Arizona Corporation Commission — Pipeline Safety Interpretation

Page 1Mr. Dan H. Weaklend Chief, Pipeline Safety Utilities Division Arizona Corporation Commission 1200 W. Washington Street Phoenix, AZ 85007 Dear Mr. Weaklend: Thank you for your letter of June 5, 1992, suggesting regulatory actions to improve operators' corrosion control programs. Specifically, you suggested we drop the generic specification approach found in Appendix D of Part 192, and adopt instead a system-specific approach. Under this alternative, operators would (1) include corrosion control criteria and procedures in their operating and maintenance plans, and (2) determine the cause of each corrosion leak and take corrective action. Because corrosion continues to be a major cause of pipeline accidents, we support your desire to see that operators do as much as possible to correct the problem. We are concerned, though, that deleting Appendix D, as suggested, would not solve the problem. Corrosion control is a complex science, the principles of which do not vary from system to system. So we see no good reason to allow variations in control criteria. In fact, lack of uniform criteria has been a problem in enforcing corrosion control under Part 195, which specifies no corrosion control criteria. Non- uniform criteria under Part 192 could further increase the enforcement workload by requiring inspectors to verify the legitimacy of criteria operators put in their plans. The Appendix D criteria were based on the National Association of Corrosion Engineers (NACE) Standard RP-01-69. NACE recently revised this standard, and we expect it will petition us to adopt the revised version. The pipeline industry's use of this new standard should assure consistent and correct corrosion control. As for procedures and leak investigations, these topic are already regulated. Section 192.453 requires gas operators to follow procedures in applying corrosion control. Similar requirements are in §193.2625 and §195.402(c)(3). Determining the cause of corrosion leaks is covered by §§192.617, 193.2515, and 195.402(c). We agree that operators with numerous corrosion leaks should be asked to explain their actions or lack of action, but the rules needed to require operators to take proper corrective actions are already in the regulations. dal\192\451\92-07-09 1#

Page 2If you have any further concern, please call Jim Thomas, Director, SouthWest Region at (703) 750 1746. Sincerely, /signed/ Cesar DeLeon, Director Office of Pipeline Safety dal\192\451\92-07-09 2#