Rerouting a section of a natural gas pipeline is always a complex project. But one of Canada’s largest pipeline companies found the endeavor even more challenging when it was mandated to relocate a pipeline in an environmentally and politically sensitive area on a tight timetable.
The section that required relocation is part of the major 30-in. natural gas corridor that traverses west to east across Canada, delivering energy to one-third of the nation’s population. The area around the pipeline was issued a safety class upgrade by the National Energy Board (NEB) when construction of a subdivision began near the pipeline. Because it was determined that the new residences would be too close to the pipeline to comply with safety standards outlined by the Canadian Standards Association, the pipeline operator chose to cut out a 900-ft section of the pipeline and build a new section farther from the new residential development. In order to maintain gas flow to customers, the pipeline was isolated upstream from the construction area and rerouted through a bypass line.
The pipeline relocation project was complicated by the fact that the new section of pipeline would run along the edge of a national park in Quebec and near a Mohawk Nation reservation. Not only did the owner/operator want to minimize any environmental damage to the area, it also sought to treat the area with appropriate respect and avoid any political concerns.
The operator partnered with pipeline service provider T.D. Williamson (TDW) to perform a Double Block and Bleed isolation using its Stopple Train system on the section of the pipeline being relocated. By employing the Stopple Train technology, the operator kept product flowing while averting gas leaks that could endanger nearby workers, especially welders using open flames.
Because all work needed to be completed before the safety class change, TDW was charged with building and testing new custom 30-in. Stopple Train equipment within just 10 weeks. TDW performed the isolations safely, on time, and without interruption of service.
TDW’s Stopple Train system is the newest of the company’s Double Block and Bleed solutions. Unlike traditional Double Block and Bleed isolations, which use two plugging heads, requiring two fittings and hot taps, the Stopple Train system inserts two plugging heads through just one entrance into the pipeline. A bleed port is affixed on the line between the two heads. The bleed is left open and monitored, and any product escaping the first seal goes into the bleed port to be removed from the line.
The Stopple Train system met all of the risk reduction and efficiency requirements of the Canadian operator. By reducing the number of line penetrations, Stopple Train technology is faster, safer, and leaves less equipment on the pipeline. It also reduces costs associated with fittings, welding, inspection services, scaffolding and crane rental, and requires fewer “hot work” permits.
In addition, the Stopple Train system has a high first-time success rate for setting plugs. Getting a good seal is critical to the success of any isolation job that uses Stopple technology. Without an acceptable seal, the plugging heads can’t be set without risk of damaging them. TDW provided the Canadian operator with a 100 percent seal with the Stopple Train system, with two seals delivering an extra layer of safety for technicians working downstream.
After TDW completed the isolation, the Canadian pipeline company successfully rerouted the gas through the temporary bypass and built the new pipeline segment a safe distance from the subdivision without incident. There was no service disruption to pipeline customers and minimal environmental disturbance.