Pipeline Safety Interpretation PI-83-0106

Page 1PI-83-0106 No. 83-8 Date: August 1, 1983 DEPARTMENT OF TRANSPORTATION RESEARCH AND SPECIAL PROGRAMS ADMINISTRATION MATERIALS TRANSPORTATION BUREAU ________________________________________________________________________ PIPELINE SAFETY REGULATORY INTERPRETATION Note: This pipeline safety regulatory interpretation applies to all operators that are subject to the rule under Federal or State law. SECTION: 192.179 SUBJECT: Valve spacing FACTS: None. QUESTION: How far apart may sectionalizing block valves be placed on an onshore transmission line being constructed in a Class 1 area? INTERPRETATION: Section 192.179(a)(4) provides that "Each point on the pipeline in a Class 1 location must be within 10 miles of a valve." A spacing of not more than 20 miles between valves will result in each point on the pipeline between valves being within 10 miles of a valve. This allowable spacing is supported by the language of the proposed rule (35 FR 5713; April 8, 1970) upon which §192.179 is based, which stated that "Each sectionalizing block valve on a transmission line must be installed at a spacing not to exceed 20 miles within areas conforming to Class 1 Location." Richard L. Beam Associate Director for Pipeline Safety Regulation Materials Transportation Bureau#

Page 2July 14, 1983 Dr. Robert L. Paullin Associate Director Office of Operations & Enforcement Department of Transportation 2100 2nd Street, S.W. Washington, DC 20590 RE: D.O.T. Regulations Part 192.179 Dear Dr. Paullin: Questions have developed on the interpretation of valve spacing under 192.179, and we would like to have an official interpretation, hopefully as soon as possible. We have a pipeline project going in within several weeks, and the valve spacing questions will be part of the problems with that job. The opening wording of 192.179 states that each transmission line must have sectionalizing block valves spaced as follows: Under sub (4) it states that each point on the pipeline in a Class 1 location must be within ten miles of a valve. A case of ambiguity exists as to whether the actual spacing between valves along a transmission line should be ten, or twenty miles. As worded under (4) above, it could be construed that if one valve is within ten miles, the requirements have been met. On the other hand, if the opening wording of 192.179 referring to sectionalizing lock valves it could also be argued that each of the two valves required to sectionalize must be within ten miles of any point on the transmission line. Please provide our office with an interpretation as soon as possible, in view of our imminent construction work where this will be arising. Yours truly, A. J. Schellenberg, P.E. Lead Gas Engineer#