Pre-Fabrication and Modularization in Smithsonian Construction

In 2013, the Smithsonian Institution began incorporating building information modeling (BIM) in its construction projects. Since that time, the Institution matured its data-driven project execution paradigm and, as of 2022, requires the use of BIM for pre-fabrication and modularization in some construction projects. 

The Smithsonian became aware of the many benefits of modularization during the construction of the National Museum of African American History and Culture – the first Smithsonian Project requiring BIM in the design and construction. The mechanical and plumbing contractor utilized BIM to do substantial offsite pre-fabrication of plumbing assemblies that were then transported to the construction site and installed.

The renovation of the National Air and Space Museum was the second project to use prefabrication and modularization, but the first project to employ the Smithsonian’s most mature BIM guidance. Although not a contract requirement, the electrical subcontractor, M.C. Dean, utilized BIM to pre-fabricate and modularize much of the electrical infrastructure, including conduit runs, panels, and the largest prefabricated electrical room they attempted at 17 feet by 71 feet and weighing approximately 69,000 lbs. 

With two Smithsonian projects having benefited from prefabrication, the Institution decided to pilot a project where prefabrication was a contract requirement. A small dormitory project in Edgewater, Maryland was chosen. The project known as the “Green Village” is comprised of six wood frame cottages to house visiting scientists at the Smithsonian Environmental Research Center (SERC). 

This project was chosen because Green Village’s wood frame construction had been proven to be easily modularized. A local Baltimore company, Blueprint Robotics, has great experience with substantial modularization of wood frame construction which incorporated all the mechanical, electrical, and plumbing (MEP) into robotically assembled wall and ceiling panels – ideal for the wood frame construction needs of the Green Village. 

In addition to being the first project to require prefabrication, the Green Village project is also the Smithsonian’s first use of the Passive House certification and has a goal of Net Zero energy. Blueprint Robotics specializes in meeting the Passive House certification requirements with their prefabricated wall panels.

Offsite premanufacture of building elements offers improved safety, quality, efficiency, and a lesser dependence on skilled labor. Since much of the prefabrication takes place inside, workers are not subject to the dangerous conditions of a job site and enjoy more comfortable climate-controlled working environments. When working indoors, higher quality can be obtained due to a more efficient workflow with better oversight and environmental conditions. 

The assembly building can be laid out in a logical fashion with vastly improved lighting and access to tools as well as automated processes that reduce errors. Much of the technical work can be carried out by robots supplied with a steady stream of material to work with. Automation is facilitated using BIM in the design and construction. The electronic 3-D model can be used to program the automation equipment to assemble the required parts.

In the case of the Smithsonian’s Green Village project, much of the six cottages’ rough-in carpentry, mechanical, electrical, and plumbing were prefabricated at Blueprint Robotics’ 200,000-square-foot plant near Baltimore, Maryland. The company coordinates the BIM and creates real-time shop drawings in 3-D production software that will produce machine files to fabricate the project. They use computer Numerical Controlled machinery to cut, fasten, drill, and route panels to accommodate the mechanical, electrical, and plumbing systems. Before leaving the facility, all windows and doors are installed in the standardized panels. The firm also handles all transportation and logistics utilizing just-in-time delivery.  Since they standardize the panel sizes, the project can be delivered on standard 53-foot trailers which do not require oversize load permits or escort vehicles. 

As prefabrication has its limitations, there are things to consider before it is used in a project. In the case of the Green Village, only the rough carpentry, mechanical, electrical, and plumbing were fabricated off-site. The preassembled wall panels needed to be connected at the site as well as the MEP. All the interior and exterior sheathing, roof, and finishes were done at the site as well. Therefore, a general contractor was employed to do site work, and foundations, and perform the final completion of the project. 

The Smithsonian has additional lessons learned from the National Air and Space Museum renovation.  As stated earlier, prefabrication was utilized but was not a contract requirement. As such, the designers did not anticipate off-site prefabrication. In some cases, robotic manufacturing techniques are not as flexible as on-site construction. For example, robotic bending and assembly of electrical conduits off-site precluded the ability to react to changes on site and tended to result in a larger conduit radius and width of ganged conduits. The design did not account for this and therefore some rerouting and coordination were needed that otherwise would not have been. 

Although prefabrication, automation, and modularization present some challenges, the benefits far outweigh them. Increased safety, quality, and efficiency gains are significant. This is being realized by the construction industry – they often outbid competitors when these methods are applied. We should all anticipate that contractors will utilize these methods and/or begin requiring them as part of our project requirements.