Camera Inspections of Gas Pipelines
About Camera Inspections
PG&E's highest responsibility is the safety of our operations, which includes rigorous and ongoing inspections of our natural gas system. As part of this work, we are conducting inspections on some segments of our natural gas transmission system using tethered, robotic cameras that check and record internal pipeline conditions. If the pipe section does not meet acceptable standards during these tests, it will be replaced with new pipe.
Camera Inspection Overview
Performing a camera inspection involves the following steps:
- First, our crews will excavate several holes along the length of the transmission line so we can access the underground pipe. For the public's safety, these holes will be securely covered when not in use.
- Next, we'll take the pipeline out of service temporarily and seal off gas from the section where the work will be performed.
- Gas will be re-routed and continue to flow to homes and businesses throughout the course of the project.
- Once the pipeline is closed at both ends, it will be purged of natural gas so the crew can open and work inside the pipe safely. At this point, depending on wind direction and other weather conditions, the smell of gas may be noticeable to nearby homes or businesses, along with a loud sound made by the equipment that forces air through the pipeline. The natural gas will quickly dissipate and will not be harmful.
- At this point, a camera will be inserted into the pipeline to record internal conditions.
- Video footage from the camera will be relayed to a nearby monitoring and recording device. Since the camera is tethered, it will travel until it reaches its maximum length.
- It will then be retrieved and re-inserted at the next excavation point. Extensive planning for camera insertion locations has been done in advance to optimize this phase of our work.
- As the camera travels the length of the pipe segment we are assessing, trained professionals will analyze the recording and determine if any additional actions are necessary.
- Once the full length of the segment is assessed, our crews will close and seal the pipeline and then restore the excavation sites.
- In order to return the pipeline to full service, we will purge the line to remove air from inside the pipe. At this point, there is a second chance of a natural gas odor and a loud noise from the work site. Again, the smell of gas will lessen as the purged air dissipates.
All project stages will be closely monitored to ensure the most stringent safety standards are applied.
What to Expect if a Camera Inspection is Being Conducted in your Area
PG&E crews will mark the construction areas and pre-staging work sites with equipment and tools. Depending on safety requirements at each construction site along the pipe segment, the following may also be visible:
- Temporary "No Parking"signs, safety cones and/or detour signs
- A traffic coordinator, or flagger, at an intersection to assist motorists
- PG&E construction crews and field teams as well as PG&E's contractors
- Machinery and construction equipment, such as a backhoe and/or a generator
- Support trucks and vans, including a trailer where the camera recording will be monitored
PG&E has a comprehensive inspection and monitoring program to ensure the safety of its natural gas transmission pipeline system.
Gas System Resources
PG&E Hotline for Gas Transmission Pipeline Location Information: 1-888-743-7431
View an additional map of the location of camera testing in the San Bruno / South San Francisco (PDF, 1.7 MB) area.