About Underground Utility Surveys
Underground Utility Surveying involves the systematic mapping of subsurface utilities through the application of Ground Penetrating Radar (GPR), radio-detection, and various geophysical methods, integrated with land surveying techniques to produce a comprehensive three-dimensional drawing, report or site markup of the subsurface.
Ground Penetrating Radar
GPR works by directing pulses of electromagnetic energy into the ground from a transmitting antenna. The energy travels though the ground where buried objects reflect the energy back to the surface which is received by the GPR’s receiving antenna. These returning signals can be interpreted on site or post-processed using specialist software to determine the depth and location of utilities below the ground.
Radio-detection
Radio-detection uses the principle of electromagnetism to detect underground services. This method can be used to locate electrical, telecom and other cables by traversing the object area in a grid pattern or by inducing a current onto the service.
Chamber Inspections
Chamber inspections involve opening and inspecting relevant manhole/ inspection chambers within the survey area to measure and record pipe/ duct positions and depths.
Post-Processing
For best results GPR data is post-processed using specialist software.
PAS: 128 - Specification for Underground Utility Detection, Verification and Location
PAS:128 is a BSI standard and is the most widely adopted standard for subsurface mapping in Ireland and the UK. We apply PAS:128 to all our underground utility surveys to ensure consistency and reliability across our projects.
PAS:128 Survey Type A - Verification
Utilities are surveyed using direct measurement techniques at locations where utilities are exposed, at inspection chambers or by exposing utilities using excavation techniques.
PAS:128 Survey Type B – Detection (most popular)
This is the most commonly used PAS:128 category. Utilities are detected, traced and mapped using one or more geophysical techniques.
PAS:128 Survey Type C (reconnaissance)
Site reconnaissance survey to validate available utility records and to assess if there are any conflicts that need to be resolved.
PAS:128 Survey Type D (desktop utility records search)
Underground Utility records plotted to drawing utilising record data which is gathered from utility providers and owners.
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