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CI/ASCE 38-02 Subsurface Utility Engineering (Quality Levels A-D)

Subsurface Utility Engineering is more than just locating underground utilities for construction activities. Subsurface Utility Engineering (SUE) is typically performed during the design phase of a construction project, and it is proven to solve conflicts with underground utilities before the construction phase even begins.

CI/ASCE 38-02 Quality Levels

Subsurface Utility Engineering is the practice of identifying underground utilities and structures on engineered construction drawings for design purposes. The data that is recorded on the drawings can have 1 of 4 different quality levels, which describes how accurate or reliable the information is.

Quality Level D

Quality Level D data is the least accurate and reliable data. This data is typically derived only from existing records or oral recollections. There is often no field investigating or evidence to support the data.

Quality Level C

Quality Level C data is slightly more accurate than QL-D data because it involves surveying and plotting visible utility surface features, such as manholes, fire hydrants, transformers, etc. and correlating this data with information obtained from Quality Level D sources like utility records.

Quality Level B

Quality Level B data is much more accurate and reliable utility data than Quality Level C because it involves the use of surface geophysical equipment to detect and designate the location of underground utilities. The location of the underground utilities and structures are then surveyed and plotted.

Quality Level A

Quality Level A data is the most accurate and reliable information because the data is derived from physically exposing and measuring the underground utility. The data collected from exposing, or “day lighting” a utility can include the utilities exact depth from grade, elevation, size, heading / orientation, material composition, and general condition. 

What Quality Level Should I Use?

The Quality Level of data you may need for your project can certainly vary depending on the type of project and what the information is needed for. Engineering of a new building or addition, or installation of gravity piping will likely require a minimum of Quality Level B data, with a few areas of Quality Level A data at key locations. If you are interested in creating a map of your existing conditions, Quality Level C data may be more cost effective, but less accurate.

If you are not sure what quality level is best for your engineering project, call us at (888) 232-5959 and we’d be happy to answer any questions you have.

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