Trends Spring 2017 - Page 11

The Big Four: SUE Levels of Assurance Subsurface utility engineering (SUE) provides information and reliability defined by four quality levels: Quality Level D: This is the most basic level for utility locations generated solely from existing utility records or verbal recollections; both typically are unreliable sources. The data provides an overall "feel" for the congestion of utilities but is often highly limited in comprehensiveness and accuracy. This level is useful primarily for project planning and route selection. Quality Level C: This commonly used level of information involves surveying visible utility facilities (e.g., manholes, valve boxes, etc.) and correlating this information with existing utility records. Often this information determines that many underground utilities were omitted or erroneously plotted. Its usefulness is primarily for rural projects where utilities are scarce or not expensive to repair or relocate. Quality Level B: Surface geophysical methods such as electromagnetic locating or ground penetrating radar are used to “designate” the existence and horizontal position of all utilities. Information obtained is surveyed to project control. This level addresses problems caused by inaccurate utility records, abandoned or unrecorded facilities, and lost references. Information can be used for preliminary engineering such as locating storm drainage systems, footers, foundations, and other design features to avoid conflicts with existing utilities. Slight adjustments in design can produce substantial cost savings by eliminating utility relocations. Quality Level A: This highest level, known as "locating," is the highest level of accuracy available. It involves the full use of SUE services, providing information for the precise plan and profile mapping of underground utilities through the nondestructive exposure of underground utilities through vacuum excavation. This level provides the type, size, condition, material, and other characteristics of underground features. Source: Federal Highway Administration Colors are Key for Awareness The next time you walk on a sidewalk or near a construction zone, you may notice spray paint on the ground. Ever wonder what the colors, codes, and numbers mean? SUE technicians and surveyors use a color-coding system to mark underground utilities in accordance with the American Public Works Association Uniform Color Code: White Proposed excavation Pink Temporary survey markings Red Electric power lines, cables, conduits, and lighting cables Yellow Gas, oil, steam, petroleum, or gaseous materials Orange Communications, cable TV, alarm or signal lines, cables or conduits Blue Potable water Purple Reclaimed water, irrigation, and slurry lines Green Sewers, drainage facilities, or other drain lines Source: American Public Works Association AyresAssociates.com │11