Gas pipe involved in Oklahoma City house explosion has history of problemsMar 19th, 2016 | By admin | Category: Natural Gas Explosions
4Stephanie Newman, left, and Bethany Partain, friends of a next-door neighbor to a house which exploded at 12409 Whispering Hollow Drive in Oklahoma City, OK, help remove belongings, Saturday, January 2, 2016. The cause of the explosion is being investigated. Photo by Paul Hellstern, The Oklahoman
The brand of plastic gas pipe that leaked and exploded in a northwest Oklahoma City neighborhood in January injuring one resident and causing nearly a half million dollars damage to dozens of homes has caused problems in other parts of the country.
Oklahoma Natural Gas’ initial report on the incident listed Driscopipe as the manufacturer of the natural gas pipe that failed in the Jan. 2 explosion. The blast destroyed a home at 12505 Whispering Hollow Drive and sent one man to the hospital with second degree burns.
The ONG report listed poor workmanship on a weld seam as the cause of the explosion. The polyethylene pipe involved in the blast was installed in 1983, the same year many of the homes in the Walnut Creek addition were built.
But beyond poor workmanship, Driscopipe from that era has been found to be susceptible to becoming brittle prematurely, said Mark McDonald, president of NatGas Consulting, a Massachusetts firm that investigates natural gas explosions.
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“This is a classic problem with Driscopipe,” he said. “What has been found is that this stuff was incorrectly developed. The polyethylene blend was not quite right in much of the pipe produced at that time. It’s known for becoming brittle prematurely which can lead to explosions. Some states have asked utilities to take it out of the ground.”
The Oklahoma Corporation Commission is still investigating the Oklahoma City explosion. It’s uncertain how long that review will take and what, if any, corrective actions may be ordered.
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Another natural gas explosion destroyed a home Saturday at 10829 NW 32 Terrace in Yukon. An Oklahoma City Fire Department spokesman said a stove had recently been removed from the house and a pipe was broken, causing the house to fill with gas. The blast doesn’t appear to be the result of an infrastructure failure.
Miles of pipeline
ONG is a division of OneGas, a publicly traded company. ONG manages about 20,000 miles of pipeline in Oklahoma.
In Arizona, Driscopipe came under scrutiny after a 39-year-old man suffered burns over 80 percent of his body in a 2014 explosion in Ahwatukee, Ariz., the result of a leak in line made by the company. Another leak in the same residential area resulted in the evacuation of homes.
An investigation by a Phoenix TV station found 57 instances of leaks involving Driscopipe in Arizona. Two more fires in Yuma were attributed to the pipe. All of the Arizona cases involved the M8000 model pipe. ONG did not disclose the model number of the pipe involved in the Oklahoma City explosion in its initial report to state regulators.
“The results of our monitoring activities do not indicate any problems with Driscopipe used in our system,” ONG spokesman Cherokee Ballard said in an email. “Any gas pipeline, regardless of material, can be subjected to forces that cause the line to leak and no particular type, Drisco included, is immune to such occurrences.”
ONG also said polyethylene pipe is considered a safe material in the industry and is used widely in its systems.
Other brands of polyethylene pipe also have histories of failing.
A 1999 NTSB bulletin warned of problems with polyethylene pipe made in the 1960′s through early 1980′s. That warning centered on pipe made by DuPont and Century Utility Products. There have been no previously reported problems with Driscopipe in Oklahoma, corporation commission spokesman Matt Skinner said.
ONG listed poor workmanship as the cause of the Jan. 2 blast citing a lack of fusion in one of the pipe’s joints. Under Oklahoma statutes utility companies are required to conduct inspections on distribution lines they install in residential areas. Utilities typically hire a third party to conduct the inspections and must maintain records of those inspections for state regulators. The line involved in the Jan. 2 explosion was about 2,000 feet long. Projects of a mile or longer require more detailed filings with the commission.
The Oklahoman requested ONG provide inspection reports involving the section of pipe that failed, but the utility declined to provide the information saying those documents contain personnel identification and infrastructure security information that can’t be released. ONG said that the pipeline in question met or exceeded all safety and performance standards before it was put into service.
Corporation Commission officials say it not feasible for state regulators to review every inspection report.
“Due to the sheer magnitude of pipe and records for each foot of pipe and the size of our staff, it is impossible for the department to review the records of every foot of pipe for all construction projects,” Dennis Fothergill, Pipeline Safety Department, said.
McDonald, who is not investigating this explosion, said polyethylene was thought to be a wonder material when it was first put into widespread use several decades ago. The plastic pipe was expected to last up to 70 years.
“Back then it was thought the polyethylene would last forever,” McDonald said. “They thought it was a super material. It was cheap and easy to install a 100 foot length versus 100 feet of cast iron, which is obviously much heavier and expensive to transport and install.”
But McDonald said many of those working with polyethylene pipe during its early beginnings weren’t fully trained on how to install it properly. The installation requires joining different segments of pipe with a butt joint. The technique involves heating the pipe to create the fusion.
“Plastic is very specialized,” McDonald said. “A lot of the problems that have come from the polyethylene have come from incorrect installation. It really is a problem in the industry with pipe of that era. I think gradually, as more has become understood about how to work with it, the workmanship has improved, but there is a lot of it in the ground that wasn’t installed properly.”
McDonald said the way utility companies fill in the area around newly installed pipeline also can cause problems. Some companies simply fill in the trenches with material dug up when the pipeline was installed. But that can also damage plastic pipes over time.
“When I worked for a gas company we took the pile of dirt that came out of the ground and put it right back into the ground,” he said. “In a lot of cases you can have rocks that will end up sitting on the pipe and damaging it that way.”
Sand is an ideal filler, McDonald said.
The corporation commission has set no timeline for its final report on the January explosion. Regulators are still working with ONG to get the information it needs, Skinner said.