Subsurface Utility Engineering is a process that allows the owner to mitigate their risk prior to starting construction. This goal is reached by use of cutting-edge technology, but more importantly, diligence. The American Society of Civil Engineers (ASCE) has developed guidelines and established “quality levels” for subsurface utility verification. Since the advent of CADD, Robayna and Associates has prepared Quality Level D and C utility surveys, but only as of the late 20th century, has it become financially feasible to extend the services to what ASCE considers Quality Level B and A. Overall, the goal at each stage is to obtain a more clear picture of what is beneath our feet to minimize change orders and expedite final delivery of the project.
Quality Level D: Record Research and Analysis of Quality
At this level, all available records from utilities within or around the areas of work are collected. They are then analyzed with the goal of establishing a picture for the congestion of utilities within the area.
Quality Level C: Integration with Surveyed Above Ground Features
At this level of quality the goal is to increase the precision of the records obtained from the utility companies by comparing the Level D data with information collected from a design grade topographic surveys. As a result of this Level there may be further questions that need answering which may dictate a need for a greater level of quality.
Quality Level B: Marking Underground Utilities
By performing underground utility locates we can further clarify the locations of the utilities established in the Record Research during the Quality Level D analysis. Additionally, we may locate other utilities that may have not had records such as those on private properties. Once the markings are made they are collected through GPS and plotted in the design plans to add further precision to the design.
Quality Level A: Underground Locating – Excavating a Test Hole
In the previous quality levels, we have established a relatively accurate horizontal location for the utilities which may be in question; at this level, we are interested in pin point accuracy of a utility at a given location.