The number one risk to construction crews in the field are related to excavating and drilling around underground utilities. Not only do they pose a major safety risk, but damages to underground utilities can be one of the most expensive unplanned costs associated with your project.
Anyone breaking ground is required by law to notify Call 811 in advance of the excavation. Call 811 will notify Public Utility Companies that are known to have underground utilities in the area to mark-out the facilities that they own. The problem is that only 68% of the underground utilities are owned by a public utility company, leaving the remaining 32% will not be marked out and will be at risk of damage. The percentage of unmarked utilities dramatically increases when working on private property or private campuses like hospitals, universities, and industrial facilities.
Trinity Subsurface Engineering closes that gap by providing underground utility locating services using surface geophysical equipment including electromagnetic equipment and ground penetrating radar. We will confirm the utility markings provided by Call 811, and we’ll mark out every other locatable utility we can find within your project limits.
Using a variety of surface geophysical equipment, we can locate multiple utility types at a depth range between 0-15′ below the surface. The depth at which a utility can be detected is dependent on a combination of the size and material composition of the utility, the depth of the utility, the conductivity of the utility, and the material composition of the back-fill and earth materials surrounding the utility.
Electromagnetic equipment is effective at locating metallic utilities such as metallic water pipes, electric cables, telephone cables, and metallic gas pipes etc. to a depth of up to 15 feet. Electromagnetic utility locating equipment works by transmitting a radio frequency through a conductive portion of an underground utility system. The frequency can be directly applied with an active connection, or induced into the utility through electromagnetic induction.
Ground Penetrating Radar is used to aid in the confirmation of electromagnetic targets, and to designate the location of utilities and structures that were not detected using electromagnetic techniques. GPR has the capacity to locate any target whose material composition has different dielectric and conductive properties as the surrounding earth materials. Utilities with similar characteristics as the soil are difficult to locate with GPR, such as clay pipe buried in primarily clay soils.
In addition to a superior utility mark-out using paint and flags, we provide our clients with all of the documentation you need to procure any necessary work or excavation permits you need to proceed.
We’ll include a field report documenting out survey dates, utilities designated, equipment utilized, site contacts made, and any limitations or unusual field conditions encountered while performing the work.
We’ll also draft a field sketch depicting the underground utilities we found or verified. Our field sketch will be formatted on our 11″x17″ sketch template using a Google Satellite image of the work area as our canvas. Have a construction drawing you need updated instead? We can add our field sketch to any client provided PDF document.