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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-78-0109

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

Interpretation Response Details

Response Publish Date:

Company Name:

Individual Name:

Location State: MS Country: US

View the Interpretation Document

Response text:

November 27, 1978

Mr. Richard Sanders
Chief, Pipeline Safety
Mississippi Public Service Commission Walter Sitters State Office Building P.O. Box 1174
Jackson, Mississippi 39205

Dear Mr. Sanders:
We apologize for the delay in answering your letter of August 1, 1978, regarding Section

With your letter, you included a sketch which shows a schematic of a regulator installation,
including valves on the inlet and outlet of a regulator and a bypass valve. A relief valve is shown
on the piping at the outlet of the regulator with valve ahead of it which is marked "locked."
You asked:

1.           "Should an inspector cite this system under Part 192.199(h)?"

2.           "Should an inspector cite this system under any other portion of the code?"

3.           "Should an inspector accept this as meeting the law - and if he liked, recommend to
the operator that locking the valve would be good practice?"

Since Section 192.199 is in Subpart D - Design, it only applies to facilities that were readied for
service after March 12,
1971, or replaced, relocated, or otherwise changed after November 12, 1970. If the facilities
illustrated by your diagram were built or changed prior to these dates, Section 192.199(h) would
not apply. Assuming this to be so, and the relief valve does not have sufficient capacity as you
illustrate, then, should the system be over pressured, Section 192.619(b) or Sec 192.621(b) could
be applied.

If your diagram describes facilities built or changed after the above date(s), Section 192.199(h)
would apply to the regulator installation. However, paragraph only applies to gas line valves
installed between the system to be protected and Relieving or limiting device. It does not apply to
valves in bypass lines because such valves do not make the relieving or limiting device

With regard to your third question, the Materials Transportation Bureau normally does not recommend
pipeline safety practices that are not required by the regulations.

We trust that this response will enable you to resolve these items of concern.
Sincerely, Cesar DeLeon Associate Director for
Pipeline Safety Regulation
Materials Transportation Bureau
Mississippi Public Service Commission
P.O. Box 1174
Jackson, Mississippi 39205
August 1, 1978

Dear Mr. Pollen:
A question has risen as to whether or not operators should be cited under Part 192.199 (h). Please
note attachment "A" that I have prepared to enlighten you as to some of the findings our personnel
have experienced during inspections of operators.

It is my contention that the by-pass valve should be locked, since it would allow pressures to
exceed the maximum allowable operating pressure of the downstream distribution system. I am not
sure whether or not
192.199, Part (h), would cover or any other portion of the code covers such a situation.

Your assistance in answering the questions that I have prepared on attachment "A" would be of
assistance to our operations in the State of Mississippi.
Respectfully yours, Richard Sanders
Chief, Pipeline Safety

Regulation Sections

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