Rhode Island Public Utilities Commission — State Waiver

ri-dpuc-122076-providence-gas-complete.pdf, page 1Official PDF-- -----~- . -~- DEPARTMENT OF TRANSPORTATION MATERIALS TRANSPORTATION BUREAU WASHINGTON. D.C. 20590 • orc 201976 Mr. John Callahan State of Rhode Island and Providence Plantations Division of Public utilities and Carriers Providence, Rhode Island 02903 Dear Mr. Callahan I This refers to the Division's action dated June 23, 1975, (OPSO Dooket No. RI-75-1), granting the Providence Gas company (PGC) a waiver from compliance with the corrosion control requirements of 49 CFR 192.455(a) for Type 316 stainless steel fittings manufactured by Amp, Inc. for use in plastic pipelines. The Office of Pipeline Safety Operations (OPSO) stayed the action by telegram dated August 25, 1975, basically on the grounds that the information presented by the Division in support of its action did not show that the soils in which the fittings would be used in Rhode Island were not corrosive to Type 316 stainless steel. On october 17, 1975, the Division appealed the stay, based on additional information provided by PGC in support of its need for a waiver. Conourrent with reoeipt of the appeal, we were considering ru1emakinq on the same subject matter as the waiver. Consequently, we delayed deoiding the appeal until a notice of proposed ru1emaking was issued to avoid possible inoonsistent aotions. Enolosed is a oopy of Notioe 76-1 issued September 22, 1976, in Dooket OPSO-37, proposing to exempt oertain small alloy fittings from Seotion 192.455. Our review of the additional information submitted indi- oates that PGC has conducted surveys in typical areas where it plans to use the fittings to determine whether or not soil resistivity and soil pH were conducive to oreating a corrosive environment to Type 316 stainless steel. Based on PGC's operating history, and the results of the surveys as correlated with the "Engineering Soil Survey of Rhode#

ri-dpuc-122076-providence-gas-complete.pdf, page 2Island” produced by the University of Rhode Island Experiment Station, it appears that the corrosively of soils in the area of use would be detrimental to small Type 316 stainless steel fittings installed in plastic pipelines. Therefore, we determined that the requested waiver may be granted by the Division subject to the following conditions: A. Each fitting installed under this waiver— 1. May not have a size greater than that required for 2 inch minimal size plastic pipe; 2. Must be designed to prevent leakage caused by localized corrosion pitting; 3. Must be electrically isolated when installed; 4. Must have its location identified in a manner that still will assure future identification of that location; and 5. Must provide a 95 percent confidence level of corrosion control and reliability based on statistical inspection sampling of those fittings installed by year at intervals not exceeding 3 years. B. Findings resulting from inspections under condition A. 5. must be submitted in writing to the Division. In addition, PUC must immediately report to the Division any failure of a fitting installed under this waiver resulting from corrosion. C. The waiver terminates upon the effective date of a final rule resulting from Motion 76-1 in Docket OPSO-37 to ensure that the fittings installed under the waiver will only be subject to the provisions of that Final rule. Sincerely, Signed Cesar DeLeon Acting Director Office of Pipeline MTP-30; GM; LMF; peg; 11/15/76 TEW: TGC-50; 11/29/76, REW: GM; 12/2 REW: LMF; 12/8 & REW: GM; 12/9/76 cc: MTP-1, 10, EA file: RI-75-I Enclosure#