ASHRAE Journal - November 2020 - 71

COLUMN INDUSTRY 4.0

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 that can become
disorganized, inefﬁcient chaos.
The building blocks of today's construction sites are
designing to meet a code requirement or functionality
within the space using the same methods and technologies from the last 100 years. When designing for the new
world, designers must design with the intention to collaborate with the contractor.
Intentional design is critical in off-site fabrication.
When a contractor needs to build things in assemblies,
engineers must use new methods that are more productive and minimize on-site labor. This off-site fabrication
strategy is more conducive to an efﬁcient build cycle.
The key to a successful prefabrication project is to
have all involved parties participate in the design phase
before using an off-site construction model. This eliminates the need for rework.
Compared to traditional building strategies, off-site
fabrication can run more efﬁciently because it is a coordinated effort, and the process has to be coordinated for
these technologies to work. Inherently, there is a need
for a higher level of quality control to prefabricate offsite and bring the assemblies on-site.
Off-site prefabrication mitigates risks and provides a
higher quality product to the owner. It also reduces costs
and schedule because different trades are able to work
off-site on parts of the building more efﬁciently than
fabricating those building systems on a construction
site.
An advantage for off-site fabrication is the working
crews are experienced and in the same manufacturing facilities that are roofed, clean environments. In
addition, this gives the trades the advantage to build
assemblies at chest level, not necessarily in the ceiling. Productivity of manufacturing at chest level and
on the ﬂoor is substantially increased when compared
to working 15 ft (4.6 m) in the air. And this method is
safer. Because fewer tradespeople are available amid
the current labor shortage, ﬁnding ways to be smart
and efﬁcient is imperative. Companies can see offsite fabrication as a cost savings and return on equity.
Improved quality is also inherent. Building off-site

allows for work to be checked easier, minimizes rework
and increases labor productivity.

Tools

It is a paradigm shift to use these tools and ﬁnd partners on the construction side that have the capability
and desire to do it. Contractual arrangements such as
design build or integrated project delivery try to contractually bring team members together with a common
ﬁnancial goal. While these practices are helpful, the
true guiding principle needs to be team members from
design and construction wanting the same outcome and
driving toward the same success.
Collaborative design software takes inputs from a
basic load calculation of a space and transforms it into
an energy model based upon limited information other
than building use. These same tools take into account
the manufacturing assemblies that will build the system. For example, for sheet metal systems the ductwork
in the model no longer represents just a spatial constraint, but rather the pressure class of the sheet metal,
gauge and type of metal, seam construction and joining
method.
These tools provide the knowledge for a manufacturing intent at the same time as the initial design. They
have also allowed for the development of multi-trade
assemblies in which mechanical, electrical, plumbing,
ﬁre protection and low-voltage cabling are all built in
a single environment off-site and installed in hours,
rather than in days with previous "silo" methods.
Even with the available tools, technologies and innovations available, all team members have to be on the same
page to have success.

New Build vs. Renovation

While prefabrication tends to be more used in new
construction projects, prefabrication can also apply
to renovations and equipment replacements, but
the constraints and requirements are speciﬁc to the
project.
Designers can prefabricate systems for renovations,
but sometimes the project calls for speciﬁc variations
and versatility. For example, a mechanical room that
needs a new piece of equipment might have a set of
double doors, so the prefabricated assemblies have to ﬁt
through the doorway. This can be done using strategies
such as removing precast panels.
N OVEM BER 2020

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ASHRAE Journal - November 2020

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