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[MW:6251] Application of B31G - Strength of corroded Pipe

By Materials & Welding

Dear all,

 

One of plant project engineer has asked me to make document for Minimum required wall thickness for the piping  which is acceptable to run the process with defined design condition under corroded condition.

 

As per my understanding this the same Min. wall thickness based on calculation of required wall thickness for design pressure and design temperature ..ie  Min. wall thickness which is ( Nominal wall thickness – manufacturing tol..- Corrosion allowance ).

 

But one of our old engineering manual has listed the use of ASME B31G , manual for determining the remaining strength of corroded Pipelines,  after reading this manual , I can state that this manual gives the strength of corroded portion of the pipeline. Defined parameters in this specification is based on Depth of corrosion and length of the metal loss.

 

My query is how can I use this ASME B31G for defining the minimum required wall thickness requirement for existing piping network in plant.

 

Do you agree that my initial assumption of Min. wall thickness ie. Nominal wall thickness – Mfr. Tol. – Corrosion allowance is a right approach ?

 

Waiting for your suggestions.

 

reg

 

 

Rahul

 

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