Vulnerability of welded joints and active damage mechanisms in petrochemical plants and processes: reliability through programming of risk based inspection (RBI) – Part II

Abstract

The special process of welding still plays a key role in the fabrication of pressurised equipment for the energy processing and generation industry. Similarly, welding is extensively used in repair, modification and overlay/cladding procedures and during the maintenance operations for large plants. However, the harsh statistics relating to faults shows welded joints to be among the most ‘at risk’ areas with regard to various active damage mechanisms. Within the framework of the management of plant risk and equipment integrity, the Risk Based Inspection (RBI) method, with the aim of prioritising and optimising the inspection strategy, focusses attention on the criticality of welded joints with the framework of problems related to both simple mechanical vulnerability and physico-chemical aspects such as corrosion and/or stress corrosion. The aim of this paper is to offer an overview of the interactions existing between the various active damage mechanisms in plants and welded joints in addition to indicating the criticality associated with these interactions, with the purpose of optimising the management of plant risk and inspection strategies for resolving them.