Life Cycle Assessment of a Brick Bearing Wall
Below, the introduction, scope definition, and charts of metrics by lifecycle stage have been excerpted from the full text. For the complete analysis — including conclusions and recommendations, detailed information on each life cycle stage, and complete calculations — please download the pdf (3MB).
Introduction & LCA Goals
Life Cycle Assessment (LCA) is becoming an increasingly important methodology for assessing building materials. It is particularly useful for understanding the production-related impacts of materials, as well as the potential trade-offs between life cycle stages.
This analysis of a brick bearing wall is both quantitative (tracking a series of economic, environmental, and ethical metrics across all life cycle stages) and qualitative (describing each life cycle stage and its impacts). In order to make this LCA as specific as possible, Longworth Hall in Cincinnati, Ohio, is used as a point of departure; however, industry-wide data also has been tracked whenever possible. Although Longworth Hall was constructed in 1904, present-day data has been used — effectively calculating the impacts of building Longworth Hall today.
Because of brick's durability, the costs and benefits of a brick wall are incurred over a long period of time and over many life cycle stages, making it difficult to assess through traditional means. LCA is uniquely poised to clarify these costs and benefits.
Longworth Hall, also knows as B & O Freight Terminal, is a brick masonry structure built in 1904. At 1,277 feet in length and five stories high, it is one of the largest buildings of its kind. It is listed on the National Registry of Historic Places, and is currently used as an office building.
As with all LCAs, this analysis is limited by the availability of information. The author has tried to make the assessment as transparent as possible, highlighting assumptions and gaps in data. The results are also compared to EIOLCA, an existing LCA tool. Comments and questions are appreciated and welcomed.
Scope of Analysis
This analysis looks at the economic, environmental, and ethical impacts of a brick bearing wall throughout its entire lifecycle — from the extraction of raw materials through the end of its useful life. Mapped above are the major materials and points of transportation included in the lifecycle of a brick wall. Also included in this diagram are three potential end of life pathways: reuse, downcycling, and landfilling. Not included is the supply chain of power generation (e.g., the total supply chain for electricity used in brick manufacturing). Also absent are the "accessories" of a brick bearing wall: metal coping, flashing, etc., as well as the supply chain of the equipment and tools required for manufacturing and construction (e.g., mixers, scaffolding, etc.).
This analysis focuses primarily on clay. A brick bearing wall is composed of 71% brick by volume. Brick, in turn, is composed of 80-85% clay. Clay therefore accounts for 57-60% of a brick bearing wall by volume. A more complete Life Cycle Assessment, however, would include all of the constituents shown in the diagram above. In addition, this analysis assumes downcycling as the end of life pathway, both because it is common practice and because data is readily available. It further assumes that all transportation is by truck (also common practice). Finally, this analysis tracks six quantitative metrics through all lifecycle stages: greenhouse gas (GHG) emisisons, water use, injury/illness rate, fatality rate, and mean annual wage.
Metrics by Life Cycle Stage
For the complete analysis, please download the pdf (3MB).