Memo: Internal — Pipeline Safety Interpretation

Page 1SUBJECT: INFORMATION: Questions on Section 192.625, Odorization of Gas FROM: Richard L. Beam Associate Director for Pipeline Safety Regulation, DMT-30 TO: James C. Thomas Chief, Southern Region, OOE, DMT-16 THRU: Robert L. Paulin Associate Director for Operations and Enforcement, DMT-10 Your memo of October 3, 1968, provided additional information to that in your memo of June 9, 1983, which now enables OPSR to respond more fully to questions posed in three cases, than was possible in our response of September 14, 1983. In the conditions described in Case 1, the pipeline may be either transmission or distribution depending upon the size of the direct sale customer. From a strict reading of the definitions in §192.3 of "transmission line" and "distribution line," one would classify this line as a "distribution line" and thus it would be required to be odorized. However, an interpretation of November 30, 1978, to East Tennessee Natural Gas Company (a copy of the entire package is attached) recognizes the similarity between delivery to a distribution operator and delivery to a direct sale industrial customer of similar size (flow rate) as justification for classifying the upstream pipeline as transmission. The determination of whether such a line is transmission or distribution would therefore have to be made in each case based upon the definitions of §192.3 and the attached interpretation. If the line is determined to be transmission and located in a Class 3 or 4 location, the line would also be required to be odorized under §192.625(b) unless it meets one of the exceptions under that section. In Case 2 the line serving the customer and operating at or above 20 percent of the SMYS stress level is a transmission line as defined in §192.3. As in Case 1, a transmission line in a Class 3 or 4 location must be odorized under the requirements of §192.625(b) unless it meets one of the exceptions under that section. In Case 3 that portion of the pipeline operating at or above 20 percent of the SMYS stress level would be similar to Case 2 and the same requirements would apply. That portion downstream of the pressure regulator would be similar to Case 1. Your memorandum also requests guidance as to how to distinguish between a "large volume customer" and an industrial or farm tap customer. At this time we are not aware of any such DB C:\WP51\INTERPRT\192\625\84-01-12 1#

Page 2guidelines nor any basis for establishing such guidelines other than adopting some arbitrary flow rate, which has not been done, as the dividing line between classifications. Attachment DB C:\WP51\INTERPRT\192\625\84-01-12 2#