METHOD FOR DETERMINING THE REMAINING STRENGTH
OF CORRODED PIPELINES*
FOLLOWING ASME B31G CODE

With this method, you may determine

· Safe Maximum Pressure for the corroded pipelines.

This method includes all pipelines within the scope of the pipeline codes that are part of ASMEB 31 Code Piping, i.e., ASME B31.4, Liquid Transportation Systems for Hydrocarbons, Liquid Petroleum Gas, Anhydrous Ammonia, and Alcohols; ASME B31.8, Gas Transmission and Distribution Piping Systems; and ASME B31.11, Slurry Transportation Piping Systems. Parts 2, 3 and 4 are based on material included in ASME Guide for Gas Transmission and Distribution Piping Systems.

  You may also obtain :

• Percentage pit depth - %
• Maximum allowable longitudinal extend of the corroded area
• Design Pressure
• Safe Maximum Pressure for the corroded area

 Furthermore you will be able to:

  · Check your existing body line of pipes for different conditions .
  · Check your pipes operating modifying someone of the parameters as follows:
     - Nominal Outside Diameter of the Pipe
     - Nominal Pipe wall thickness
     - Measured Longitudinal extent of the corroded area
     - Measured Maximum depth of the corroded area
     - Maximum Allowable Pressure
     - Appropiate Design factor
     - Temperature derating factor

 LIMITATIONS

• This Method is limited to corrosion on weldable pipeline steels categorized as carbon steels or high strength low alloy steels. Typical of these materials are those described in ASTM A 53, A 106, and A 381, and API 5L. (The current API 5L includes all Grades formerly in API 5LX and 5LS.)
• This Method applies only to defects in the body of line pipe which have relatively smooth contours and cause low stress concentration (e.g., electrolytic or galvanic corrosion, loss of wall thickness due to erosion).
• This method should not be used to evaluate the remaining strength of corroded girth or longitudinal welds or related heat affected zones, defects caused by mechanical damage, such as gouges and grooves, and defects introduced during pipe or plate manufacture, such as seams, laps, rolled ends, scabs, or slivers.
• The criteria for corroded pipe to remain in service presented in this Method are based only upon the ability of the pipe to maintain structural integrity under internal pressure. It should not be the sole criterion when the pipe is subject to significant secondary stresses (e.g., bending), particularly if the corrosion has a significant transverse component.
• This method doesn't predict leaks or rupture failures.

  Notes:

- Piping Design Factor:
                                          ASME B31.4: 0.72
                                          ASME B31.8: 0.8, 0.72, 0.6, 0.5, 0.4. (According to Location Classes).
- Steel Pipe Temperature Derating Factor: (See table 841.116A at ASME B31.8 Code).
- Additional wall thickness required for concurrent external loads shall not be included in the calculations (See Pipe Wall Thickness)
- This method is not applicable to new construction covered under the B31 Code Sections.

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EXIT DATA SHEET IS AS FOLLOWS :

INPUT FOR CALCULATION METHOD
METHOD FOR DETERMINING THE REMAINING STRENGTH
OF CORRODED PIPELINES*
ASME B31.G