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Subsurface Utility Engineering (SUE) is 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. [This definition is contained in: Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data, CI/ASCE 38-02, American Society of Civil Engineers, 2002.]
Major SUE activities are:
Scope of Work
The process of developing a written project-specific work plan package that consists of scope of work, levels of service vs. risk allocation, project schedule and desired project delivery method. The SUE work plan package is agreed upon by the SUE provider and the client, describing the SUE work to be performed.
The process of using a surface geophysical method or methods to interpret the presence of a subsurface utility and mark its approximate horizontal position on the ground surface or on above-ground surface markers.
The process of exposing and recording the precise vertical and horizontal location and providing utility size and configuration of a utility.
The process of surveying, designating and locating information to project control and transferring it into the client’s CADD system, GIS files, or project plans.
The engineering process of using a conflict matrix to evaluate and compare depicted designating information with proposed plans (highway, bridge, drainage, and other) in order to inform all stakeholders of potential conflicts, potential resolutions and costs to cure.
SUE generally works as follows:
The project owner assumes responsibility for taking appropriate actions to consider and deal with utility risks. On small projects where few utilities are present, this may only involve making a conscious decision to proceed with the project using readily available information. On larger, more complex projects, the services of an engineer may be employed to provide expert advice and to use available technologies to provide better information.
The engineer, when involved, will advise the project owner of utility risks and recommend an appropriate quality level of utility data for a given project area at the appropriate time within the project planning and design process.
The project owner will then specify to the engineer the desired quality level of utility data. The engineer will apply the desired utility quality level to the project owner in accordance with the standard of care and will be responsible for negligent errors and/or omissions in the utility data for the certified utility quality level.
SUE provides many benefits. Proper use of this cost-effective professional engineering service will eliminate many of the utility problems typically encountered on projects, including:
• Delays to projects caused by waiting for utility relocation work to be completed so construction can begin;
• Delays to projects caused by redesign when construction cannot follow the original design due to unexpected utility conflicts;
• Delays to contractors during construction caused by cutting, damaging, or discovering utility lines that were not known to be there;
• Claims by contractors for delays resulting from unexpected encounters with utilities; and
• Deaths, injuries, property damage, and releases of product into the environment caused by cutting utility lines that were not known to be there.
The American Society of Civil Engineers (ASCE) has developed an important standard of care guideline, Standard Guideline for the Collection and Depiction of Existing Subsurface Utility Data, CI/ASCE 38-02. This standard guideline describes four quality levels of utility depiction:
Quality Level D
Information derived from existing records or oral recollections.
Quality Level C
Information obtained by surveying and plotting visible above-ground utility features and by using professional judgement in correlating this information to Quality Level D.
Quality Level B
Information obtained through the application of appropriate surface geophysical techniques to determine the existence and approximate horizontal position of subsurface utilities.
Quality Level A
Information obtained by exposing and measuring the precise horizontal and vertical position of a utility at a specific point.
Both these standards have different purposes and actually complement each other.
Generally speaking, ASCE 38-02 sets out guidelines for how to qualify the accuracy of mapping existing infrastructure and relay that information to a drawing. ASCE goes into the SUE process and roles and responsibilities of the SUE professional and the owner. It’s more prescriptive.
CSA S250 sets out requirements for classifying the accuracy of newly installed or exposed infrastructure. The CSA S250 accuracy levels are an expansion of the ASCE 38-02 Quality Level A, providing provide a finer level of detail to define the positional location of the infrastructure which translates into a better defined reliability in the accuracy of the record.
Copies of ASCE Standard 38-02 can be obtained from the ASCE Bookstore or by calling 1-800-548-2723.
Firms providing SUE services shall be licensed with the provincial engineering body for the provision of engineering services
(i.e. PEO, APEGGA)
It is recommended that project owners consider the following, not necessarily all-inclusive, criteria when selecting a SUE provider. Providers of SUE services should be able to:
• Demonstrate a thorough knowledge and understanding of designating, locating, and data management activities,
• Provide designating and locating services to the extent desired by the contracting agency,
• Survey SUE data acquired during the designating and locating phases to project control and transfer it into the contracting agency's CADD system, GIS files, or project plans.
• Individuals assigned by the SUE provider to carry out the work should be well trained, experienced, and capable.
• Individuals in charge of the work are responsible for certifying deliverables and should be engineers employed by the SUE provider in accordance with provincial professional registration requirements.
• The project manager should have previously been involved in the management of one or more SUE contracts and must be available to commit sufficient time to the project.
Other team members should have previously been involved in SUE designating, locating, surveying, and/or mapping activities.
Resources of the provider should be adequate to carry out the SUE work in a timely manner, considering other possible commitments of work and the contracting agency's anticipated needs, including a possible need for work on several projects to take place simultaneously.
A wide range of equipment is necessary to detect the variety of underground utilities that may be present. Equipment available for utilization by the provider should include, but not be limited to, the following:
• ELF, VLF, LF electromagnetics, magnetometers, terrain conductivity meters, resonant sonics, and other geophysical designating equipment,
• Vacuum excavation or comparable nondestructive locating equipment,
• State-of-the-art surveying and data recording equipment, Software systems compatible with the contracting agency's CADD system.
Providers of SUE should have:
The financial capacity to provide the required services,
Measures of protection for the contracting agency against errors and omissions of data collection, interpretation, and management.
Providers of SUE services should be able to provide:
Vertical data accurate to within ± 15 mm (0.05 ft),
Horizontal data accurate to applicable survey standards.
Providers of SUE services should:
carry adequate insurance covering all aspects of the work. Minimum amounts should be in accordance with the contracting agency's requirements.
Damage prevention and safe excavation only
Sketches and paint on ground
Limited to marking individual members utilities
Assist with engineering and design
During the engineering stage of the project
Stamped drawing, field data and technical report
Comprehensive mapping of all underground utilities
dedicated to exceeding our customers' expectation on every project
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