# Harco Corporation — Pipeline Safety Interpretation

**Citation:** PI-72-030  
**Type / status:** guidance / guidance  
**Agency:** Pipeline and Hazardous Materials Safety Administration  
**Effective:** Not stated  
**Published:** 1972-07-14

PI-72-030 response to Harco Corporation concerning 192.467.

## Document text

<<<PAGE 1>>>

Mr. B. Husock, P.E.
Harco Corporation
Corrosion Engineering Division
4600 East 71st Street
Cleveland, Ohio 44125
Dear Mr. Husock:
This is in reply to your letter dated May 31, 1972, regarding an interpretation of Section
192.467(a), 49 CFR.
Your specific question was regarding Section 192.467(a) which states, in part, "....each buried or
submerged pipeline must be electrically isolated from other underground metallic structures...."
You inquired whether this requirement applied to all gas distribution systems under all
circumstances whether or not cathodic protection is eventually applied.
Section 192.467(a) does not apply to all gas distribution systems. It is intended to apply to all
new pipelines.
Existing distribution systems are covered by Section 192.467(b), which requires insulation
wherever electrical isolation of a portion of a pipeline is necessary to facilitate the application of
corrosion control. However, existing distribution lines must be cathodically protected only in
areas in which active corrosion is found (Section 192.457(b)(3)). Isolation assures an insulating
barrier between metals of different anodic potentials, facilitating corrosion control. Accordingly,
electrical isolation of existing distribution lines is not required under all circumstances, but only
where necessary to facilitate the application of corrosion control required by Section
192.457(b)(3).
We trust that this will answer your specific question.
If we can be of further service, please let us know.
Sincerely,
/signed/
Joseph C. Caldwell
Director
Office of Pipeline Safety
DB
C:\WP51\INTERPRT\192\467\72-07-14
1

## Provenance

- Official: Yes
- Source: <https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1972/PI72030.pdf>
- Source ID: `phmsa`
- SHA-256: `63dc7ce99ff5af624347f377c94d5a008104e5d6b2306ceead38a378e94580b5`
- Retrieved: 2026-08-20T00:59:31.977Z
- Exported: 2026-08-23T03:26:40.736Z
- Document slug: `phmsa-interpretation-pi-72-030`

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