Statement by Rod Dyck
Associate Director
Pipeline Division
National Transportation Safety Board
Pipeline Safety Hearing
November 15, 2000

According to the Research and Special Programs Administration (RSPA), it regulates over two million miles of natural gas pipelines and about 157,000 miles of hazardous liquid pipelines.

The operation of pipelines with integrity problems has been a recurring issue in accidents investigated by the National Transportation Safety Board. In 1987, as a result of investigations into three pipeline accidents (Beaumont, Kentucky; Lancaster, Kentucky; and Mounds View, Minnesota), the Safety Board recommended that RSPA require pipeline operators to periodically inspect their pipelines to identify corrosion, mechanical damage, and other time-dependent defects that may affect their safe operation.

RSPA has completed a final rule on integrity management, and plans to publish it in the Federal Register this month.

Accidents investigated by the Safety Board involving the operation of pipelines with time-dependent defects have continued to occur.

For example, in 1994, in Edison Township, New Jersey, a natural gas transmission pipeline ruptured. The gas ignited, sending flames 400 to 500 feet upward and destroyed eight buildings. Examination of the ruptured pipe revealed previous mechanical damage to the exterior of the pipe that reduced its wall thickness. A crack grew to critical size when it then ruptured. Contributing to the rupture were brittle properties of the pipe material.

In 1996, almost 500,000 gallons of gasoline were released into marshland near Gramercy, Louisiana, when a previously damaged section of pipeline ruptured. This slide shows mechanical damage found on the pipe. A contractor damaged the pipe about six months before the rupture occurred.

In 1996, nearly a million gallons of fuel oil were released into the Reedy River near Fork Shoals, South Carolina, when a section of corroded pipe ruptured. In 1987, an in-line inspection device was run through this segment of pipe. The inspection contractor noted an anomaly at the eventual rupture location. The anomaly was assessed as a dent and was judged to require no corrective action. In March of 1996, another in-line inspection device generated data that indicated pipe wall thinning. The Safety Board found that the subsequent efforts by the pipeline operator to measure the extent of the wall thinning were insufficient and did not reveal the full extent of corrosion damage. Before the corroded segment of pipe was replaced, the pipe ruptured during a pressure surge.

In 1996, a rupture of a pipeline near Lively, Texas, sent a butane vapor cloud into a residential area. The vapor ignited as two residents in a pickup truck drove into the vapor cloud, killing both. In May of 1995, an in-line inspection tool was run through the pipe, generating data that led to the conclusion that the rupture area only had light corrosion damage. The Safety Board found that rapid corrosion had occurred on the pipeline since the 1995 in-line inspection.

In 1998, a rupture in a pipeline in a landfill at Sandy Springs, Georgia resulted in the release of more than 30,000 gallons of gasoline. When the pipe was excavated, it was found to be buckled and cracked. The Safety Board found that the pipeline ruptured because of settlement of soil and trash underneath the pipeline.

The Safety Board is currently investigating six other pipeline accidents that occurred during 1999 and 2000 that may also involve pipeline integrity problems.

A 1999 pipeline rupture in Knoxville, Tennessee released over 50,000 gallons of diesel fuel into the Tennessee River. A brittle-like crack was found on the pipe. The Safety Board is investigating whether corrosion initiated the crack and if the material's toughness had a role in this rupture. Two days before the rupture, an in-line inspection device was run through the pipe segment, with no anomalies in the rupture area reported.

In June 1999, in Bellingham, Washington, a pipeline accident released approximately ¼ million gallons of gasoline, and three persons lost their lives. We found several areas of external mechanical damage in the vicinity of the rupture. The arrow in the figure points to the gouge in which the rupture initiated. In 1996 and 1997, the pipeline operator conducted in-line inspections of the pipeline, which indicated the presence of anomalies in the area of the subsequent rupture. The pipeline was not excavated in this area before the accident.

In January 2000, in Winchester, Kentucky, a pipeline accident released about 490,000 gallons of crude oil. Safety Board investigators found a dent on the bottom of the pipe in the rupture area.

In March 2000, in Greenville, Texas, a pipeline accident released about 565,000 gallons of gasoline. We found indications of cracking that initiated at the edge of a longitudinal seam weld.

In April 2000, near the Chalk Point Electric Power Generating Station in Maryland, a pipeline accident released about 125,000 gallons of fuel oil. We found a crack in a buckle at a bend. In 1997, an in-line inspection of the pipeline was conducted. The inspection report indicated the presence of a welded pipeline fitting at the approximate location of the bend. However, there was no fitting at this location.

In the case of an August 2000, natural gas pipeline explosion and fire near Carlsbad, New Mexico that killed twelve people, we found significant internal corrosion at the rupture location. The pipeline segment that ruptured was constructed in 1950.

Today, we will focus on technologies available to assess the integrity of pipelines, such as the use of in-line inspection tools. We need to identify the benefits and limitations of these tools, and to determine the status of ongoing research.

Tomorrow, this Pipeline Safety Hearing will provide a forum to address the capabilities of pipeline operating systems to identify leaks and provide sufficient alarms, so that controllers can take timely action to reduce the consequences of leaks.

The lack of timely recognition that a release has occurred has also been a recurring issue in accidents. For example, in the May 1996, accident near Gramercy, Louisiana, almost immediately after the rupture, several alarms sounded in the pipeline operator's control room, some showing that pumps had automatically shut down. The pipeline controller said that he initially believed that the alarms resulted from refinery activities that had in the past generated alarms and which also automatically shut down pumps. One alarm reported a line balance alarm, showing that the amount metered from one part of the pipeline differed significantly from another part. The controller said that he had anticipated a positive value from the line balance alarm because of the shut down of the pumps. He said that he therefore did not read the full alarm message and did not note that the line balance alarm showed a negative value. The controller worked to restart pumps that had shut down automatically. About an hour after the rupture, the controller received another line balance alarm. This time the controller closely examined data and then concluded that a leak had occurred. Ultimately, 500,000 gallons of gasoline were released.

In the case of a November 1996, pipeline accident near Murfreesboro, Tennessee, a pipeline rupture resulted in the release of about 85,000 gallons of diesel fuel. During the accident, a controller did not notice an overpressure condition building against a closed valve at a pump station because the control room displayed an incorrect location for a pressure transmitter. The system recorded a sudden pressure drop at another pump station, but no alarms occurred. Although company procedures required shut down of the line in the event it was blocked, the controller continued to operate the pipeline and eventually succeeded in reopening the closed valve. He continued to pump diesel fuel through the ruptured pipeline for approximately one hour until he realized that the expected pressure rise on the pipeline was not occurring.

The Safety Board is currently investigating five other accidents that may involve a delay in recognition of a leak.

For example, in the February 1999, pipeline accident in Knoxville, Tennessee, the pipeline was not operating when the pipeline ruptured. Records from the pipeline operator's control room indicated a sudden, but small pressure drop at a pump station. No alarms were relayed to controllers. The pipeline was started up twice before controllers concluded that the pipeline ruptured, about 4 ½ hours after the rupture.

In the June 1999, Bellingham, Washington, pipeline accident, the pipeline operator reported that the computer systems became unresponsive because of inadequate computing capacity during the time frame that the rupture occurred. Controllers did not recognize that the pipeline had ruptured and restarted the pipeline. About an hour after the rupture, controllers shut down the pipeline.

In the January 2000, Winchester, Kentucky pipeline accident, the controller shut down the pipeline about two hours after the rupture.

In the March 2000, Greenville, Texas pipeline accident, at the time of the rupture, a pump automatically shut down. The controller didn't recognize the reason for the shutdown and started another pump in an attempt at keeping the line running.

In the April 2000, pipeline accident near the Chalk Point Electric Power Generating Station in Maryland, the pipeline operated for over one hour after the first indication of an abnormal operation. Metering instruments for monitoring the pipeline were not functioning during a maintenance operation that was ongoing at the time.

The Safety Board staff has been deluged with requests to participate on panels. With just one day devoted to each topic, we simply do not have time to include all requests and have had to make difficult choices in choosing our panelists. Therefore, we invited those that we could not include on panels to provide us with additional information for subsequent review and consideration.

For the panelists that are participating, we thank you for sharing your knowledge and experiences with us.

Agenda | Hearings