Source: Li, M., Zhang, Y., & Li, G. (2018). Stress Analysis of Patched Pipes under Internal Pressure. Journal of Pressure Vessel Technology, 140(3), 031201.
An ASME standard patched repair cannot be performed by guesswork. ASME PCC-2, Article 2.01 (Insert Plates) and Article 2.02 (External Lap Patches) dictate strict design parameters. Material Matching
The design must account for the high eccentricity and bending stresses induced by the thickness offset of the lap joint. asme standard patched
It is important to distinguish between a repair and an alteration under API 510.
Rules for Construction of Pressure Vessels (specifically Mandatory Appendix 6 for specific examination types and general design philosophy) Source: Li, M
However, if the repair follows ASME PCC-2 strictly, most jurisdictions treat it as equivalent to new construction for legal operation, except in:
This is the primary guide for patching. It provides mandatory rules for: Journal of Pressure Vessel Technology, 140(3), 031201
: Often used in conjunction with ASME. Note that the NBIC generally prefers flush patches (insert plates) or weld overlays over external "lap" patches for permanent repairs. 4. Inspection and Testing
, following the most current version (including errata) is mandatory. Audit Failures