66” Hot Tapping Procedure. Photo: LAN
108” x 84” Interconnect. Photo: LAN
stone moments requires filming from specific angles and can bring the UAV into close proximity of construction equipment. That proximity poses several obvious hazards to a UAV, including collision risks with heavy equipment or surrounding trees and powerlines. Thankfully, the bulk of the footage captured by a drone, including capturing pre- and post-construction footage and tracking construction progress, can be achieved from relative safety high above a site. Even at altitude, there are hazards that still pose a risk to UAVs: airspace restrictions such as those surrounding Bush Intercontinental Airport or over downtown during major sporting events, electromagnetic interference from high- voltage transmission lines, thermal updrafts in major industrial areas, and even attacks by territorial hawks. To mitigate risks, the drone pilot needs to plan and be ready to take swift action. All of these hazards and more can come into play in dense urban envi- ronments, such as the 72-inch waterline through Houston’s downtown area. Capturing footage of the construction progress there requires more than just careful navigation around structures. The pilot must also frequently reposition to ensure a strong signal to the drone and remain vigilant and avoid non-participants in the surrounding area. Conclusion Water and wastewater utilities around the country are increasingly looking at better ways to monitor their construction projects. The advantages that UAVs offer such as capturing activities over vast distances, saving time and money, and communicating intricate techni- cal processes make them an ideal solution. With drone technologies becoming more advanced every year, their potential applications for the utility industry are numerous.
Milestones In addition to monitoring the overall progress of the project, UAVs are also an ideal vehicle for recording technical procedures. Major con- struction activities, such as hot tapping large-diameter water lines or installing interconnects, are difficult to show from the ground. For example, during the summer of 2019, a drone was used to capture the entire hot tapping procedure of a live 66-inch water line. From the ground, the line of sight is interrupted by support beams, trench boxes and various other equipment, obstructing views of the operation. Capturing the entire process from the ground would have required filming and switching from multiple angles. On the other hand, once the drone was positioned above the site, it allowed a clear view of the entire process. This summer, an 84-inch gate valve was installed at an interconnection between the new 108-inch waterline and an existing 84-inch waterline. An enormous, 35-ton valve was delivered to site on the back of an 18-wheeler, as crews waited anxiously and crowded around the steel- shored shaft where it was to be installed by a sky-high crane. Hovering in position, the drone watched and recorded as the valve was carefully lifted from the truck, slowly swung around to the shaft, and, ever so delicately, lowered into position between the pipe pieces. Such an intri- cate procedure required complete precision and concentration until the valve was securely bolted in place. The drone captured the procedure from a unique perspective, allowing a view of the entire area as well as down into the shaft. It was imperative to document these big milestones during the construction of Houston’s largest waterline. Drones can reposition around during these procedures, moving seamlessly from one per- spective to another without getting in the way or putting a cameraman in jeopardy. Footage like this has become an efficient mechanism for communicating technical construction operations and is beneficial for staff/crew training. Challenges These benefits give drones a clear edge over filming from the ground, but they are not invulnerable. The drone pilot must carefully navigate the environment around the construction project. Documenting mile-
NATASHA F. LOMBARD, E.I.T, AND WILLIAM W. BYLAND, E.I.T are engineers at Lockwood, Andrews & Newnam, Inc. (LAN), a national planning, engineering, and program management firm. They can be reached at nflombard@lan-inc.com and wwbyland@lan-inc.com, respectively.
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