Tualatin, a city of approximately 26,000 people, is proud of its new public library, the one building that serves all age groups. It is the city gemstone that represents the culmination of cooperative design efforts by city officials and the architectural design team to achieve community goals. The building shape presented many lighting design challenges because of its 4x4 rectilinear ceiling, radial floor design and limited budget. The project uses daylighting wherever possible, and includes occupancy sensors for small spaces, timers for local tasks, time clocks for large open areas and photocells for daylit areas.

The overall light level objective is 30 footcandles maintained, and all light sources have a color temperature of 3000 K. Throughout the project, vertical surfaces are washed with GE 28-watt Starcoat® Ecolux® T5 lamps. Horizontal surfaces are lighted with GE 39-watt ConstantColor® CMH® ceramic metal halide lamps. All vertical casework lighting is provided by LED systems. Dimmable cold cathode rings, indirect and exposed, provide visual accents.

A number of new fixture designs are featured in this project, minimizing the number of lamp types used and providing continuity in fixture appearance. Suspended dimmable fixtures with dual GE 42-watt Triple Biax® compact fluorescent lamps provide ambient light. Dimmable stack lights with GE 21-watt T5 lamps provide vertical illumination plus an upward component from a narrow slot on top of the fixture. A new minimal bracket design with hidden electrical wiring is fully adjustable to simplify installation. Because the stacks are radial, the arm length changes every three feet. Matching dimmable tapered radial pendants provide lighting over low stack areas.

Fixtures in the stack area are individually addressable via the Internet to allow zoned daylight management. A new UL924 emergency lighting solution was also created, allowing specific fixtures to be switched off and others dimmed to 10% rather than full load operation. As a result, inverter load was reduced 83% with a savings of $30,000 and the elimination of 19 large hazardous waste batteries.

The lighting power density for the total library, as built, is 1.3 watts per square foot. With tuning and controls, the adjusted watts per square foot drops to 0.9. Through a well-executed daylighting design and sophisticated control system, the lighting for the Tualatin Public Library is functional, aesthetically pleasing and energy efficient.