The ability to determine, using a uniform approach, which joints in a unit, plant or company represent the highest level of risk of leakage is extremely useful. Similarly to Risk-Based Inspection (RBI), Risk Based Joint Integrity (RBJI) allows the identification and allocation of resources to the joints that pose the greatest risk of failure. This ensures that the appropriate level of effort is placed in the most appropriate locations.
This paper outlines a quantitative methodology for assessing the probability of failure for any given pressure boundary bolted joint. It allows rapid calculation across a range of joints without resorting to the typical qualitative, reactive, experienced-based methods commonly employed to assess risk of joint leakage (i.e.: waiting for the joint to leak in order for it to be labelled a bad actor). This methodology has been successfully employed in a number of applications over the past three years, such as justification of heat exchanger replacement (demonstrating the expected improvement in joint integrity) and assessment of residual risk associated with historic joint assembly practices. Future applications include assessment of risk and definition of acceptable residual risk during the project design phase in order to eliminate problematic joints prior to fabrication and using the methodology to reduce the time associated with leak-testing of piping systems during maintenance turn-around activities.