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Interpretation Response #PI-82-0107

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

Interpretation Response Details

Response Publish Date: 07-28-1982

Location state: MO    Country: US

View the Interpretation Document

Request text:

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

November 1, 1976

Mr. Leonard M. Coffelt
Missouri Public Service Commission
P.O. Box 360
Jefferson City, Missouri 65101

Dear Mr. Coffelt:

This responds to your letter dated September 21, 1976, asking that we review a previous interpretation dated October 12, 1973, regarding 49 CFR 192.357(d). You ask whether that interpretation permits "service regulators to be installed within a building without venting the diaphragm breather vent to the outside atmosphere."

Section 192.357(d) reads:

"Each regulator that might release gas in its operation must be vented to the outside atmosphere."

The October 12, 1973, interpretation essentially provides that Section 192.357(d) does not apply to a regulator which does not release gas in its operation.

That interpretation was not intended to permit installation of a regulator with a diaphragm breather vent inside a building without placing the discharge end of the vent outside the building. Sections 192.199(e) and 192.355(b)(2) are clear that the outlet of each regulator vent must be located outside.

Original Sign By
Cesar DeLeon
Acting Director
Office of Pipeline
Safety Operations

Response text:


July 28, 1982

Mr. Dale W. Johansen
Assistant Director, Gas Department
Engineering Section
Missouri Public Service Commission
P.O. Box 360
Jefferson City, Missouri 65102

Dear Mr. Johansen:

We apologize for the lateness of our response to your letter of April 14, 1981, asking whether §192.357(d) requires nonrelief type service regulators, which would release gas only upon failure to have their breather vents vented to the outside atmosphere.

As indicated by the enclosed interpretations (dated October 12, 1973, and November 1, 1976), §192.357(d) does not apply to non-relief type service regulators because they do not release gas during operation. Nevertheless, nonrelief type service regulators that have breather vents are subject to the requirements of §192.355(b)(2) and must he installed so that gas escaping from the vents in the event of diaphragm or other failure is released into the outside atmosphere.
We trust that this response will satisfy your concerns.

Melvin A. Judah
Acting Associate Director for
Pipeline Safety Regulation
Materials Transportation Bureau

Regulation Sections

Section Subject
§ 192.199 Requirements for design of pressure relief and limiting devices