Workers carefully weld two pipeline sections together.
Southern California Gas Company (SoCalGas®) is the nation’s largest distributor of natural gas, delivering safe and reliable service to nearly 21 million customers through almost 6 million meters. To reach those customers, natural gas is transported over 4,000 miles of gas transmission pipelines, 48,000 miles of distribution pipelines and 49,000 miles of service lines.
At SoCalGas, the safety of our employees, our customers and the communities we serve has been and will continue to be our highest priority. Reflecting that commitment to safety, we construct, operate, and maintain our pipeline system to meet or exceed all applicable federal and state regulations and requirements.
SoCalGas routinely performs various pipeline maintenance and safety tasks, including patrolling, inspecting, testing, repairing and replacing pipelines. Sometimes pipelines are replaced to meet expanding customer and/or gas system needs as well as to accommodate infrastructure improvement projects of cities, counties and state agencies.
A pipeline replacement project is generally a significant construction operation. Typically, the new pipeline segment is installed adjacent to the existing pipeline, which allows the construction work to proceed without stopping the flow of natural gas through the original pipeline.
A trench is carefully excavated alongside the path of the original pipeline into which the replacement pipeline will be laid. New pipeline is made of steel and comes with a coating on the outside that prevents moisture from coming into direct contact with the steel and causing corrosion. The new replacement pipeline sections, usually 40 to 60 feet long, are carefully welded together to create a continuous length of pipeline that is then lowered into the trench using cranes.
Before being placed into service to carry natural gas, the interior of the replacement pipeline segment is thoroughly cleaned to remove any dirt or construction debris. Then it is given a final safety check with a hydrostatic pressure test which pumps water into the pipeline segment and pressurizes it to a level well above which it will operate. If the pressure test reveals no leaks, the pipeline is ready for use.
The natural gas remaining in the existing pipeline segment is safely vented and it is disconnected from the main pipeline. Next, the replacement section is connected to the main pipeline and it is safely brought into service.
Pipeline replacement is one of the many ways SoCalGas maintains the safety and integrity of its natural gas pipeline system.
Whenever SoCalGas installs a replacement pipeline in a community, we make every effort to minimize and mitigate any impacts. Potential community impacts may include seeing trucks and equipment on the streets, excavation sites, temporary “No Parking” signs on streets, possible lane reductions or closures, detours and temporary delays on surface streets.
The community also may hear some work-related noise and notice an occasional natural gas odor. We strive to provide continuous natural gas service for our customers throughout the replacement project process, but in some instances there may be temporary natural gas service interruptions.
The time needed to install a replacement pipeline may take several weeks and varies depending on a number of factors such as the length of the process for obtaining necessary permits, permissible working hours as determined by the local jurisdiction, traffic control issues, length of pipeline being replaced, location of the pipeline, ease of access to the pipeline, amount of excavation necessary to install the replacement pipeline, and even the weather.
When the pipeline replacement is complete, the excavated areas are “back-filled” by returning the removed soil into the trench, and later graded and restored as closely as possible to their preconstruction condition. Any needed street or property repairs are also made.
SoCalGas appreciates the co-operation and patience of our customers and the communities we serve as we work to enhance the safety of our natural gas pipeline system.