Standard Terms and Conditions

Client agrees to meet and perform all requirements described in this document and has fully read and understands all items listed within this document.

Our goal is to provide you with the answers to your questions regarding what lies below the surface. Customer acknowledges it understands that our results are based upon the quality of the data retrieved which is determined by a variety of factors, including, but not limited to, the limitations listed in the “Equipment” section of this document. These limitations are inherent to all locating equipment. The decision to proceed with drilling, excavation or any destructive methods is left entirely up to the customer.

GPRS will not accept liability for an inaccurate interpretation or any other reason, and customer agrees to release and indemnify GPRS and its owners and agents from all losses and damages from all alleged negligence and/or contract claims by customer or any third party. These terms and conditions supersede any other previous terms and conditions either oral or written.

It is the customer's responsibility to prepare the site for scanning, including clearly identifying areas to be scanned, securing access to all areas required for scanning, and keeping these areas clean and free of obstructions. Delays caused by customer's failure to do so may result in an increased price.

If GPRS provides maps or CAD drawings, please note that the map is not survey quality. These are representations of GPRS’ utility findings performed on a previous date. The GPRS scan performed was of limited scope and utilities outside this scope are not shown.

Equipment

  • 400 MHz GPR Antenna. The antenna is mounted in a stroller frame which rolls over the surface. The surface needs to be reasonably smooth and unobstructed in order to obtain readable scans. Obstructions such as curbs, landscaping, and vegetation will limit the feasibility of GPR. The data is displayed on a screen and marked in the field in real time. GPR works by sending pulses of energy into a material and recording the strength and the time required for the return of the reflected signal. Reflections are produced when the energy pulses enter into a material with different electrical properties from the material it left. The strength of the reflection is determined by the contrast in signal speed between the two materials. The total depth achieved can be as much as 8’ or more with this antenna but can vary widely depending on the conductivity of the materials. Conductive soil types such as clay may limit our depths to 3’ or less. As depth increases, targets must be larger in order to be detected and nonmetallic targets can be especially difficult to locate. Depths provided should always be treated as estimates as their accuracy can be affected by multiple factors. For more information, please visit: Link
  • 1600 MHz GPR Antenna. The antenna is approximately 6”x9” and rolls over the surface. The antenna needs a reasonably smooth, unobstructed surface for scanning so we would not be able to scan within 3” of obstructions such as walls and metal tracks unless they are removed prior to our work. The data is displayed on a screen during the scanning and marked on the surface in real time. GPR works by sending pulses of energy into a material and recording the strength and the time required for the return of the reflected signal. Reflections are produced when the energy pulses enter into a material with different electrical properties from the material it left. The strength of the reflection is determined by the contrast in signal speed between the two materials. The total depth achieved can be as much as 18” or more with this antenna but can vary widely depending on the conductivity of the materials and other factors such as the spacing of the reinforcing. No harmful radiation is emitted and the work can be performed at any time with people in close proximity. For more information, please visit: Link
  • 2000 MHz GPR Antenna. The antenna is only approximately 4”x3.5” and rolls over the surface. The antenna needs a reasonably smooth, unobstructed surface for scanning so we would not be able to scan within 1.75” of obstructions such as walls and metal tracks unless they are removed prior to our work. The data is displayed on a screen during the scanning and marked on the surface in real time. GPR works by sending pulses of energy into a material and recording the strength and the time required for the return of the reflected signal. Reflections are produced when the energy pulses enter into a material with different electrical properties from the material it left. The strength of the reflection is determined by the contrast in signal speed between the two materials. The total depth achieved can be as much as 18” or more with this antenna but can vary widely depending on the conductivity of the materials and other factors such as the spacing of the reinforcing. No harmful radiation is emitted and the work can be performed at any time with people in close proximity. For more information, please visit: Link
  • 2300 MHz GPR Antenna. The antenna is only approximately 4”x3.5” and rolls over the surface. The antenna needs a reasonably smooth, unobstructed surface for scanning so we would not be able to scan within 1.75” of obstructions such as walls and metal tracks unless they are removed prior to our work. The data is displayed on a screen during the scanning and marked on the surface in real time. GPR works by sending pulses of energy into a material and recording the strength and the time required for the return of the reflected signal. Reflections are produced when the energy pulses enter into a material with different electrical properties from the material it left. The strength of the reflection is determined by the contrast in signal speed between the two materials. The total depth achieved can be as much as 18” or more with this antenna but can vary widely depending on the conductivity of the materials and other factors such as the spacing of the reinforcing. No harmful radiation is emitted and the work can be performed at any time with people in close proximity. For more information, please visit: Link
  • Electromagnetic Pipe Locator. The EM locator can passively detect the electromagnetic fields from live AC power or radio signals travelling along some conductive utilities. It can also be used in conjunction with a transmitter to connect directly to accessible, metallic pipes, risers, or tracer wires. A current is sent through the pipe or tracer wire at a specific frequency and the resulting EM field can then be detected by the receiver. A utility’s ability to be located depends on a variety of factors including access to the utility, conductivity, grounding, interference from other fields, and many others. Depths provided should always be treated as estimates as their accuracy can be affected by multiple factors. For more information, please visit: Link
  • Infrared Camera. The thermal camera can detect changes in temperature as small as <0.1°C with accuracy with 2°C. This is often used for locating radiant heat tubing. The system should be heated near to or after the start of the project in order to have contrast between the temperature of the tubing and the slab. For more information, please visit: Link
  • Traceable Rodder. The rodder has a copper wire encased in 5/16” of fiberglass. The line is pushed through accessible pipes before placing an electromagnetic signal on the wire which is then traced from the surface. The maximum traceable depth is 10’ depending on the soil conditions and the maximum distance is 300’. The line can be pushed through a pipe with direct access such as a sewer line at a cleanout or a storm drain catch basin. We may not be able to push through deeper pipes within manholes and conduits will not be accessed by GPRS. The signal cannot be located through metallic pipes. For more information, please visit: Link
  • GPS. This handheld GPS unit offers accuracy down to 4 inches, however, the accuracy will depend on the satellite environment and obstructions and should not be considered to be survey-grade. Features can be collected as points, lines, or areas and then exported into Google Earth or overlaid on a CAD drawing. For more information, please visit: Link
  • Sewer Camera. The sewer camera has a 2” diameter, self-leveling camera head that provides high quality images in pipes up to 9” in diameter. There is also a 512 Hz sonde behind the camera that can be located from above ground and provide the approximate depth to the pipe for pipes up to 10’ deep. The locatable signal from the sonde will not pass through metal pipes or solid metal barriers except for cast iron. The camera and sonde are pushed through the pipe and access will need to be obtained through a cleanout or an open pipe within arm’s reach and can be pushed through for a maxium of 200’. Access to confined spaces such as manholes would need to be provided and facilitated by the client. Video and photos of the interior of the pipe can be provided but GPRS does not provide inspection services or make judgements regarding the integrity of the pipes. For more information, please visit: Link
  • 512 Hz Sonde. The sonde can be connected to the end of the traceable rodder and pushed through an accessible pipe. This sonde transmits a signal at a 512 Hz frequency that can pass through cast iron pipes or nonmetallic pipes and be detected at depths of up to 10’-15’ depending on the conditions. The signal can then be located from the surface using RD. For more information, please visit: Link
  • Magnetometer. The magnetometer detects the magnetic field of a ferromagnetic object. It responds to the difference in the magnetic field between two sensors. It is interpreted in the field by listening to changes in frequency as emitted by a speaker on the device. Larger metallic objects can be located at depths of up to 10’ or more but total depths will depend on the size, type, shape, and orientation of objects along with the amount of interference from other objects. For more information, please visit: Link
  • Electromagnetic Induction (EMI). EMI instruments contain two sets of coils that are located on opposite ends of the tool. One set of coils is used to transmit a primary magnetic field, which generates an electrical current into the ground. The induced current then generates a secondary magnetic field, which is sensed by the coils in the receiver end of the instrument. The EMI is moved over the surface without coming in contact with the surface so it is not affected by the terrain. However, EMI results are affected by surface features including vehicles, reinforced concrete, and buildings and will not be used in the vicinity of above-ground obstructions. Data is then displayed on a control unit indicating the conductivity of the earth or buried objects. The data is post-processed and displayed in a color-coded contour map which shows relative changes in conductivity. This contour map will be provided by GPRS for interpretation by the client. For more information, please visit: Link

Void Terms and Conditions

GPR technology cannot determine the depth to the bottom of the void. GPRS can mark the lateral extent and depth to the top of the void, but cannot provide depth to the bottom or volume calculations.

Cemetery Terms and Conditions

Customer understands that GPR works by identifying changes in physical properties such as density and conductivity. In cemetery/grave scanning, the actual bodies are very close in properties to the soil, and can be difficult to “see”. The best readings come from the air pocket (void) within an intact coffin, or sometimes from burial vaults or metallic objects which may be part of the coffin or burial. Older burials (before ~1940) can often be difficult to locate, most likely because the coffins have collapsed and the void is no longer present. GPR is a good tool for unmarked grave locating; however, it is not without its limitations. In general, our maximum depth penetration is 3-7’ deep, however, this depth is completely dependent on the composition of soils in the area being surveyed. Customer acknowledges that age, condition of the grave, soil and how it was buried will affect the ability to determine its existence. Given these factors, GPRS CANNOT guarantee it will be able to locate ALL unmarked/known graves on site.