Cross Bore Mitigation

understand what's underneath trademark trinity subsurface
Evan Mowbray

Cross Bore Mitigation

Subsurface utilities are often in close proximity with one another. Utility congestion is the phenomenon of having several utilities within close proximity of each other. This congestion can occur in both big cities and wide open fields, as all of these services are required to maintain our regular ways of life. Even though utilities provide a great service to our communities and homes, occasionally they meet at crossroads and cause unintended problems. Oftentimes utilities pass through each other, intersecting the lines usually by complete accident, but occasionally on purpose with enough neglect of existing subsurface utility conditions.

A cross bore going through a pipe, captured from the inside of the pipe by a video pipe inspection crawler.

This is considered a cross bore. A cross bore is defined as a utility going into another utility, often caused by installing the second utility through trenchless methods. This situation occurs with sanitary and storm pipes primarily due to their general size compared to other utilities, which are installed through pipes via trenchless installation methods without careful consideration of the surrounding area. The second utility is often drilled through the pipe horizontally into the ground to travel to other areas, leading to intersections that wouldn’t be detected by looking at the flow of a pipe from the outside until there’s a problem, such as a blockage. A cross bore could be caused by unmarked or incorrectly mapped utilities during construction projects. These cross bores can be particularly dangerous, exposing the crossing utility to the elements. It also creates the potential for pipe blockages, creating an obstruction for built-up waste to prevent water from leaving the pipe. In the worst case scenarios, a cross bore could lead to more serious issues, such as gas leaks, if the new utility installation is damaged from inside the pipe. With all of this in mind, How do we find out about these issues and correct them?

An image of a Trinity Subsurface technician using an Envirosight remote control system to explore the inside of a pipe with a video pipe inspection crawler.

Cross bores can be discovered by thoroughly inspecting a pipe prior to any additional utility installations or removal. Often this starts by cleaning the pipe through jetting. Pressurized water is pushed through the pipe, making sure that there are no blockages to clearly see what is inside. Cleaning the pipe also helps mitigate the issue both by ensuring there is no blockage and making sure the crossing utility isn’t obscured. This process also allows for a video pipe inspection crawler to go through the pipe without any issues or potential to damage a cross bore. Sending the video pipe inspection crawler through the pipe allows identification of defects, blockages and, of course, cross bores. With a rotating camera to look around the pipe, a pipe crawler can make sure that a cross bore isn’t present from any angle within. CCTV video evidence and recorded data detailed in reports, this data allows the utility owner to understand the exact point and depth of the intersecting utility. Thankfully, our team at Trinity Subsurface offers a variety of services to inspect and clean pipes, as well as locating and exposing utilities through ground penetrating radar and vacuum excavation. Visit our website to find out more information regarding our pipe cleaning, inspecting, and repair services, and visit our blog to learn even more about how we understand what’s underneath your next big project.

Back to Blog