Attalus SnapCure 140 is a pre-impregnated glass-fibre epoxy composite developed specifically for the repairing of non-through wall and through wall defects on pipework in the Petroleum, Petrochemical and Natural Gas industries. The composite repair system is designed entirely around speeding up the repair process with the aim of saving plant operators and owners time and money.
The two international standards that composite repairs are qualified, designed, installed, tested, and inspected to are: ISO 24817:2017 & ASME PCC-2-2018
As part of the qualification process for both international standards, testing is required to assess the short-term performance, measurement of the toughness parameter, the impact performance, and the performance on different geometries, of the composite. These tests are mandatory in qualifying the composite for both non-through wall and through-wall pipework defects.
This report details the short-term pipe spool survival test conducted for the qualification of Attalus SnapCure 140 in accordance with testing methods detailed in the following below.
• ISO 24817:2017: Annexes B.7, C, D & F
• ASME PCC-2-2018: Mandatory Appendices 401-III, IV & VI.
Testing was conducted on ASTM A106 Grade B Carbon Steel and all surfaces were prepared using a pneumatic MBX Bristle Blaster in order to gain a surface profile to SSPC-SP No.11.
The testing completed has demonstrated that the Attalus SnapCure 140 composite system meets the minimum requirements of the aforementioned articles.
Annex C / Mandatory Appendix 401-III describe the testing method for the qualification of repairs to non-through wall defects (Type A defects). The purpose of this test is to confirm the repair system has acceptable interlaminar shear and bond strength. It demonstrates the integrity of a structural repair up to the yield level of the original pipe, and determines the maximum percentage wall loss of a pipe that can be repaired.
A 1.5m long 6” SCH 40 ASTM A106 Grade B Carbon Steel pipe spool was purchased from MJ Wilson Group Ltd. A defect was machined into the pipe spool by Cutting Edge Precision Engineering Ltd. The machining left 1mm of the original wall thickness remaining at the lowest point. The value of 1mm was chosen as defects with less than this wall thickness are classified as through-wall by both ISO 24817:2017 and ASME PCC-2-2018. The defect is shown in Figure 1 below.
The defect was filled with an epoxy metal repair paste which acted as a load transfer material to transfer load from the pipe spool to the applied engineered composite, Attalus SnapCure 140. A picture of the spool after the application of the epoxy metal repair paste is shown in Figure 2 below. This epoxy metal repair paste was left to fully cure before the next stage of the preparation.
The surface of the pipe spool was then prepared using a pneumatic MBX Bristle Blaster to gain a surface profile to SSPC-SP No.11. Surface preparation was done over the entire repair area, and is shown in Figure 3.
Once the surface preparation was complete the entire repair area was degreased to remove any contaminants that may have affected the bond of the composite to the pipe spool. Once degreased, 32 layers of Attalus SnapCure 140 were applied. The number of layers was calculated for both Annex C & Mandatory Appendix 401-III.
The curing process was started as soon as 32 layers of Attalus SnapCure 140 were applied. The composite was cured using a Kuhlmann Pipe Systems heating blanket, in accordance with the curing schedule (1 hour at 120°C). Figure 5 shows the fully cured composite laminate ready to be tested.
Pressurisation of the pipe spool was done using a Hi-Force 990 bar Air Hydro Pump. The pump was connected to the spool via pressure rated hydraulic hoses with a 5-way manifold to which a pressure release valve and a Keller (1000bar) Digital Pressure Gauge were connected.
The test rig setup is shown in Figure 6 below. The pipe spool was situated inside an enclosed testing area. The pump was located outside of this area to keep the operator safe.
The pipe spool was pressurised to failure, with failure occurring from the edges of the composite wrap. The test pressure was increased in accordance with ASTM D1599.
The results of the pressure test are shown in Figure 7. The spool survived the test pressure and was held for approximately 30 seconds. At this point Icarus Engineers observed no visual signs of degradation and it was decided that the test spool would be tested until failure to ascertain the limits of the Attalus SnapCure 140.
The ultimate failure pressure of the repair, as can be seen in Figure 7 above, was 435.196 bar. The failed composite laminate can be seen in Figure 8 below. Attalus SnapCure 140 was therefore found to fail at 108.196 bar above both the ISO 24817:2017 and ASME PCC-2-2018 minimum requirements.
