Buildings are recognized as a technological sector where large improvements in sustainability-related categories are achievable. Concepts such as the net-zero energy building indicate the perceived potential to reduce the environmental impacts of buildings to a very high degree (e.g. Architecture 2030, International Living Future Institute, President Obama's Better Buildings Initiative). The question of what is environmentally sustainable is best addressed through the use of life cycle assessment (LCA) . Currently, LCA is not explicitly used in common green building rating systems such as the US Green Building Council's (USGBC's) Leadership in Energy and Environmental Design (LEED), nor is it commonly used by building design, construction and management professionals.
Indoor Environmental Quality - A common finding of building LCA studies is that the use phase typically dominates life cycle environmental impacts, due primarily to a long useful life and high energy inputs. However, most LCAs do not include the building's direct impacts on its occupants, though these impacts also occur primarily during the use phase and can be significant (Hellweg et al. 2009). For commercial buildings, some of the impacts on occupants may decrease their productivity, leading to lower revenue or otherwise reducing the owner's financial return on investment. Although the technique of life cycle cost analysis (LCCA) has been developed to enable comparison of alternative strategies for long-lived assets like buildings from a financial bottom line perspective, productivity impacts are often not included because they are difficult to quantify.
Dynamic LCA - The long service life of buildings also introduces a need to examine the possibility of changes over time with respect to any life cycle metric. Acknowledging the complex dynamics of the natural and built environments leads to a better understanding of future predictions as occurring within a range of scenarios rather than as a single value. However, the current state of the practice in LCA is to assume a static, unchanging set of values for the duration of the use phase, due to the additional data requirements for modeling system dynamics and generating multiple scenarios.
Recent development in sensing and building automation technologies indicates that the additional data requirements of dynamic life cycle modeling may be within reach. Real-time measurements of building requirements such as energy usage and indoor air quality are already implemented in some automation and control systems. The needs of a sensor network used for life cycle modeling may not extend significantly beyond those for a building system diagnostic and control network. Such a network could provide the dynamic building operations portion of the LCA database; when coupled with time-dependent information on external industrial and environmental systems, it could give true life cycle updates in real time.
Projects under Green Buildings:
Dynamic Life Cycle Assessment: Framework and Application to an Institutional Building
Analyzing the Practice of Life Cycle Assessment: Focus on the Building Sector
Living Building Challenge, Phipps Conservatory & Botanical Garden's Living Building Project
Indoor Environmental Quality in a Dynamic Life Cycle Assessment Framework for Whole Buildings: Focus on Human Health Chemical Impacts
A Materials Life Cycle Assessment of a Net-Zero Energy Building
Life-Cycle Thinking and Green Building Rating Systems: Global Perspective on Building Energy Use and Environmental Impacts
A Sequential Decision Framework to Support Trade Space Exploration of Multi-Hazard Resilient and Sustainable Building Designs