utility mapping

SUE Is More Than Utility Mapping

With the right tools, subsurface utility engineering is change order and risk mitigation

Subsurface utility engineering (SUE) has come a long way since it was first introduced in the early 2000s. The adoption of this practice has set a high. but attainable. bar for the collection and depiction of existing utilities.

The utility locating and utility engineering sector has been an industry in growth mode — even during the recessions — since I joined it in the late 1990s. Infrastructure investment maintained the locating industry’s strength and, since the mid-2000s, subsurface utility engineering (SUE) has added to the growth.

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Looking at the late 1990s and early 2000s, the gap between existing infrastructure and the infrastructure required to maintain our modern world started showing. This gap and the required renewal to maintain our modern high standards has created a phenomenon of infrastructure “not living up to our current needs.” It has come to light with several instances of utility failures, infrastructure breakdowns and sometimes, even harm to life and limb.

Evolution of Data Handling in Utility Mapping

To maintain our current level of modern infrastructure at the high standards that we have grown accustomed to, we must come up with new and innovative ways to maintain, renew and expand our modern utility network.

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Throughout my tenure, I’ve been lucky to see a technological revolution and further heavy reliance on digital data in this industry. At the beginning of my career, utility locates were done through a hand drawn ticket process and utility engineering information was conveyed through hand drawn sketching. The result was a physical handoff of the information when it came to one call tickets or private locates. Reports were handwritten and it was the beginnings of CAD transposed from hand drawn field sketches of utility engineering investigations.

This information was hard to manage, and the quality, storage, transmission and conveyance of detailed and accurate information was poor. The transition from paper-based sketching to automated and computer sketching of data in the early 2000s was a great step forward but also unfortunately, a misrepresentation of the accuracy of the data.

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Utility locate data in one call scenarios, private locate scenarios and utility engineering investigations was being transformed into digital form, with the schematic representation of utilities depicted, rather than the spatial accuracy.

This form of depiction of utility infrastructure data remained in place until around 2007 with the extensive market penetration of accurate data collection with a GPS. Previously, this equipment was commonly used by surveyors but here, was heavily adopted by the utility engineering industry. Thus began the need and adoption of a professional surveyor during utility engineering investigations.

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Subsurface Utility Engineering as a Standard

One of the early goals of those involved with the sector was to achieve a common standard that could be followed, regardless of state and provincial boundaries. The initial steps were taken by the American Society of Civil Engineers (ASCE) and Construction Institute (CI), by creating CI/ASCE 38-02 as the basis for where the industry is today. Further steps were made with the publication of the CSA S250-11 Standard in Canada, in 2011.

Every jurisdiction may have its own formatting CAD layers, but the depicted information should be uniform throughout North America. By having quality levels from CI/ASCE 38-22, each underground utility is placed with its associated quality level from D to A.

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Having this common system enables engineers throughout North America to plan and execute a project, based upon the highest quality of information and mitigating the risk derived from using the unreliable methods of the past.

As defined in CI/ASCE 38-22, SUE is a discipline of engineering dealing with managing certain risks associated with utility mapping, at appropriate quality levels. SUE is not to be confused with just a locate function, which unfortunately, many firms and jurisdictions mistakenly reduce the practice as.
It should also not be forgotten that SUE is more than just mapping at appropriate quality levels. It is engineering review and the due diligence of the Utility Engineer signing and sealing the SUE report and drawing.

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A Comprehensive Utility Engineering Approach

A truly diverse SUE firm should hold all disciplines involved in the process: accurate record collection, designating, locating, utility coordination, relocation design and more. SUE can act as the complete package when used in conjunction with the Transportation Association of Canada (TAC) Guideline for the Coordination of Utility Relocation and the P3 version of taking a project through inception, planning, preliminary design, detailed design, early works, final design, construction, and project completion.

Although rooted in engineering, the SUE firm needs all types of professionals including engineers (with conventional open cut and trenchless experience), technologists, CAD operators, project managers, SUE field technicians and support staff.

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A great sample of a project involving multiple aspects of SUE is the use and deployment of all the geophysical tools available on a day-to-day basis, rather than one-offs for a specific site.

I’ve seen many firms try to define what geophysical tools to use and apply to their best practices or their standard operating procedures. I have found that the use of both the electromagnetic induction (EM) locating and ground penetrating radar (GPR) as a standard practice works to provide maximum coverage of geophysical data, with discovery of conductive and nonconductive utilities within the area of work.

GeoScan SUE Project

Tools and Best Practices in SUE

With SUE, I have seen that the most common practice is to designate all the utilities possible through hook up and trace with a standard EM locate set, then do a box or circle sweep with a single or multi frequency transmitter and receiver system. Adding the use of a GPR system as standard operating procedure provides the ability to designate conductive and nonconductive utilities. Yes, the technology is not ideal for all soil conditions. However, you can find additional information by looking for trenches and other anomalies that could greatly affect the condition of planning and design.

By adding all the available tools to your utility engineering toolbox and adding them to your standard operating procedures, you can achieve best practice in your designation and information gathering process. You can also greatly increase your risk mitigation while reducing the need for change orders, utility relocations or accommodation in your design and project management related to utility designation operations.

Ophir Wainer is the vice president of market expansion and education at GeoScan Subsurface Surveys.

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