Subsurface Utility Engineering 101

Apr 21, 2016

 
Trisha D. Frederick, P.E., MBA, LEEP AP
Utility Engineer

Need to learn more about Subsurface Utility Engineering, commonly referred to as SUE?

Imagine this. You are the project manager for a roadway project. It was advertised to the public that the roadway would be done in January, and it is now June. Six months behind schedule and the project is not complete. Home and business owners are upset because of the backed up traffic, and everyone is looking to you for an answer.


The reality is that someone on your project team failed to find all the utilities present within the project limits. As a result, you found a utility during construction and your project is now months behind schedule because the private utility owner is not able to move their utility overnight. What would you say to your newfound friends of the public? How do you explain the extra costs to your client? Better yet, what can you do to make sure this does not happen to you?!


Well, in order to protect yourself from getting in this position, I suggest that you invest in a proper SUE program for your project. SUE is the acronym for Subsurface Utility Engineering. It describes the engineering process for identifying, locating, relocating and/or adjusting utilities…especially those utilities that you suspect could be in conflict with your proposed construction plans.


The origin of SUE stems from:

  • Inability to obtain reliable underground utility information
  • Poor records maintenance by facilities
  • Addressing certain risk and safety concerns of traditional approaches
  • Expansion, modernization, and changing utility technology
  • The ultimate goal of SUE is to maximize opportunities for successful project completion while improving job site safety and minimizing risk.

Honestly, performing SUE could be the most tedious, time-consuming, unpredictable task listed on your Gantt chart…at the same time it could be the most cost-saving, risk-averse method for ensuring that your project is safe, on schedule, and within budget!


The official definition for SUE could be found under ASCE 38-02, and is as follows: “A branch of engineering practice that involves managing certain risks associated with utility mapping at appropriate quality levels, utility coordination, utility relocation design and coordination, utility condition assessment, communication of utility data to concerned parties, utility relocation cost estimates, implementation of utility accommodation policies, and utility design”


There are four levels of SUE. They are referred to as “Quality Levels” and range from Quality Level D (basic level) to Quality Level A (most accurate level). It is not required that all levels be performed on every utility; the Quality Level performed will vary based on the requirements of the project.


So the descriptions for the four Quality Levels of SUE are…


QUALITY LEVEL D - The most basic level where utility locations are identified only by utility records or verbal recollection. The level is primarily useful for project planning activities.


QUALITY LEVEL C - Involves surveying visible above ground utility facilities and correlating that information with existing utility records.


QUALITY LEVEL B - Involves the application of surface geophysical methods to determine the existence and horizontal position of virtually all subsurface utilities within a project’s limits. Non-destructive technology including Ground Penetrating Radar and Electromagnetic (EM) tools are often leveraged at this stage to accurately detect even non-conductive underground assets including PVC pipe, sewers and assets containing broken tracer wires. Level B information is correlated with Level C & D to provide a comprehensive subsurface utility dataset that includes abandoned lines and other discrepancies, while confirming the accuracy of record data.


QUALITY LEVEL A - the highest level of accuracy presently available. It provides information on the precise vertical and horizontal positions of underground utilities along with the type, size, condition, material and other characteristics of the assets. This is usually accomplished through hydro-vacuuming or hand digging in a select area.


Always remember that the key to conducting an outstanding SUE operation is to start the process as early as possible, preferably during the planning phases of the project. The earlier your project team is able to identify and relocate utilities the better!


Interested in learning more about the key steps to a successful SUE program? Well stay tuned for my follow-up article!



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