Pipeline Safety Interpretation PI-82-0108

Page 1PI-82-0108 July 29, 1982 Mr. R. G. Keearns Williams Pipe Line Company P.O. Box 3448 Tulsa, Oklahoma 74101 Dear Mr. Keearns: Your letter dated February 16, 1982, requested a waiver from compliance with §195.310 by using a digital pressure gauge in lieu of a dead weight tester. Enclosed is a Pipeline Safety Regulatory Interpretation of §195.310 which states that the use of a dead weight tester is not required. Hence, a waiver from compliance with §195.310 is not required in order to use the proposed digital pressure gauge for hydrostatic testing. Sincerely, Melvin A. Judah Acting Associate Director for Pipeline Safety Regulation Materials Transportation Bureau Enclosure#

Page 2No. 82-6 Date: July 29, 1982 DEPARTMENT OF TRANSPORTATION RESEARCH AND SPECIAL PROGRAMS ADMINISTRATION MATERIALS TRANSPORTATION BUREAU PIPELINE SAFETY REGULATORY INTERPRETATION Note: A pipeline safety regulatory interpretation applies a particular rule to a particular set of facts and circumstances, and, as such, may be relied upon only by those persons to whom the interpretation is specifically addresses. SECTION: 195.310 SUBJECT: Use of a digital pressure gauge in lieu of a dead weight tester during hydrostatic test. FACTS: Williams Pipe Line Company letter dated February 16, 1982, requested a waiver from compliance with §195.310 to use a digital pressure gauge instead of a dead weight tester. INTERPRETATION:Section 195.310 does not require the use of dead weight testers during hydrostatic test. The purpose of the use of the term is to assure that substantial evidence of testing is kept and when §195.310 was adopted, dead weight testers were in common use. Comparable data from modern equipment will suffice in meeting the requirements of §195.310. Melvin A. Judah Acting Associate Director for Pipeline Safety Regulation Materials Transportation Bureau#

Page 3February 16, 1982 Mr. Melvin A. Judah Acting Associate Director for Pipeline Safety Regulations Materials Transportation Bureau U.S. Department of Transportation 400 Seventh Street, S.W. Washington, D.C. 20590 Dear Mr. Judah: In accordance with Sub-part E of Regulations for Transportation of Liquids by Pipeline, Part 195.310, we now use the deadweight tester for measurement of pressure during hydrostatic testing. The field survey type deadweight tester, however, has presented certain problems as follows: 1.The weights are easily dropped and scored making their mass and, therefore, the accuracy of their measurements dubious. 2.We do not have the facilities to calibrate deadweights and, therefore, must trust the original manufacturer totally. 3.Determining a pressure reading with a field deadweight tester is complicated, making operator error a common problem. Our research has turned up a pressure measuring device which we feel offers better accuracy than the field deadweight tester is actual service. Enclosed are technical specifications of the "Gauge 1" digital pressure gauge, manufactured by Vaetrix, a division of Taylor Tools. We have tested one of these units and found it operates well within the accuracy specifications. We therefore request a waiver to use the "Gauge 1" digital pressure gauge in place of the field deadweight tester for which deadweight testers are currently required by federal regulations. Very truly yours, R. G. Keearns Manager of Environmental Affairs and Pipe Line Safety#