Northern Illinois Gas — Pipeline Safety Interpretation

Page 1January 15, 1993 Mr. Carl P. Hendrickson Director Codes and Standards Northern Illinois Gas P.O. Box 190 Aurora, IL 60507-0190 Dear Mr. Hendrickson: I apologize for taking so long to respond to your letter of September 21, 1992, in which you commented on a statement we made in the withdrawal notice in Docket PS-115. The statement was that the grandfather exception (49 CFR 192.619(c)) has practical effect only for pipelines in Class 1 locations because of the additional limits on maximum allowable operating pressure (MAOP) that §192.611 places on pipelines in more populated areas. You suggested the statement should be corrected because it may mislead operators to believe the grandfather exception does not apply to certain distribution system segments. We recognize that the statement disregards application of the grandfather exception to high pressure distribution systems. However, we do not believe this oversight needs correction because §192.619(c) is not a new rule for which operators may need proper instruction on compliance. It is widely used, longstanding provision that is clearly drafted to cover all pipeline segments, including distribution segments. Also, §192.621 is the primary rule governing the MAOP of high pressure distribution systems; and the grandfather exception does not apply under §192.621. So, even if an operator incorrectly assumes the grandfather exception does not apply to a particular distribution line segment, that assumption would not affect the operator's responsibility to meet §192.621. To illustrate, you mentioned that for some pipeline segments insufficient records may exist to substantiate compliance with §192.621. In such case, the operator may not rest on the grandfather exception. Instead, the operator must appropriately test or inspect the segments to establish the data needed to meet §192.621. We appreciate your concern about correct application of the pipeline safety standards. Please let me know if we can provide any further clarification. Sincerely, Cesar De Leon Director, Regulatory Programs Office of Pipeline Safety dal\192\619\93-01-15#