DGI provides both public and private locating services, using GPR and/or Pipe and Cable locating technologies for the same low pricing. We do not differentiate between the two types of surveys, and often find that each technology compliments the other.
The general methodology followed is to conduct a site reconnoiter in an attempt to locate any or all of the above-ground expressions of the utilties present within the area of interest. Pipe and Cable locating equipment can then be used to trace the utility through various types of substrate, by transmitting a frequency of known wavelength through the conduit or cable (via conduction or induction), and then tracking the strongest signal returns. Signal return strengths are dependent upon the composition of the utiltiy, (e.g. cast iron or copper), and DGI makes use of different RF instruments to cover a broad range of frequencies (8K to 486KHz) in an effort to maximize signal travel length and return strength.
Following the RF survey using the pipe and cable locating equipment, a GPR survey is conducted to locate anomalous data returns that may be indicative of buried stuctures; undocumented or documented UST's and associated plumbing; utilities; voids or differneces in the homogeneity or heterogeneity of the sediment substrate. The use of GPR can also truth the results and conclusions drawn from the RF survey. In addition, where one technology may not provide a data set that is interpretable (based upon field conditions), the other may be efficient.
Phone 516.326.0586, Fax 516.616.6194