Photo © W.S. Klem
Whole Building LCA (WBLCA) tools
A myriad of tools assess material choices for sustainability benchmarks. Whole building LCA tools use life-cycle inventory at the individual system level (e.g. flooring, wall) or for entire buildings. These tools are accepted in many green building certification programs, including Leadership in Energy and Environmental Design (LEED) and Green Globes.
Athena’s Impact Estimator for Buildings provides access to life-cycle data without requiring advanced skills. It can model more than 1200 structural and envelope assembly combinations, allowing for quick and easy comparison of design options. Users input basic information about building geography, size, and height, and a model is developed by creating a series of assemblies, such as walls, floors, and roofs. Alternatively, users can import a bill of materials from any computer-assisted design (CAD) program. These materials are used to create a life-cycle inventory, and are assessed using the Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts (TRACI) methodology (TRACI is a life-cycle assessment [LCA] methodology developed by the U.S. Environmental Protection Agency [EPA] and the most commonly used method in North America). Results can be summarized by assembly group and life-cycle stage, with final reporting on greenhouse gas (GHG)-related impacts.
Commercial license tools, such as Tally and Oneclick, integrate architect and engineer software to assess environmental impacts of building material lists. Tally pulls its material life-cycle inventory information from GaBi, an international life-cycle inventory database, and Oneclick relies on published environmental product declarations (EPDs), which some experts warn may not be well suited for whole building LCAs due to inconsistencies across product categories.
Photo © Chad Davies
Other tools may be helpful after the building has been designed. For example, the Embodied Carbon in Construction Calculator (EC3) facilitates the comparison of EPDs within the same material categories. It is currently in beta form and work is being done to properly characterize wood EPDs.
The Carbon Calculator for Wood Buildings focuses on the volume of structural wood in a building, then estimates how much carbon is stored in the wood, the GHG emissions avoided by not using steel or concrete, and the amount of time it takes North American forests to grow that volume of wood.
The product level
The ability to assess the environmental impact of a building ultimately rests on the life-cycle information for each component material. However, sometimes stakeholders just want this information at the product level.
An EPD is a standardized, third-party verified label that communicates the environmental performance of a product to industrial and end-use consumers. An EPD is based on an LCA report, and includes information about both product attributes and production impacts. The nature of EPDs also allows summation of environmental impacts along a product’s supply chain—a powerful feature enhancing the utility of LCA-based information.
| FOREST CERTIFICATION |
| Forest certification assesses a landowner’s forest management against a series of agreed standards related to water quality, biodiversity, wildlife, and forests with exceptional conservation value. Wood is one of the few building materials that have third-party certification programs in place to demonstrate products being sold have come from a responsibly managed resource. As of 2020, more than 243 million ha (600 million acres) of forest in the U.S. and Canada were certified under one of the four internationally recognized programs employed in North America.*
* Consult the Intergovernmental Panel on Climate Change (IPCC) Special Report on Climate Change, Desertification, Land Degradation, Sustainable Land Management, Food Security, and Greenhouse gas fluxes in Terrestrial Ecosystems. |
