A recent lighting renovation enabled Northwood Middle School, in Fort Wayne, to increase light levels in classrooms and labs to 50 footcandles with one watt per square foot. At the same time, the school significantly reduced energy consumption while decreasing the number of lamps used in each classroom.

Northwood Middle School, which houses grades six through eight, was constructed in 1959. Before the retrofit, classrooms were illuminated with three rows of four-foot, two-lamp wraparound fluorescent fixtures.

The 24 units in each room consumed 95 watts each, for a total power consumption of 2280 watts per classroom. According to Jerry White, president, Engineering Consultants Inc. (ECI), Fort Wayne, the existing quality of illumination in each classroom was a problem. Because fixtures were perpendicular to the writing surface, students and teachers had to contend with shadows and glare.

During the retrofit, 12 two-lamp 2’ x 4’ PG Series fixtures from Holophane-owned MetalOptics Corporation were installed in each classroom. The units are six inches deep, with 18-cell parabolic louvers, and are mounted on 8-foot centers. Mounting height is nine feet. Input watts are 76 per fixture using a 1.18 ballast factor electronic ballast for a total of 912 input watts.

Lamps used are T8 32-watt, 3500° Kelvin, 85 CRI.

“When we design a lighting system for a school, we encourage the customer to consider color rendering to achieve the best possible illumination,” White said. “Studies have shown that educational benefits in a school setting are directly proportional to the quality of the lighting. When students have difficulty reading because of poor visibility, it’s hard for them to gather and retain information.”

The same PG Series fixtures were installed in the school’s labs. Initial illumination levels measured on lab benches were 112 footcandles.

“While the PG Series fixtures are rather unconventional for this type of application, we have confirmed that we can successfully light a classroom—and increase the illumination levels—with substantially fewer kilowatts,” White said. “Although the PG Series fixtures are more costly to purchase initially, the school will save money in the long term because the system includes fewer fixtures and consumes less energy.”

An occupancy sensor with a key-operated override switch controls lighting fixtures in each room. This allows teachers to turn off the fixtures during videos or other presentations.