Materials Choices Matter
An Eco-Balance Evaluation of a LEED Certified Building.
ABSTRACT: Since environmental sustainability becomes a central concern in the design process in both architectural education and practice, research on quantifying buildings impact on the environment is growing worldwide. Although many designers seek LEED certification, some claim their buildings to be sustainable based only on certification. In fact, unless a Life Cycle Assessment (LCA) study is carried out, it is difficult to quantify and evaluate the environmental burden a particular building, or a construction material, has on its surrounding environment. The study method employs a quantitative LCA approach in calculating these impacts. The paper models an office building over a service life of 60 years and its implications on the environment from cradle to grave. It also quantifies and compares the total impacts this building has throughout this life span. The case building is located in Michigan in the U.S. where steel construction is the dominant method of construction for commercial type. The building is a 1-story LEED certified building that uses a geothermal HVAC system and has many sustainable materials used. The study calculates the environmental footprint of the building per unit area (impact to air, water, and land). The study discusses the importance of setting metrics beyond LEED to choose more sustainable materials based on their environmental impact. To narrow down to the critical materials, the study provides an assessment to which building component (structure, enclosure, floors, roofs) contribute the most to the total building impacts where the worst burden and critical materials could be identified and replaced. The outcome highlights where LEED rating system may fall short regarding the best materials alternatives to use and in which component of the building. This contributes to reduced total impact through selecting these alternatives based on the least damage to the environment.
KEYWORDS: Environmental Profiling, Impact Assessment, Life Cycle Assessment, LEED.