Piedmont Natural Gas Company, Inc. — Pipeline Safety Interpretation

Page 1February 2, 1977 Mr. E. L. Manning Vice President Operations Services Piedmont Natural Gas Company, Inc. P.O. Box 1968 Charlotte, North Carolina 28233 Dear Mr. Manning: This responds to your letter dated October 5, 1976, in which you ask for clarification of the relationship between 49 CFR 192.619(a) and 49 CFR 192.621(a) regarding the maximum allowable operating pressure of pipelines in a high pressure distribution system. Section 192.619(a) prescribes the maximum allowable operating pressure for all steel and plastic pipelines. Section 192.621(a) prescribes additional limitations which apply to pipelines in high pressure distribution systems. In order to establish a maximum allowable operating pressure for a high pressure distribution pipeline, you must comply with the requirements of both sections. More specifically, you have asked whether Section 192.619(a)(3) requires that pressure be limited to the highest actual operating pressure occurring during the 5 years preceding July 1, 1970. Under the requirements of Sections 192.619(a) and 192.621(a), this limitation would apply only if it is the lowest pressure among those listed in the two sections and the pipelines concerned were not tested or uprated as stated in Section 192.619(a)(3). Sincerely, Cesar DeLeon Acting Director Office of Pipeline Safety Operations dal\192\621\77-02-02 1#

Page 2October 5, 1976 Mr. Cesar DeLeon Acting Director Office of Pipeline Safety Operations Department of Transportation 2100 Second St., SW Washington, D.C. 20590 Dear Mr. DeLeon: Piedmont Natural Gas requests a clarification of the relationship between Sections 192.619 and 192.621 of D.O.T. 192. We have always felt that the two sections are independent, with 192.619 applying only to pipelines in the traditional USAS B31.8 sense and not to a distribution system. We do not feel that 192.619 was intended to supplement 192.621. In particular, we do not think the law requires us to limit distribution system pressures to the highest actual operating pressure to which the segment was subjected during the 5 years preceding July 1, 1970. The interpretation in this area is quite important to us since the outcome could have a major impact on how Piedmont operates its distribution systems and the future flexibility of these systems. It seems evident to us that if 192.619(3) was intended to apply to a high pressure distribution system, it would have been repeated in 192.621, as 192.619(a)(1), (a)(6), and (b) were repeated. Would you please consider this matter and advise us whether or not 192.619 applies to a distribution system. Sincerely, E. L. Manning, Vice President dal\192\621\77-02-02 2#

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