Leak Rupture Boundary Calculator, Training Manual, and Final Report

Summary:
The Leak-Rupture Boundary (LRB) Calculator and Training Manual provide a tool that allows operators to determine the leak-rupture boundary for a pipe segment based on properties such as the diameter, toughness, and yield strength. Operators can use the calculator for risk modeling and consequence analysis. This tool includes a closed-form solution that allows the calculation of the LRB as a percentage of SMYS with a confidence that 97.5% of pipelines with the selected attributes of yield strength, toughness, diameter, and wall thickness would fail by leak instead of rupture. A user-friendly calculator was created to allow operators to perform analysis for specific pipe segments. This product contains the Final Report PDF, Training Manual pdf and the .CDF file to install the calculator after downloading the Wolfram CDF Player.

Project Objective:
The objective of this project was to develop a tool that allows operators to determine the leak-rupture boundary for a pipe segment based on properties such as the diameter, toughness, and yield strength. Operators can use the calculator for risk modeling and consequence analysis.

Project Description:
Transmission pipes operating at pressures greater than 20% Specific Minimum Yield Strength (SMYS) in High-Consequence Areas (HCAs) are required to comply with the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration’s Subpart O Integrity Management regulations.

For pipelines operators to ensure that their limited assessment resources are focused on the highest-risk segments, a technical basis is needed to understand which
segments could possibly fail by leak versus rupture, and regulators need the technical justification that forms the basis of integrity-management regulations.

Two studies on the topic have been conducted in recent years. These studies (Leak vs. Rupture Considerations for Steel, Low-Stress Natural Gas Transmission Pipelines and Criteria for Reinspection Intervals for Low-Stress Steel Pipelines) indicate that failure by rupture may occur at a pressure that produces a hoop stress above 30% of the pipeline’s SMYS. While these reports provide valuable information, the industry could benefit through further validation.

In this project, research involved an international incident review and mathematical modeling to develop a calculator to determine the leak-rupture boundary (LRB) for specific pipe segments.