{"operation":"document","citation":"PI-72-051","title":"Columbia Gas Service Company — Pipeline Safety Interpretation","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"1972-11-26","effective_on":null,"summary":"PI-72-051 response to Columbia Gas Service Company concerning 192.105, 192.3.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-72-051.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-72-051.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-72-051","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1972/PI72051.pdf","body":"<<<PAGE 1>>>\n\nMr. Don T. Caffery\nColumbia Gas Service Company\nFranklin, Louisiana 70538\nDear Mr. Caffery:\nThis is in response to your letter of October 31, 1972, in which you ask what is meant by 40\npercent of SMYS.\nThe term SMYS is defined in §192.3 of 49 CFR Part 192 to mean specified minimum yield\nstrength. As an example, Trade B pipe made to API 5L specification has a specified minimum\nyield strength (SMYS) of 35,000 pounds per square inch (psi) 40 percent of SMYS (35,000 x\n0.40) is 14,000 psi.\nThe meaning of the term \"40 percent of SMYS\" may be shown by an example of its application in\nthe regulation. Thus, §192.607 requires an operator to determine the class location of each\nsegment of pipeline with a maximum allowable operating pressure that will produce a hoop stress\nof more than 40 percent of SMYS.\nHoop stress is commonly determined by the basic formula\nS = PD where S is hoop stress in psi, P is internal\nπt\npressure in psig (pounds per square inch gage), D is outside diameter in inches, and t is wall\nthickness in inches. (This basic formula, in transposed form and with additional factors for safety\npurposes, is used in §192.105 to determine the design pressure for steel pipe.)\nWhere B pipe referred to above, made of Grade B steel, is in a segment of pipeline operating at a\npressure of 200 psig, and has an outside diameter of 8.625 inches with a wall thickness of 0.250\ninches, the hoop stress determined by the basic formula is 3450 psi. Since in this example the\nhoop stress (3450 psi) is less than 40 percent of SMYS (14,000 psi), the provisions of §192.607\nwould not apply for the particular segment of pipeline.\nI trust this answers your question. Please advise if we may be further assistance on this matter.\nSincerely,\n/signed/\nJoseph C. Caldwell\nDirector\nDB\nC:\\WP51\\INTERPRT\\192\\607\\72-11-26\n1\n\n<<<PAGE 2>>>\n\nOffice of Pipeline Safety\nDB\nC:\\WP51\\INTERPRT\\192\\607\\72-11-26\n2","truncated":false,"body_characters":1911}