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Interpretation Response #PI-03-0104

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

Interpretation Response Details

Response Publish Date: 06-11-2003
Company Name: Montana-Dakota Utilities Company    Individual Name: Mr. Douglas M. Lee, P.E.
Location state: ND    Country: US

View the Interpretation Document

Request text:

Montana-Dakota Utilities Co.
400 North Fourth Street
Bismarck, ND 58501

May 14, 2003

Richard Huriaux
Office of Pipeline Safety, Research and Special
Programs Administration, U.S. Department of Transportation
400 Seventh Street, S.W., Rm. 7128
Washington D.C. 20590-0001

Re: CFR 19 Part 192.721 (b)

Dear Mr. Huriaux:

With respect to the above referenced regulation, I have found a disparity in how many operators interpret this regulation and look forward to resolution through your interpretation. The regulation clearly states that this additional patrolling is necessary for "Mains in places or on structures where anticipated physical movement or external loading could cause failure or leakage must be patrolled -". Based on this verbiage combined with operational experience of over 75 years, one could easily attest that pipelines properly supported on structures such as bridges or buildings are not subject to movement that could cause failure or leakage. Just as stream crossings can wash out, a bridge could fail due to flooding conditions and a prudent operator will monitor all areas subject to movement following any natural or man-made activity that could affect the integrity of its system.

Attached are photographs of a "main" attached to an apartment complex. Based on the verbiage of 192.721 (b), it appears that the operator is granted the discretion to either include or exclude this piping from quarterly or semi-annual line patrols. Can you either confirm this interpretation or provide additional insight to the position held by the Office of Pipeline Safety?

Thank you for your response in this matter.


Douglas Lee, P.E.
Senior Staff Engineer

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