PDFWAC 480-93-155

Increasing maximum allowable operating pressure.

(1) If a gas pipeline company wants to uprate to a MAOP greater than sixty psig, the company must submit to the commission for review, at least forty-five days before uprating, a written plan of procedures including all applicable specifications with drawings of the affected pipeline systems. At a minimum, the plan must include the following:
(a) A list of all affected gas pipeline facilities, including pipes, fittings, valves, and other affected equipment, with the manufacturer's specified maximum operating pressure limits, their specified minimum yield strength (SMYS) at the intended MAOP, and any other applicable specifications or limitations;
(b) Original design and construction standards;
(c) Original pressure test records;
(d) Previous operating pressures identifying the dates and lengths of time at that pressure;
(e) Records of all leaks, regardless of cause, and the dates and methods of repair;
(f) Where the pipeline is being uprated to a MAOP that produces a hoop stress of twenty percent or more of the SMYS, records of the original welding standards and welders;
(g) Maintenance records of all affected regulator stations and system relief valves for the past three years or three most recent inspections, whichever is longer;
(h) Where applicable, relief valve capacities at the proposed MAOP compared to regulator flow capacities, with calculations;
(i) Cathodic protection readings of the affected gas pipeline and facilities, including rectifier readings, for the past three years or three most recent inspections, whichever is longer; and
(j) Any additional information that the commission may deem necessary to evaluate the pressure increase.
(2) Uprates must be based on a previous or current pressure test that will substantiate the intended MAOP.
[Statutory Authority: RCW 80.01.040, 80.04.060 and 81.88.040. WSR 08-12-046 (Docket PG-070975, General Order R-549), § 480-93-155, filed 5/30/08, effective 6/30/08. Statutory Authority: RCW 80.04.160, 80.28.210, and 80.01.040. WSR 05-10-055 (Docket No. UG-011073, General Order No. R-520), § 480-93-155, filed 5/2/05, effective 6/2/05. Statutory Authority: RCW 80.01.040, 80.04.160, 81.04.160, and 34.05.310. WSR 01-20-061 (Docket No. A-010827, General Order No. R-491), § 480-93-155, filed 9/28/01, effective 10/29/01. Statutory Authority: RCW 80.01.040. WSR 92-16-100 (Order R-375, Docket No. UG-911261), § 480-93-155, filed 8/5/92, effective 9/5/92.]