feature BUILDING ENVELOPE decreasing ambient air temperature • Creating a beautiful, natural environment for occupants, guests, and wildlife • Contributing between 6 and 14 points to the U.S. Green Building Council, Washington, Leadership in Energy and Environmental Design (LEED) certification.
Going underground A superior water-management solution goes beyond the outdated curb-and-gutter design. For instance, a gauged water-release, passive retention system—sometimes referred to as subsurface irrigation and storage—is an onsite water-management-and-reuse system that collects, filters, retains, and distributes water below ground. This type of system can collect and reuse nitrates, phosphates, and other pollutants as nutrients for the vegetation above ground. It also cuts down on pollutants that may enter groundwater from rainwater runoff. Not only does the system convert pollutants to usable fertilizer for vegetation, but onsite water-management and reuse systems can also remove floatables, skim oil and grease, and even tap sediment before those elements are released into the ground or natural bodies of water. A geomembrane liner can help with soil erosion. When properly designed, in combination with other water-storage products, a subsurface irrigation and storage system is a great, low-maintenance water-management tool. The United States spends billions of dollars each year to build large sewer systems that can handle additional rainwater. Stormwater management can help alleviate the need and expense for those larger systems as well as control flooding, which contributes to the spread of pollution, contaminates drinking water, and threatens the safety of people in an affected community. Moreover, water-management systems can create multi-functional green spaces or permeable parking with exceptional drainage and water-collection capabilities. Water captured with these technologies can result in using 50% to 80% less potable water indoors and for landscape irrigation, resulting in decreased dependence on municipal water supplies. By bringing together passive subsurface irrigation, water storage, and filtration, an on-site, underground stormwater-retention system makes possible adjustments to fit a building’s footprint and help building owners and managers achieve hydrologic responsibility. Conventional perforated-pipe systems with geotextile lining have also been a popular option as a drainage mechanism, but many eventually fail due to silt buildup in the geotextile. These systems often need to be replaced after a few years, which can become very costly and cause further damage to the property. 20
COMMERCIAL BUILDING PRODUCTS
MAY 2013
Real and artificial turf Subsurface systems are ideal for various applications, including green spaces, athletic fields, parks, sidewalks, and even parking lots. Heavy rains and standing water particularly affect parks and athletic fields, which are costly to build and maintain. Water-management systems alleviate the stress put on these environments by heavy rains. Subsurface systems leverage gravity to pull water down below ground, where it is stored in chambers. Capillary rise pulls the water upward to irrigate natural turf. This process provides
Installation of plants goes quickly with preplanted mats. The colorful sedum will thrive even in dry conditions with minimal irrigation.
water management for natural sports fields and outdoor artificial turf. Not only can water-management systems fertilize the natural vegetation in a park and minimize standing water, but they also alleviate a major concern: heat. With artificial turf, surface temperatures may exceed 180 F as a result of the sun’s ultraviolet light reacting with compounds in the synthetic turf. The excessive heat can contribute to heat-related health hazards for the athletes. Gauged waterrelease passive-retention systems may include a damp field base that allows the heat to dissipate, creating a natural cooling effect that can reduce field-surface temperatures on hot, sunny days. The systems can also allow moisture to enter the sandbased infills from below grade for optimal cooling and playability.
Hydrologic responsibility and LEED The commercial-building community uses LEED, R-values, and other measures to build smarter, more efficient structures. Water efficiency is one of the five core categories for LEED certification. Installing a subsurface irrigation and storage system may help achieve LEED credits in the following categories: Sustainable Sites, Water Efficiency, Materials and Resources, Innovation and Design, and Regional Priority Credits. Applying a vegetative roofing system to a commercial structure is another way to help achieve LEED certification. We are seeing a major shift toward standards and codes at the local, state, and national level that are more rigid, especially for new commercial construction. Codes and standards vary by state and
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locality. The U.S. Department of Energy, Washington, Building Energy Codes Program outlines commercial building codes at http://www.energycodes. gov/states/. With the countless environmental problems caused by stormwater runoff, it is important to be proactive about incorporating water-management solutions into commercial-construction, facilitymanagement, and corporate social-responsibility plans. Water-management solutions and best practices are crucial to protecting the environment, ensuring a building is performing at the highest level, and complying with building and energy laws. As architects, contractors, and facility managers strive to be more environmentally conscious, water-management practices will become part of the model to construct smart, high-efficiency buildings. The building envelope controls the energy use, efficiency, and performance of a facility. Regulating rainwater runoff is just as important as keeping water out of a building to avoid mold and mildew damage. Keeping water out of the facility is also crucial to maximizing the energy efficiency of the building. There is a variety of building products that function together to protect a commercial building from rain and other environmental elements. For example, cavity wall systems made of ethylene propylene diene terpolymer (EPDM) synthetic—an elastomeric rubber membrane with a tradition of superior performance in harsh environments including commercial roofing and environmental containment—can help protect masonry walls from water damage by forming a barrier to moisture ingress in cavity-wall construction by directing water to a building’s exterior. Rainscreen systems can also protect the building envelope from water and natural elements. A rainscreen is an exterior cladding product that sits away from a building’s exterior wall, forming an air cavity. This gap allows moisture to drain away from the building instead of getting trapped in the wall, where it could result in mold or infiltrate the structure. An added benefit: Rainscreens help improve a building’s energy use and performance. It is important to note that building-envelope solutions vary according to facility, geographic location, and climate. There is no one-size-fits-all solution, which is why it is important to partner with experts to select building-envelope materials and products that are right for a project. Bill Johnson has been with Firestone Specialty Products, Indianapolis, for 15 years. He currently serves in warranty and field services and as the installation-training manager.
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