Using BIM to calculate accurate building material quantities for early design phase Life Cycle Assessment
Authors:   , Berg Brian 
Published: November 2021

<p>This research simplifies the calculation of the Initial Embodied Energy (iEE) for commercial office buildings. The result is the improved integration of Life Cycle Assessment (LCA) assessments of building materials into the early stages of the building design process (sketch design). This maximises the effectiveness of implementing design solutions to lower a building’s environmental impact.  This thesis research proposes that building Information Models (BIM) will make calculating building material quantities easier, to simplify LCA calculations, all to improve their integration into existing sketch design phase practices, and building design decisions. This is achieved by developing a methodology for using BIM LCA tools to calculate highly detailed material quantities from a simple BIM model of sketch design phase building information. This is methodology is called an Initial Embodied Energy Building Information Model Life Cycle Assessment Building Performance Sketch (iEE BIM LCA BPS). Using this methodology calculates iEE results that are accurate, and represent a sufficient proportion (complete) of a building’s total iEE consumption, making them useful for iEE decision-making.  iEE is one example of a LCA-based indicator that was used to test, and prove the feasibility of the iEE BIM LCA BPS methodology. Proving this, the research method tests the accuracy that a BIM model can calculate case study building’s building material quantities. This included developing; a methodology for how to use the BIM tool Revit to calculate iEE; a functional definition of an iEE BIM LCA BPS based on the environmental impact, and sketch design decisions effecting building materials, and elements; and an EE simulation calibration accuracy assessment methodology, complete with a function definition of the accuracy required of an iEE simulation to ensure it’s useful for sketch design decision-making.  Two main tests were conducted as part of proving the iEE BIM LCA BPS’ feasibility. Test one assessed and proved that the iEE BIM LCA BPS model based on sketch design information does represent a sufficient proportion (complete) of a building’s total iEE consumption, so that are useful for iEE decision-making. This was tested by comparing the building material quantities from a SOQ (SOQ) produced to a sketch design level of detail (truth model 3), to an as-built level of detail, defined as current iEE best practices (truth model 1). Subsequent to proving that the iEE BIM LCA BPS is sufficiently complete, test two assessed if a BIM model and tool could calculate building material quantities accurately compared to truth model 3. The outcome was answering the research question of, how detailed does a BIM model need to be to calculate accurate building material quantities for a building material LCA (LCA) assessment?  The inference of this thesis research is a methodology for using BIM models to calculate the iEE of New Zealand commercial office buildings in the early phases of the design process. The outcome was that a building design team’s current level of sketch design phase information is sufficiently detailed for sketch design phase iEE assessment. This means, that iEE and other LCA-based assessment indicators can be integrated into a design team’s existing design process, practices, and decisions, with no restructuring required.</p>