15
Locating Cast-Iron Pipes
As illustrated in Figure 25, cast-iron pipes produce the strongest magnetic signals at their
joints.
Figure 25: Signal Patterns Provided by Cast-Iron Pipes
After an initial sweep search identifies the general direction of the pipe, the steel pipe joints or
transition points can be more accurately traced by the following procedure:
1. Set the Sensitivity control to maximum (XH indication).
2. Hold the locator vertically approximately 1 to 1-1/2 feet above the surface.
3. Walk without turning or tilting the locator.
4. Mark the locations where the maximum signal levels occur.
5. Return to an area of maximum signal strength and hold the locator several inches
above the surface. The sensitivity will probably have to be reduced during this
second pass. Four-inch pipes can be located at depths up to 9 feet.
Locating Steel Drums
As shown in Figure 26,
the GA-92XTd's signal
pattern will vary
depending on the vertical
or horizontal orientation of
the drum and how deep it
is buried.
A fifty-five gallon drum
can be located at depths
ranging from 4 feet to 9
feeet.
Figure 26: Signal
Patterns Provided by
Steel Drums