Memo: Internal — Pipeline Safety Interpretation

Page 1ACTION: Interpretation of 49 CFR, 192.327(a) M.A. Judah Acting Associate Director for Pipeline Safety Regulation, DMT-30 DMT-50 In response to your memorandum of September 5. 1980, and the attached request from Al Kuhn of Northwest Alaskan Pipeline Company for an interpretation of 49 CFR 192.327(a) concerning depth of cover and specifically the point from where the depth of cover should be measured, we submit the attached interpretation. We do not concur with Northwest Alaskan's interpretation in their letter of August 28, 1980, for section 192.327. They stated: "The word' cover' shall mean 'the minimum depth or thickness of backfill around the pipe measured from any point on the circumference of the pipe.'" This does not conform to the intent of the regulation which is for a pipe buried in an excavated ditch and with thickness of cover measured as a vertical distance from the top of the pipe. Attachment DB C:\WP51\INTERPRT\192\327\80-12-17 1#

Page 2No. 80-17 Date: December 17, 1980 DEPARTMENT OF TRANSPORTATION RESEARCH AND SPECIAL PROGRAMS ADMINISTRATION MATERIALS TRANSPORTATION BUREAU PIPELINE _________________________________________________________________ SAFETY REGULATORY INTERPRETATION NOTE: _________________________________________________________________ A pipeline safety regulatory interpretation applies a particular rule to a particular set of facts and circumstances, and, as such, may be relied upon only by those persons to whom the interpretation is specifically addressed. SECTION: 192.327(a) SUBJECT: Cover over buried pipelines FACTS: None QUESTION:: What is the meaning of "cover" and the reference point for measurement? INTERPRETATION: The "cover" required for buried transmission lines refers to the depth of backfill that is placed on top of a pipeline that has been installed in a ditch. It is that minimum vertical distance measured between the topmost part of the pipe after installation in the ditch and the restored grade level directly over the pipe after burial is completed. This interpretation applies only to the buried mode of gas pipeline where there is cover over a pipeline which has been installed in an excavated ditch. Where there is a different mode such as a pipe partially buried below grade or with the bottom of the pipe resting on grade, the requirements of this section would not apply. Other sections including 192.103 (Subpart C), 192.161 (Subpart D), 192.317, 192.319, and 192.327(c) (Subpart G), among others, would apply as appropriate, for a pipeline partially buried below grade or resting on natural grade. Melvin A. Judah Acting Associate Director For Pipeline Safety Regulation Materials Transportation Bureau DB C:\WP51\INTERPRT\192\327\80-12-17 2#