Flying high with a point of view and supplying invaluable information for construction.
Unmanned autonomous aerial vehicles, better known as drones, are proving to be a common and almost required tool at job sites.
Drones are being used for tasks ranging from speeding up data collection and reducing reliance on helicopters and planes, to performing up-close thermal inspections, identifying structural defects and cracks, conducting site surveys, volumetric stockpile calculations, live-streamed walkthroughs and more. Drones are well-suited for quickly modeling buildings and large areas. Using drones for photogrammetry can enable faster and more frequent modeling at a lower cost than traditional mapping methods.
“The benefits of using drones on construction projects are plentiful: better progress tracking, coordination, sequencing, safety and more,” says Dmitry Korolev, CEO, TraceAir Technologies, Redwood City, Calif. “Our users report that drones save them hours of time each week on tasks like billing verification, surveying, traveling between job sites and conducting visual site inspections. Furthermore, having a visual record of the project can pay dividends if there’s a financial, legal or environmental dispute.”
Bird’s Eye View
“Using drones for such tasks helps improve job-site safety, decreasing the frequency and severity of on-site incidents associated with hazardous tasks such as inspections at dangerous heights or exploration of spaces with harmful materials, temperatures or gasses,” says Rodney Murray, professional services training and consultant for Skyward, a Verizon company, St. Charles, Ill. “This also helps save construction companies significant workers’ compensation costs.”
Andrew Wolfe, pilot in command (PIC) at Drone Brothers, Troy, Mich., agrees that drones keep employees safe. “[They] look for safety issues on the job site. Are the workers wearing their safety helmets and vests? Are safety barriers set up correctly? Is the site maintained and kept clean and organized? No more climbing on stockpiles or a slippery ladder trying to get a look at the roof.”
At Jacobsen Construction in Salt Lake City, corporate communications manager Ben Lockhart says drones are being used on many projects. “Primarily, we are mapping a project site to use for site logistics planning as well as documenting progress. We also thrill our clients with 360-degree panoramas taken with a drone that immerses the viewer into the project site. Project members and owners really appreciate the updates from these images when they are working remotely, especially during the COVID-19 pandemic.”
Austin, Texas-based Green Knight Metal Roofing uses drone photography or video to assess the scope of their work or the current needs of a potential project. The company finds this very helpful for assessing projects that may be difficult to access otherwise. For example, a three-story commercial project, such as an apartment building. “We will also occasionally use drone photos and video to help homeowners assess their roofs in order to aid in insurance claims,” says Green Knight’s partner-business development Joel Kenty. “However, the more common use of drones in our business is to take marketing photos of completed projects.
Occasionally, we will take before and after photos, trying to take them from the same vantage point. We will also take video of the completed projects and edit them together to make short marketing videos. We use these photos and videos in our marketing on our website, social media, YouTube, etc. We also keep good records of these photos for the sales team to use in prospect meetings. They can pick the set of photos or video that most closely matches the prospect’s project so that they can try to visualize what their project will look like at completion.”
This bird’s eye view of job sites helps with pre-planning, site staging and quality assurance. “Drones can provide a different perspective of a greenfield project site, such as natural sloping, adjacent property concerns, nearby environmental concerns such as watershed, creeks, habitats, etc.,” says Michelle Gray, national environmental health and safety (EHS) leader, DPR Construction, Sacramento, Calif. “We have used drones to do modeling of the building with actual site versus BIM. For metal structures drones can allow for inspections of connections-bolts or welding to be done safely from the ground. On some of our large projects they map and track any water accumulation and leakage areas on roofs. By providing an infrared camera on the drone we can look for cooler areas on the roof membrane after water/rain events.”
“We’re seeing more companies add LiDAR (Light Detection and Ranging), thermal cameras and other sensors to help verify whether things are operating within set standards,” Murray says. “These infrared cameras can capture data outside of the visual spectrum that your eye or a regular camera cannot detect, offering insights you may not be able to uncover with a visual inspection.”
An Ideal Tool
Rather than driving to multiple sites and walking each site, Wolfe contends drones are an ideal tool to help speed up the site selection process. “Multiple sites can be flown in minutes and the data collected can be shared with the developer to take measurements, view current site conditions, etc. This is especially helpful to save on travel costs.”
With drones, there are no longer any questions about what phase of the development the site is at. For instance, they can measure and inspect metal roofs. “If a roof needs to be replaced, we can capture extremely precise measurements of the entire roof for estimation purposes,” Wolfe says. “By using an infrared camera, we can identify potential leaks in the roof, where there is loss of heat. [Also,] Drones speed up the process of measuring stockpiles. Using traditional survey methods, it takes up to a week to capture and process stockpile information. With today’s drone technologies, we can speed this process up to days or even hours.”
Drones help DPR Construction do inspections and visuals of the project site quicker and these video segments or real-time views can be sent to those who need that information. Gray says, “It’s a great way to show the team and our clients the progress that we are making. It is also awesome to collect these and show our DPR coworkers, who can take pride in what we have built and the history of our company.”
The Correct Color
Metal roofing can be reflective and it can appear to be different colors in different lighting. Many drone operators have found photographing their projects shortly after sunrise, or shortly before sunset minimizes this. Pick the time of day, cloud covering and the camera aperture setting combinations that will most accurately produce the correct color of metal.
Kenty explains when the sun is low in the sky it makes for better photos. “Another option is to fly mid-day on a day with full cloud cover. This actually produces the best shots but it is difficult to schedule a photo shoot without knowing what the weather will be. I also look at the orientation of the project before scheduling. The shots will come out better if the sun is behind the drone so if the front of the house is facing west, I generally schedule the shoot late in the day. I am also very conscious as to tree cover. Trees close to the project will cause shadows, which detract from the photo.”
Korolev says presently, “Photogrammetry for metal construction is not as accurate as we’d like to effectively capture projects solely with drones. In the future, higher-resolution cameras may solve this issue. Until technology catches up, using aerial drone data in combination with LiDAR and other reality-capture solutions can provide the data needed for metal construction.”
Drones and Regulations
Krishnan Hariharan, CEO of Kespry Inc., Menlo Park, Calif., says it is important for pilots to be aware of FAA regulations and restricted areas/no-fly zones etc. For unmanned aircraft systems (UAS)/drones under 55 lbs., the primary rule contractors need to adhere to are within FAA Part 107 or “The Small Unmanned Aircraft Rule.”
“This rule provides operational limitations, certification and responsibilities for the remote pilot in command, and aircraft requirements,” says Arthur Branch Jr., a principal aviation systems engineer for The MITRE Corp., McLean, Va. “Under Part 107 the UAS operator must hold a remote pilot airman certificate or be under the direct supervision of a person that does. Qualifying/obtaining a remote pilot airman certificate includes passing an aeronautical knowledge test or part 61 pilot certificate (other than student pilot) and completing a flight review and small UAS training course, and being vetted by the TSA. This certificate is available for aspiring operators and aviators at least 16 years old.”
How can contractors best deal with drones and no-fly zones/restricted areas? Branch says contractors looking to operate small UAS (less than 55 lbs.) must adhere to all the same restrictions as manned aircraft (such as temporary flight restrictions) and are responsible for checking Notices to Airmen (NOTAMs) and weather conditions. “Furthermore, Part 107 outlines additional airspace restrictions for UAS, such as a maximum altitude of 400 feet above ground level (AGL) or, if higher than 400 feet AGL, remaining within 400 feet of a structure.”
At Jacobsen Construction, nine Jacobsen pilots have undertaken training and possess an FAA Part 107 Remote Pilot certification. “Along with keeping an eye on weather conditions we fly in compliance with all FAA rules such as during daylight hours, within line of site, and at an altitude below 400 feet from ground level,” Lockhart says. “Where needed, we obtain the proper airspace authorizations to safely fly in areas that require operating in those areas.”
Original Article — Metal Construction News