Stages of pipeline construction
TransCanada Pipelines Limited is a Canadian compant with more than 65 years’ experience in the responsible development and reliable and safe operation of North Amercanenergy infrastructure. Our pipelines are designed, built and operated to ensure the long term safety and reliability of our natural gas systm.
Prince Rupert Gas Transmission is committed to designing, constructing and operating the project in a safe and environmentally responsible manner.
Eight stages of pipeline construction
1. Clearing and grading
Topsoil is removed and the ground is prepared along the right-of-way, ensuring a level-working surface. The topsoil is collected and stored so it can be replaced following construction.
Construction crews dig a trench for the pipe. The trench is then filled with the preserved soil. This process ensures the topsoil is returned to its original position.
Pipeline crews line up sections of the pipe along the edge of the trench. A machine bends the pipe so that it follows the pipeline route and the contour of the land.
Welders join the pipe segments together. Pipeline joints are coated with an anti-corrosion material and then inspected. Extreme care is used to properly weld the pieces together. Each seam is examined through a nondestructive inspection process.
Following careful inspection, specially designed cranes are used to lower the sections of welded pipe into the trench. A separate crew completes the final welds (tie-ins) connecting continuous lengths of pipeline that have been lowered into the trench.
The stored soil is returned to the trench to bury the pipeline.
7. Pressure testing
The pipeline is filled with water and pressurized to a level that exceeds the operating pressure of the pipeline, ensuring it’s ready to transition safely to operation.
Once testing is complete, final techniques are employed to stabilize the right-of-way and return the ground surface to its original contours for drainage patterns. The topsoil is replaced, allowing for the re-establishment of appropriate vegetation. The goal is to bring the land as close to the original state as possible.
PNW LNG announced a positive final investment decision in June this year, with two conditions: Approval of related legislation by the B.C. legislature (approved on July 22, 2015), and approval of an environmental assessment certificate by the Canadian Environmental Assessment Agency. Should the certificate be awarded, PNW LNG will decide whether to confirm their investment decision and PRGT will begin site preparation for camp locations and other related sites shortly thereafter, followed by pipeline construction activities. PRGT expects to begin pipeline operations in late 2019 or early 2020.
Natural gas becomes LNG when it is chilled to -160 Celsius.