BEFORE THE WASHINGTON UTILITIES AND TRANSPORTATION COMMISSION In the Matter of the Request by Cascade ) Natural Gas Corporation for Authorization ) DOCKET UG-990537 to Operate a High Pressure Service Set and ) Natural Gas Service Line at a Pressure ) ORDER GRANTING Greater Than 500 psig Within Five ) REQUESTED Hundred Feet of Buildings Intended for ) AUTHORIZATION Human Occupancy (WAC 480-93-020). ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ) On March 26, 1999, Cascade Natural Gas Corporation filed a request with the Washington Utilities and Transportation Commission for authorization to operate a high pressure service set and natural gas service line at a pressure greater than 500 psig within five hundred feet of a building intended for human occupancy in Whatcom County pursuant to the requirements of WAC 480-93-020, Proximity considerations. FINDING OF FACT 1. On July 21, 1971, Cascade Natural Gas Corporation requested from the Washington Utilities and Transportation Commission a waiver under Rule 3 of the Commission’s Rules and Regulations to operate a natural gas pipeline at a maximum pressure in excess of 250 psig within 100 feet of any building intended for human occupancy. More specifically, the Company requested approval to construct and operate a sixteen inch, high pressure pipeline in Whatcom County at a pressure of 550 psig with a maximum allowable operating pressure of 600 psig. On July 26, 1971, the Commission approved the request. 2. The pipeline was initially constructed to provide natural gas to industrial users such as the ARCO Refinery and the INTALCO Aluminum Facility near Ferndale. As a result of the natural gas pipeline being in close proximity to the rural residents in the County, many residents requested natural gas service. With the sparse population and the large distance between buildings, the Company determined that an intermediate pressure distribution system was not economical or feasible and relied upon high pressure farm taps or high pressure service sets as the mechanism to provide appropriate pressure natural gas service to the end user. 3. The Company has requested authorization from the Commission to install a high pressure service set and service line to a residence located at 1898 W. Badger Road, Lynden, Washington. The proposed high pressure service set will be located approximately 205 feet from the building and approximately 15 feet from the high pressure pipeline. 4. The pressure of the service line providing natural gas to this proposed customer will be reduced to 60 psig at the high pressure service set. 5. Buildings intended for human occupancy are located within 500 feet of the sixteen inch, high pressure pipeline or high pressure service sets associated with this pipeline. Docket UG-990537 Page 2 The Commission has previously authorized the Company to provide natural gas service to certain buildings adjacent to this high pressure transmission pipeline for which the Company has taken steps to mitigate the concerns associated with high pressure natural gas service lines. The Company has implemented these items to increase the level of safety for those customers for which natural gas service is provided by means of a high pressure service set attached to this high pressure pipeline: •Installation of the high pressure service set as remote as possible to the building without creating an unreasonable risk to the high pressure service set itself, •Installation of an excess flow valve (EFV) to reduce or stop the flow of natural gas in the event that the natural gas line between the EFV and the building is ruptured. The EFV is generally placed as close to the high pressure transmission pipeline as possible, or •Replacement of the high pressure service line and high pressure service set with an intermediate pressure distribution system operating at a pressure of 60 psig or less. 6. The Company and Commission staff have evaluated the facility in question to determine if public safety will be compromised by the operation of the proposed high pressure service set and natural gas service line. At this time, staff does not consider the installation of this proposed facility to significantly impact public safety. The hoop stress on the high pressure service line at this pressure will be less than 10% of the specified minimum yield strength of the pipe. The most restrictive requirement by federal natural gas pipeline safety standards requires that natural gas pipelines in a highly populated area be operated at a pressure that produces a hoop stress of no greater than 40% of the specified minimum yield strength of the pipe. The high pressure service line in this sparsely populated rural area will be operated at stress level much lower than required in a populated area. In addition, the system will be installed such that any component that operates at a pressure greater than 500 psig will be located at a sufficient distance from buildings to allow for the venting and dissipation of natural gas with minimal risk of accumulation within any building intended for human occupancy. ORDER THE COMMISSION ORDERS: 1. Cascade Natural Gas Corporation shall be granted authorization to operate a high pressure service set and natural gas service line at a pressure greater than 500 psig within five hundred feet of a building intended for human occupancy in Whatcom County pursuant to the requirements of WAC 480-93-020, Proximity considerations. This authorization will be applicable only for the residence located at 1898 W. Badger Road, Lynden, Washington. 2. Cascade Natural Gas Corporation will maintain a distance of approximately 205 feet from the high pressure service set to the residence. The minimum distance from the high pressure service set to the residence will be at least 200 feet. Docket UG-990537 Page 3 3. The Commission retains jurisdiction over this matter to effectuate the provisions of this order. DATED at Olympia, Washington and effective this 14th day of April, 1999. WASHINGTON UTILITIES AND TRANSPORTATION COMMISSION CAROLE J. WASHBURN Secretary