The Future of SUE Includes Deep Locating

December 6, 2017

Knowing where utility lines are located is critical. No owner wants to encounter a surprise during construction, which could ultimately delay a project and increase costs dramatically. Safety is a primary concern as well, especially when encountering natural gas or petroleum pipelines.

According to the Pipeline and Hazardous Materials Safety Administration (PHMSA), which is a U.S. Department of Transportation agency, America’s pipeline transportation system now runs for more than 2.6 million miles. Increased pipeline safety regulations issued by the PHMSA in 2017 have brought forth a heightened awareness to be in compliance and improve safety.

That includes proper mapping and having accurate records. Not all of those pipelines exist on as-built records, and many are not depicted accurately.

Locating deep utilities brings an added degree of difficulty. Standard locating equipment is typically only effective up to depths of 10 or 15 feet, depending on factors such as the utility’s material composition, soil conductivity and the overall depth of the utility.

However, a combination of new technology and techniques is now allowing subsurface utility engineers to designate a utility more than 40 feet underground, as Halff Associates did recently for an oil and gas client. Halff developed the High Dynamic Deep Locating (HDDL) system that has accurately detected 12-inch steel and 4-inch steel pipelines when standard designating techniques proved ineffective.

Spar unit

A pipeline alignment is established at a pad site.

Halff HDDL Advantages

Consider some of the benefits of this new process.

Efficient and cost-effective: Typically, there will be a series of mobilizations for a utility project such as this. The first would involve a SUE crew arriving at the location and designating the utility. A survey crew would then come out to gather data and record measurements of the utility. HDDL allows for equipment to perform the markings and survey concurrently, cutting that time and effort in half. In essence, a vertical and horizontal profile of the utility—at any interval requested—can be created in real time because of the two services being performed in tandem.

HDDL Graph

The image above shows the variance between Halff HDDL designations (in purple) and a bore profile (in red). The green line is the existing ground.

Test hole reduction: The early, proven success of this process has made performing expensive test holes either unnecessary or reduced the need for them significantly. Many deep test-hole efforts result in hitting a thick rock layer that can’t be penetrated or exceeding the capabilities of most vacuum excavation trucks. The rock and depths of more than 40 feet are not a hindrance for Halff’s HDDL system, which is being conducted in coordination with existing equipment.

No weather delays: This utility-locating effort is also not weather dependent. Halff marked the entire corridor of a 12-inch, 44-foot-deep line in pouring rain.

Convenient post-processing: Another benefit of the HDDL system is the creation of quicker, more efficient post-processing products. Once data and coordinates are downloaded, they can be placed into a 3D map or used to create a digital terrain model (DTM) that shows a graphic representation of the location’s surface. The pipeline can be shown within a cross section, modeled in 3D, or simply placed over an aerial photograph.


A utility is shown over an aerial photograph.

When a pipeline company acquires new assets, it is not unusual for there to be a lack of accurate as-built records. The HDDL system allows subsurface utility engineers to develop vertical and horizontal profiles for deep utilities efficiently. This information allows clients to accurately know the location and depth of their facilities. This data then can be used for record documentation and construction verification purposes.

The HDDL system has already proven itself, showing accurate and dependable utility designating in solid rock, where previous efforts to designate or perform test holes were unsuccessful. It’s an effective process that cuts costs, manages risk, and prevents untimely delays.

Would you like to know more about Halff’s High Dynamic Deep Locating system? Write to