Consulting-Specifying Engineer - May 2008 - (Page 24) Illuminating students Lighting can suck up a large amount of any school’s energy costs, and both school officials and lighting designers are looking for quick fixes to reduce this cost. Upgrading fixtures and ballasts can increase efficiency as much as 40%. But tightening budgets and rising energy prices demand that lighting designers and engineers do more. What’s left? Take control of the lighting systems. A school building is a 20- to 50-year investment, so by selecting the right products and control system, O&M costs can be controlled over the life of the building. Taking control Lighting controls can function many ways within a school: •Occupancy sensors, so lights turn on only in a classroom with students or activity •Timed lights that turn on and off during certain parts of the day and change as daylight changes through the year, or as scheduling events dictate •Photosensors that react to changing daylight levels within a classroom that dim or turn off electric lights when not needed •User-controlled dimmable systems that are adjusted according to the visual needs of the teacher. James R. Benya, PE, FIES, principal at Benya Lighting Design in West Linn, Ore., says that ASHRAE 90.1-2007 will most Lighting controls and proper daylighting techniques can have an enlightening impact in the classroom. BY AMARA ROZGUS, Senior Editor ighting is such a subjective thing. Some designers aim for the maximum prescribed foot-candles in all situations, figuring the client will want everything to be as bright as possible as code allows. Others create intricate designs that meet the average standard foot-candle recommendations for the space, leaving shadows and hot-spots that are awkward and inefficient to some, yet dramatic and interesting to others. Still other lighting designers try to see how low they can go, and aim for the least amount of kilowatt hours consumed to help reduce energy costs and carbon emissions. This may be the best option in schools, which tend to require varied lighting design solutions for its different types of rooms—and also have some of the tightest budgets. According to ASHRAE 90.1-2004 and the Illuminating Engineering Society of North America (IESNA), the lighting level should be determined by the visual task. If the task is more intensive, such as intricate drafting or detailed work, the light level should be higher. Most K-12 classrooms, however, don’t have highly intensive visual requirements anymore due to the influx of technology and computers, meaning that lighting levels can be designed fairly standard in each classroom, which is what we’ll discuss here. L likely include a credit for adding lighting controls. Therefore, control systems that reduce wattage per square foot will be given the credit they deserve. This reduction increases energy efficiency, which reduces energy costs and will help owners and engineers obtain points when applying for USGBC LEED points, for example. Benya suggests going one step further. He said that to beat the code, know what technology was used when the code was determined, and use a better technology. By staying ahead of the technology curve, lighting designers will not only design schools with better lighting options, they’ll save money along the way, especially if they keep up with appropriate O&M. The trick is to dictate what kind of lighting is needed in a classroom before selecting a control system. For example, many high schools teach several classes on computers (or students’ laptops), which requires a different type of overhead light—without glare. Also, because blackboards are a thing of the past, lighting on white erase boards is a whole different ballgame. Dimmable systems set up in appropriate zones offer the right lighting in multimedia classrooms or those with audio-visual options. It’s key in these cases that the teacher can override the programmed lighting system so that lighting is darkened for screens at the 24 Consulting-Specifying Engineer • MAY 2008
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