{"operation":"document","citation":"PI-91-025","title":"Pipeline Safety Utilities Division — Pipeline Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"1991-08-29","effective_on":null,"summary":"PI-91-025 response to Pipeline Safety Utilities Division concerning 192.463.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-91-025.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-91-025.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-91-025","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1991/PI91025.pdf","body":"<<<PAGE 1>>>\n\nMr. Dan H. Weaklend\nChief, Pipeline Safety\nUtilities Division\n1200 West Washington\nPhoenix, AZ 85007\nDear Mr. Weaklend:\nI am responding to your July 28, 1991 letter regarding the enforcement of criteria 1-A(1), in\nAppendix D, Title 49, Part 192, Code of Federal Regulations. In addition, you inquired about\npossible Office of Pipeline Safety (OPS) Rulemaking regarding criteria for monitoring cathodic\nprotection. I will specifically address each of your questions.\nQUESTION 1. Is the fact that an operator incurs a corrosion leak and has used the -0.850\nON criteria for testing without considering the \" bulk soil IF drop\" a valid reason to cite an\noperator?\nANSWER: Appendix D, Part II, Part 192 of Title 49, is clear that voltage (IR) drops other than\nthose across the structure-electrolyte boundary must be considered for valid interpretation of\nvoltage measurements.\nOPS has been following an enforcement policy developed in the mid 1980's under which, when an\noperator claims he has accounted for the IR drop. OPS will accept that claim. If, however, the\noperator had a leak due to corrosion, OPS may ask the operator to demonstrate the adequacy of\ncorrosion protection and hoe the operator considered the IR drop in determining the adequacy of\nthe corrosion protection. If this was done improperly, the operator could be subject to\nenforcement action. It has never been OPS's position that the occurrence of a corrosion leak is\nsufficient evidence of a violation and the operator is to be cited.\nOPS recognizes that corrosion can occur under certain circumstances, such as, disbonded coating,\nshielding, or under bacteria attack even when a pipeline is protected against corrosion. However,\nif disbonded coating, shielding effects, bacteria attack, or other legitimate factors which may\nprevent current flow through the electrolyte to the pipe are ruled out, and the IR drop was not\nproperly considered, an operator could be subject to enforcement action.\nIt is possible to consider the IR drop on magnesium anode protected systems. If an inspector or\noperator places the half cell on the surface of the soil/ ground and obtains an abnormally high\npotential, there is a good possibility that the half cell is over an anode. To ensure that it is not\nDB\nC:\\WP51\\INTERPRT\\192\\755\\91-08-29\n1\n\n<<<PAGE 2>>>\n\nover an anode, an inspector or operator should simply move the half cell upstream or downstream\nfrom that point and take a reading. OPS does not require operators to disconnect anode wires in\norder to read instant-off potentials on distributed sacrificial anode protected systems.\nQUESTION 2. Is it true that OPS is planning on issuing a standard criteria for monitoring\ncathodic protection?\nANSWER: As you are aware, the National Association of Corrosion Engineers (NACE) is\nmeeting this fall to possibly adopt new standards for cathodic protection. If NACE does adopt a\nnew standard, it is likely that OPS would initiate rulemaking to adopt this new standard. If\nNACE does not adopt this new standard, there is a possibility that the existing NACE Standard\nRP-01-69-83 mat be withdrawn. If the NACE Standard RP-01-69-83 is withdrawn, then the only\ncathodic protection standard to evaluate the adequacy of corrosion protection on pipelines in the\nUnited States would be in Appendix D Part 192. Should this happen, it is likely that OPS would\ninitiate a rulemaking project to update the criteria listed in Appendix D.\nI trust I have been responsive to your questions. If you need further clarification regarding\nenforcement policies, please contact Jim Thomas, Chief, Southwest Region. Your cooperation is\nappreciated.\nSincerely,\nGeorge W. Tenley, Jr\nAssociate Administrator for\nPipeline Safety\nNOTE: This Letter belongs in Appendix \"D\"\nDB\nC:\\WP51\\INTERPRT\\192\\755\\91-08-29\n2","truncated":false,"body_characters":3799}