Engaging landowners

For months, or even years, in advance of construction, teams are in contact with landowners and other stakeholders to keep them informed. Communication continues throughout the construction and post-construction process. Whenever possible, construction is planned to take place when it will create the least disruption for landowners and wildlife.

Surveying and staking

Survey teams travel the pipeline route to stake the right-of-way and temporary workspaces. The right-of-way is the area where the pipeline will be buried, as well as where construction activities occur. It can be up to 40 metres wide.

Preparing the right-of-way

Clearing crews enter the right-of-way to limit the amount of vegetation and structures in the area. In cultivated areas, the top soil (the top 15 to 25 cm containing the organic material that supports vegetation) is carefully removed and set aside, as it will be replaced during reclamation. The depth and type of top soil is identified and recorded during the environmental assessment by the survey crew.

All soil layers are segregated so they can be replaced in the same order.

Digging the trench

To minimize the disturbance, machines create a trench precisely the width and depth necessary for the type of pipeline being built. The equipment used to dig the trench varies depending on both the type of soil and trench required.

Machines create a trench precisely the width and depth necessary for the type of pipeline being built. Photo courtesy of Enbridge Pipelines.

The trench digging crews move quickly, sometimes covering several kilometres in a day.

Stringing the pipe

Crews re-stake the center of the trench area and lay out individual lengths of pipe, which have been brought in from nearby storage areas and carefully placed end-to-end along the right-of-way. Every element is focused on maximizing strength and safety, including the type of steel used, the thickness of the pipe and the corrosion-resistant coatings.

The pipe is precisely designed for the conditions it will be exposed to.

The pipe is carefully laid into the trench. Photo courtesy of TransMountain Expansion.

Welding the pipe

The sections of pipe will be joined together by welds. Welding shelters are sometimes placed over pipe segments so welders can fuse the segments together while protected from wind or weather. Welders use techniques to make the points where the pipes connect even stronger than the steel in the pipe.

Each and every weld is inspected using an X-ray or ultrasound, and is 100% certified.

Bending the pipe

To match the contours of the land, a pipe-bending machine may be used. It’s a gentle and gradual process that retains the strength and shape of the pipe, but allows the operator to follow the safest, most responsible route.

Coating the pipeline

To prevent corrosion, special coatings are applied to the pipe, during the manufacturing process. The coatings are formulated to actually bond to the molecules in the steel, creating a powerful shield. The protective coatings are precisely designed for the conditions outside the pipeline. In cases where internal coating is needed to reduce friction, the lining is adhered to the pipe during manufacturing and the welded joints are coated at the site.

Epoxy coatings are commonly used in North America to protect against water permeation and abrasion from materials in the soil. The coatings bond to steel pipe through a mechanism commonly referred to as polar bonding.

Pipeline coatings are formulated to actually bond to the molecules in the steel, creating a powerful shield. Photo courtesy of Enbridge Pipelines.

“The polar bond allows for excellent adhesion of the pipeline coating, thus offering superior protection for the life of the pipeline,” according to Matt Alliston, Canadian vice president of domestic markets with Specialty Polymer Coatings, a CEPA Foundation member that makes high-performance coatings for pipelines, marine vessels and other industrial projects.

Positioning the pipeline

The welded pipeline is then gently lowered into the prepared foundation of the trench. Bulldozers using cranes called side booms carefully place the pipeline into the prepared trench bed. The side booms are designed to prevent damage to the pipe and its exterior coating.

A pipeline is placed in position to be lowered into the trench. Photo courtesy of Enbridge Pipelines.

Installing valves and fittings

At this point, the shutoff valves and remote sensors are installed. The sensors will send information to the master control room on flow rate, pressure and temperature, allowing technicians to closely monitor the line.

Special valves can quickly shut off the pipeline in case of emergency.

Restoring the site

Once the pipeline is in place in the trench, the topsoil is replaced in the sequence in which it was removed and the land is returned to its original shape.

The process from staking the right-of-way to beginning restoration of the site can take place in as little as 10 days.

Testing under pressure

The pipeline is put through a rigorous series of tests, including pressure testing for a minimum of eight hours using nitrogen, air, water or a mixture of water and methanol. Results are analyzed and shared with the regulator prior to approval to open the line.

Remediating the land

Environmental experts like biologists and agrologists remediate the land with indigenous vegetation. Wildlife experts ensure no long-term impacts to animals have occurred. The operator begins a monitoring and remediation period of no less than three years immediately following the completion of initial right-of-way restoration. The three-year period ensures any impacts from construction can be identified and corrected.

After the pipeline is placed in the trench, it undergoes thorough examination and testing. Photo courtesy of Enbridge Pipelines.

Environmental specialists remediate and monitor the land

Regulating every metre of the pipeline

The Pipeline Act of 1949 set the stage for the Canada’s pipelines to become the safest in the world. Strictly regulated for life, at the either federal or provincial government level, pipelines must follow rules detailing how pipelines will be built, operated and even retired – while always putting the environment and safety as their primary considerations. Pipeline operators follow high standards for pipeline materials and methods that are set by third-party organizations like the CSA Group.

Nothing is left unexamined in the interest of safety.