Not All Private Utility Locating Projects Are Created Equal
If you’re in the construction industry or have hired a construction contractor (whether residential, commercial, industrial, government, etc.), there’s a good chance you know of or have heard of utility locating services. In the current utility locating climate, significant advances have been made in cost and capabilities with the continued development and use of Ground Penetrating Radar (“GPR”).
Everyday, GPR is used as a means to provide safe excavation and project planning in order to avoid costly damages. This blog focuses on the uniqueness of projects and compatible services we address on a daily basis. For example, understanding that identifying utility adjacent to a hospital versus a furniture store is not as straightforward as one might think.
Outside of utility congestion surrounding each of these examples, the real challenge becomes the ever-changing variables based on the following factors:
Utility Type – Gas and electrical lines emit a different signal and at varying frequencies. Since differing utilities may be installed near one another, and of similar materials, it increases the chance of “Signal Bleeding” resulting in inaccurate indications.
Materials Installed - Materials often change based on the year of installation, intended purpose, and even the County where the project is located. PLA and Polymer vs Gasketed or Hot Tapping Cast Iron, creates multiple variables when locating that can change the entire approach to verifying the type of utility line.
Termination Points – Splits, splices, gaskets, welds, wire nuts, pull boxes and vaults can all contribute to signal bleed. Each termination point creates an opportunity for the electromagnetic signal to disperse. In a short distance this effect is often minimal, but, for example, a 1,000’ + distance these termination points can drastically affect accuracy and require additional access points to continue the locating process.
Access Points – Transmission lines may not have many access points as their pathway is usually from point A to point. However, primary service lines have multiple splits feeding A – B – C – D within the surrounding area. Moreover, there may be separate third-party regulations when locating transmission lines which can increase the time and involvement of that particular utility and the overall project progress.
Soil & Cover Conditions – Extremely wet or compacted soil types can change the way a signal is carried, how far it is carried and how accuracy is maintained over longer distances. Cover such as Asphalt often undergoes multiple changes throughout the year; repaves or extreme degradation. While cover is primarily an obstacle for GPR and not EM locating, it must still be taken into consideration when performing a locating project.
Lastly, variables such as foot and vehicle traffic may play a large role in the progress of a private utility locating project. It’s important to note, that critical access points can be in areas outside the scope of where neither the locator nor the contractor control. It is common to find vaults, valves, or transformers in neighboring business parking lots or even on main public roadways. This expands the scope of work for the locator while adding potential delays for conditions unknown prior to commencing a location project; even when a job walk is performed.
Understanding these examples and the challenges they present, helps manage expectations for clients in project progress and timeline. It also aids in a general understanding of the costs of services. While reviewing a request for proposals, locating companies account for these variables while still trying to stay competitive without sacrificing quality or safety. Submitting valuable information, such as as-built drawings, and minimizing the variables set forth above when obtaining a bid helps to increase safety and reduce costs.
For more information visit www.AxisDetects.com or contact us directly to discuss your project and find out how we can keep your project moving forward.