Why Refreshers on Existing Utility Information Are Important
It’s a new year, and the new year often comes with refreshers to get you restarted back on track. When it comes to construction, one of the biggest refreshers that you can do is review your existing utility infrastructure. While you may feel that you’ll be good to start digging based on previous knowledge, you might want to consider reviewing what’s underneath your site.
Sometimes you’ll have an idea of where existing utility lines are based on previous projects at the site. This level of utility information is known as Quality Level D data, based around word of mouth or memory of a previous project. This information is somewhat unreliable in making accurate assumptions about a project site due to information being lost over time, but can be a great baseline for locating existing utilities. You may even have detailed plans listing marks of where utilities were surveyed at some point. Even with plans, refreshing your knowledge of utility locations is still important for a number of reasons.
First, the full extent of existing utility services may not be covered by existing plans. There are a number of reasons why something might not be marked on an existing sketch. If a locating technician lacks access to various areas of a site, it might prevent a full analysis of underground infrastructure as a result of limitations. Services such as 811 might only cover public utilities for their utility locating surveys, marking only what’s owned by public utility companies, not private ones. This might end up resulting in an incomplete record of utility information despite appearing to cover every known utility in the area. There’s also the potential for abandoned or unknown utilities and structures as well that may have been missed in previous surveys.
Second, there may be areas outside of the scope of work that weren’t covered by a previous project that are a concern with your current and future projects. Some utility lines may not be a concern depending on the limits of disturbance. If you’re building a fence around a building, you might not be as worried about hitting the utilities right against the building, and they might not be marked for a number of reasons.
Third, utilities are not static. They’re transporters of gas, water, electricity, and communications. They’re physical lines that wear down over time. Utility lines can shift under the surface through a variety of activities, including erosion, root movement, and human activity. Work is done on them often and they’re intertwined with other existing infrastructure, overlapping and intersecting in various ways. This can make some plans confusing, especially if they’re not thoroughly investigated.
Having a new utility survey done in and around the project site is the best way to remedy these issues. Electromagnetic locators (also known as EM locators) and ground penetrating radar (also known as GPR) are powerful tools in determining the horizontal locations of utility lines. A split box is useful in determining additional lines as well as metallic objects, such as underground storage tanks. Combined, these tools allow for a locator to make markings and map out the locations of utilities. These marks can also act as a good baseline for test holes, which can be excavated through the use of air or hydro vacuum excavation, determining exact depth, direction, and other properties of utility lines. This method of safe digging is especially useful in congested utility intersections where existing utility knowledge may be skewed.The best place to start on your construction goals in 2024 is by understanding what’s underneath, and our team at Trinity Subsurface can help. Visit our website to find out more about our services to help you determine utility locations and resolve potential utility conflicts!
