If a school architect does not implement sound design practices to improve indoor air quality, there may be a negative health impact on the occupants. This can also lead to “Sick Building Syndrome” and “Building-Related Illness,” asthma and severe allergic reactions to pollutants such as volatile organic compounds (VOC), particles, and allergens from dust mites and mold. Children are more susceptible than adults to air pollution, because their immune system and developing organs are immature. Thus, it is expected that schools with bad IAQ would have a lower average daily attendance than a school with good IAQ. Consequently, schools with good IAQ are likely to receive more funding because more students are attending class daily. Schools are also likely to have high teacher retention rates and will spend less on substitute teachers for sick staff members. This can improve continuity in school programs and provide students with higher quality educations. These effects are also true of higher education buildings that must cater to a diverse faculty and student population with a broad range of health issues. In fact, a New York Times study stated that almost 50% of students have asthma or other pulmonary diseases.
Rainscreen façades are emerging as the system of choice for buildings across a variety of commercial sectors including education. Terra cotta is playing a key role in this growing trend for sustainable building envelopes. To date, hundreds of buildings in the United States showcase the warmth and modern design of terra cotta panels backed by a system that increases the building’s energy efficiency and creates an indoor environment ideal for academic success.
Breathable Building Envelope = Positive Indoor Air Quality
In a back-ventilated rainscreen façade, the joints are left open so that air can come in under the system, through the panel joints and exit there as well. Because the air barrier is continuous and connected to the windows and dissimilar materials, the air cavity in the wall becomes both pressure-equalized and back-ventilated. Benefits include:
Moisture Control -The open joint rainscreen system allows air to circulate behind the terra cotta panels to provide pressure equalization. This prevents water from being drawn into the building wall cavity. A vapor barrier on the outside face of the backup wall acts as a final air and water barrier. This keeps the building dry and protected from the worst weather conditions without the use of grout or sealants and without need for maintenance. This includes positive and negative wind loads, seismic, thermal and normal movement.
Eliminates Mold and Mildew -Germs and microorganisms don’t have the chance to develop inside the wall cavity because moisture can escape through the open joints to the outside. Since damp places allow mold and mildew to grow and multiply, their elimination can provide a healthier environment and better outcomes for children and people with immune deficiencies. Asthma sufferers, known to be adversely affected by mold and mildew, will also benefit from better IAQ.
Humidity Control -Eliminating air infiltration and exfiltration through the wall helps maintain the relative humidity inside the building. Proper relative humidity level is critical to enhancing indoor air quality.
Performance Benefits = Low Lifecycle Cost
Energy Efficiency -The open joint system eliminates air infiltration and exfiltration through the wall. This can reduce the required size of HVAC equipment by as much as a third. The savings come from a dramatic reduction in the loss of treated (heated, cooled, humidified) air as well as the superior insulation benefits of a rainscreen façade.
Long-term Durability -A system with a naturally ventilated wall cavity has an 80 year-plus life expectancy and helps to eliminate the potential for “sick building syndrome,” a condition common to closed cavity walls. Moisture is removed from areas with structural steel studs which eliminates corrosion in the structural wall.
Low Maintenance -With no silicone sealant or mortar and grout, the tiles will not experience leaching of dirt and film over the panels and can be simply cleaned with water. Materials like terra cotta are non-fading and resistant to frost, corrosion, salt water and other aggressive substances.
High Performance Products = LEED Opportunities
Points can be earned for good indoor air quality and also from recycling the terra cotta and aluminum materials. In some cases the aluminum support system is manufactured with recycled aluminum. Without the need for sealants, this system also eliminates off-gassing.
Case Study: University of MichiganIn 2009, students and faculty at the University of Michigan’s Stephen M. Ross School of Business settled into a gleaming new $145 million state-of-the-art building on the Ann Arbor campus. The 270,000-square-foot facility is a major step forward for the school, which previously was scattered between four different facilities on campus. The six-story, L-shaped building was designed by New York-based architects Kohn Pedersen Fox and features more than 100,000 square feet of terra cotta tile. The building earned a Silver designation by the USGBC’s Leadership in Energy and Environmental Design (LEED) rating system, garnering all 36 points that it attempted across six environmental categories including sustainable sites, water efficiency, energy and atmosphere, materials and resources, indoor environmental quality, and innovation and design process.
A terra cotta rainscreen façade was also used in another sizable project at the university. Located at the northern edge of the central campus, the Biomedical Science Research Building acts as a front door to the university’s medical complex. Designed by Ennead Architects (formerly Polshek Partnership), its central atrium marks a transition in the building’s massing between an L-shaped rectilinear wing that contains 250 biomolecular research labs, and an organic, free-form wing that contains researchers’ offices. The atrium features a café, where casual interactions can easily take place. It also accommodates major conferences and seminars, banquet tables for fundraising events, temporary seating for ceremonial events, and flexible display for trade shows or other exhibits. Four bridges span the atrium, connecting the labs to the office wing at each level. Liberal glazing allows views throughout the space and into the laboratories and offices. Terracotta and stainless-steel panels clad the laboratory wing, while the rainscreen double curtainwall improves insulation and diminishes air filtration.