Northwest Pipeline Corporation — Pipeline Safety Interpretation

Page 1May 29, 1981 Mr. Lloyd A. Hightower Director, Operations Northwest Pipeline Corporation P.O. Box 1526 Salt Lake City, Utah 84110 Dear Mr. Hightower: Your letter of May 1, 1981, requests our approval of an aerial survey technique that has been developed to monitor the level of cathodic protection on a buried pipeline. We understand the technique would be used to comply with 49 CFR 192.465(a), which requires that cathodically protected pipelines be tested annually to determine if protection is at the levels required by §192.463 and Appendix D to Part 192. These regulations do not require the use of specific testing methods, and any technique may be used that accurately shows the cathodic protection levels. This office does not recommend one test method over another, and our approval is not needed for an operator to use a new method. Sincerely, Melvin A. Judah Acting Associate Director for Pipeline Safety Regulation Materials Transportation Bureau dal\192\463\81-05-29#