USA Banner

Official US Government Icon

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure Site Icon

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

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

Interpretation Response #PI-03-0104 ([Montana-Dakota Utilities Company] [Mr. Douglas M. Lee, 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: Montana-Dakota Utilities Company

Individual Name: Mr. Douglas M. Lee, P.E.

Location State: ND Country: US

View the Interpretation Document

Response text:


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

June 11, 2003

Mr. Douglas M. Lee, P.E.
Senior staff Engineer
Montana-Dakota Utilities Company
400 North Fourth Street
Bismarck, ND 58501

Dear Mr. Lee:

This is in response to your letter of May 14, 2003, which asks for an interpretation of 49 CFR 192.721 as it applies to the frequency of patrolling of gas distribution mains that are attached to an apartment building.

Section 192.721(a), Distribution Systems: Patrolling, states that the frequency of patrolling of gas mains is to be determined by the gas distribution pipeline operator based on an evaluation of conditions that could lead to failure or leakage, and the possible hazards to the public. Section 192.721(b) specifies patrol frequencies for "mains in places or on structures where anticipated physical movement or external loading could cause failure or leakage. . ."

The question is whether a gas main attached to a building is subject to "anticipated physical movement or external loading" that could cause system failure or leakage and require specific patrolling frequencies as specified in § 192.721(b). Generally, pipelines installed in or on structures, including buildings and bridges, are not subject to movement or loadings that could cause failure if the pipeline is designed, constructed, and maintained in accordance with 49 CFR Part 192.

Moreover, under § 192.721(a) the gas distribution pipeline company is responsible for making a determination of patrol frequency based on its evaluation of the conditions which could cause failure and leakage, subject to confirmation during inspections by State or Federal pipeline safety personnel.

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
192.721 Distribution systems: Patrolling