Process Devised For Monitoring Leak Threats Using GIS

Distribution Integrity Management Rule
By James Stout, UGI Utilities, Inc., and Tony Sileo, Opvantek, Inc. | February 2009 Vol. 236 No. 2

Thus, when reference is made in this article to “Locating Your Leaks,” the authors mean knowing both the geographic location of the leak (relative to other facilities in the system) as well as the specific facility record on which the leak occurred.

UGI Infrastructure

UGI Utilities, Inc. distributes natural gas to customers in eastern and northeastern Pennsylvania. Until recently, we have operated a little more than 5,000 miles of main and served over 300,000 customers. Having just purchased PG Energy (now called Penn Natural Gas), we have increased the size of our business by about 50% so that we are now serving almost 500,000 customers and operate almost 8,000 miles of main. In the combined company, 76% of the services are plastic and 13% of them are unprotected metallic services. The remaining metallic services (11%) are cathodically protected in some way.

In March 2008 UGI signed an agreement to purchase PPL Gas Utilities Corp. Pending PUC approval, the new company will be called UGI Central Penn Gas. This acquisition will increase UGI customer count by 16% to almost 550,000 and increase its miles of main by another 49% to over 11,500 miles. The distribution of service material type in the combined company will be about the same, percentagewise.

DIMP Plans

UGI has completed extensive re-engineering of the processes and tools used to collect and maintain data about leaks and repairs on its distribution system. Its previous process was:

  • Leaks were found or re-inspected by roving leak surveyors or those called out on odor calls. Details were captured on a paper leak form.
  • Repairs were documented on separate paper form.
  • Non-leak excavations did not fit this process well.

For each repaired leak, the following basic information was collected:

  • Field assigned leak identification.
  • Main identification determined by office staff.
  • Political subdivision.
  • Street address.
  • Survey method.
  • Leak “location” (in street or behind curb).
  • Classification (leak grade).
  • Sketch with readings.
  • Repair action.

The paper forms were keyed into a mainframe system. The original paper was filed by map grid in each leak surveyor’s office. There are multiple leak surveyor offices throughout the operation area. Some of the shortcomings of this process were that leak locations were not apparent to field personnel; surveyors had to manage paper docs; and old documents were archived in a “vault,” that is, they were not readily accessible.

New Process

UGI’s new process, started in 2006, was one portion of a multi-year asset management project named “FLAME” (Field Level Asset Management Environment). In the new process, leak, leak repair, and pipe inspection data is captured electronically, in the field, on new mobile GIS platforms. Initial leak entry is still completed by roving leak surveyors or those called out on odor calls. Repair crews then enter repair details and pipe inspection information on an electronic repair form, accessed from a button on the Leak form. The system also supports non-leak inspections and exposed pipe reports.