Prescribed Light

Treating patients since 1736, New York’s Bellevue Hospital Center is not only the oldest public hospital in the country, it also holds the distinction of serving U.S. presidents and United Nations diplomats.

Consequently, when it came time to create a new ambulatory care facility, the design team, led by Pei, Cobb, Freed and Partners, was charged with radically transforming this venerable institution into an advanced medical campus. In adding 207,040 sq. ft. of waiting areas, examination/treatment rooms and administrative areas, one of the greatest challenges of this project was blending the old with the new.

And in the case of the lighting team’s portion of this challenge, it meant providing smart, yet cost-effective and energy-efficient lighting solutions that reinforced the bold architectural concepts of the center’s additions while respecting the beauty of the historic building.

Furthermore, the design team desired to revitalize the facility to serve as a glowing beacon to the community, displaying not only new architecture, but technology and design excellence. Thus, the lighting designers were tasked with developing a solution for perimeter offices that not only provided adequate lighting for office occupants, but also proclaimed the facility’s nighttime identity to the New York public. So as not to generate huge power bills, it was decided that the lighting system would need to maximize energy efficiency by using available daylight and monitoring actual occupancy. A system based on the DALI protocol—Digital Addressable Lighting Interface—proved to be the answer.

Integrating intelligence

The system selected uses direct/indirect intelligent light fixtures that integrate occupancy and daylight sensor intelligence into each fixture. Each fixture is 8 in. long and has two lamps in cross section—four total. Two lamps are controlled and dimmed for nighttime building lighting and daytime lighting when sufficient daylight is not available. The nighttime lighting automatically turns on to a dimmed intensity at dusk and turns off automatically at 11 p.m. The second pair of lamps is controlled by occupancy. When the occupant walks into the room, these additional lamps are turned on if there is inadequate daylight. When the room is unoccupied, these lamps turn off. All of the sensors are integrated into the fixtures.

The arrangement sounds complicated—and costly—but developments in technology allowed the team to achieve the hospital’s goals at minimal cost. In fact, the energy savings will pay for the system in three years.

In brief, the team implemented Lightolier’s iGEN DALI-based system, which allows the necessary functions to be programmed into individual ballasts. Changes in functionality can then be accomplished by simple reprogramming without the need for rewiring. The intelligent control system was incorporated into a light fixture developed for flexible office environments. The “Agili-T” system, also developed by Lightolier, enables space users to easily relocate light fixtures for future space planning changes or reprogram fixtures for future space use changes.

Unique features include “feedback” information for the facility. Essentially, energy usage can be monitored and adjusted as required. Since the ballasts are also dimming ballasts, intensities can be varied based on user needs or other functional requirements. Besides the direct energy savings offered by such intelligent systems, these strategies are extremely sustainable. The upshot is that reusing light fixtures—instead of disposing of them—when a facility requires plan or use changes, minimizes waste. (See “DALI = Sustainability” below).

Control, control, control

Since the building was designed to maximize natural light, including in the new 90-ft., atrium that marries the new with the old, it made sense for all of the lighting systems in the center to be governed by an intelligent programmable relay system that controls the lights automatically, based on time of day, daylight availability and functionality. The lighting systems that can be turned on and off based on time of day are predominantly located in public spaces without significant amounts of daylight. For example, the atrium and waiting areas require electric lighting when adequate daylight is not available. This was accomplished with daylight sensors, calibrated and integrated with the relay system. At the same time, local low-voltage manual switching stations are strategically located throughout the facility to allow lights to be controlled based on function and to override any timed or daylight-controlled spaces. For the most part, however, the lighting systems basically run themselves, allowing for minimal intervention by the facility staff.

In general, light sources used throughout the facility were chosen for their efficiency, color-rendering capability and lamp life. The team also made every attempt to minimize the different lamp types to facilitate easy maintenance. Thus, T8 fluorescent lamps were selected for general patient areas and T5 fluorescent lamps were used in the First Avenue administrative areas. Compact-fluorescent lamps were specified for most circulation areas, and ceramic metal-halide lamps installed in the tall public space areas. The designers were able to keep all lamp types to 12 for the entire building.

The atrium

While energy savings were important, the lighting team was equally tasked with aesthetics in marrying the old and the new. The facility’s new entry atrium, which has become the emblematic heart of the campus, is perhaps the best example of this work. Approximately 10,000 daily visitors enter the facility beneath a sheltering overhang and do so while passing through transparent glass entrances that treat them to an axial view of the original monumental entrance portal. Following suit, the entry and lobby are illuminated with ceramic metal-halide recessed low-brightness downlights and wallwashers, and the brick entry walls are bathed with light. These particular light fixtures were selected for their optical performance, long life and good color-rendering properties. Essentially, the effect of the light is delivered with minimal fixture presence.

Upon entering the 90-ft.-high atrium space, one experiences the powerful historic brick wall rising through a sloped skylight to its pediment-capped culmination. The conjunction of the sweeping, curved balconies of the new building and the handsome, historic brickwork is celebrated in natural light during the day, as all of the atrium’s electric lighting is automatically turned off to conserve energy and prolong lamp life.

The original monumental entrance is illuminated with 1,000-watt, five-degree metal-halide spotlights mounted near the top of the atrium. These fixtures have large shielding hoods that minimize glare for atrium occupants and are located where they can be easily accessed for maintenance with a basic ladder. Furthermore, historic lanterns were removed, restored and reinstalled flanking the entry. The historic entrance can easily be seen from First Avenue, adding to the visual excitement of the space.

The same metal-halide spotlights used to illuminate the entrance wash the historic brick wall, except that the light is delivered by reflecting mirrors mounted within the atrium skylight structure, inside of window pockets (see “Key Lighting Products Specified” below for more on this product). These new windows were designed to swing in so the fixtures could be relamped and aimed from within the historic building. The reflecting mirrors have been installed on the trusses and are also positioned to bathe the historic brick wall with warm, soft lighting.

An actual mockup was built while the building was under construction to test this concept. What was unique about the mockup was the fact that it was installed upside down, demonstrating the lighting effect from the floor, as opposed to the atrium ceiling. This system was the first of its kind, illuminating a 90-ft. wall from a remote location. This was done to enable maintenance staff to completely re-lamp fixtures from inside the historic building, without the need for lifts or scaffolding. A detailed lighting analysis also determined the effectiveness of intensity and distribution, which was confirmed by the mockup.

The ambulatory care side of the atrium is illuminated using cove lights that feature the curved atrium edge. Stagger-mounted high-efficiency T8 fluorescent strip light fixtures were designed with perforated metal shields to provide continuous light without visible socket shadows. The lighting assembly was integrated into an architectural cove so that sightlines from above would be minimized. Besides reinforcing the curvature of the space, this lighting system adds a dynamic, fluid component.

Beyond the atrium

Moving into the facility itself, waiting areas on every floor have a graphic wall that spans almost the entire length of the building. This wall is illuminated with compact fluorescent wallwash fixtures, selected for their optical performance, good color and long life. Good wallwashing provides uniform lighting without “scallop” patterns of light. The illuminated graphic not only provides ambient lighting for the waiting areas, but it also supports the entire wayfinding concept developed by the project team. Specific colors are used for specific departments on specific floors so patients can easily navigate their way around the building. Additional complementary recessed compact fluorescent downlights are used in waiting areas and customer service desks to blend with wallwashing light.

Patient circulation areas are also lighted using recessed compact fluorescent downlights and wallwashers. These light fixtures are appropriately scaled for corridor lighting and provide a comfortable environment for the patients. Patient rooms are lighted using recessed indirect light troffers. These fixtures were selected based upon performance criteria as well. Patients can be examined without any disabling glare, and the exam rooms appear bright with all wall surfaces illuminated. This is extremely important in heath-care environments, in addition to the fact that creating a welcoming, non-institutional look was an important goal for the design team.

The administration spaces located on the west elevation, First Avenue side of the building were yet another challenge for the team. These private offices serving medical and administrative functions were designed to use daylight to the greatest extent possible. The ceiling heights are 10.5 ft. at the window wall, lowered to 9 ft. at the interior. The large aperture at the window allows for significant daylight penetration. Supplemental shades were also implemented to provide adequate shielding from direct sun.

A wonderful public reception

The completion of this ambitious project is a significant milestone in the long history of Bellevue Hospital. Because the ambiance of this facility promotes health and well-being, visitors to the new ambulatory care building and the other campus buildings are experiencing a new grand public space in New York. The atrium has been so well-received that it has become a major space for events.

But the lighting solutions of the atrium and the west elevation offices had some associated risk since they had never been done before. Therefore, careful planning, analysis and mockups were very helpful, as is always the case with new technologies.

And besides looking good, the lighting design is very energy efficient at 11 watts per sq. ft. If one considers the smart relay lighting controls in the public spaces and the DALI system in the administrative offices, the net effective usage is equivalent to 0.6 watts per sq.ft.—barely one-third of what is allowed by the New York State Energy Code. This could only be accomplished in a building that has been designed to maximize the use of daylight. Finally, operational and maintenance issues were equally weighted in considering all aspects of the lighting systems so that the facility can have the same appearance for years to come.

DALI = Sustainability

A benefit of intelligent lighting is the fact that it’s a tool for sustainable design, providing benefits in the LEED design criteria categories of energy management, control, commissioning/materials and resources reduction.

For example, the DALI-based iGEN unit provides a useful means of organizing energy-management strategies via flexible and simplified daylight harvesting, enhanced task tuning, scheduling and load shedding. Furthermore, its integrated sensor technology reduces the size of control zones. It can also achieve 40% to 60% lighting energy savings beyond ASHRAE 90.1 1999 and 2004.

Another plus is that its independence from power circuits provides flexibility and eliminates “home runs,” reducing wiring materials and costs 20% to 30% with a reduced number of components in order to execute the control scheme.

Intelligent lighting technology also provides documentation and verification of energy reporting and management.

—By Meg Smith, Sustainabilty Specialist, Lightolier/iGEN, New York

Key Lighting Products Specified

Beyond Lightolier’s “Agili-T,” at least two other lighting technologies proved key:

Kurt Versen downlights and wallwashers. Specifically, these lamps utilize precision optics that deliver the appropriate light distribution with minimal apparent source. The reflectors also use a diffuse finish to further reduce source appearance.

Zumtobel Staff—MIROS. The company’s projector-mirror system offers an intriguing solution for reflecting light into distant spaces with high ceilings. MIROS is designed to flood a room with light without revealing its source. The spatial separation of the source and the reflector creates completely new lighting possibilities. The beauty of MIROS lies in the way it provides ample, ergonomically appealing lighting, without competing with the space’s design aesthetic. The luminaire uses a 1,000-watt metal-halide five-degree beam. The computer-designed reflector ensures perfect focusing and low beam divergence. The reflectors are offered in specular, matte and perforated to provide different distribution.

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