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Interpretation Response #PI-13-0010 ([City of Susanville] [Mr. Craig Platt])

Below is the interpretation response detail and a list of regulations sections applicable to this response.

Interpretation Response Details

Response Publish Date:

Company Name: City of Susanville

Individual Name: Mr. Craig Platt

Location State: CA Country: US

View the Interpretation Document

Response text:

Mr. Craig Platt
Public Works Director
City of Susanville
66 North Lassen Street
Susanville, CA 96130-3904

Dear Mr. Platt:

In a letter to the Pipeline and Hazardous Materials Safety Administration (PHMSA) dated October 23, 2013, you requested an interpretation concerning the applicability of the Federal pipeline safety regulations to a natural gas pipeline operated by the City of Susanville (City). Your letter essentially asked whether PHMSA considers the City’s 6-inch, 10.75-mile-long pipeline to be a transmission line or a distribution line.

You stated that the City takes delivery of natural gas from Tuscarora Gas Transmission Company at a custody transfer meter station located approximately 10.75 miles north of Susanville. At this location, the City district regulator station reduces the line pressure down to 350 psig to feed the Susanville 6-inch pipeline. From the Tuscarora custody transfer meter, the pipeline travels approximately 3 miles to a pressure regulator station where the gas pressure is reduced from 350 psig to 90 psig for a branch running to a state correctional facility and to 60 psig for another branch running to a cogeneration power plant. From the pressure regulator station controlling delivery pressure to the correctional facility and the power plant, the pipeline extends an additional 7.75 miles to the City of Susanville gate station where gas pressure is further reduced from 350 psig to 50 psig to feed the City's PE distribution piping system and all of this piping transports odorized gas.

A pipeline is classified as a “transmission line” if it meets any one of the three conditions in the definition of "transmission line" at § 192.3.

Section 192.3 defines a gas “Transmission line” as:

[A] pipeline, other than a gathering line, that: (1) transports gas from a gathering line or storage facility to a distribution center, storage facility, or large volume customer that is not down-stream from a distribution center; (2) operates at a hoop stress of 20 percent or more of SMYS; or (3) transports gas within a storage field.

NOTE: A large volume customer may receive similar volumes of gas as a distribution center, and includes factories, power plants, and institutional users of gas.

The City may be currently operating the line at 350 psig, but it has an established Maximum Allowable Operating Pressure (MAOP) of 1000 psig. This MAOP was verified by Dan Newton, Interim Public Works Director/City Engineer for the City of Susanville, in an email to Mr. Jason Dunphy of PHMSA’s Western Region Office dated June 9, 2014. Under Part 192 regulations, the MAOP is used to calculate the percentage of Specified Minimum Yield Strength (SMYS) at which the pipeline is allowed to operate. Based on the information you provided, the pipeline is allowed to operate at 36 percent of SMYS, which exceeds 20 percent of SMYS. Therefore, the City of Susanville pipeline appears to be a transmission pipeline per the definition of “transmission line” at § 192.3.

I hope this information is helpful. If we can be of further assistance, please contact Tewabe Asebe, Transportation Specialist, Standards and Rulemaking Division, by phone at (202) 366-5523 or by email at




Alan K. Mayberry
Deputy Associate Administrator
for Policy and Programs

City of Susanville-PI-13-0010-10-10-2013-Part 192.3
T:/PHP-30:Interps:Open:City of Susanville

Regulation Sections

Section Subject
192.3 Definitions