Page 14 - New Mexico 811 Magazine 2022 Issue 3
P. 14

Subsurface Utility Engineering vs. Locating What’s the Difference
In 1998, the Federal Highway Administration (FHWA) made it clear to the National Transportation Safety Board
(NTSB) that Subsurface Utility Engineering should be used during the development of highway projects and one-call notification centers and/or utility companies should be notified to mark the ground indicating the location of the underground utilities prior to any excavation. This is a concept we firmly believe in – Subsurface Utility Engineering is for design, as one- call/utility notification and markings (locating) are for construction.
The following explains the difference, including when it is appropriate to use which process, between Subsurface Utility Engineering and locating.
Q. What is locating?
A. Locating determines the approximate horizontal location of an underground utility line that may exist within a pre-specified area.
12 • New Mexico 811 2022, Issue 3
Q. What is Subsurface Utility Engineering?
A. Subsurface Utility Engineering (SUE) is a highly efficient, nondestructive engineering process that incorporates civil engineering, surface geophysics, surveying and mapping, noninvasive vacuum excavation and asset management technologies to identify and classify quality levels of existing data and maps the locations of underground utilities.
Q. When is locating appropriate?
A. According to the FHWA, locating is sufficient for marking utility facilities immediately prior to excavation or construction.
Q. When is SUE appropriate?
A. SUE is also appropriate in identifying the location of underground utilities prior to construction. SUE
is even more appropriate, however, when used during the design phase
of a construction project, and, in fact, the FHWA has stated that SUE should be used for design purposes. The information SUE provides contributes
to informed design decisions. If SUE data reveals the existence of a utility conflict, those involved in the project find out before any damage is done and can work to develop viable design or utility relocation alternatives to resolve the conflict.
Q. Do locators and Subsurface Utility Engineering providers use the same equipment to locate underground utilities?
A. Not necessarily. Locators generally use a pipe-and-cable device and detect one utility. SUE providers use various geophysical prospecting technologies – such as Pipe-and-Cable Locators, Electromagnetic Imaging (EMI), Acoustical, Pulse, Ground Penetrating Radar (GPR), Three Dimensional Radar Tomography, etc. – to image and detect as many utilities as possible at the site.
Locators, hired by a utility company, typically only provide information
on that one utility and visit many
sites during the day. Performing SUE investigations take much longer because
Vacuum excavation is used to locate the exact horizontal and vertical location of buried utilities.


































































































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