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Full encirclement repair sleeves with fillet-welded ends are often used as permanent repairs on pipelines to reinforce and develop pressure retaining repairs on areas with defects, such as cracks, dents, or corrosion. In-service failures have occurred at pressure retaining sleeves as a result of defects associated with the sleeve welds, such as hydrogen-induced cracks, undercut at the fillet welds and inadequate weld size.
Currently, there are no reliable methods to carry out a quantitative fitness for service assessment for a sleeve fillet ...
Currently, there are no reliable methods to carry out a quantitative fitness for service assessment for a sleeve fillet weld with a weld fault because:
the stresses at the sleeve end fillet weld roots and toes are not easily determined;
stress intensity factor solutions are not available for the sleeve fillet weld geometry; and
current inspection procedures cannot effectively define the size of weld defects.
After completion of a sleeve fillet weld, it is currently common practice to carry out a visual inspection and magnetic particle inspection (MPI) to determine whether weld toe defects exist. With continuing advances in nondestructive examination (NDE) technologies, the ability to not only inspect for toe and root flaws but also to size these cracks and inspect and size root flaws is becoming a reality.
BMT Canada Ltd. (BMT) completed a project  to develop stress intensity factor solutions for a variety of sleeve end fillet weld cracking scenarios, including different cracking locations and different loading conditions. The current project was focused on developing standalone software calculators (Excel and standalone executable program) to automate the calculation of the stress intensity factors. In addition, the project included a sensitivity analysis to identify significant trends in the behavior of sleeve end fillet weld cracking and identify the major parameters that contribute to the calculated stress intensity factors.
 In the Matter of an Accident on 19 February 1985 near Camrose, Alberta on the Pipeline System of Interprovincial Pipe Line Ltd.”, National Energy Board, Canada, 1986.
 T.F. Cross and C.A. Robertson, “Northeast U.S. products line upgraded after major line break”, Oil and Gas Journal, February 15 1988, Vol. 86, No. 7, pp 35‑40.
 Failure on NOVA approx. 1992.