Interpretation Response #PI-74-0114 ([Delmarva Power and Light Company] [Mr. Walter G. Robbins])

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

Interpretation Response Details

Response Publish Date: 05/08/1974

Company Name: Delmarva Power and Light Company

Individual Name: Mr. Walter G. Robbins

Location State: DE Country: US

View the Interpretation Document

Response text:

May 8, 1974

Mr. Walter G. Robbins
Mr. John H. Samonsky
Mr. Nicholas H. Barchock
Delmarva Power and Light Company
800 King Street
Wilmington, DE  19899

Gentlemen:

Thank you for your letter of April 12, 1974, asking questions with respect to the meaning of the term "transmission line."

First, you describe a 12-inch transmission line, operated below 20 percent of SMYS, which feeds a distribution system through 75 district regulator stations.  You ask if a district regulator station is a "distribution center" and, if so, does transmission exist only to the first regulator station or to each of the 75 stations?

Answer.  In 49 CFR 192.3, the term "transmission line" is defined as follows:

            "'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 or storage facility;

            "(2) Operates at a hoop stress of 20 percent or more of SMYS; or

            "(3) Transports gas within a storage field."

Under this definition, one terminus of a transmission line is a "distribution center."  This terminus marks entry of gas into a distribution system.  In the system you describe, we assume the lines downstream from the outlet of each regulator are mains and service lines, which constitute a distribution system.  Thus, each regulator stations is a "distribution center," and the line connecting the 75 regulator stations is a continuous "transmission line."

Secondly, you describe an LNG plant which serves as a storage facility.  Boil-off from the plant enters distribution by an 8-inch which runs 2,500 feet into a main tapped with services.  You ask, since gas is transported from a storage facility, is the 8-inch line a "transmission line"?

Answer.  If there are no services on the 8-inch line, since it runs from a "storage facility" to a "distribution center" (connection with a main), it is by definition a "transmission line."  On the other hand, if the 8-inch line is a common source of supply for more than one service line, then by definition  it is a "main" under section 192.3.

Finally, you ask how characterization of the lines affects reporting under 49 CFR Part 191, noting that you only file distribution reports.

Answer.  Lines which fail within the definition of "transmission line" should be reported as such under Part 191.  However, 40 CFR 191.13 requires the 8-inch line which conveys gas from the LNG storage facility to be reported as a "transmission line" regardless of its characterization.  In future reports, please indicate those transmission lines previously reported as distribution lines.

                                                                        Sincerely,

                                                                        /signed/
                                                                        Joseph C. Caldwell
                                                                        Director
                                                                        Office of Pipeline Safety

Regulation Sections