Electromagnetic methods are ProMark’s employed techniques to detect underground utilities made of metal, or containing materials e.g. steel and copper. Examples of these utilities include water, natural gas, fuel lines, electricity and telephone. In order to detect these utilities using electromagnetic survey techniques, a radio frequency is induced onto the utility. This signal is carried by the conductor along its length and is detected above ground with radio frequency antenna.
Often, buried electrical and telephone utilities radiate their own electromagnetic field and can be readily detected using the radio frequency (RF) without conducting a current. By detecting the maximum strength at several locations, the surface trace of an underground utility can be detected.
Non-Metallic pipes do not accept, produce or transmit and electromagnetic frequency. If such a utility is found without a tracer wire, i.e. a clay, PVC, HDPE or plastic pipe, for water mains, gas and sewers. Then the (GPR) Ground Penetrating Radar System is utilized to locate the utility.
GPR is a geophysical method that uses the latest radar technology to image subsurfacing. It is used in the enviornmental, geotechnical and engineering field as a non-destructive method using electromagnetic radiation. (Less than a cell phone) It can detect objects of all composition, not just metallic objects. GPR can be used in a variety of media including soil, rock, concrete, asphalt and other materials. It is like a “Subsurface Ultra Sound”.