Breath Of Fresh Air: Ng Teng Fong General Hospital And Jurong Community Hospital
Rory Daniel/CPG Consultants.
To support natural ventilation for 82 percent of the wards and provide a window for every patient, the floor plate geometry staggers the headwall of the beds in a sawtooth shape.
Rory Daniel/CPG Consultants
Ng Teng Fong General Hospital and Jurong Community Hospital were together a winner of one of the 2017 COTE Top Ten Awards, a prestigious sustainable design awards program from the AIA Committee on the Environment.
Rory Daniel/CPG Consultants
Precast concrete forms extend out of the floor slabs to provide shading to the floors below.
Rory Daniel/CPG Consultants
Ward planters on the patient floors offer pleasant interior and exterior views.
Rory Daniel/CPG Consultants
Connected by a walkway, the acute care and outpatient clinic at Ng Teng Fong General Hospital and step-down Jurong Community Hospital incorporate the full spectrum of care in one campus, a first for Singapore.
Rory Daniel/CPG Consultants
Louvered jalousie windows located near a nurses’ station provide the staff with access to natural ventilation, while sunscreens help control heat gain and glare.
Rory Daniel/CPG Consultants
HOK and CPG’s eco-friendly design features natural ventilation, daylighting, photovoltaics, solar thermal collectors, rainwater collection, and a grey water system.
The opening of Singapore’s Ng Teng Fong General Hospital (NTFGH) and Jurong Community Hospital (JCH) two years ago was already an impressive feat. With a combined 1,100 rooms, the $461 million pair of hospitals, which are managed by JurongHealth, are the country’s first to fulfill the Singapore Ministry of Health’s new mandate—a part of its aggressive Healthcare 2020 master plan—to provide better patient-centered services in an integrated manner by pairing acute care and outpatient specialty services with a general community hospital. Nestled in a scenic
1.9 million-square-foot campus, the eight-story NTFGH clinic tower and 16-story regional hospital (opened in June 2015) support patients requiring urgent care, while the 12-story JCH (opened in October 2015) provides step-down care to patients requiring longer-term rehabilitative and palliative services.
But what’s garnered international attention and acclaim in recent months is the campus’ impressive environmental story. Delivering an energy use intensity (EUI) of 72 kBtu per square foot per year, the super-energy-efficient design utilizes 38 percent less energy than a typical Singaporean hospital and 69 percent less than the average U.S. hospital. “It challenges the traditional model of a hospital, both from American and Singaporean perspectives,” says Bill Roger, regional director of healthcare at HOK (San Francisco), which was the design consultant on the project.
Designed to Singapore’s Green Mark Platinum standards—which certifies buildings based on energy efficiency, water efficiency, environmental protection, indoor environmental quality, and other green features—the project was awarded one of the 2017 COTE Top Ten Awards by the American Institute of Architects Committee on the Environment (COTE). The Top Ten Awards recognize sustainable design excellence across the globe and require submissions to demonstrate how a project aligns with COTE’s criteria for social, economic, and ecological value.
Ng Teng Fong General Hospital and Jurong Community Hospital are one of the few healthcare projects to receive this coveted distinction, which is given out annually.
One of the most noteworthy design feats of the buildings was delivering not only views, but operable windows and naturally ventilated spaces to most patients. Other sustainable design highlights include 90 kW photovoltaic arrays on both buildings, designed specifically to offset the site’s lighting, and heat recovery, heat pumps, and heat exchangers with runaround coils to maintain required temperatures in the operating rooms. A chiller plant measurement and verification system sub-meters and tracks the system’s ongoing energy use, solar thermal collectors deliver 100 percent of the campus’ hot water needs, and a grey water system treats sewage for cooling tower re-use. Additionally, the campus features rainwater harvesting; T5 and LED lighting; daylight and occupancy sensors; and a building management system with monitoring, occupancy levels, and sleep modes for energy conservation.
Optimizing building layout
Providing every bed on the NTFGH and JCH patient floors with a view and natural ventilation began with a floor plate geometry that staggers the headwall of the inpatient wards in a sawtooth shape to create a space for each patient to have their own window (see diagram on page 44). “Departing from a linearly arranged communal ward layout, the wards are installed in a fan-shaped design with the beds rotated at an angle, creating a window with a view for every bed,” says Juby Koshy Varghese, senior architectural associate at CPG Consultants Pte Ltd. (Singapore), the architect of record. This unique aerodynamic form, coupled with single-loaded corridors and a funnel-shaped floor profile, maximizes wind flow and more effectively draws the wind in and out of the windows through the floor plate. Additionally, delivering natural ventilation for 70 percent of the buildings was achieved by the design team taking advantage of unique prevailing breezes, which reverse from one direction to another during Singapore’s two yearly monsoon seasons. By keeping the shape and layout of the patient floors as narrow as possible and providing enough distance between the window openings on both sides of the rooms, the wind can easily travel across a floor and escape from both directions.
As a result, 82 percent of the inpatient areas are passively cooled and naturally ventilated, with a small percentage of mechanical fan-assisted ventilation coming from ceiling and exhaust fans. In the event of seasonal haze in Singapore, caused by illegal agricultural and industrial fires in southeast Asia and exacerbated during the dry seasons, the windows will close and both NTFGH and JCH make use of a centralized air filtration system to filter the polluted air, Varghese says. “The impure air will be effectively filtered out before it even enters the room.”
To address infection control, the team used computational fluid models prior to construction to accurately map out the wind flow direction to make sure that the wind would not flow across multiple patients and spread germs before exhausting, says Mara Baum, sustainable design leader at HOK. The positioning of the layout and the size and placement of the windows ensure that the wind passes over only one patient bed before leaving the building.
While the layout allowed the team to achieve natural ventilation, it also created a challenge in transferring the structural load from the irregular shape in the upper floors to the more traditionally shaped floorplate at the building’s base. In other words, the structural system holding up the building has a significantly different shape at the base than the higher floors. The project team, including CPG Consultants Pte. Ltd. and the building envelope consultant Studio 505 (Melbourne, Australia), identified the issue early on and designed structural connectors in an interstitial floor between the towers and base building to transfer the structural load between the two floor plates.
With lots of daylighting and ventilation coming into the building, properly shading openings to prevent solar heat gain and glare was key. Fortunately, Singapore’s location near the equator means that the sun’s position at any given time of day changes only slightly throughout the year, making the exterior sun shading plan relatively easy to create, Baum says.
Overall, three levels of sun shading were built into the design, including large overhangs extending from the concrete floor slab to provide shading from the ceiling plane to the floor below. Smaller horizontal and vertical sun shades were installed in louvered jalousie windows. Custom external shading devices, including sliding sun screens and light shelves, deliver shading to at least 60 percent of the critical façades where patients and staff reside. Even green roof vegetation, located next to windows on multiple floors of both buildings, is considered a tertiary shading element, with the added benefit of evapotranspiration helping to lightly cool the ambient temperature inside the buildings while absorbing and trapping a small amount of pollutants. (For more on the building’s green façade, see sidebar, “Healing Oasis”)
The naturally ventilated design also eliminates mechanical cooling requirements for 70 percent of the building, allowing the hospital to install smaller cooling towers. The towers use a specially treated grey water and air handling unit condensate for their water needs, a process that enables more cycles of water reuse. “So not only does the cooling tower use reclaimed water, it’s able to use the water more effectively than conventional city water,” Baum says.
The campus’ other conservation strategies include water-efficient plumbing fixtures and a rainwater capture system to help irrigate the extensive landscaping on-site. The facilities don’t need too much rainwater due to the tremendous rainfall in Singapore (an average of 91 inches per year), but irrigation ensures that the plantings, particularly on the building, remain green. In addition, sub-meters and leak detection facilitate monitoring, maintenance, and control of the cooling tower, toilets, and irrigation system, leading to less water waste.
A lesson for all
After two years of operation, the wards’ ventilation performance is getting high marks from users. Based on patient and staff surveys, which were conducted in March 2016 after nine months in use, the average indoor temperature of 84.5 degrees Fahrenheit was accepted by 93 percent of surveyed users and the average relative humidity of 63.7 percent was considered comfortable by 90 percent. In addition, 80 percent reported that the lighting levels are “just right” with a good amount of natural daylight, 90 percent of the patients interviewed agree that the ward design has helped them recover, and 90 percent of the staff state that the ward design has helped them become more productive in their work.
Could it be an example worth following for hospitals around the world? Jury members for the COTE Top Ten Awards think so, describing the project as an “extraordinary model for hospitals to behave as healing environments, not seen in the United States. The passive strategies demonstrated here are a model for hospitals around the world.”
But in terms of its applicability for U.S. hospitals, specifically, Roger says that cultural differences might make that difficult to achieve. For example, the Singaporean patient population is more accepting of warmer indoor temperatures, which allows the solutions used at NTFGH and JCH. Furthermore, Baum says that thermal comfort data for tropical climates like Singapore suggests occupants aren’t just comfortable in warmer temperatures but are actually uncomfortable and less productive in cooler temperatures. “This research also tells us that air movement from natural breezes is very important, and that can go a long way toward making people more comfortable without the need to have a specific fine, narrow temperature range, which we usually have to design to in North America,” she says.
However, Baum suggests that there may be opportunities for more flexibility in designs than building teams realize when it comes to ventilation and the temperatures occupants expect in the West. For example, U.S. hospital patients and staff may be comfortable in healthcare spaces a few degrees warmer than current accepted standards, or there may be more ways to incorporate natural ventilation than are currently explored (for more on natural ventilation, see “Winds of Change”). Ultimately, Rogers says, “I’m hopeful that over time, the ability to open up your window could become as standard as the single room.”
Barbara Horwitz-Bennett is a freelance writer based in Jerusalem. She can be reached at firstname.lastname@example.org.
With a variety of garden spaces and vegetated walkways included on the campus of Ng Teng Fong General Hospital (NTFGH) and Jurong Community Hospital (JCH)—including a pathway garden along the bridge connecting the two buildings—patients, staff, and visitors are afforded outdoor areas for rehabilitation, respite, and dining.
For example, ward planters are aligned and positioned to be viewed from each patient’s window, thereby creating a unique façade. Although not accessible, the planters feature assorted plant types of various sizes (including trees up to two stories tall) and are serviced by water sensors and drip irrigation.
Among the assorted gardens, a mobility park next to JCH with direct access from a rehab facility is the first of its kind in Singapore and incorporates mock-ups of various modes of public transportation. “The park includes steps and ramps, multi-terrain walkways, a sensory garden, and a pedestrian crossing with traffic lights as part of its holistic care to help patients reintegrate back into the community,” says Juby Koshy Varghese, senior architectural associate at CPG Consultants Pte. Ltd., the architect of record on the project.
Opening date: June 2015 (Ng Teng Fong General Hospital), October 2015 (Jurong Community Hospital)
Owner: Singapore Ministry of Health
Total building area: 1.8 million (includes Ng Teng Fong General Hospital, Jurong Community Hospital, and Specialty Outpatient Clinic)
Total construction cost: $461 million
Cost/sq. ft.: $248
Architecture: HOK (design consultant and medical planning), CPG Consultants Pte. Ltd. (architect of record), Studio 505 Melbourne (design consultant)
Interior design: Bent Severin and Associates Pte Ltd.
Engineering: CPG Consultants Pte Ltd. (structural/civil), Parsons-Brinkerhoff Asia (MEP)
Construction: GS Engineering and Construction
Green Mark consultant: ZEB Technology Pte Ltd.
Landscape: Peridian Asia Pte Ltd.