Electric current travels through the coils of copper wire (pictured) that are evenly spaced along the pipeline. This system creates a magnetic field, which is used to measure the level of pipe corrosion. Credit: 4D Imaging |
Just
days before the 2010 PG&E pipeline disaster in the Bay Area
community of San Bruno, residents in the neighborhood reported smelling
gas. As it turns out, natural gas was leaking from faulty welds along
the pipe that were failing under pressure. The gas line eventually
exploded and registered as a small earthquake. The blast killed eight
people and destroyed 40 homes. Similar conditions exist elsewhere, and
global pipeline failures occur with regularity.
Nationwide,
our network of more than 2.5 million miles of pipeline is aging. More
than a third of the pipeline infrastructure is over 50 years old, and a
reliable method to monitor corrosion hasn’t really existed. Until now.
Jerome
Singer, professor emeritus of EECS and engineering science, and two
Berkeley Engineering alumni have developed a way to keep tabs on
pipeline health by using an magnetic resonance imaging (MRI) machine
similar to the ones used in hospitals. Their technology is called the
Magnetic Response Imaging System (MRIS), and it will be able to look at
the state of underground pipelines.
Comparing
the more familiar medical MRI with the pipeline version, Singer says,
“Both involve turning on a magnetic field and getting a response signal,
which provides an image. For pipelines, we receive a signal that
determines the thickness of the pipe material, and we measure that
reduction as well as the remaining metal thickness.”
As
a professor of radiology at UCSF in the 1970s, Singer pioneered
magnetic resonance imaging research that helped advance technology that
achieves tissue resolution down to a cubic millimeter. When Singer
retired in 2005, he was approached by Glen Stevick (Ph.D.’93 ME), who
was updating one of Singer’s earlier MRI machine designs.
After
collaborating on that project, Stevick suggested that he and Singer
form an engineering firm along with David Rondinone (Ph.D.’02 ME). They
started 4D Imaging in Berkeley, specializing in engineering forensics.
“We
do structural health management,” says Stevick. “We see so many
pipeline failures, but we would rather do a pre-mortem on a pipeline
than a post-mortem.”
To
obtain an image of a pipeline, 4D’s system relies on a system of copper
wire coils that are installed every two meters. A power supply at one
end sends pulses of electric current to the coils, which creates a
measurable magnetic field. As the pipe starts to fail, the magnetism
decreases, indicating that it is time for repair or replacement. The
monitoring data can be viewed remotely via a secured website.
“The
system can detect metal loss as low as 0.05% of the original wall
thickness,” says Singer. “Users can set up an alarm system that
immediately communicates when metal loss reaches a specified level of
concern for the degree of corrosion.”
As
the technology and the MRI process develop and become more robust,
Stevick says, the system will be able to provide increasingly refined
images of pipeline flaws and corrosion.
The
team developed prototypes of the tool with a grant from Chevron, and is
in talks with both Chevron and Occidental Petroleum about installing
MRIS monitors along some of the country’s aging fuel pipelines.
Meanwhile
the firm is helping to analyze the 2010 San Bruno pipeline explosion as
well as the Deepwater Horizon drilling rig explosion in the Gulf of
Mexico.
Their
office is easy to recognize; it’s an airy warehouse on Gilman Street in
Berkeley with a rusted hunk of the Alaska pipeline resting on top of a
storage unit.
