Main Line Valve Replacement Project

GTS provided program and project management support in Southern California on a 26-inch natural gas transmission line running from Lebec, CA to Newhall, CA. The project, located within the Angeles National Forest near San Bernardino, consisted of replacing a vault, flanges, and a leaking valve. GTS was requested to conduct an AB 1937 evaluation and it was determined by GTS to be clear. The details of the proposed project were to replace the 18-inch Main Line Valve assembly with more modern equipment to ensure system safety and reliability.

The Main Line Valve Replacement project had many challenges to overcome. For teams to reach the valve location, 1.1 miles of existing access road in the Angeles National Forest needed to be restored for safe travel, which included grading to remove existing ruts from the road. Due to the site location being situated in an environmentally sensitive area on a steep hillside within the Angeles National Forest, there were multiple items that were required, such as:

  • Biological Survey Report
  • Erosion Control Plan
  • Habitat Restoration Plan
  • Fire Prevention Plan

The above-mentioned requests were required to ensure the project team was taking all safety and precautionary measures to keep environmental disturbances to a minimum. In addition, GTS was required to obtain a hot work permit from the local Fire Marshall to allow the performance of grinding, cutting, and welding inside the Angeles National Forest. The project permitted approximately 7,500 square feet (0.172 acre) of temporary disturbance area to accommodate the work area and construction staging areas. Surface level brush clearing was required around the 18-inch Main Line Valve to allow for an excavation of a 15-foot by 30-foot bell hole needed to adequately perform the work. In order to utilize the necessary work area, relocation of approximately 20 Protected Flora (Mariposa Lily) was required. The project included three staging areas that were located on previously disturbed gravel turnouts that were utilized to prevent additional environmental disturbances.

Ultimately, this project removed 32-feet of 1967 vintage pipe and replaced it with 48 feet of new pipe consisting of main line, valves, and flanges. As part of final commissioning, the new 24-inch valve assembly was hydrostatically tested and de-watered. Appropriate precautions were taken to ensure no water was released to ground or drained, until after water analysis results were received to ensure environmental compliance.


Project Highlights: