moisture penetration is one of the most common causes of problems in buildings. Rain-screen walls minimize rain infiltration by applying principles of pressure equalization. A brick masonry pressure-equalized rain-screen wall utilizes intentional openings in the brick masonry and compartmentation to equalize the pressure in the cavity behind the exterior brick and thus minimize rain penetration.
Renewable Energy Incorporation of renewable energy sources into a building design can significantly reduce reliance on fossil fuels used by the building during operation. Passive solar energy is a free resource, and brick masonry can be utilized as part of several passive solar design strategies.
Safety and Security Brick masonry promotes occupant health and safety through fire-resistant construction and resistance to impacts and wind-borne debris. In addition, the durability of brick masonry gives long-lasting results.
Environmentally Preferable Materials, Products and Durability Consideration of the environmental impact of building materials and products is an important element in a sustainable design, though it is only one of several criteria to be considered for product selection. Materials should be evaluated over their entire life cycle, from raw material extraction to end of useful life. This life cycle assessment (LCA) of a building material or product must include accurate evaluation of product service life. Brick masonry has a service life of over 100 years. Environmental effects associated with brick are distributed over this long lifespan. Other products used with brick may have considerably shorter lifespans. Building construction can generate significant waste. Because of the small, modular nature of brick, on-site construction waste can be almost completely avoided through careful design and detailing. In addition, scrap brick is easily crushed and recycled for new uses, thus avoiding the landfill. Packaging from brick is minimal and easily recycled. Use of salvaged materials avoids the environmental impacts associated with new products. Salvaged brick, especially sand-set pavers, can
Photo by Thomas McConnell, Courtesy LZT Architects
Conservative Concrete Durable, energy efficient and recyclable – a quick evaluation of concrete applications and it’s easy to determine that this versatile building material is sustainable. Just how major a role it will play as the green building movement continues to proliferate depends on how many are willing to take a closer look. “It’s an extremely durable product,” the first and foremost sustainable attribute according to Gary Bailey, AIA, and principal/owner of Innovative Design, Inc. Bailey’s firm has been focused on sustainable design since 1977. These days, he favors insulated precast concrete to assist with daylighting and to average out building temperatures due to concrete’s thermal mass. “Because of the way heat transfers through concrete, it acts as a storage element, storing warm air in winter and cool air in the summer.” Since concrete does not provide a food source for mold or mildew, Bailey also counts indoor air quality as another component of concrete structures in sustainable design. “Look at health issues in this country, with regards to allergies and asthma—buildings are a big part of that problem. Concrete mitigates those issues.” Echoing the sentiment regarding the versatility is Lionel Lemay, vice president of technical resources for the National Ready-Mixed Concrete Association. “For instance, look at pervious concrete,” says Lemay. Beyond its primary benefit of stormwater management, he points out that pervious concrete allows for more planting of trees, absorbs noise, potentially decreases the urban heat island effect, and, it can be recycled. In fact, concrete was the most recycled material in North America by weight in 2005, according to a survey by the Construction Materials Recycling Association (CMRA). Survey results indicate that recycling companies recovered as much as 140 millions tons of concrete in 2005. Equally impressive, recycling plants were able to recycle 99 percent of what they took in. “We want the green building community to realize all of the solutions concrete can provide,” said David Shepherd, AIA, and director of sustainable development for the Portland Cement Association.
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The Austin Research Center for the Homeless (ARCH) designed by LZT Architects uses a site-poured, stacked concrete frame. To meet the standards of LEED Silver Certification, designers mixed a high volume of flyash into the concrete.
While Shepherd considers concrete’s durability, energy performance and recyclability to be its strongest green attributes, he stresses the importance of the application. “It’s how the concrete is used that has the far greatest impact on environmental performance,” notes Shepherd. With proper application, concrete can provide sustainable solutions for a host of green issues, including: reducing undesirable sound transmission, increased energ y performance, urban heat-island reduction, locally available materials sourcing, improving indoor air quality,lighting efficiency, stormwater management and thermal mass. Visit www.ConcreteThinker.com for a further explanation of these solutions. The Portland Cement Association represents cement companies in the United States and Canada. It conducts market development, engineering, research, education, and public affairs programs. More information on PCA programs is available at www.cement.org.
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