{"operation":"document","citation":"PI-76-0115","title":"Pipeline Safety Interpretation PI-76-0115","source_type":"guidance","agency":"Pipeline and Hazardous Materials Safety Administration","status":"guidance","official":true,"published_on":"1976-09-28","effective_on":null,"summary":"PI-76-0115 concerning 195.228.","machine_formats":{"json":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-76-0115.json","markdown":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-76-0115.md"},"app_url":"https://regulus.evalyn.ai/document/phmsa-interpretation-pi-76-0115","source_url":"https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/legacy/interpretations/Interpretation%20Files/Pipeline/1976/g76-09-28_Tyree_195.228-DBX.pdf","body":"<<<PAGE 1>>>\n\nPI-76-0115\nSeptember 28, 1976\nMr. Gordon T. Tyree\nQuality Control - Field Surveillance , Officer\nState of Alaska\nOffice of the Pipeline Coordinator\nP. O. Box 1782\nAnchorage, AK 99510\nDear Mr. Tyree:\nThis is in response to your letter of August 3, 1976, in which you asked about repairing a defect in a girth weld\nlocated on the side opposite from where another defect was repaired as shown in the sketch enclosed with\nyour letter.\nIn accordance with Section 195.230(b):\n\"A weld that is found unacceptable under Section 195.228 may not be repaired unless -\n(b) The segment of the weld to be repaired was not previously repaired.”\nAlso, in accordance with Section 195.232(c):\n“A cylinder of the pipe containing a weld must be removed and the ends rebeveled whenever -\n(c) The weld was repaired and the repair did not meet the requirements of Section 195.228.\"\nThe requirement prohibiting double repair of girth welds was adopted from the B31.4 and B31.8 codes used by\nthe liquid and gas pipeline industries, respectively. It apparently was placed in the codes to maintain a high level\nof workmanship which has been the rule in pipeline welding as evidenced by a low accident rate each year from\ngirth welds. Of the total accidents reported to us from liquid pipelines, less than 2 percent annually originate\nfrom girth welds.\nThere were no comments to this prohibition by companies from either the gas or liquid pipeline industries\nwhen the regulations were proposed. This indicates the desire of the pipeline industry to continue the practice\nof not allowing double repair.\nOur primary concern with double repair is that excessive concentration of stress will result in the heat affected\nzones where the repair is made. Repeated repairs in the same segment without completely removing the weld\nmetal of the previous repairs will increase this stress concentration and possibly result in failure of the weld.\nRepeated cycles of alternating heating and cooling of the weld can embrittle the weld and also lead to possible\nfailure.\nThis problem exists also where there are defects which are repaired from both the outside and inside of the\npipe as your sketch indicates. The heat affected zone could be common for the repairs of each and the\nresultant high stress concentration cannot be tolerated.\nTherefore, where more than one weld defect exists at one location in a girth weld and a single repair does not\neliminate the defects, the second repair is not allowed, unless the second repair is not in the same segment as\nthe first, a segment being defined as that portion of the weld which has been subjected to one repair, including\nthe heat affected zone incident to that repair. In your example, the second repair would probably be allowed if\nit is made from the opposite side of the weld from the first and the opposite side repair area does not come\ninto contact with the original repair area, including heat affected zones.\nThank you for your interest in pipeline safety.\nSincerely,\nSIGEND\nCesar DeLeon\nActing Director\nOffice of Pipeline\nSafety Operations","truncated":false,"body_characters":3072}