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The OneBridge Team has been busy extending CIM’s Crack Management functionality to now include full Pressure Cycle Fatigue Analysis (PCFA). This allows our customers to be fully compliant with the most recent CFR regulations set forth in Part 1 of the Gas Mega Rule - §192.712(d) as well as API RP 1176 Assessing and Managing Pipeline Cracking. OneBridge has integrated Modified MAT-8 pipeline fracture prediction modelling into the CIM solution as both a Fatigue Analysis/Fitness for Service and an optional PCFA Crack Management Module. 

MAT-8 was developed as a Pipeline Research Council International (PRCI) project that was strongly validated by pipeline industry experts as the most current and accepted methodology to analyze cracks on oil and gas pipelines. 

CIM incorporates updates from Modified MAT-8, ensuring OneBridge customers remain current with the various crack methodologies.

Calculating Failure Pressure and Crack Growth

This new analysis builds upon CIM’s current capability to calculate the failure pressure for crack and crack-like features as well as calculate non fatigue related growth and remaining life for cracks. ILI data is ingested into the CIM platform, similar to CIM’s Corrosion Management module. Auto-generated pre-analysis reports help users understand the nature of their inspection results, even before any engineering calculations are performed.

Failure pressure can then be calculated for all reported crack and crack-like features using several models i.e. Raju-Newman, log-secant, MAT-8 and Modified MAT-8 models, with an option to include ILI tool tolerances. ​Growth rates and remaining life can be calculating using​ different analytical methodologies, including fixed growth (linear), half-life analysis calculating the crack growth by comparing the change in crack size between two or more ILI runs. 

Fatigue Crack Growth - Simplified Fatigue Analysis

Users already have the functionality to perform a basic fatigue screening analysis on all reported crack ILI data using the Simplified Fatigue Analysis. This makes use of a numerical integration of the Paris Equation and inputting a cyclic index to estimate pressure cycling severity as well as information regarding the pressure drop along the pipeline. This is to ensure that the pressure at the location of the crack is correctly estimated and accounted for.

Fatigue Crack Growth - Pressure Cycle Fatigue Analysis (PCFA)
With this NEW analysis, user-provided pressure data can be uploaded into CIM allowing for a more accurate understanding of crack growth due to pressure cycle fatigue. This PCFA release, included in an optional enhanced Crack PCFA Management Module, provides a calculation of pressure cycling at discrete locations using Rainflow counting of ingested pressure data. This estimation of pressure cycling severity combined with the Modified Mat-8 methodology performs a full fatigue analysis. 

The analysis results support further sensitivity studies, the prioritization of anomalies, as well as determination of the need for a reassessment, either via hydrotest or ILI. This will help users make more informed decisions.

Going forward, we’ll be implementing more failure pressure models, pressure cycling data analysis, pressure profile calculations, and engaging our customers for their input.

Demonstrate Compliance 
Per CFR §192.712(d), introduced as Part 1 of the Gas Mega Rule: “When analyzing cracks and crack-like defects, an Operator must determine predicted failure pressure, failure stress pressure and crack growth using a technically proven fracture mechanics model appropriate to the failure mode (ductile, brittle or both), material properties (pipe and weld properties), and boundary condition used (pressure test, ILI, or other).” 

Furthermore, “If a pipeline is susceptible to cyclic fatigue or other loading conditions that could lead to fatigue crack growth, fatigue analysis must be performed using an applicable fatigue crack growth model.” 

It’s worth noting that liquid pipelines tend to be more susceptible to pressure cycle fatigue analysis and the Mega Rule was the first regulation to require consideration of cycle fatigue for gas pipelines. 

Accordingly per liquid Code §195.452(g), “Stress corrosion cracking (SCC) and other cracking (pipe body or weld) excavations and findings, including in-situ non-destructive examinations and analysis results for failure stress pressures and cyclic fatigue crack growth analysis to estimate the remaining life of the pipeline” must be considered as part of the information analysis aka data gathering and integration of integrity data.

CIM: Your Crack Management Solution
OneBridge Solutions’ Crack Management provides a consistent and intelligent approach to traditional methods of crack analysis that is fully compliant with current regulations and industry standards. By reducing the effort of exporting crack data to other applications, risking copy & paste errors, and managing disparate data formats, it provides an efficient solution to your crack management needs.

See our Crack Management Overview

Register Now for our Upcoming Webinar on Crack Management
OneBridge Solutions will be hosting a webinar to present and introduce CIM’s Crack management and optional PCFA Crack Management Module. Please RSVP here.

To find out more about CIM’s Crack Management capabilities, Contact OneBridge today.