Utility Locators (M-13)

1. Q: How does it work?
   A: A utility locator consists of a transmitter which can be hooked onto a pipe or wire and which generates an RF signal (often at 8kHz or 33kHZ) using the pipe or wire as an antenna. A receiver is used to trace the radiation from the underground conductor.
   

2. Q: What is the geologic model?
   A: A conductor (usually metallic) is required for propagation of the signals. Larger objects (such as tanks) will sometimes radiate from their entire surface and can be located. Some conductors will also radiate at the power frequencies (60/180 Hz) due to grounding problems or simple induction from power lines.
   

3. Q: What are the requirements?
   A: Access to one end of the wire or pipe is usually necessary for best results. In an induction mode, some near surface piping can be caused to radiate by the transmitter placed on the surface.
   

4. Q: What are the pitfalls?
   A: Complex piping and crossovers require time and effort to sort out. Persistent observation is required to clear sites for drilling safety. PVC and fiberglass do not conduct electricity and, without tracer wires, are hard to find. GPR from the surface and in-pipe sondes are the alternatives.
   

5. Q: What logistics are needed?
   A: Crew size is usually one person.
   

6. Q: What are the deliverables?
   A: Utilities are usually marked on the ground or cleared drilling sites are outlined on the ground with paint.
   

7. There is no additional detail available at this time.