What is in this article?:
Laser mapping can be used for surveying building conditions and exterior elevations, which then can be integrated into building information models.
RMF Engineering Inc. and Waldon Studio Architects (WSA) used 3-D imaging to design the renovation of a 2,500-sq-ft area in the basement of a building on the campus of the National Institutes of Health (NIH) in Bethesda, Md. The project had a number of critical requirements, including the installation of a dedicated HVAC system, the raising of ceilings to accommodate large video screens, and minimal interruption of existing services and daily operations.
A detailed field survey was conducted to verify the routing and location of all existing utilities. Some of the utilities, such as domestic water and sanitary piping, are to remain in place, while others, such as supply and return ductwork and large electric and local-area-network conduits, are to be relocated to accommodate architectural renovations. The sprinkler piping, chilled water, and heating water are to be extended and connected to the new HVAC equipment.
The project was a great candidate for 3-D modeling because of the significant number of utilities (plumbing, chilled and hot water, laboratory services, ductwork) in a small area, as well as the extensive nature of the renovation. The design team was able to do basic project planning, such as perform preliminary calculations, develop conceptual layouts, and make major decisions regarding system selection, while the 3-D imaging was being prepared. This accelerated the design process by at least several weeks.
The laser-mapping process needs to be incorporated at the onset of a BIM project. For the NIH renovation:
1) A third party specializing in the use of laser-mapping equipment—TransCon Imaging Solutions—was brought in. Multiple scans were taken to identify the various utilities, which were stacked above one another. These scans were combined to create an accurate 3-D representation of the space. This part of the project, including setup, scan, and travel time, took less than a day. The more compact the utilities (and, of course, the larger the area), the greater the number of required scans.
2) Once the laser scan was completed, the data was sent to the design team and converted using BIM software. WSA cut sections through the point clouds and built all of the piping, ductwork, and equipment components. This took about three days.
3) The basic BIM product was delivered to the engineering team. RMF’s first task was to check the alignment of all of the images and make adjustments as needed.
4) Once the building information model displayed all existing conditions accurately, a follow-up field survey was conducted. The team identified the type of utility associated with each image in the point cloud, as well as properties of the utilities, such as type of piping and whether the piping was insulated. The follow-up survey was essential to addressing questions that could not be answered by the building information model.
The time spent developing a dimensional layout and routing all of the utilities was greatly reduced.
Without the use of 3-D imaging through laser mapping, the field portion of the project would have taken approximately two weeks. Instead, it took only about three days. Not only did laser mapping save time in the field, it saved time in creation of the model and increased the accuracy of the final documents. This saved both architectural and engineering time and helped to enhance coordination between the architecture and engineering teams. Because of the size, time frame, and complexities of the project, the use of 3-D laser mapping was well worth the expense.
Although construction on the NIH project has yet to begin, the information about the existing utilities obtained from the 3-D model is expected to help the construction team to avoid time delays and cost overruns attributed to existing conditions. This is especially critical with a client that, like NIH, wants to minimize downtime and remain operational throughout renovation.