Is it a Transmission Line?

Recently the Railroad Commission of Texas asked for an interpretation of “transmission line” as defined in §192.3.  Operators in Texas had revised the classification of pipelines operating below 20% SMYS from transmission to distribution.

Read PHMSA’s response below:

Ms. Stephanie Weidman
PHMSA Program Director
Railroad Commission of Texas
1701 North Congress Avenue
P.O. BOX 12967
Austin, Texas 78711-2967

Dear Ms. Weidman:

In a September 14, 2016, letter to the Pipeline and Hazardous Materials Safety Administration (PHMSA), you requested an interpretation of 49 CFR Part 192. You specifically requested an interpretation of § 192.3 for a definition of a transmission pipeline.

You stated that “[o]ver the past few years, the Commission’s (RRC) Pipeline Safety program has cited alleged violations of the State safety regulations pertaining to pipeline permitting (T-4) requirements for intrastate transmission and gathering pipelines.” You stated that “[c]ertain pipeline operators have revised and transferred previously operated and regulated natural gas transmission pipeline systems that operate at a hoop stress below 20% of SMYS, to a natural gas distribution pipeline designation or purpose.” You stated that “[o]ne particular operator based on their [sic] opinion has changed over 600 miles of pipelines from a status of transmission to distribution pipeline.”

You provided two examples of pipeline systems the RRC considers “to be transmission from historical and current operating conditions.” In addition, in a November 15, 2016, email you provided PHMSA summary of pipelines that the operators arbitrarily converted from transmission to distribution pipelines.

Section 192.3 defines a transmission line as:

Transmission line means 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.

A pipeline that meets any of the three conditions listed under the definition in § 192.3 is a transmission line in accordance with 49 CFR Part 192. Therefore, a pipeline that operates at a hoop stress of less than 20 percent of its specified minimum yield strength, but meets either condition one or three, meets the definition of a transmission line.

PHMSA agrees, per § 192.3, with RRC’s interpretation that any pipeline system other than a gathering line that transports gas from a gathering line or storage facility to a distribution center meets the definition of a transmission pipeline regardless of whether it operates at a hoop stress below 20 percent of SMYS. If we can be of further assistance, please contact Tewabe Asebe at 202-366-5523.


John A. Gale
Director, Office of Standards
and Rulemaking

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