Technology evolves when the foreseeable need arises.
With infrastructure constantly expanding, the network of underground utility lines below our feet continues to become more complex and congested. Cables and pipes layer upon each other at various depths and directions, serving different purposes, each one with a potential to pose great risk should it be damaged during excavation. For safety and future planning, it is vital to understand the location of these facilities. This involves different methods of locating, and reinforces the benefit of storing data for long term use.
We will discuss methods for locating in greater detail next month, but in general, metallic utilities can be located by using a transmitter to apply an electromagnetic field that wraps around the conducting metal of the cable itself. The receiver, or wand, from the paired equipment can be tuned to the oscillation frequency of the electromagnetic field and can trace the position of the field as it travels down the path of the conducting metal of the utility.
For subsurface utilities not composed of metallic material, and thus not capable of carrying an electromagnetic field, such as those made out of clay, concrete, or plastic, equipment such as the Ground Penetrating Radar (GPR) is used. The GPR uses radar pulses in the microwave band of the radio spectrum to create subsurface images, similar to an MRI you would get at the hospital.
The congestion of underground facilities, type and condition of lines, and the conditions of the ground will influence method of location. This means that not only is it necessary to utilize current locating equipment, but since ground conditions will change in the future, the locations of these lines need to be recorded, and better yet, they should be mapped.
