector and at every level, includin...
Sponsored by

7 Steps to Improve Oil & Gas Asset Decommissioning

Global competition and volatile markets are creating a challenging business climate for project based ...
Sponsored by

The impact of aging infrastructure in process manufacturing industries

Process manufacturing companies in the oil and gas, utilities, chemicals and natural resource industri...
Sponsored by

What is System Level Thermo-Fluid Analysis?

This paper will explain some of the fundamentals of System Level Thermo-Fluid Analysis and demonstrate...

Accurate Thermo-Fluid Simulation in Real Time Environments

The crux of any task undertaken in System Level Thermo-Fluid Analysis is striking a balance between ti...

6 ways for Energy, Chemical and Oil and Gas Companies to Avert the Impending Workforce Crisis

As many as half of the skilled workers in energy, chemical and oil & gas industries are quickly he...
Sponsored by
Available Webcasts

On Demand

Global LNG: Adjusting to New Realities

Fri, Mar 20, 2015

Oil & Gas Journal’s March 20, 2015, webcast will look at how global LNG trade will be affected over the next 12-24 months by falling crude oil prices and changing patterns and pressures of demand. Will US LNG production play a role in balancing markets? Or will it add to a growing global oversupply of LNG for markets remote from easier natural gas supply? Will new buyers with marginal credit, smaller requirements, or great need for flexibility begin to look attractive to suppliers? How will high-cost, mega-projects in Australia respond to new construction cost trends?

register:WEBCAST


US Midstream at a Crossroads

Fri, Mar 6, 2015

Oil & Gas Journal’s Mar. 6, 2015, webcast will focus on US midstream companies at an inflection point in their development in response to more than 6 years shale oil and gas production growth. Major infrastructure—gas plants, gathering systems, and takeaway pipelines—have been built. Major fractionation hubs have expanded. Given the radically changed pricing environment since mid-2014, where do processors go from here? What is the fate of large projects caught in mid-development? How to producers and processors cooperate to ensure a sustainable and profitable future? This event will serve to set the discussion table for the annual GPA Convention in San Antonio, Apr. 13-16, 2015.

This event is sponsored by Leidos Engineering.

register:WEBCAST


The Future of US Refining

Fri, Feb 6, 2015

Oil & Gas Journal’s Feb. 6, 2015, webcast will focus on the future of US refining as various forces this year conspire to pull the industry in different directions. Lower oil prices generally reduce feedstock costs, but they have also lowered refiners’ returns, as 2015 begins with refined products priced at lows not seen in years. If lower per-barrel crude prices dampen production of lighter crudes among shale plays, what will happen to refiners’ plans to export more barrels of lighter crudes? And as always, refiners will be affected by government regulations, particularly those that suppress demand, increase costs, or limit access to markets or supply.

register:WEBCAST


Oil & Gas Journal’s Forecast & Review/Worldwide Pipeline Construction 2015

Fri, Jan 30, 2015

The  Forecast & Review/Worldwide Pipeline Construction 2015 Webcast will address Oil & Gas Journal’s outlooks for the oil market and pipeline construction in a year of turbulence. Based on two annual special reports, the webcast will be presented by OGJ Editor Bob Tippee and OGJ Managing Editor-Technology Chris Smith.
The Forecast & Review portion of the webcast will identify forces underlying the collapse in crude oil prices and assess prospects for changes essential to recovery—all in the context of geopolitical pressures buffeting the market.

register:WEBCAST


Emerson Micro Motion Videos

Careers at TOTAL

Careers at TOTAL - Videos

More than 600 job openings are now online, watch videos and learn more!

 

Click Here to Watch

Other Oil & Gas Industry Jobs

Search More Job Listings >>
Stay Connected