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A main line valve assembly of an El Paso Corp. natural gas pipeline in Houston is equipped with an acoustical monitoring system to let engineers know if vibrations from heavy machinery are affecting the integrity of the pipe.
A technology used to detect the location of sniper fire in war zones is helping prevent damage to natural gas pipelines.
The system, adapted by General Electric's Houston-based oil and gas pipeline services business from a French defense firm, has been installed on two Houston-area pipelines. One is a section of an El Paso Corp. pipeline in northwest Houston that ignited when it was ruptured last year.
By listening to sound waves traveling through the natural gas in the equipped pipelines, operators in a remote control room can detect and pinpoint to within a few feet the location of an object striking a pipeline, such as a construction backhoe. In some cases the system can detect if digging is happening in a pipeline right-of-way, even if machinery hasn't come in contact with the pipe.
A warning goes to the pipeline operator immediately, letting the operator intervene before the pipeline is breached or respond to a rupture more quickly.
Jesus Soto Jr., vice president of operations services for El Paso's pipeline business, said the ThreatScan system GE installed on its pipeline near Katy should help protect both the pipeline and its neighbors.
"Today you don't have any other technology than this system that can detect impacts or right-of-way encroachment," Soto said.
National phone numberThe single largest cause of pipeline accidents in the United States is damage caused by third-party excavation — digging by someone other than the pipeline's owner and operator, according to data compiled by the Pipeline and Hazardous Materials Safety Administration.
Since 1988, third-party excavation has caused 26 percent of the 5,900 significant pipeline incidents. That compares with corrosion (18 percent), material failure (15 percent) and natural force damage (8 percent).
Significant incidents are defined as cases resulting in fatality or injury, more than $50,000 in damage, a release of five barrels or more, or a fire or explosion.
In 2005 the Federal Communications Commission created a single national phone number — 811 — for companies to call before digging to ensure they avoid underground utilities. The number links more than 60 call centers around the country that help companies and individuals avoid digging into water lines, power lines and pipelines.
Everyone from homeowners digging holes for a new tree to home builders putting up new subdivisions should use the 811 service, said Bob Kipp, president of the Common Ground Alliance, a group of industry and government agencies aimed at preventing damage to underground utilities.
The group also helps collect data on underground utilities damage to better analyze ways to prevent it. Kipp noted that in Colorado, for example, much of the effort to advertise the 811 service had been focused on road construction companies because it was assumed they were the top culprits in damaged utilities.
But when the state analyzed the incident data, it realized the top cause of damage was landscaping, so the state shifted its education efforts.
"Fence building is another surprising cause of damage found in the data," Kipp said. "But if you look at most new residential developments you'll find the facilities are placed on the lot lines. And where do you dig a fence post?"
Decline in incidentsWhile the number of pipeline damage incidents caused by outside excavation has declined in recent years, the potential for injuries and property loss can be significant. That's why El Paso has installed the ThreatScan system on a section of its Tennessee Gas Pipeline that runs through northwest Houston near Katy.
Rural going residentialMuch of the area is rural, but residential developments are closing in, leading to a number of incidents where excavators have stuck or nearly struck the pipeline.
In February 2007 a home builder's bulldozer ruptured a line on the system, which later ignited and burned for several hours. There were no fatalities related to the incident, but some injuries were reported.
The ThreatScan system uses specially designed microphones called hydrophones to detect vibrations carried through gas in a pipeline. The sensors then send data via satellite to GE's ThreatScan call center in Houston, or for installations in Europe, to a center in Florence, Italy.
The hydrophones are about 10 miles apart, but by filtering the sound waves for speed and frequency, they can narrow the location of the sound to within a few feet, said Jeff Johnson, the head of sales for GE's ThreatScan business.
If GE identifies a potential threat, the call center immediately contacts the pipeline operator with the information.
GE developed the technology based on a system created by 01dB-Metravib, an acoustics measurement and monitoring firm.
The system has been used to locate the source of gunfire in war zones. It has even been paired with automated-weapons systems that train guns on the source of the hostile fire.
When a pipeline is struck, operators typically don't know it happened unless the party that hit it reports it or a breach of the pipe causes a drop in flow and pressure that shows up on gauges the company monitors.
Some companies, including El Paso, regularly fly over rights-of-way with helicopters in search of potential problems such as nearby excavation or construction. But a small breach might not immediately register in control center data, and its location is hard to pinpoint from there.
Starting in KansasThe detection system was first installed in the U.S. last year on a section of the Southern Star Central Gas Pipeline near Wichita, Kan. In Texas, it's been installed in a section of Spectra Energy pipeline near Mont Belvieu and on a Transwestern pipeline in Amarillo, in addition to the northwest Houston site.
Doug Murray, eastern area director for Transwestern, said the system hasn't detected any strikes on the pipeline, but twice it detected work going on in the pipeline right-of-way by a company drilling a new water well and another contractor digging with a backhoe.
"It allowed us to respond and get into the area while one of the operations was still running and right after one of them had shut down," Murray said.
"It's an extra level of security that hopefully prevents trouble."