Pipeline Safety: Hydrostatic Pressure Testing – Short Version

Summary

Southern California Gas Company ensures the safety and integrity of its pipeline system through routine Hydrostatic Pressure Testing. This process involves using water to test pipeline segments at pressures higher than usual operational levels, checking for leaks or ruptures. After the test, the pipeline is dried, repaired, and safely reintroduced into service. The entire procedure, which involves venting gas, sealing the pipeline, and using foam plugs, is done with precision to protect the environment and maintain service reliability for over 21 million customers.

Takeaways

• 😀 Southern California Gas Company is the largest distributor of natural gas in the U.S., serving nearly 21 million customers.
• 😀 Safety is the highest priority for Southern California Gas, and they routinely conduct tests to ensure pipeline integrity.
• 😀 One common method for assessing pipeline integrity is the Hydrostatic Pressure Test.
• 😀 The Hydrostatic Pressure Test uses water to exert pressure on a pipeline, higher than its usual operating pressure, to check for leaks.
• 😀 Before the test, the pipeline is temporarily removed from service, and natural gas inside is safely vented.
• 😀 Excavations are made at both ends of the pipeline segment, and short sections are removed to seal the ends for testing.
• 😀 Water from nearby tanks is pumped into the pipeline to fill it and push out any air, before the pressure test begins.
• 😀 The pipeline is pressurized to levels above its normal operating pressure to detect potential leaks or ruptures.
• 😀 If the test reveals leaks, the pipeline segment is either repaired or replaced. Otherwise, the pipeline is restored for use.
• 😀 After a successful test, the water is drained, disposed of properly, and the pipeline is dried using foam plugs.
• 😀 Finally, the pipeline is reconnected to the system, and natural gas is safely reintroduced, ensuring normal operation.
• 😀 Hydrostatic Pressure Testing is a vital tool for maintaining the safety and integrity of Southern California Gas Company's pipeline system.

Q & A

What is the primary focus of Southern California Gas Company's operations?

Southern California Gas Company focuses on the safe and reliable distribution of natural gas to nearly 21 million customers through over 4,000 miles of transmission pipeline.

What is the purpose of conducting pipeline integrity tests?

Pipeline integrity tests are conducted to ensure the pipeline segments are sound and maintain safety standards.

What is Hydrostatic Pressure Testing?

Hydrostatic Pressure Testing is a process where water is used to exert pressure on a pipeline, testing it at levels higher than its normal operating pressure to check for leaks.

What steps are involved in preparing the pipeline for a Hydrostatic Pressure Test?

First, the pipeline is temporarily removed from service by closing valves at both ends. Then, natural gas is safely vented, and excavations are dug to expose the pipeline. Short sections of pipeline are removed from both ends, and test head caps and end caps are installed.

How does water get into the pipeline during the test?

Water is pumped from nearby water tanks into the test head cap, which contains a foam plug. The water pushes the foam plug through the pipeline segment, displacing air and filling the pipeline with water.

What is the purpose of holding the pressure during the Hydrostatic Pressure Test?

Holding the increased pressure for eight hours or more helps to identify any leaks or ruptures in the pipeline segment.

What happens if a leak or rupture is found during the test?

If a leak or rupture is found, the pipeline segment will be repaired or replaced.

How is the pipeline cleaned after a successful Hydrostatic Pressure Test?

Compressed air is used to push the foam plug through the pipeline to drain the water. Multiple foam plugs are used to dry the pipeline thoroughly.

What happens after the pipeline is dried and the foam plugs are removed?

Once the pipeline is dry, new pre-tested replacement pipe is installed at both ends of the segment, reconnecting it to the system. Nitrogen gas is injected into the pipeline to help vent remaining air, and natural gas is safely reintroduced into the pipeline.

How is the excavation site restored after the test?

The excavated areas are graded and restored to as close to their original condition as possible.