Environmental Performance Evaluation of Enclosure Systems Alternatives in Office Buildings in the U.S.
Low impact materials have become key player towards achieving environmental sustainability in the built environment. 5uch materials also contribute to carbon neutral buildings, responding to AIA 2030 challenge and many other initiatives by governmental and professional institutions. Building enclosure incorporates many construction materials that contribute to overall embodied energy and environmental impact. It also affects building operational energy as a barrier between indoor and outdoor environment. The study method employs a quantitative Life Cycle Assessment (LCA) approach in calculating environmental impacts of enclosure systems. 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 of the assembly systems of this building throughout this life span. The case building is located in the Midwest in zone 5, where steel construction is the common method of construction for commercial type in the region. The building is a 1-story high that incorporates few sustainable materials. The study calculates the environmental footprint of the building per unit area (impact to air, water, and land). To achieve its goal, the study provides an assessment to which building component (structure, walls, floors, roofs) contribute the most to the total building impacts where the worst burden, among its assembly systems, is identified. The outcome tests other materials alternatives to use in the roofing system to minimize its impact. The paper employs a "what if” scenario analysis to evaluate replacing high- impact materials with alternatives that have less impacts and briefly calculate the reduction in the total impacts against the original construction materials.