Pure Technologies

When Speed and Accuracy Count: Enwave Houston and Oklahoma City Successfully Deploy Sahara Tool for Leak Inspection Projects in Record Time


Courtesy of Courtesy of Pure Technologies

Sahara technology is winning accolades from satisfied owners and operators of buried infrastructure the world over. In North America, two recent projects demonstrate the benefits of using this in-line tethered tool for critical leak detection surveys, especially when speed and accuracy are paramount.

Sahara is the first tool designed for live inspection of large diameter mains, and one of the most accurate tools available for detecting and locating real-time leaks, gas pockets and structural defects in complex networks typically found in urban environments.

The tool is inserted via a valved appurtenance, and then moves through the pipeline using the flow of water and a small drag chute – all without interrupting service. Once the sensor tool is inserted, it remains tethered to the surface. This allows for real-time results and maximum control, as the tool can be winched back and forth to immediately confirm suspected leaks and other anomalies. The sensor is also tracked at ground level by a staff member, allowing for precise spot markings for excavations.

Oklahoma City welcomes Sahara leak detection survey on critical main

In March 2015, McKee Utility Contractors (McKee) retained Pure Technologies (Pure) to perform a quick-turnaround leak detection survey on a troublesome 72-inch Transmission Main (TM) in Oklahoma City. The critical TM, which is composed of prestressed concrete cylinder pipe (PCCP) and transmits potable water, is owned and operated by Oklahoma City Water Utilities (OCWU).

In this instance, OCWU suspected a leak along a low point of the line where surface water was noticed. A previous catastrophic failure on the line compelled the utility to call on the prime contractor McKee to dig, locate, and repair the leak.

Thwarted by two days of digging and not finding the leak, McKee called on Pure to assess approximately 4400 feet of pipe and to determine the location of the leak source and any gas pockets using Sahara leak detection technology.

Quick mobilization, short turnaround timing

The planning and execution took place in short order. McKee contacted Pure on Saturday, the project planned on Sunday and by Monday a field crew and equipment were mobilized to the site in Oklahoma City. On Tuesday, a single inspection was performed, and one (1) leak was detected 360 feet downstream from the Sahara insertion point. The leak was classified as a large leak based on the audible range. The inspection continued for a total inspection distance of 546 feet. No other leaks were detected at the time of inspection.

Based on the results I’ve seen, I’m never again digging up another pipe without Pure and its technology…”

By the time Pure began extracting the Sahara tool, McKee had ordered a backhoe enroute, and by afternoon the pipe was excavated, the leak located, and the repairs were able to begin.

Shane McKee, president of McKee was extremely pleased with the accuracy of the Sahara technology and the fast turnaround from the Pure team. “Based on the results I’ve seen, I’m never again digging up another pipe again without Pure and its technology to help guide the process.”

Houston energy company deploys Sahara tool to quickly locate leak in chilled water line

Large cities often operate central chilled water plants to cool water that is then sold to building owners for use in air conditioning.

In Houston, Enwave Houston delivers chilled water through 5.4 miles of pipe to air-condition 24 buildings, including Minute Maid Park, home of the Houston Astros. The 27,000 ton system uses ice storage technology to help keep central business district buildings comfortable in spite of summer's high temperatures and humidity.

In December 2015, Pure was retained by Boyer Inc. to perform a Sahara inspection on Enwave's 24-inch Chilled Water Supply pipeline (CWS) and also on their 24-inch Chilled Water Return pipeline (CWR). The purpose of the inspection was to locate a suspected leak on one of the dual lines that run parallel along the downtown core.

Data identified events associated with leaks and air pockets

Boyer proposed two separate insertions during the planning phase. Pure completed both proposed insertions over a two-day period for a total of 795 feet of pipeline inspected. Acoustic data was collected and recorded during the inspections as the Sahara sensor traversed the main. The data was evaluated to identify events associated with leaks and pockets of trapped air.

During the inspections, one leak and zero air pockets were detected. The Sahara sensor was tracked above ground to track the sensor along each pipeline and verify the endpoint of each endpoint. The leak was located 144 feet downstream from the insertion point on the second day with sub-meter accuracy, allowing a pinpoint excavation to be made for repairs, minimizing disruption to downtown Houston traffic, and minimizing the contractor's cost of excavation and road restoration.

When time and accuracy matter, utilities count on Sahara

The two case studies demonstrate the efficacy of the Sahara leak detection system. When time and pinpoint accuracy matter, Sahara gets the job done right.

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