You may be trying to access this site from a secured browser on the server. Please enable scripts and reload this page.
Turn on more accessible mode
Turn off more accessible mode
Skip Ribbon Commands
Skip to main content
Top Link Bar
NEWS & EVENTS
Speeches & Testimony
Most Wanted List
The Investigative Process
Data & Stats
General Aviation Safety
Administrative Law Judges
Strategic Plans & Reports
Safety Recommendation Details
Most Wanted List
On September 21, 2015, at 12:03 p.m., an employee of Bonefish Grill in Centreville, Virginia, called the Fairfax County 911 Center to report a gasoline odor.1 The Fairfax County Fire and Rescue Department (FCFRD) immediately dispatched units to the restaurant in the Centre Ridge Marketplace shopping center. (See figure 1.) After arriving at the scene, firefighters confirmed everyone had left the restaurant; they established an incident command center, and they began the investigation. They did not detect the presence of flammable vapor inside Bonefish Grill and ruled out a natural gas leak; however, they noted a gasoline odor coming from the storm drains at the shopping center. Firefighters detected the presence of flammable vapor in most of the storm drains behind Bonefish Grill and Chipotle. Flammable vapor in some storm drains in front of Bonefish Grill was as high as 100 percent of the lower explosive limit (LEL); however, no liquid was visible in the storm drains. After establishing that the gasoline did not come from the gas station that was located about 400 feet west of Bonefish Grill and that gasoline was not illegally dumped into a storm drain, firefighters considered that the odor could be coming from a leak in a nearby, buried Colonial Pipeline Company pipeline. Colonial confirmed the pipeline leak 2 days later.
TO THE COLONIAL PIPELINE COMPANY: Revise the dent excavation evaluation procedure to require either (a) the repair of all excavated dent defects, or (b) the installation of a local leak detection system at each location where a dent is not repaired, continuous monitoring for hydrocarbons, and prompt corrective action to stop a detected leak.
Original recommendation transmittal letter:
Closed - Acceptable Action
Centreville, VA, United States
Pipeline Accident Brief: Colonial Pipeline Company Petroleum Product Leak, Centreville, Virginia
Addressee(s) and Addressee Status:
Colonial Pipeline Company (Closed - Acceptable Action)
Safety Recommendation History
Colonial Pipeline Company
We note that you revised your pipeline integrity management program (IMP) manual, paying specific attention to guidance on dent assessment and management. The IMP manual now includes dent data analysis and assessment practices, and it describes the development and enhancement of your dent risk ranking prioritization matrix (DRRPM), which is your process for evaluating dents on your mainline pipeline system to prioritize where excavation and inspection is warranted. Based on the DRRPM analysis results, you excavated and inspected over 600 dents (all of which were below the federal Pipeline and Hazardous Materials Safety Administration regulatory threshold for action) to better understand the factors and conditions that influence dent fatigue failures. You then used your findings to improve the DRRPM process and the IMP. One significant revision to your IMP was a modification you made to your dent repair criteria following the Centreville incident and several other crack-in-dent failures on your mainline pipeline system between April 2015 and April 2016, all of which were shallow, bottom side dents from which cracks formed as a result of pressure cycle fatigue. In February 2016, you revised your dent repair criteria to require that all excavated dents longer than 6 inches and greater than 1/8 inch deep be repaired. These revised dent repair criteria are now incorporated into your pipeline maintenance manual (PLMM). We note that, based on the dent repair criteria in the PLMM, you expect that all excavated dents will be repaired; however, a dent repair may not be completed following excavation due to technical constraints, such as fit-up or welding restrictions. In these short-term cases, you will consider installing a local leak-detection system on a case-by-case basis, and you will monitor that system until dent repairs can be made. We further note that you have constructed a portable, skid mounted leak-detection system with remote data acquisition capabilities to use when it is determined that a local leak detection system is needed. For any long-term monitoring situation where a permanent dent repair is not completed, you are committed to installing a local leak detection system, though you believe this would be an extremely rare occurrence. The actions you have taken satisfy Safety Recommendation P-17-3, which is classified CLOSED--ACCEPTABLE ACTION.
Colonial Pipeline Company
-From Gerald Beck, PMP, Vice President and General Manager Operations: As follow-up to our conversation last week during your visit to Colonial Pipeline Company (Colonial), I am writing to clarify Colonial’s position on addressing NTSB Recommendation P-17-3 and our approach to dent repair. The clarification relates to the installation of leak detection systems in situations where Colonial excavates a dent and cannot make a permanent repair. In Colonial’s letter to NTSB regarding Recommendation P-17-3 (dated April 25, 2019), it was stated that local leak detection systems would be considered on a case-by-case basis when conditions did not allow for permanent repair of dents. The case-by-case meant that in short term situations meaning “days” to make the permanent repair due to permitting, accessibility, physical constraints (road), weather, etc. delays, Colonial would monitor by others means because it would not be able to install a leak detection system for the previous mentioned reasons. Any long term monitoring situation where a permanent repair of a dent is not completed, Colonial is committed to installing a local leak detection system. In short, the case-by-case statement, was about making a permanent repair the main objective, so a local leak detection system would not be needed. Colonial believes this would be an extremely rare occurrence but wanted to recognize there may arise a situation that wouldn’t allow for leak detection to be safely installed. Colonial is committed to always installing local leak detection when conditions do not permit a permanent repair to be installed to address an excavated dent. The leak detection systems will remain active and operational until a permanent repair can be made per Colonial’s Pipeline Maintenance Manual and approved repair procedures. It was a pleasure meeting with you. I appreciate you taking time in your busy schedule to visit Colonial and meeting with Colonial’s Board of Directors and Management Team.
Colonial Pipeline Company
-From Gerald Beck, VP and General Manager, Operations: This recommendation was initially included in the NTSB Pipeline Accident Brief for the Centreville product release, PAB-17/01 adopted June 5, 2017. A subsequent letter was issued by NTSB to Colonial on June 15, 2017. Recommendation P-17 -3 states the following: "Revise the dent excavation evaluation procedure to require either (a) the repair of all excavated dent defects, or (b) the installation of a local leak detection system at each location where a dent is not repaired, continuous monitoring for hydrocarbons, and prompt corrective action to stop a detected leak.” Following the Centreville leak that occurred in September 2015, Colonial has been making continuous improvements to our pipeline Integrity Management Program (IMP) Manual, with specific attention to dent assessment and management. The IMP Manual has been revised to include industry- leading data analysis and assessment practices for dents, including the development and enhancements of Colonial's Dent Risk Ranking Prioritization Matrix (DRRPM) process. The ORRPM is an internally-developed data Integration process for evaluating all dents on Colonial's mainline pipeline system (Lines 01 , 02, 03, and 04), where the potential threat of fatigue cracking in dents is most significant. It is a systematic and structured process that provides the basis for consistent analysis of dents present on Colonial's system. The process includes analytical finite element analysis (FEA) along with independent Subject Matter Expert (SME) analysis of in-line inspection (Ill) signals from high resolution caliper and ultrasonic technologies. The process incorporates historical pressure cycling data to prioritize where excavation and inspection of dents may be warranted. Based on the DRRPM analysis results, Colonial has excavated and inspected over 600 dents (all of which are below PHMSA regulatory thresholds for response actions) to better understand the factors and conditions that influence dent fatigue failures. The learnings from the inspections and observations completed on the excavated dents are incorporated into, and used to continuously improve, the DRRPM process and the integrity management program. The learnings are also shared with the Ill vendors and independent Ill data analysis SMEs to improve the Ill algorithms and tool probability of detection/identification and FEA models. One of the most significant changes to the IMP is a modification to Colonial's dent repair criteria. The revision was made following the Centreville incident and several other crack-in-dent failures on Colonial's mainline pipeline system that occurred between April 2015 and April 2016. These dents were all shallow bottom side dents that had cracks form as a result of pressure cycle fatigue. Based on a review of the data for these fatigue crack failures, Colonial issued in February 2016 a revised dent repair criteria that requires repair of all excavated dents that have a length of greater than 6-inches and are greater than 1/8 inch deep. These revised dent repair criteria, which have resulted in the repair of all dents excavated since their issuance, are now incorporated into Colonial's Pipeline Maintenance Manual (PLMM). Based on the stringent criteria established for dent repair in the PLMM, Colonial expects that all excavated dents will be repaired, which addresses the first part of NTSB's recommendation to Colonial. However, there may be a few exceptions where dent repair is not completed following excavation due to technical constraints such as fit-up or welding restrictions. In these cases, Colonial will consider installing a local leak detection system on a case-by-case basis, and in those instances will monitor that system until dent repairs can be made. Colonial recognizes that Recommendation P-17-3 states that leak detection is required for all dents that are excavated and not repaired. Colonial believes that the current research and industry understanding on dent behavior and management supports evaluation of whether local leak detection is necessary on a case-by-case basis, however. If it is determined that a local leak detection system is appropriate. Colonial has constructed a portable, skid mounted leak detection system with remote data acquisition capabilities that can be mobilized and applied for this purpose as needed. The portable system is solar powered with back-up power supply. The system can be scheduled to monitor at any frequency and set threshold alarm levels for reporting to Colonial. Additional systems can be built as needed. The availability of this portable system addresses the second part of the NTSB recommendation to Colonial. The use of local leak detection systems, when appropriate, has been included in Colonial's PLMM. As described above, Colonial believes it has fully addressed NTSB Recommendation P-17-3 and is requesting that Colonial's response be considered acceptable. that Recommendation P-17-3 be considered closed, and that the administrative record be updated to reflect this determination on NTSB's website. Additional Activities and Actions Taken In addition to the actions taken to directly address NTSB's Recommendation P-17-3, Colonial has been leading the industry to improve the tools and processes being applied to the assessment of dents and driving continuous improvement in dent integrity management. These processes and tools are being developed working with USDOT PHMSA, the American Petroleum Institute (API), Pipeline Research Council International (PRCI), and other pipeline operators. Colonial's leadership of industry activities and research programs includes the following actions: Coordinating the Colonial- USDOT PHMSA Crack-in-Dent (CID) Task Force: The Task Force was formed and met in August 2016 to open dialogue between Colonial and PHMSA to better understand the conditions and causal factors that were leading to Colonial's mainline CID failures. Colonial submitted an initial report to the CID Task Force in December 2016 and has been providing quarterly updates to the Task Force through the PHMSA Centreville Amended Corrective Action Order CPF No. 1-2015-5018H following the initial report. Colonial is coordinating with PHMSA to share our learnings and advancements made in dent assessment and management. Industry Benchmarking: Colonial has been coordinating and facilitating industry benchmarking meetings among a group of liquids pipeline operators that have interest in dent fatigue assessment and management processes. The benchmarking meetings provide the opportunity for collaborative learning from shared knowledge and experiences pertaining to research, integrity management, and operational best practices. Accelerated /LI Crack Tool Runs: Colonial is maintaining an in-house program related to mechanical damage inspection and integrity assessment, including accelerating the mainline crack Ill program and development of detailed data integration processes. Coordinating and Leading Research Proarams: Colonial is acting Chair of the PRCI Research Steering Committee and leading Mechanical Damage research in PRCI. PRCI has led the industry in the development of improved dent assessment and management tools that are being used to enhance pipeline safety. AP/ Recommended Practice on Dent Assessment and Management: Colonial personnel are providing leadership for development of an API Recommended Practice for Dent Assessment and Management (RP 1183). As Chair for the RP Team within API, Colonial is leading the development of this important document that will integrate all of the learnings and best practices obtained from Colonial's internal program, other operators' integrity management programs, research results, and operator best practices for managing dents. The RP provides the process and tools to conduct screening and engineering assessment (e.g .• fitness for purpose, engineering critical assessment) for mechanical damage features. These processes and tools represent revised criteria for the assessment of dents and account for the factors that lead to pipeline failures caused by dents. Supporting the Long-term Future of the Industry and Dent Management: Colonial is working with Georgia Institute of Technology (Georgia Tech) on a PHMSA-funded research project that is focused on fatigue life damage accumulation in dents. This work and Colonial's efforts to employ students from Georgia Tech will help develop and engage the next generation of pipeline engineers and technical specialists to drive continuous improvement and pipeline safety. While these actions are not specifically targeted to address NTSB Recommendation P-17-3, they are relevant related actions being taken by Colonial and the pipeline industry to improve pipeline safety. Colonial's efforts in responding to the CID failures on its system are substantial and are improving the approach that the industry is taking to assess and manage dents, and Colonial wants to inform NTSB of the actions taken and improvements that have been made, and will continue to be made. Conclusion As set forth above in the first section of this letter, Colonial believes it has fully addressed NTSB Recommendation P-17-3. For those reasons, Colonial is requesting that Colonial's response be considered acceptable, that Recommendation P-17-3 be considered closed, and that the administrative record be updated to reflect this determination on NTSB's website.
Colonial Pipeline Company
On June 5, 2017, the NTSB adopted its report on the September 21, 2015, pipeline leak at a shopping center in Centreville, Virginia.1 The details of this accident and the resulting safety recommendations may be found in the investigative report, which can be accessed at http://www.ntsb.gov under report number PAB-17/1. As a result of this investigation, the NTSB is issuing four new recommendations, including two to the Pipeline and Hazardous Materials Safety Administration, one to the Association of Oil Pipe Lines and the American Petroleum Institute, and the following recommendation to Colonial Pipeline Company: P-17-003.
Strategic Plan, Performance & Accountability Reports & More
Directions to Conference Center
Web Policies & Notices
Annual Review of Aircraft