Where is the line drawn between boiler "Repair" and "Alteration&q

[rmillercwi]

Perhaps this isnt the correct forum but since I could find no listing for NBIC I will ask here.

The NBIC clearly establishes differences between Routine, Repair, and Alterations to boilers previously in service. I understand Routine repairs as basic repairs to non pressure items with no actual formal inspection required. Get the AI's blessing, Fix it, write up an R-1 and get on with your life.

However the distinction between Repairs and Alterations are not so clear. I guess that a Repair is when you are using the same materials and procedures to repair pressure parts as was originally listed and the boiler is not being re-rated. No revised calculations required. An Alteration would be whenever you alter the design to the point of requiring a re-rating. Is this correct? If so, what if you are repairing a CS pipe run that has failed due to FAC and the sound judgement fix is to simply change out the elbows with 1.25 cr? Is this an Alteration?

Please advise

 

[metengr]

To better answer your question, I need you to review Appendix 4 (Glossary of Terms) and Appendix 6 of the National Board Inspection Code. Appendix 6 contains examples of repairs and alterations are listed and discussed.

 

[rmillercwi]

Thanks metengr. The glossary and examples clarifies most of my questions.

In regards to my example with the elbow replacement of a higher grade material, it would be an alteration and require new calculations, drawings, wps, etc to be reviewed and approved prior to commencement of work. Correct?

 

[metengr]

No, this is not an alteration. We issued an interpretation some time ago on this matter. If you review the examples of repairs, a material substitution that results in equivalent or higher allowable stress values from that originally specified is considered a repair (see paragraph s in Appendix 6).

 

[rmillercwi]

You are correct sir. I didnt bother to look and see what "except as permitted in 6-2000" refered to

I assumed because P-4 material has a higher yield strength, cr content,etc. than p-1 material (not equivalent)it did not apply.

 

[CodeRef]

Don't forget NBIC Interpretation 98-14........

http://www.nationalboard.org/NationalBoard/Nbic/Interpretation/1998/Interpretation_1998.aspx