# O. L. Birchfield — Pipeline Safety Interpretation

- **operation:** document
- **citation:** PI-72-021
- **title:** O. L. Birchfield — Pipeline Safety Interpretation
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 1972-05-26
- **effective on:** Not available
- **summary:** PI-72-021 concerning 192.609, 192.705.
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- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-72-021
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1972/PI72021.pdf
**body:**

<<<PAGE 1>>>

May 26, 1972
Mr. O. L. Birchfield
P. O. Box 5364
Abilene, Texas 79605
Dear Mr. Birchfield:
This is in reference to your letter dated April 22, 1972, regarding aerial photography of pipelines.
We do not have any bulletins covering the aspects of photography as related to population density
and other ecology protection of pipelines transporting gas, oil or oil products. The regulations set
forth the different population densities for class locations, but it is the responsibility and choice of
the operator as to how this density is determined.
We also have not established any guidelines as to recorded information that will satisfy the
requirements for patrolling of pipelines. The regulations require patrolling of pipelines, but it is
the responsibility and choice of the operator as to how this regulation is met.
We trust that this will answer your specific questions. If we can be of further assistance, please
let us know.
Sincerely,
Joseph C. Caldwell
Director
Office of Pipeline Safety
*
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