# Memo: Internal — Pipeline Safety Interpretation

- **operation:** document
- **citation:** PI-78-033
- **title:** Memo: Internal — Pipeline Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 1978-12-19
- **effective on:** Not available
- **summary:** PI-78-033 response to Memo: Internal concerning 192.747.
- **machine formats:** - **json:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-78-033.json
- **markdown:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-78-033.md
- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-78-033
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1978/PI78033.pdf
**body:**

<<<PAGE 1>>>

December 19, 1978
SUBJECT: Request for Interpretation of
Section 192.747
FROM: Chief, Southern Region
TO: Associate Director of Pipeline
Safety Regulation, DMT-30
The attached letter highlights some of the problems we find in trying to enforce section 192.747,
i.e., many buried valves which, id designated as key valves, becomes a continuing maintenance
problem. We have taken the position that one designated valve that controls the operator's supply
does not meet Section 192.747 except (1) where only one valve exists on the distribution main
and (2) where the system is extremely small, rural in nature, and does not have a well defined
commercial area.
Therefore I request your interpretation of the following questions:
(1) For a typical distribution system having a well defined business district, and class 1, 2,
and 3 areas; will one key valve suffice assuming that the valve controls the system supply and that
multiple main valves do exist within the system?
(2) If the answer to 1 above is "no," what minimum number of key valves would suffice?
What system areas should they control?
James C. Thomas
Attachment
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