PROJECT BACKGROUND
Gibson Energy is a major liquids infrastructure company involved in the storage, processing, and optimization of refined products. Gibson Energy has operations across North America, including its Edmonton terminal and hub, with approximately 1.7 million barrels of storage and rail loading capabilities. As part of an operations expansion project, Gibson required additional storage capacity to be added to their Edmonton tank farm, which included two new 435,000 bbl. tanks.
PROJECT SCOPE
To increase the tank farm capacity while working around the constraints of a tight land footprint, the project included excavating and the removal of approximately 3.3 feet (1 meter) of existing subgrade. In addition, 2800 lineal feet (850 m) of a 12’ (3.6 m) vertical concrete wall was constructed around the perimeter of the tank farm. This was required to provide 110% storage capacity for the tank farm.
As part of the secondary containment system, the expanded tank farm area was double-lined, which included a primary and secondary geomembrane system. The bottom secondary containment liner was Enviro Liner® 6040 (1.00 mm), a blended polyolefin alloy material combining Linear Low-Density Polyethylene (LLDPE) and High Density Polyethylene (HDPE) with an advanced UV and antioxidant package. The Enviro Liner® secondary liner was welded to an existing HDPE liner in the tank farm. To ensure both chemical resistance and fire protection, the primary liner was HAZGARD® 635FR.
HAZGARD® 635FR is a unique fire-retardant geomembrane material designed for the secondary containment of flammable and combustible liquids, including gasoline and alcohol-blended gasoline, diesel and biodiesel-blended diesel, jet fuels, and crude oil. An LP10 (285 g/m2) nonwoven geotextile cushion layer fabric was installed under the Enviro Liner® 6040 secondary containment liner. An LP16 (450 g/m2) nonwoven geotextile overlay fabric was placed on top of the HAZGARD® 635FR primary liner on the floor section, which was backfilled with compacted soil. Both the Enviro Liner® 6040 and the HAZGARD® 635FR materials were installed on the 2800 linear feet of a 12-foot-high vertical wall.
CHALLENGES & RESULTS
Multiple installation challenges included attaching the double-lined geomembrane system to the 3.6 m vertical wall. This required erecting a custom modular scaffold to allow for material handling, mechanical anchorage, and welding of the geomembrane panels. Another challenge was the 450 steel piles and pipe boots penetrating the floor and wall area. This required both the primary and secondary liners to be welded and sealed using fabricated pipe boots and mechanical anchorage methods. Both liners also needed to be mechanically connected to the perimeter concrete wall. A final challenge was working within the tight space constraints of the existing tank farm.
To help meet the project challenges, Layfield prefabricated many of the liner sections and components in its Edmonton, Alberta fabrication plant. Layfield’s construction group welded the factory-fabricated and manufactured roll stock panels on-site using thermal wedge and extrusion welding. The geomembrane CQA methods for welding included destructive seam testing for tensile peel and shear properties, non-destructive air channels, and vacuum box testing for all seams. The project was completed in two phases, starting in 2023 and ending in 2024. Maintaining strict compliance with safe working practices was also a critical project requirement for all stakeholders. The tank farm expansion project was completed safely with no reported safety incidents.
The success of this project is attributed to the innovative geosynthetic materials supplied and installed to meet the unique and challenging site conditions. Also, the combination of the factory and field welding methods used during the installation by Layfield’s construction team. The project required strong project management, planning, and experienced workmanship. All stakeholders also worked cooperatively to complete the project on time and on budget.
