Protecting Your Company from Over-Pressure Events
In this case study, explore a critical incident involving an over-pressure event in a low-pressure gas system, leading to severe consequences. Learn from the findings and recommendations to enhance safety measures and prevent such incidents in the future.
Uploaded on Feb 25, 2025 | 0 Views
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Presentation Transcript
Protecting Your Company from an Over-Pressure Event 1 February 25, 2025
Merrimack Valley Incident September 13, 2018 Pipeline replacement program to replace aging cast-iron low pressure system System fed by 14 regulator stations reducing pressure from 75 psig to 0.5 psig When tying over one of the regulator stations to the new main, the abandoned main still had the regulator sensing lines tied to it Detecting pressures lower than set point, the regulators opened fully, delivering 75 psig into the low-pressure system Pressure monitoring was in place on newly replaced system, but there was no ability to remotely control By the time responders arrived and shut down the station, damage to 131 structures, several explosions, injuries and a death had occurred 8,600 customers lost service 2 February 25, 2025
How did this happen? Columbia Gas low-pressure system (at incident location) 3
4 February 25, 2025
Findings The location of the regulator sensing lines were not identified in the constructability review of the project, nor was much consideration given to the impact of the project on pressure regulation and control Records of the sense line locations were not included in the work package; therefore, their relocation was not specified as part of the work process No formal Management of Change (MOC) was conducted to analyze the risks and appropriate counter-measures of the project 5 February 25, 2025
As a Result NTSB Five urgent recommendations to the State of Massachusetts and NiSource, Inc. AGA Publishes Leading Practices to Reduce the Possibility of a Natural Gas Over-Pressurization Event 6 February 25, 2025
Response Companies employ both procedural and physical safeguards for abnormal operating conditions like an over-pressure event 1. What are your potential sources of over-pressure? 2. What procedures/equipment do you have in place to protect against over-pressure? 3. Are there any gaps or room for improvement? 7 February 25, 2025
NTSB Recommendations 1. Ensure adequate Subject Matter Expert (SME) review of engineered drawings. 2. Evaluate current or implement comprehensive review process for construction, commissioning and take-down plans. 3. Review records management system to ensure all records are accurate, reliable and complete, particularly as they relate to pressure control and over-pressure protection. 4. Implement an MOC process to present, analyze and propose countermeasures to project risks. 5. Develop control procedures to safely execute changes approved through the MOC process including pressure monitoring points and critical personnel. 8 February 25, 2025
Other Recommendations 6. Standardization of regulator station and meter set designs 7. Tertiary over-pressure protection (slam-shut or full relief with standby-monitor configuration) 8. Increased pressure monitoring (telemetry) 9. Security of facilities prevent vandalism AND operator error 10.Increased training and awareness for operators and contractors 11.Incorporate over-pressure into your DIMP/TIMP plan 9 February 25, 2025