This is the most common lighting design problem in any educational facility whether an elementary school, high school, vocational school or institution of higher learning. A classroom can take many forms and can be quite literally any space with the building where learning occurs. In some cases, students spend their entire day inside one classroom while in other cases, different subjects are taught in that same classroom to different groups of learners during day and evening hours. As the most intensively used spaces in the building the lighting design must allow for a wide variety of instructional methods.
The arrangement of furnishings, resources and task areas, even the placement of instructor and the students in today’s classrooms is as varied and as flexible as in a modern office. The lighting needs to be equally flexible and responsive. With laptops becoming a standard fixture at each student’s work area, lighting that was adequate for fixed vertically oriented display screens, will now be problematic for screens that move about the workspace and tilt as much as 55 degrees off vertical. Designs for new and future school construction include advanced glazing materials and window and skylight placement to provide overhead light for tasks, while minimizing heat loss or gain and HVAC loads. Daylight control systems incorporate window baffles, shades and diffusers to adjust to the sun’s seasonal movement while daylight harvesting sensors and controls adjust lighting illuminance levels for maximum energy savings and extended lamp life.
General Purpose Classrooms
These typically accommodate 20-75 students and have a rectangular floor plan of at least 350 square feet. Windows supply general illumination and contact with the outside world. They usually run the length of one wall and are a few feet high or they may occupy the entire wall space floor to ceiling. Some classrooms are windowless or may have a single small window in a corner. Windows usually have shades or blinds to control daylight for AV presentations.
Lighting for classrooms should:
Provide uniform distribution
Provide sufficient illuminance levels and contrast ratios for tasks or activities
Blend with and complement the space architecture and décor
Be visually stimulating and motivating (light source’s CRI and CCT)
Luminaire design is important. Choose commercial grade luminaires like those in office buildings.
Suspended indirect or direct/indirect luminaires provide high quality light reflected off the ceiling for uniform distribution and less shadow or glare. Walls and ceilings should be light in color and ceiling should be at least 9 feet. For classrooms with low ceilings, use surface mount or recessed fluorescent luminaires. Look for high efficiency luminaires that illuminate the entire height of the walls to prevent a "cave-like" effect and make the space more visually appealing.
Luminaire placement is important. The easiest approach for flexibility is to provide indirect or direct/indirect uniform illuminance on horizontal work surfaces throughout the space. Consider orientation of luminaires in relation to:
Position of desks or worktable groupings
Chalkboards or white boards
Location of windows
The photometrics (light distribution characteristics) of the luminaires
The need for flexible arrangement of furnishings
A perimeter lighting arrangement (luminaires 2-3 feet from the wall) offers the advantage of uniform illumination throughout the space and a sense of openness due to wall illumination. It also provides lighting for wall mounted displays and chalkboards.
Supplemental accent lighting may be needed for the “instructor zone” to highlight speech communication, chalkboards, whiteboards, easel graphics or demonstrations. This is usually a combination of both vertical and side lighting luminaires.
Lighting controls should be included so that luminaires can be selectively dimmed or switched off to accommodate changes in space configurations or presentation media.. Luminaires can be circuited and controlled in rows parallel to the window as part of a daylight harvesting system. Occupancy sensors should be used to switch off lights when the space is vacant.