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Interpretation Response #PI-04-0101

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

Interpretation Response Details

Response Publish Date: 01-22-2004
Company Name: Dominion Transmission, Inc.    Individual Name: Mr. Martin C. Schwoeble
Location state: WV    Country: US

View the Interpretation Document

Request text:

Dominion Transmission inc.
445 West main Street
Clarksburg, WV 26301

Richard D. Huriaux
Department Of Transportation, Office Of Pipeline Safety
400 7th Street
Southwest, Room 7128
Washington D.C., 20590

November 3, 2003

RE: Interpretation Request

Dear Mr. Huriaux,

This letter's purpose is to ask for an interpretation of CFR Part 192.739, "Pressure Limiting and Regulating Stations: Inspections and Testing" for Dominion Transmission Incorporated (DTI).

DTI is currently inspecting numerous small regulators downstream of the first initial regulators (first or second main pressure cut) on fuel gas lines that feed various types of equipment such as main compressor units, pipeline heaters and dehydration systems, etc. Typically, these types of fuel regulators consist of 1" or smaller. They are not intended to protect a transmission pipelines maximum operating pressure. Their sole purpose is to provide protection for the operating equipment. These types of small regulators are usually installed by the manufacturer of the equipment and would require major piping changes to conduct an inspection of them.

Part 192.739 states that "Each pressure limiting station, relief device (except rupture discs), and pressure regulating station and its equipment must be subjected..." to inspection annually, not to exceed 15 months. What is the proper definition of a pressure limiting or regulating "station"? An interpretation found in WinDOT, dated 06/28/88, states that a pressure regulating station is any regulator serving a downstream "main". This is not the case regarding the aforementioned equipment examples.

It is DTI's stance that the jurisdictional transition point should be the first valve downstream of the last regulator and/or relief valve associated with the first pressure cut from the transmission pipeline, including any regulator within the by-pass. If a measurement device used for consumption exists beyond this point, then the measurement device becomes the jurisdictional transition point. All downstream pressure limiting and regulating devices from this jurisdictional transition point would then be exempt from Part 192.739.

DTI has a vast amount of these types of small fuel line regulators throughout our operating system and the inspection of them is a burdensome task that is costly and has been found to be of no benefit. DTI thereby requests that the Office of Pipeline Safety please grant these types of small fuel regulators be exempt from Part 192.739.

We appreciate any input you may have regarding this matter. If you have any questions, please feel free to contact me via the following phone numbers:

Office: (724) 468-7726
Cell Phone: (724) 433-4038


Martin C. Schwoeble
DTI Pipeline Integrity Compliance Specialist

Response text:


U.S. Department of Transportation
Research and Special Programs Administration
400 Seventh Street, S.W.
Washington, D.C 20590

January 22, 2004

Mr. Martin C. Schwoeble
Pipeline Integrity Compliance Specialist
Dominion Transmission, Inc.
445 West Main Street
Clarksburg, WV 26301

Dear Mr. Schwoeble:

This is in response to your letter of November 3, 2003, in which you request an interpretation of the Federal gas pipeline safety regulation at 49 CFR 192.739, Pressure Limiting and Regulating Stations: Inspections and Testing. The question arises from small regulators on the Dominion Transmission, Inc. (DTI) system that provides protection for operating, or end-use, equipment. These types of regulators are installed by the manufacturer of the equipment and are not intended to be inspectible by pipeline operators.

Section 192.701, Scope, notes the Subpart M "prescribes minimum requirements for maintenance of pipeline facilities." Section 192.739 must be read in cognizance of this scope statement. It is clear that § 192.739 is intended to address inspection and testing of pressure limiting and regulating stations that are necessary to maintain safe pressures on the pipeline facility, not on end-use equipment.

This is consistent with the June 28, 1988, interpretation letter cited in your letter. In that interpretation, we note that a regulator subject to § 192.739 would have to fall within the definition of "pressure limiting station" or "pressure regulatory station" as these terms are defined in the ASME B31.8 standard. Under these definitions, it is clear that any regulator serving a downstream piping is a pressure regulating station and is subject to inspection and testing in accordance with § 192.739. Conversely, a regulator that is NOT intended to protect a downstream piping, but rather serves only to protect end-use equipment, such as a compressor, would not be subject to § 192.739.

If you have any further questions about the pipeline safety regulations, please contact me at (202) 366-4565.


Richard D. Huriaux, P.E.
Manager, Regulations
Office of Pipeline Safety

Regulation Sections

Section Subject
§ 192.701 Scope