BUILDING ENERGY - Fall 2016 - 45
Challenge competition, KieranTimberlake wanted to calculate
the full magnitude of benefits that could be realized from the
material reuse of Loblolly House. This off-site fabricated home was
assembled with reversible connections to ease reconfiguration,
replacement and reuse of the materials in the future. The design
team intuited that this building strategy would offer environmental
benefits in the form of reduced embodied carbon, but had yet to
quantify the total savings that could be realized from reusing every
building element. Loblolly House was modeled three dimensionally
with precision using Autodesk® Revit® to facilitate coordination
with fabricators and ensure elements assembled off-site would fit
together with a high degree of tolerance.
To begin the LCA, a bill of materials was generated from the
Revit model; however, granular data such as coatings and adhesives
that would allow a full calculation of the building's embodied energy
were not included in the model. To fill in the additional information,
the team conducting the analysis used a variety of calculation
methods, including reviewing component specifications and
shipping manifests to determine the type and quantity of materials
present in Loblolly House. After establishing these quantities, they
sourced the data on the embodied carbon and energy associated
with each material from the Granta CES Selector, limiting the scope
of impacts to those created during manufacturing. In its search, the
team discovered a dearth of information for many typical building
materials. Additionally, the calculation process was long, taking
more than five weeks for an 1,800-square-foot project.
Despite the slow pace, the team saw the potential for
designers to leverage the embodied carbon data for a given
material if only it was accessible to them during the design phase.
For example, though half of Loblolly House's material impacts
were found in the insulation, the home is a summer retreat with
one façade that opens fully to catch offshore breezes, meaning
very little insulation was actually needed in the home.
If the material impacts had been known to designers during
the modeling phase, that portion of the project's environmental
impact could have been minimized. But at the time, the pace
of assessment did not coincide with the design process. This
incongruity, coupled with the scarcity of environmental impact
data for materials, underscored the need for a tool that could
integrate material impact data into a modeling workflow.
CREATING A LIFE CYCLE ANALYSIS
WORKFLOW FOR DESIGNERS
Seeing the value of the Loblolly House analysis, KieranTimberlake
began to calculate embodied energy on other projects, ultimately
seeking a workflow that provides LCA data to designers in real time.
After the firm created a proof-of-concept application called the Real
Time Environmental Impact Tool (RTEI), it partnered with Autodesk®,
who provided the development team training and support to ensure
proper compatibility with Revit® software and access to a variety of
opportunities for peer review.
As part of the development process, KieranTimberlake also
deepened their understanding of LCA standards by reviewing
relevant industry protocols such as ISO 14040 and 14044. To
meet industry standards, they needed to use quality-assured data
specific to the architectural industry, and also examine impacts
from all stages of a building's life cycle: material manufacturing,
transportation to site, construction, maintenance and replacement,
operations and end of life. Furthermore, it became apparent
the limited scope of embodied carbon and energy would need
to be expanded to include more impact categories. Given the
North American focus of the firm's work, the US EPA TRACI 2.1
CHART COURTESY OF KIERAN TIMBERLAKE.
NESEA.ORG * 45