The new 268,000-square-foot Clackamas High School opened in April with a focus on daylighting. Though it has taken some time to get used to, Principal Dean Winder said the school is operating effectively. Photo courtesy of Interface Engineering Inc.

One of the principal tenets of green building design is the widespread use of daylighting. While the use of daylighting requires architectural choices in glazing materials, solar control and building siting and geometry, the integration of daylighting design and electric lighting falls squarely on the lighting designer or electrical engineer. At the new 268,000-square-foot Clackamas High School in Clackamas, Ore., daylighting was a central element in the architectural design and energy conservation program.

Interface Engineering Inc. (Portland, Ore.) was chosen to provide lighting design, electrical engineering and building commissioning for the project, which is expected to receive a Leadership in Energy and Environmental Design (LEED) certification from the U.S. Green Building Council. Architect Heinz Rudolf of BOORA Architects, Portland, Ore., wanted to make a major statement that a far more energy efficient high school could be designed on a conventional budget. The final product, which opened in April 2002, had a construction cost of $31 million ($118 per square foot), well within the envelope of conventional building costs for large schools in the Portland area.

“In the past, innovative lighting controls in schools simply consisted of switches that permitted banks of lights to be turned on or off,” Rudolf said. “The Clackamas High School design, based on ‘functionalism,’ or design through analysis, required a team effort to evaluate building orientation, massing, material systems, light reflectivities of materials and state-of-the-art fixtures, together with fully integrated computerized control and dimming systems in an effort to maximize daylight to the fullest extent.”

The task of designing lighting systems and commissioning the lighting controls to implement the daylighting program fell to Robert Dupuy, LC, IALD, and Scott Micucci, PE, senior lighting designers at Interface. Working with the manufacturer, Lithonia, the team chose to implement the lighting controls with the Synergy controller. According to Dupuy, “this is the most complex installation we know of to date of the Synergy controller.” Micucci was responsible for commissioning the lighting control system (making sure it worked according to design intent). Challenges included both software issues, such as programming the controls hand-in-hand with the factory representative, and hardware issues, such as bad relays and proper placement of hundreds of photocells.

“One of the benefits of control systems such as Synergy,” said Micucci, “is that incremental changes in system operation can be made on the spot, without an electrician, during building operations.” The project employs photocells to tell the lighting controls to dim the electric lighting whenever daylight is sufficient to meet specified ambient lighting levels. Controls also include occupancy sensors to turn off lights in unoccupied classrooms. Software also turns off most lights when school is not in session or the building is unoccupied. In many projects, this software is often tied in directly to the building security system.

According to Dupuy, a national award-winning lighting designer, daylighting design needs to be an ongoing collaboration between architect, lighting designer, control manufacturer, energy engineer and electrical engineer. “The first steps,” he said, “are to reduce ambient lighting levels, then to choose efficient fixtures – such as T5HO units – and only then to start messing around with elaborate control schemes.”

Interface served as an innovative consultant and major contributor to successfully mix daylighting with electric lighting, according to architect Rudolf. “Interface’s design includes a control system with completely new applications to provide utmost flexibility for controls, measurement and verification,” he said.

Architects also need to support the daylighting design intent by choosing reflective colors for the building interior and finding ways to get daylight into the building without bringing in glare from direct sunlight penetration. “In this project, we were able to reduce overall lighting energy demand by 57 percent compared with an Oregon code building,” said Dupuy, “and this also allowed the natural ventilation design to work better by reducing building heat gain from lights.” As a result, the finished project is expected to use 44 percent less energy than a “code” building in Oregon, according to the project’s DOE-2 energy model. Initial numbers on energy savings “are meeting our expectations,” according to Dave Church, physical plant director for the North Clackamas School District.

As the person responsible for designing and then commissioning the lighting controls, Micucci spent a lot of days (and nights) at the school, trying to get the software to do what the architect and engineers wanted, so that the system would be “invisible” to the teachers and staff. “What we wanted,” he said, “was that whenever daylight was sufficient, the electric lights would dim or not go on at all, and whenever a space was unoccupied for more than 20 minutes, the lights would go off.” Micucci says that the main lesson is that lighting designers should have to commission their own work: “it’s the only way you can make sure that what you designed to happen is actually what’s happening in the building.”

Interface’s team also strongly recommends that the design team have very specific statements of design intent from the beginning of the project and that the ultimate users of the building – teachers and staff – are represented at key design meetings early in the process. Communication and coordination with the architectural team is also a critical component of project success; otherwise, design intent will not be realized in the end. For example, a simple LED light that would indicate to teachers that the classroom lighting control system was working was “value engineered” out of the design at Clackamas. As a result, teachers may spend a lot of time toggling the control switches, further confusing the software. “In retrospect,” said Dupuy, “we probably should have made a bigger fuss over such ‘small’ issues, because they’ll ultimately have a lot to do with end-user satisfaction.”

Natural and artificial light work together in Clackamas High School. Daylighting design was an ongoing collaboration between architect, lighting designer, control manufacturer, energy engineer and electrical engineer. Photo courtesy of Interface Engineering Inc.

As the school’s first-year anniversary approaches, it seems that staff and students are happy with the combination of natural and artificial light. “In general, the school is operating effectively,” said Principal Dean Winder. “I haven’t heard that there’s too much or too little light.” It has taken everyone time to get used to the new system, Winder noted.

Physics teacher Dan Robinette agreed. “It’s a different way to think about lighting,” he said. “But for the most part, I don’t give it much thought. I’m aware that the lights are controlling themselves maybe once or twice a week.”

Robinette and other staff members at Clackamas were trained on the new system during a fall inservice training, a crucial piece to making the system successful, according to its designers. “Training for staff as to not only the ‘how’ but the ‘why’ is critical,” noted David Pickett, PE, Interface vice president and senior electrical engineer. “You just can’t walk away from the system and expect staff to understand how it works.”

The team also found out that sophisticated lighting controls are new enough that they had to spend a lot of effort telling the contractors exactly why they were doing what they had specified. Micucci commented, “With any new technology, to achieve the goal you have in mind, you have to collaborate with the contractor to avoid overlooking any pieces of the puzzle, no matter how small.” As the saying goes, “the devil is in the details, and it’s all details!” EDC

Sidebar: Designer’s Notes

Key elements on integrating lighting controls with the architecture and electric lighting systems:

Does the architecture support the logical layout of daylight apertures and electric lighting to be controlled? Do the plan and section of the building work together for this purpose?

Does the intended function (plan) work if the electric lighting is controlled in response to daylight contours (section)?

Do the energy savings justify the original capital investment and expected maintenance expenses? If the answer is no, reasons other than financial need to be understood.

Will the automatic and manual controls make sense to the user? If not, one can be assured that measures will be taken to disable the system.

For better of worse, today’s lighting control systems have the technical and programming abilities to provide any combination and sequencing the designer can imagine. Quite often this can result in a system that doesn’t match the intuition of the average user who may not have the same technical sophistication or sense of possibilities as the design engineer.

The ultimate daylit building is one that needs no electric lighting during normal daylight hours. The most successful control systems make changes that are imperceptible to the occupants.

Contributed by Craig Oty, PE, Interface Engineering, Inc.