Technology Report 2022

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Ultra-High Frequency EM Safety Sweep and its Effect on Damage Prevention


This case study describes an on-site utility sweeping technique to find difficult-to-locate facilities such as cast or ductile iron with electrically resistive joints, damaged tracer wire or tape, short side services, and old or abandoned lines. It can also be used to verify existing locate marks prior to excavation. The technique uses locating equipment that is currently available and easy to learn and use. The technique led to significant reductions in damages by in-house crews.

  • Following a non-injury strike to a high-voltage power line in 2010, Peoples Gas sought a solution that would reduce damages to all lines, with an emphasis on unmarked lines, as well as verify existing locate marks prior to excavation.
  • The resulting solution has three parts: the technology (ultra-high frequency EM locator), the technique (the safety sweep, highly effective in finding unmarked lines), and the training (both in the classroom and the field).
  • Peoples Gas realized a decrease in damages of 67% from its in-house crews using this new solution, and a 77% decrease in damages with the root cause of “Facility Not Marked” between 2016-2019.

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