Sick Building Syndrome: Healing Health Facilities
Innovative strategies improve air quality inside health-care facilities so that patients don't end up sicker than when they arrived
When we think of Sick Building Syndrome, the first context that comes to mind for most of us as the cause of the coughing, discomfort, and irritation usually associated with it is a hermetically sealed, over-air-conditioned high-rise office building. The last place you would expect to encounter it is in a building meant for healing. Yet hospital occupants, patients and staff included, are just as likely to fall victim to building-related illness as office workers. In fact, a recent study by the National Institute for Occupational Safety and Health shows that, outside of the manufacturing sector, work-related asthma rates are higher among those employed in the health care industry than in any other group of workers.
When it comes to the indoor environment of health care facilities, the chief concern doctors have for their patients remains infection control, especially since weakened immune systems are more susceptible to contagions. Estimates from the Institute of Medicine indicate that nosocomial infections—those contracted by a patient while under medical care—account for more deaths annually in the United States than motor vehicle accidents. While there is little design professionals can do to prevent hospital-acquired infection that results from human error—improper sterilization, for instance—architects and engineers are putting into practice inventive measures to improve the indoor air quality (IAQ) of health care facilities and reduce the risk of airborne ailments.
There are a number of indoor air pollutants that contribute to poor IAQ and the spread of airborne disease. These include biological contaminants such as molds and bacteria, and combustion pollutants like carbon monoxide and toxic particles. Even the building itself is a factor, since toxic substances emitted from building materials and furnishings degrade IAQ. This off-gassing, as it is known, is a by-product of such pervasive materials as paint, varnishes, carpet, flooring, insulation, adhesives, and particleboard. The harmful volatile organic compounds (VOCs) that are emitted from these materials can have adverse short- and long-term health effects. One of the easiest and most cost-effective approaches to improving IAQ is eliminating individual sources of pollution. It has become common practice today in the design of health care facilities to utilize natural materials—linoleum flooring, cotton insulation, undyed wool carpet, among others—as well as products with low or no VOCs. Additionally, more and more hospitals are switching to nontoxic cleaning products.
The need to vent
While source control is a straightforward first step toward improving IAQ, ensuring proper ventilation is an obvious, if not more formidable, task. Several recent health care projects make enhanced ventilation a design priority. At Dell Children's Medical Center of Central Texas in Austin, Ohio-based architecture firm Karlsberger brought the outside in by incorporating six courtyards—all open to the sky, and all but one enclosed on all sides by building walls—that serve as air intakes for the hospital's innovative mechanical system.
Replete with flora representing the various ecosystems found within central Texas, as well as numerous water features, the courtyards—referred to as the "lungs" of the building—provide the interiors with clean, oxygenated air from an extremely controlled environment. "In the old children's hospital, they complained that they could detect a faint smell of lawn-mower exhaust in the operating room when the lawn was being mowed," recalls Joe Kuspan, AIA, principal at Karlsberger. The new arrangement avoids such scenarios: Within the courtyards, a couple of which are inaccessible, there is no lawn maintenance (the few small patches of grass are artificial), or trucks pulling into a loading dock spewing fumes. Throughout the hospital campus—located on a former municipal airport site—smoking is prohibited, and this is strictly enforced in the courtyards that are open to patients, visitors, and staff for physical therapy activities and outdoor dining.
Locating the air intakes at these courtyards provides other advantages as well. With Texas's sweltering summer days, taking air in from the roof, as is typically done, would mean filling the building with super-heated air. Instead, the roof is equipped with heat-recovery units located at the upper elevation of the courtyards, above a series of stacked air handlers, which are distributed on each floor. Rather than utilizing a single, consolidated, rooftop air-handling unit—which can be as large as a transit bus and typically pushes air down through shafts over long distances—Karlsberger "right-sized" these individual air handlers for specific zones of the hospital, each having varying needs. "While some parts of a hospital are like an office building," Kuspan explains, "other parts, such as the operating rooms, have very stringent air requirements." By reducing the distance air travels through ducts, the chances of picking up dirt and other particles along the way were lessened, and maintenance made easier. The setup was also well-suited for establishing smoke zones, a fire-safety requirement for hospitals.
At the same time that plans for Dell were being developed, the local utility, Austin Energy—noted for being among the greenest public utilities in the country—was looking for projects in which to locate cogeneration plants. With a $1 million grant from the Department of Energy, Dell and Austin Energy established an on-site combined cooling heating power (CCHP) plant that utilizes state-of-the-art natural-gas-fired turbines. The CCHP is 75 percent more efficient and releases fewer carbon dioxide emissions than burning coal at a distant power plant.
Other low-polluting elements were used in the hospital's interiors. These include low-VOC paints and adhesives and linoleum flooring, which requires only soap and water cleanup rather than the continuous waxing and stripping that is often done to sheet vinyl and vinyl composition tile, the most common hospital floor finishes. Even the pest control is chemical free. "I've never walked into a new building before that didn't have that new-building smell," says Kuspan. "There's no odor whatsoever because of the materials we used."
Measures to improve IAQ were only part of Karlsberger's overall effort to make Dell among the most sustainable and efficient hospitals in the country. The new building was designed as the first acute-care facility to achieve platinum-level LEED certification. "Our business is helping kids get and stay healthy," says Robert Bonar, Dell's president and C.E.O. "How could we look the public in the eye and tell them such if we knew that we had just filled the building with materials that are off-gassing formaldehyde and other harmful products? Building healthy, sustainable buildings is the right thing to do for our kids who come here for care."
Architects at Perkins+Will had that same mindset when they designed a new 54,000-square-foot facility for New York Foundling. The primary mandate of the agency, founded as a home for abandoned children in 1869, is to ensure the health and well-being of the children of New York City. In their new mixed-use building, scheduled to break ground this summer, a charter school will share space with an outpatient clinic for neighborhood children and their families. "The project presents unique opportunities for health care design, in particular with socially based, initiative-driven organizations like Foundling," says Peter Syrett, AIA, Perkins+Will associate principal and designer. "The building really should be a manifestation of its values and role in the community, so we approached it as a design team that way."
The building's location in the Mott Haven section of the South Bronx presented a number of challenges, as well as opportunities, for the designers to align Foundling's mission with the architecture. With one of the highest asthma rates in the city, air quality both inside and outside the building became a design focus. According to the Mott Haven Longwood Community Asthma Partnership, a sister project of Foundling, the Bronx has almost twice the childhood asthma death rates of the city as a whole. A study by the New York City Department of Health and Mental Hygiene concurs, pointing out that the asthma hospitalization rate for that neighborhood of the South Bronx in particular is higher than that of the entire city.
Foundling's team did not want the new building to contribute to the asthma burden, but rather aid the overall health of the community and be a catalyst for change in the local environment—one whose overall air quality has been degraded due to the presence of light industry and the heavily trafficked Major Deegan Expressway, which is immediately adjacent to Foundling's site.
To that end, the combustion-free building will not be a point source of pollution in the community—the new facility relies on a ground-source heat pump rather than a furnace. Its bore field contains three wells 1,500 feet deep; electricity is used to temper the ground water for both heating and cooling purposes. On the exterior, the design also calls for a large vegetative wall and two intensive roof gardens, as well as gardens both inside and out. These elements are meant to act as biofilters in a similar fashion as the flora in the courtyards at Dell Children's hospital.
Turning their attention inside, the designers relied on the Environmental Protection Agency's list of asthma triggers to determine which substances to avoid. While the list includes items such as cigarette smoke and mold, it also includes 17 chemical compounds that are common components in construction and building materials, which in addition to VOCs and formaldehyde, include styrene, isonates, and aerosols. "Wherever possible, we are going to avoid their use in the building so that the indoor environment doesn't trigger an asthmatic episode, or, in the long run, contribute to the eventual onset of asthma for someone," Syrett explains. "What goes into a building has a direct impact on the health and well-being of its occupants."
Another trigger the architects hope to avoid is dust, both during construction and within the finished building. The building's design calls for minimal overhangs, ledges, and exposed piping so that there is less opportunity for dust to accumulate and become a respiratory irritant. In accordance with what is becoming standard practice at most health care facility construction sites, air locks and walk-off mats will be used during construction of Foundling. Additionally, ducts will be capped and sealed as work progresses so that dust doesn't settle inside and get spewed out once the mechanical system is fired up. That system uses a HEPA filter with a MERV rating of 14—among the highest available, and commonly employed in hospitals.
One thing Foundling does that most hospitals do not do is incorporate operable windows. While opening a window to let in the fresh air is usually a no-brainer for improving IAQ, in Foundling's case, the poor air quality outside led the architects to weigh this decision quite heavily. "In the end, we still think it's important for people to be able to open windows," Syrett says. "And we thought about the building in a longer trajectory. It is our hope that the point-source pollution will become less of a problem in the future, which is something to consider when you're designing for a 50-year building. One of the biggest issues with hospitals and other hard-core health care environments is sealing people in."
While some older hospitals have retained their operable windows, you would be hard-pressed to find new hospital buildings in the U.S. that feature them. "Health care providers worry about infection control above almost everything else," explains Walt Vernon, principal at Mazzetti & Associates. "There are documented instances of airborne transmission of pathogens from one space to another in buildings that use natural ventilation." But after becoming frustrated with the current paradigm of hospital design, Vernon, a cocoordinator for the Green Guide for Health Care (available for download at www.gghc.org), began to research how natural ventilation and displacement-ventilation systems would affect IAQ in a health care setting.
Even though these systems are commonly used in hospitals outside the U.S., the practice here is to stick with what you know. "There's a lot of science behind the use of overhead mixing systems," adds Vernon. "We don't have the same kind of data today on displacement systems." But Vernon is trying to change that. He has teamed up with Oakland-based health care giant Kaiser Permanente to test displacement ventilation in one-bed hospital rooms. In displacement ventilation, cooler supply air is introduced at a low velocity at the floor level, displacing the warmer room air and creating a zone of fresh, cool air at the occupied level. Heated, contaminated air rises to the ceiling and is exhausted out. (The trend in hospitals is toward single-bed design, and it is believed that displacement ventilation will work more effectively in that scenario.)
In the meantime, displacement ventilation is being used in facilities that do not deal with acute-care needs. (It is worth noting that Dell Children's hospital utilizes underfloor air distribution in its nonclinical, administrative areas.) The new Dan Abraham Healthy Living Center at the Mayo Clinic in Rochester, Minnesota, was designed by BWBR Architects and PSA-Dewberry around an approach to wellness that emphasizes research and the application of advanced technology.
Inside the 115,000-square-foot building—which includes spaces for aerobic conditioning, strength training, and massage therapy—a 7,500-square-foot pool enclosure, containing three pools for swimming and aquatic therapy, received special treatment by HVAC designers.
Two large air-handling units serve the main program spaces of the building, while a third, separate unit was designed strictly for the pool enclosure. This unit keeps the pool area under negative pressure so that air is drawn into it, preventing chlorine odors from escaping into adjacent spaces. "In considering patron comfort and health, the ultimate goal was to eliminate chlorine odors in this area," explains Mike Morris, of LKPB Engineers.
Conditioned air is delivered around the perimeter of the pool via an underground concrete air plenum. This allows the conditioned air to evenly and slowly rise into the pool enclosure, minimizing the chill to a wet swimmer walking around the pool. The even distribution also helps prevent chloramines from collecting on the pool deck. A UV-light treatment system is located in the pool recirculation piping to break down the chemical properties of chloramines, helping to eliminate the amount of chloramines in the water, and ultimately, in the air.
The design of health care facilities has traditionally focused on patient health and safety. Recent projects are proving that there is no better way to do this than by designing healthy buildings. "Health care projects currently represent a very small percentage of total LEED projects," cites Adele Houghton, AIA. But Houghton, the Green Guide for Health Care project manager, also points out that that number has grown significantly since the launch of the guide's Version 2.0 in November 2004. And the number is expected to continue to climb as the country experiences the largest health care construction boom in more than half a century.
