Pipeline strength testing, also called Hydrostatic Pressure Testing, is a proven industry technique to confirm the strength of the pipeline, validate its safe operating pressure and identify any weaknesses for repair.
The test involves safely isolating and clearing the pipeline of all natural gas, then completely filling the pipeline with water. The water is then pressurized to a level much higher than normal operating pressure, and the test pressure is held and monitored for a minimum of eight hours. If a section of pipeline does not meet acceptable safety standards, it is replaced and then re-tested.
Our interior-pipeline inspection programs identify any flaws, corrosion or other damage for further inspection, repair or replacement. Two types of tools are used for these interior inspections:
With automated valves, PG&E can quickly stop the flow of gas and improve response times during an emergency.
In select locations, we are automating pipelines valves so that they can be operated remotely from our 24-hour gas control center. Some of these valves will also close automatically if a significant change in pipeline pressure is detected.Fact sheet: Automating Pipeline Valves
With proper maintenance and monitoring, steel pipelines can last more than a hundred years. Still, some of our pipelines were installed before the benefits of modern manufacturing and construction techniques, or have not been designed for use with high-tech “smart pig” internal inspection tools.
Where appropriate, we’re replacing these pipelines using industry recognized and proven installation techniques.Fact sheet: Replacing Pipelines
We regulate pressure on our pipeline system through a series of safety measures, including pressure regulator stations and overpressure detection devices.Over the past few years, PG&E has increased its standards for safe operations. In order to meet these new standards, we have reduced pressure in some transmission pipelines to increase the margin of safety. As we validate records, complete strength tests or replace pipeline sections, we will work with our regulators to confirm any pressure adjustments.
We’re overhauling our pipeline records system, making sure that all records are traceable, verifiable and complete.As part of this modernization process, we are collecting, scanning and indexing documents from dozens of PG&E field offices. This transition from paper-based record keeping toward a modern electronic data management system will help prioritize work across our system and allow employees to have improved access to data.
© Pacific Gas & Electric Company