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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Interpretation Response #PI-03-0108 ([Southwest Gas Corporation] [Mr. James F. Wunderlin, P.E.])

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

Interpretation Response Details

Response Publish Date:

Company Name: Southwest Gas Corporation

Individual Name: Mr. James F. Wunderlin, P.E.

Location State: NV Country: US

View the Interpretation Document

Response text:



Mr. James F. Wunderlin, P.E.
Vice President/Engineering
Southwest Gas Corporation
5241 Spring Mountain Road
P.O. Box 98510
Las Vegas, NV 89193-8510

Dear Mr. Wunderlin:

This is in response to your August 13, 2003, request for an interpretation of the gas pipeline distribution system valve regulations at 49 CFR 192.181 and 192.747. Section 192.181 addresses spacing of emergency valves, location of emergency valves on the inlet piping to a regulator station, and accessibility and operability requirements for all valves installed on a main for operating or emergency purposes. Section 192.747 requires the operator to perform annual checks and service on these valves to ensure safe operation of the gas system.

You request a response to the following questions:

1) Does § 192.181(c)(l) require an operator to maintain every valve installed on a gas system, even if they are not identified as emergency "key valves" for operating or emergency purposes,... as readily accessible in accordance with § 192.747?

No. Section § 192.181(c)(l) is in Subpart D, Design of Pipeline Components. It addresses minimum requirements for the design and installation of pipeline components. It does not require an operator to maintain all valves in accordance with § 192.747.

Valve maintenance is addressed in § 192.747, Valve Maintenance: Distribution Systems. This section requires that "[e]ach valve, the use of which may be necessary for the safe operation of a distribution system, must be checked and serviced at intervals not exceeding 15 months, but at least once each calendar year." In compliance with this regulation, Southwest Gas has designated many, but not all, gas distribution system valves as "key valves."

2) Is an operator required to abandon, remove, or render inoperable valves not identified as emergency "key valves."

No. An operator is not required to "abandon, remove, or render inoperable valves" simply because they are not identified as "key valves." The pipeline safety regulations at 49 CFR Part 192 do not address this issue.

All valves installed in a gas pipeline system must comply with § 192.53, General, which requires that all components installed in a gas system must be structurally sound, chemically compatible with the gas transported, and qualified in accordance with the requirements of 49 CFR Part 192, Subpart B, Materials. Valves in gas systems must also meet the requirements of § 192.145, Valves, which requires that each valve be manufactured and tested in accordance with standard API 6D. In addition, an operator must also include all valves in leak inspection programs and corrosion control programs.

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
192.747 Valve maintenance: Distribution systems