Source: Kim, J., Lee, S., & Kim, M. (2020). Finite Element Analysis of Patched Tubing under High-Temperature and High-Pressure Conditions. Journal of Pressure Vessel Technology, 142(2), 021201.
The weld must be a full-penetration butt weld.
Welding must be done using a Welding Procedure Specification (WPS) qualified according to ASME Section IX. asme standard patched
: A flush patch, using a butt-welded full-penetration joint, is often preferred over a fillet-welded lap patch where feasible. It offers a smoother surface, better stress distribution, and may be easier to inspect.
flowchart TD A[Damage Found on In-Service Component<br>(e.g., Corrosion, Crack)] --> BFitness for Service (FFS)<br>Assessment (e.g., API 579); B -- Not Fit for Service --> CSelect Repair Method; B -- Fit for Service --> D[Continue Monitoring]; Source: Kim, J
In industrial pressure equipment (vessels, piping, boilers, tanks), localized damage such as corrosion, erosion, cracking, or mechanical impact may occur without compromising the entire component. A is a repair plate or section welded or bonded over the damaged area. The American Society of Mechanical Engineers (ASME) provides standardized rules for such repairs to ensure safety, integrity, and code compliance.
An component is a pressure vessel or piping system that has undergone a structural repair using a welded or mechanically attached patch, executed strictly according to ASME code rules. Journal of Pressure Vessel Technology, 142(2), 021201
Repairs must generally be performed by a company holding a valid "R" Certificate of Authorization from the National Board, ensuring the repair complies with the NBIC 2.2.2 .