# Pipeline Safety Interpretation PI-75-0116

- **operation:** document
- **citation:** PI-75-0116
- **title:** Pipeline Safety Interpretation PI-75-0116
- **source type:** guidance
- **agency:** Pipeline and Hazardous Materials Safety Administration
- **status:** guidance
- **official:** true
- **published on:** 1975-12-02
- **effective on:** Not available
- **summary:** PI-75-0116 concerning 192.103.
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- **app url:** https://regulus.evalyn.ai/document/phmsa-interpretation-pi-75-0116
- **source url:** https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1975/g75-12-02_Williams_192.103-lmxs.pdf
**body:**

<<<PAGE 1>>>

PI-75-0116
December 2, 1975
Mr. J.L. Williams
Williams Brothers Engineering Company
6600 South Yale Avenue
Tulsa, OK 74136
Dear Mr. Williams:
This is with regard to the telephonic conversation between you and Mr. George L. Mocharko of this Office concerning
installing gas pipelines uncased under a hard surface road.
Your interpretation of 49 CPR §192.103, §192.105, and §192.111(b)(2) is correct per your letter and attachments dated
August 4, 1975.
We trust this adequately responds to your inquiry.
Sincerely,
SIGNED
Cesar DeLeon
Acting Director
Office of Pipeline
Safety Operations

<<<PAGE 2>>>

Williams Brothers Engineering Company
6600 South Yale Avenue
Tulsa, Oklahoma 74136
July 31, 1975
U. S. Department of Transportation
Office of Pipeline Safety
Washington, D. C. 20590
Attention: Mr. Ceasar De Leon
Subject: Interpretation of Sub-Sections 192.103, 192.105, and 192.111(b)(2)
Gentlemen:
Attached is a print of our Figure 1-12.
Sub-sections 192.103, 192.105(a) and 192. 111(b)(2) deal with external loads, design formula for steel pipe, and design
factor (F) for steel pipe.
The attached Figure 1-12 is an example that illustrates our interpretation of these sub-sections of the code. Basically our
interpretation is that for any given pipe size and wall thickness; and for a given design factor (F) the design pressure
(internal pressure allowed) will be a lesser pressure when installed uncased under a hard surface road than when
installation results in parallel encroachment on roads right-of-way.
Our interpretation is based upon:
A. 192. 103
Pipe must be designed with sufficient wall thickness, or must be installed with adequate protection to withstand
anticipated external pressures and loads that will be imposed on the pipe after installation.
B. 192.105 (a)
t = Nominal wall thickness of the pipe in inches. ... additional wall thickness required for concurrent external
loads in accordance with 192.103 may not be included in computing design pressure.
C. API RP 1102 Fourth Edition, September 1968 - Recommended Practice for Liquid Petroleum Pipelines Crossing
Railroads and Highways
Paragraphs 3.1 a, b, and c.
Using this information Figure 1-12 has been constructed and indicates that for 12.75" 0.D. x .255" W. T., X-60 pipe the
design pressure would be limited to 1350 psig for an uncased road crossing of a hard surfaced road in a Class 1.location,
while the design pressure for the same pipe would be 1440 psig for parallel encroachment on highways or public streets
in a Class I location.
Please advise if you concur with our interpretation of the regulations.
Your prompt consideration of this matter will be appreciated.
Yours very truly,
WILLIAMS BROTHERS ENGINEERING COMPANY
J. L. Williams Attachment
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