Pipeline Remaining Strength Calculations (B31G) - CAESAR II - Help

CAESAR II Users Guide

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CAESAR II
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CAESAR II Version
12

Main window ribbon: Analysis > Components/Equipment > B31.G

Evaluates corroded pipelines to determine when specific pipe segments must be replaced. The original B31G document is conservative. CAESAR II performs additional calculations to modify the original criteria. This additional work can be found in project report PR-3805, by Battelle, Inc. The details of the original B31G criteria, as well as the modified methods, are discussed in detail in this report.

CAESAR II determines the following values according to the original B31G criteria and four modified methods. The values are

  • The hoop stress to cause failure

  • The maximum allowed operating pressure

  • The maximum allowed flaw length

The four modified methods vary in the manner in which the corroded area is estimated. The methods are:

  • .85dL

Approximates the corroded area as 0.85 times the maximum pit depth times the flaw length.

  • Exact

Determines the corroded area numerically using the trapezoid method.

  • Equivalent

Determines the corroded area by multiplying the average pit depth by the flaw length. Additionally, an equivalent flaw length (flaw length * average pit depth / maximum pit depth) is used in the computation of the Folias factor.

  • Effective

Uses a numerical trapezoid summation; however, various sub-lengths of the total flaw length are used to arrive at a worst case condition. If the sub-length that produces the worst-case coincides with the total length, the Exact and Effective methods yield the same result.

To begin, specify a new job name in the New Job Name Specification dialog box or click Browse to navigate to an existing job file.

All CAESAR II analyses require a job name for identification purposes. After you create or open a job, you can enter input data and then define, analyze, and review your data.

The software opens the Pipeline Remaining Strength Calculations (B31G) window. The window consists of two input tabs: Data Tab and Measurements Tab.

After the data is entered, click Run Analysis to begin the computations. A typical output report is shown below:

  • For additional information or backup on these computations, an intermediate computation file is generated.

  • For more information on the analysis methods used by this command, see the B31G document or the Battelle project report PR-3-805.