Joint Industry Project Overview

C-FER Technologies is completing a Joint Industry Project (JIP) in partnership with four major pipeline operators to identify and evaluate the best composite or hybrid repair technologies for restoring circumferential cracks on pipelines. Alberta Innovates, a provincially owned research and innovation agency, has also recognized the benefits of these essential research activities and provided additional support to the project.

The primary goal of this evaluation is to fairly quantify the axial load-carry capacity of the repaired pipes under real-world pressures and loads.

This JIP focuses on repair technologies that do not weld to the carrier pipe, which offer various benefits for specific applications relative to traditional metal sleeves. The test program has four phases:

  1. Phase 1 – Non-destructive tensile testing (Completed)
  2. Phase 2 – Effect of installation pressure (Underway)
  3. Phase 3 – Destructive tensile testing with circumferential flaws (Proposed)
  4. Phase 4 – Long-term performance of repairs (Proposed)

Phases 3 and 4 include machined circumferential flaws in the pipe specimens to simulate real-world conditions. The specimens are subjected to axial tension and constant internal pressure.

End Applications Considered

Testing of the non-welding repair systems focuses on how these technologies will perform under realistic conditions such as external axial or bending loads on pipelines with significant axial or circumferential defects.

To date, these repair technologies have focused on repairing axial defects in pipelines (i.e. hoop reinforcement). They have been developed and thoroughly evaluated for this application, leading to standardization in ASME PCC 2 and ISO 24817. However, their evaluation for the repair of circumferential cracks (axial reinforcement) has been limited.

Few evaluations have included repairing pipelines with circumferential stress-corrosion cracking (CSCC) or girth welds defects subjected to slope and ground movement.

The JIP is addressing this gap. The current focus is on medium line sizes (NPS 12 to 24) and straight pipe geometries.

However, there is also interest in other end applications, such as:

  • small line sizes (NPS 2 to 8),
  • large line sizes (NPS 30 to 48),
  • loading conditions such as external bending with internal pressure, and
  • complex geometries such as bent pipes, elbows or tees.
Project Overview Video

Join the JIP

The project is actively looking for new JIP members to help guide the project and support later phases of the JIP.

There are two ways to join:

  1. If you are a pipeline repair technology provider: contact C-FER and ask whether your system may be suitable for JIP testing. As new systems are developed, C-FER has been tasked with identify suitable candidates. We’ll present your repair technology to the JIP members, make them aware of your technology, and see if they want to test it.
  2. If you are a pipeline operator: contact C-FER and inquire about joining this ongoing JIP. Participants share learnings, and actively collaborate on these novel repair technologies with other major operators.

Repair Technology Review

C-FER identified 34 repair technologies from 17 different vendors during a comprehensive review. The repair technologies reviewed fell into six general types as follows:

Repair Type System Description System Features
1 Wet-lay-up of composite fabric and epoxy Generally, higher tensile and bonding strengths on average than Type 2 repairs

Need to maintain the epoxy-to-fabric ratio during installation

2 Composite fabric pre-impregnated with water-activated resin Often easier to install, especially for varying geometry repairs
3 Preformed composite coil and epoxy system (i.e. layered system) Likely have a more consistent structural performance (reduce variabilities between installers and composite layers)

Usually, more challenging to customize repair for a specific application

4 Steel sleeves adhered to the pipe using epoxy (i.e. hybrid system) Likely have a higher and more consistent multi-directional load capacity than composite fabrics

Usually pre-compressed onto the carrier pipe

Often require larger equipment to install the repair compared to Type 1 to 3

5 Bolt-on repair sleeves/collars Avoids the challenges of adhesive mixing, curing and bonding

Axial load capacity will likely be limited by the static friction that can be achieved

Often requires larger equipment to install the repair compared to Types 1 to 3

6 Other For repair systems that don’t fall within Types 1 to 5

Phase 1: Non-destructive Tensile Testing - Completed

  • Identified six repair technologies with high potential for application
  • Compared and ranked the repair technologies in an “apples-to-apples” comparison by:
    • Installing the repair systems in a series on a length of defect-free and pressurized pipe
    • Applying a combination of axial tension and constant pressure to the pipe
    • Measuring the relative displacement across each repair system
    • Showing the load sharing effectiveness between the pipe and each repair system
  • Tested three identical specimens (each with the six repair technologies) to establish performance variability

Phase 2: Effect of Installation Pressure - Underway

  • Identified three repair technologies based on Phase 1 results
  • Investigating the effects of pipe hoop precompression and deformation on the performance of the repair systems
  • Evaluating repair performance following the “apples-to-apples” methodology of Phase 1
    • Axial tensile testing of pressurized specimens
    • Stiffness measurements of repairs to determine load sharing capacity with pipe
  • Testing seven specimens (each with three repair technologies) with different installation pressures or loading conditions

Phase 3: Destructive Tensile Testing with Circumferential Flaws - Proposed

  • Identifying three repair technologies based on Phase 1 and 2 results
  • Determining the critical sizes of circumferential flaws that the repair systems can restore
  • Testing baseline pipe (i.e. with or without a flaw, but no repair system)
  • Testing repaired pipes with simulated flaws
  • Applying constant pressure and increasing displacement-controlled axial tension until failure

Phase 4: Long-term Performance of Repairs - Proposed

  • Identifying two repair technologies based on Phase 1 to 3 results
  • Investigating creep deformation and deterioration of repair materials over time
  • Fabricating and repairing the pipe specimens similar to Phase 3 (baseline or repaired specimens)
  • Applying constant pressure and constant or cyclic axial tension over a short- or long-term period
  • Assessing the remaining load-carrying capacity of repaired pipe after term using destructive testing
  • Testing ten specimens: For each term period, 2 tests per repair system and 1 baseline test

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2020-02-22

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