Pipeline Safety Interpretation PI-79-0100

Page 1PI-79-0100 February 06, 1979 DEPARTMENT OF TRANSPORTATION RESEARCH AND SPECIAL PROGRAMS ADMINISTRATION WASHINGTON, D. C. 20590 Mr. Donald E. McCoy Transportation Safety Institute 6500 S. MacArthur Boulevard Oklahoma City, Oklahoma 73125 Dear Mr. McCoy: This is in response to your recent letter asking how much time is permitted under Part 192 to make system changes (in particular odorization) necessitated by class location changes. While §192.613(a) requires an operator to make necessary changes, no time period for compliance is specified. However, a similar provision under §192.611(c) requires confirmation or revision of MAOP within 18 months after a change in class location. In view of this similarity, it appears that an 18-month compliance period is appropriate to apply under §192.613(a). In a previous interpretation, we have stated that the 18-month period begins to run upon completion of a structure which results in a new class location (see May 12, 1978 memo to DMT-213.) Sincerely, Cesar De Leon Associate Director for Pipeline Safety Regulation Materials Transportation Bureau#

Page 2Mr. Cesar DeLeon, Associate Director Office of Pipeline Safety Regulations Materials Transportation Bureau Washington, D. C. 20590 Dear Mr. DeLeon: The purpose of this letter is to request your office's interpretation concerning CFR 49, paragraph 192.625(b) regarding the odorization of natural gas in transmission lines. The question is as follows: Suppose a transmission operator is not odorizing the gas in a segment of his pipeline system because the segment met the class location exemption allowed by either paragraph 192.625(b)(1) or 192.625(b)(3). If the operator were to detect a class location change (i.e., from Class 1 or 2 to Class 3 or 4) when performing the surveillance procedures required by paragraph 192.613(a), what period of time is he allowed under the regulations to accomplish the physical system changes necessary to now odorize the gas? Moreover, is this period of time measured from when the class locations actually changed or from when the operator detected the change in class location? Your assistance in clarifying this question is appreciated. Your very truly, Donald E. McCoy Pipeline Safety Specialist#