Lasers to Bring Order to Construction Site

Daniel C. McCarthy

Keeping track of personal items is a challenge familiar to many of us. The problem is on a much larger scale for contractors, who must coordinate hundreds of materials, workers and tools on construction sites. In a business where time is money, some estimates for large construction projects indicate that between 6000 and 12,000 hours are spent just tracking materials.

Bringing order to chaos is exactly the sort of thing at which the National Institute of Standards and Technology (NIST) excels. It seems only natural, then, that construction planned at the NIST campus will incorporate a "living lab" to allow resident scientists to experiment with improving efficiency at a work site. The project will use lidar to scan site topography, laser bar-code readers to inventory materials and three-dimensional analysis to track the progress of construction.

Groundbreaking for NIST's Emission Control Systems building could begin early next year. The structure will function as a "multimillion-dollar catalytic converter" for research associated with the institute's Building and Fire Research Laboratory, according to Larry Pfeffer, a research structural engineer at the lab. The goal is to provide a test bed and case study for the construction industry to show what can be achieved with existing, nonintrusive technologies. The key word is "nonintrusive."

Current methods generally require work to halt while materials are inventoried and construction is measured, but this is neither efficient nor always possible. "You can't do a specific subtask until all your parts are in," Pfeffer said. "Meanwhile, new parts are coming into the same area and being strewn about. There might be thousands of girders, all of which look alike. Some could be higher-grade steel, but if you use the wrong one in the wrong place, problems develop in your building."

During construction, NIST scientists will measure the efficacy of using bar codes read by laser pens to address this problem. For materials that cannot be coded, such as concrete or dirt, the researchers will experiment with laser-based survey stations that can measure noncooperative (i.e., nonreflective) targets. Coupled with global positioning systems and computer three-dimensional analysis, they hope to streamline the process of construction by tracking individual components and the progression of work on site.

"For tools and people, the point is to enhance security and safety. For materials, it's to enhance the ability to track and find the right one," Pfeffer said. NIST's study of the applied technologies could lay the groundwork for establishing industry standards.