Part of the testing program that composite repair systems are required to undergo for qualification is the installation on pipes with various hole sizes and subsequent pressure tests. The objective of these tests is to determine the lower confidence level of the energy release rate (γLCL) of the repair system. A requirement set by the standards for calculating γLCL is that the failure must occur on the edges of the repair, rather than through its thickness. However, the layer count of the composite repair may be thicker than predicted mathematically in order to have consistent through-edge failure mode. This paper reviews recent testing programs that evaluated the leak sealing capabilities of composite repairs with various thicknesses and compares the results to estimated values, regardless of failure mode. The objective of this study is to determine if, under specific scenarios, repair thicknesses less than the minimum required to pass the test can be used effectively and conservatively. The results will be compared to mathematical estimates that also highlight some key differences between the ASME PCC-2 and ISO 24817 standards.

Subject
Test methods, Materials, Piping, Materials performance, Leaks, Expected service life, Mechanical failure, Composites, Defects, Repair, Pressure, Health, safety, and environment, Toughness
Keywords:
Composites, Materials performance, Maintenance, Oil/gas/petrochemistry, Developing and updating specifications
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2023
Association for Materials Protection and Performance (AMPP)
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