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San Bruno Pipeline Rupture.

The San Bruno pipeline disaster occurred when a natural gas pipeline owned by PG&E exploded into flames in a neighborhood just west of the San Francisco Airport. The failed section of the pipeline is shown below. The devastation was immense—almost 50 homes were destroyed, and nine fatalities resulted. The image on the first page of this brochure reveals only a portion of this damage.


BEAR inspected the failure and identified its cause as defective welds in the pipeline. The intensive pressure in the line, and the increasing demand for energy from San Bruno’s expanding user base lead to this failure. BEAR's laboratory is fully equipped with specialized machinery and knowledge to test pipelines for its material properties, the types of stresses it undergoes, and strains inside of pipelines.

gas pipeline rupture

In one case, an underground gas pipeline was struck by a farmer using a "ripper." The resulting explosion lead to comprehensive damage and many injuries. The BEAR team was asked to assist in the assessment and analysis. The damaged pipe wall is shown on the right.

steam pipe inspection

In another case, a steam-heating pipe exploded under a busy intersection in Manhattan, NY. The BEAR team was asked to assess the maintenance procedures and make recommendations to avoid future incidents. The photo on the right shows the exposed underground pipes.

syncrude pipe failure causes $2 billion loss

The BEAR team approached this case with diligence and rigorous scientific analysis, considering all possible theories. The wax casting and computer stress analysis eliminated all possible scenarios except one.


Casting and reassembling of the failed pipe clearly showed that the rupture occurred only after the pipe was "buckled" by a nearby explosion.

The picture at left shows the pipe in wax after buckling, but before rupture.

pipe failure in mohave desert


Dr. Stevick conducted a primary research on the steam pipe failure at the Mohave Southern California Power Plant. The rupture destroyed the power plant and resulted in five fatalities. The pipe ruptured along a weld seam due to the mismatch of high temperature properties between the weld and basemetal.


Dr. Stevick's analysis resulted in a change in the piping code for high temperature service. His contribution to this and other codes has been substantial and continues to improve industry practices.

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