Pipeline Operations and Maintenance Flashcards

What is the purpose of a pressure regulating station in a gas distribution system?

Answer: To reduce transmission pressure to distribution pressure

A pressure regulating station reduces high-pressure transmission gas to lower pressures suitable for distribution to customers.

Which inspection method uses magnetic flux leakage to detect pipeline defects?

Answer: In-line inspection with an ILI tool

In-line inspection (ILI) tools using magnetic flux leakage travel inside the pipeline and detect wall loss, corrosion, and other anomalies.

What is the minimum depth of cover required for a steel gas transmission pipeline installed in a Class 1 location under 49 CFR Part 192?

Answer: 24 inches

49 CFR Part 192 requires a minimum cover of 24 inches for transmission pipelines in Class 1 locations.

What does 'class location' determine for natural gas transmission pipelines?

Answer: Design pressure and safety requirements based on population density

Class location is based on the number of buildings intended for human occupancy within a pipeline corridor and determines design and operating requirements.

What is the purpose of a relief valve on a gas pressure regulator?

Answer: To release excess pressure if the regulator fails to maintain set pressure

A relief valve protects downstream piping by venting gas when pressure exceeds a predetermined limit due to regulator failure.

Which document must operators of gas pipelines maintain to record all maintenance and inspection activities?

Answer: Operations and Maintenance Manual

49 CFR Part 192 requires operators to maintain an Operations and Maintenance Manual documenting procedures and inspection records.