{"operation":"document","citation":"PI-76-0120","title":"Transportation Safety Institute — Pipeline Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"1976-06-23","effective_on":null,"summary":"PI-76-0120 response to Transportation Safety Institute concerning 192.457, 195.2, 195.302, 195.304, 195.308.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-76-0121.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-76-0121.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-76-0121","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1976/gAB76_06_23_ONDAK_192.457_nlmx.pdf","body":"<<<PAGE 1>>>\n\nPI-76-0121\nJune 23, 1976\nMr. Edward J. Ondak\nProgram Manager\nTransportation Safety Institute\n6500 South MacArthur Boulevard\nOklahoma City, Oklahoma 73125\nDear Mr. Ondak:\nThis responds to your memorandum dated May 24, 1976, in which you asked for a decision concerning the technique of\nusing soil resistivity alone as an electrical survey to determine the areas of active corrosion.\nEnclosed is a copy of OPSO Advisory Bulletin No. 76-2, that contains the official OPSO interpretation of the term\n\"electrical survey.\" Although areas of active corrosion have been shown to correlate highly with soil resistivity, this\ntechnique by itself does not fully meet the requirements as set forth in the above interpretation. While the Office of\nPipeline Safety Operations permits the use of consultants, it is the operator's responsibility to choose the methodology\nto meet the requirements of the Federal safety standards.\nWe trust that this clarifies what OPSO expects in the way of compliance.\nSincerely,\nCesar DeLeon\nActing Director\nOffice of Pipeline\nSafety Operations\nEnclosure\n\n<<<PAGE 2>>>\n\nMEMORANDUM\nMay 24, 1976\nSUBJECT: Soil Resistivity as Electrical Survey\nto Determine Active Corrosion\nFROM : Program Manager, Pipeline Safety,\nTransportation Safety Institute\nTO : Acting Director, Office of Pipeline Safety\nOperations, MTP-1\nAt the 1976 Underground Corrosion Short Course held at the University of West Virginia, a discussion\nwas held with members of the Harco Corporation, a well-known corrosion consulting firm. At that time\nHarco stated that they presented a program to the Office of Pipeline Safety, as it was then known, in\nDecember of 1973, in which they outline two methods to evaluate corrosion activity on bare pipelines.\nThe March 1974 Advisory Bulletin stated that \"a technique was being used called a statistical analysis to\ndetermine areas of active corrosion. This method combines pipe to soil potential, soil resistivity, and\nleak records.\" The key word here was \"combines\" which means that more than one of the above\nmentioned techniques must be used.\nHarco Corporation is attempting to utilize a survey consisting solely of soil resistivity. Their method\nstates a probability combined with soil resistivity where a section of pipeline lies in low resistivity soil\nversus a pipeline in high resistivity soil. They then say that the probability of corrosion is greater for the\npipe in low soil than in high soil and they will therefore protect the low soil pipe first by August 1, 1976,\ncompletely ignoring the pipe in high soil until some later date.\nI don't feel the intent of the law is being met as soil resistivity alone does not determine areas of active\ncorrosion. If a pipeline is under cathodic protection, the soil resistivity does not change. I have been\nchastised by Harco Corporation for making the above statement as they say OPS approved this\ntechnique. I maintain that OPS did not approve this, as it was not stated in the Advisory Bulletin of\nMarch 1974.\nI am requesting that this matter by investigated and a decision made concerning this technique. My\nbiggest concern is the possibility that operators will get hold of this and begin taking soil resistivity\nalone. This can never determine active corrosion, only the possibility that corrosion might occur. This\nwould never comply with interpretations brought out by OPSO defining corrosion and how to find it.\nPlease let me have your thinking on the above so we can better advise operators and State agents on\nproper techniques.\nEdward J. Ondak","truncated":false,"body_characters":3547}