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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-83-0107

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: TX Country: US

View the Interpretation Document

Response text:

August 4 1983

Mr. Charles L Poole, P.E. O'Malley & Clay, Inc. P.O. Box 1976
505 Green Street
Brenham, TX 77833

Dear Mr. Poole:
Your letter 04 July 19, 1983, asks three specific questions concerning 49 CFR Section 192.469,
External corrosion control: Test stations, as it applies to a catholically protected steel natural
gas distribution system. These questions are as follows:

1.    Do the services provide "sufficient" test stations?

2.    If not, at what frequency, or spacing, should additional test stations be installed?

3.    If the services were not electrically connected to the main, or were widely scattered, what
should the test station spacing be?

If the service lines are electrically continuous with the mains, they may be used as test stations.
Spacing of test stations along the pipeline system will vary widely depending upon the type of
soil, moisture, quality of pipe coating, size of pipe, type of cathodic protection system, level of
cathodic protection, etc. Whatever the number and spacing of test points along a cathodically
protected pipeline, they must be adequate to show that the cathodic protection level along the
entire length of pipeline meets the requirements of Section. 192.463. With so many variables
involved, the distance between test stations must be based on the judgment of a person qualified by
experience and training in pipeline corrosion control methods for the specific installation and

We hope this provides the information you are seeking.


Richard L. Beam 
Associate Director for
Pipeline Sanity Regulation
Materials Transportation Bureau

Regulation Sections

Section Subject
192.463 External corrosion control: Cathodic protection