Page 10 - MASHRAE 35th Anniversary

This article was published in ASHRAE Journal, November 2020. Copyright 2020 ASHRAE. Posted at www.ashrae.org. This article may not be copied and/or distributed electronically or in paper form without permission of ASHRAE. For more information about ASHRAE Journal, www.ashrae.org.
Using Prefabrication To Improve Efficiency
BY MICHAEL COOPER, P.E., MEMBER ASHRAE
Prefabrication, also known as design for manufacture and assembly (DFMA) began with simple assemblies such as building pump and chiller skids fabricated away from the construction site. Now, air-handling units, full mechanical rooms and super skids with chillers and boilers are built off-site in a manufacturing facility. When these prefabricated systems arrive at the construction site, they are installed directly into existing or new buildings. Some assemblies can be installed in hours, as opposed to in days.
In Asia, apartments and hotels are being built almost like building with Legos®. The building’s mechanical, electrical, plumbing and other systems are built inside these “Lego” blocks, and hotels are being assembled room by room. This type of construction isn’t commonly done in North America because codes vary, and not all jurisdictions have adapted to these types of strategies.
Off-site prefabrication helps to simultaneously con- struct buildings block-by- block in different locations. As the technique becomes more mainstream, prefabrication’s benefits include reducing costs, reducing sched- ule timelines, creating a safer work environment, maintaining a steady workforce and eliminating the need for corrective work.
Over the last several decades, design and fabrication tools have changed. The days of drawings done by hand transitioned to computer-aided drafting, and now 3D drawings allow assemblies to be manufactured using automated machining.
Integrated design and fabrication have different meanings according to a person’s role. For a consulting engineer, integrated design could mean designers of multiple trades coming together in a coordinated effort. This has been going on for centuries. Fabrication has been part of the design business since its inception, with
manufacturing and assemblies of systems. However, the evolution in how both the design and fabrication come together to form a seamless entity on construction jobs is evolving. And now, the industry needs to perform design and fabrication seamlessly.
Too often designers work in “silos,” and in that silo they create what they believe to be the most efficient and cost-effective design to meet the owner’s needs. Contractors are always looking for ways to put an assembly together to save just one fitting or become more productive with the limited availability of skilled labor. Bringing designers and contractors together is what the industry finds difficult. How the design and construction industry moves forward is critical.
How It Works
Off-site fabrication allows engineers, designers, contractors and other critical team members to work together efficiently. The mentality of designing and fabricating together across trades and then installing complete assemblies can allow for increased accuracy and organized, neat and efficient systems, compared to other strategies that take weeks to design and
Michael Cooper, P.E., is an executive vice president for Bernhard based out of New Orleans.