ESTIMATED REPAIR FACTOR(ERF), FOR PIPELINE-REG

[gkvengat]

Dear All,
we found corrosion in our pipeline, hence we performed ILI-MFI and found ERF less than 1 as per ASME B31G.

When I referred ASME B31G, I couldn't find ESTIMATED REPAIR FACTOR(ERF) criteria.

Please clarify in which clause ERF (ERF less than 1 or greater than 1)criteria is specified in ASME B31G.

 

[1503-44]

ERF > 1 indicates repair is required, or MAOP must be reduced.



Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[gkvengat]

Thanks, noted. This criteria "ERF > 1 indicates repair is required, or MAOP must be reduced" in which clause of ASME B31G mentioned. I couldn't found in code.

 

[1503-44]

If you do not reduce MAOP, or otherwise make repairs when such is indicated by the factor, its probably better to claim you never heard about B31G.

Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

A quick GOOGLE shows that ERF is actually just what Integrity Engineers use to show whether a defect is acceptable to ASME B31G or not.

SO it is simply a ratio number, I presume of the MAOP calculated by 31G divided by the current MAOP of the pipeline.
Hence why it is not in B31G itself, it has just become a useful number to show in a report.
You get the same in stress analysis reports with an easily scanned number to show when an item is above the max allowed stress or not.
This from a Penspen document.

4 The ‘ERF’ or ‘Estimated Repair Factor’ is a popular method for assessing the significance of a defect.
The ERF calculation is another way of expressing an ASME B31G assessment [6]
. If the ERF is less
than one the defect is acceptable to ASME B31G. If the ERF is greater than one the defect is not
acceptable to ASME B31G.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[gkvengat]

Thanks lot for more clarity on ERF and I understood.

Yes, I don't have exposure of ASME B31G and i never worked in it.

I have one more question, can you please clear it?

Is it correct, instead calculating the ERF, can I go with ASME B31G,clause 3 TABLES OF ALLOWABLE LENGTH OF CORROSION
The following are applicable to Tables 3-1 through 3-12M:, to make decision to accept and reject corrosion.