SUE uses a series of four quality levels (QLs): QL-D involves gathering record data, which may include digital records, paper records, internet searches or site inspection. QL-C entails surveying visible above-ground utility features, such as manholes, valve boxes, utility marker posts and more and this information is then correlated with existing utility records.
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QL-B determines the existence and horizontal position of underground utilities using surface geophysical techniques. This level also includes obtaining two-dimensional mapping information, which aids in decision-making for design, utility relocations and installations. QL-A is the highest and most effective SUE level currently available. Non-destructive digging equipment is used to determine precise horizontal and vertical positions of underground utilities. When surveyed and mapped, precise plan and profile information is available for design decisions and justification. QLs are used to convey the level of confidence and the methods employed to determine a utility’s position. Once the QL has been determined, the SUE work has been performed and a computer-aided design (CAD) file has been created depicting the best-known position of the utilities, a conflict matrix is produced. This is created to determine if utility relocation is needed for the project to be successful. Identifying the risks and potential conflicts before a project starts is vital to the planning and design phases of any project.
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