Three ways to light a classroom

It is often said that lighting is for people rather than buildings. This applies even more so for classrooms. Although a common objective of lighting is to enable work to be carried out quickly and accurately without discomfort, this is a narrow approach when applied to classrooms.

The real function of the lighting is to facilitate learning. This should make the designer think more holistically. One difference is that the students no longer face the same direction all day. There aren’t serried ranks of desks but, often, individual tables where students can work in groups.

The chalkboard has long disappeared but you still need a lot of light on the walls. This is not only to see the whiteboard, but also flip charts, notices, bookshelves etc. This situation changes with interactive “smartboards”.  In effect, these produce a projected image which can be hard to read if there is too much illumination on them. The simplest solution is to have a separate dimmer/Off control for the ceiling luminaire(s) which illuminate this wall.

By far the best, and most helpful, guidance available is the “Lighting for Education” LG5, 2011 published by the Society of Light and Lighting in conjunction with the UK Department for Children, Schools and Families, DCSF, (previously called the DfES).

The guidance gives a lot of emphasis to the benefits of daylight, but these aren’t always realisable if you are refitting an existing classroom.

One aspect of the lighting which is crucially important is the concept of mean cylindrical illuminance. In simple terms, it is the illumination on the students’ faces. LG5 recommends at least 150lx Ecyl to achieve a good result. Lighting software can calculate this in seconds.

Lighting Guide 5 recommends, amongst other criteria, 300 lx for the task areas such as desks (more for specialist areas like labs). Interestingly, teachers require 500 lx. This is quite simply down to the age difference. Older people require more light for the same visual performance.

Lighting can account for 30% of the electrical consumption in schools. Make sure the luminaires are dimmable and linked to a daylight harvesting system. But always remember the lighting is to help the students learn. Saving energy is important but should be secondary to producing the best learning environment. 

Classrooms come in as many different shapes and sizes as the children.  In this Design Clinic, our classroom measures 10m x 7m with a 3m ceiling.

This uses continuous runs of recessed LEDs to produce a seamless line of light across the whole ceiling. The main benefit of the C80 is that you can have custom-made lengths and 90° corner units, thus you can match the lighting exactly to the architecture and room dimensions.

The LED C80 is available in three different light outputs: approximately 2,800 lm/m, 1,800 lm/m and 800 lm/m. Our scheme, achieving over 400 lx, uses the 1,800 lm version. Again, depending on the application, an opal or micro-prismatic optic is available. The opal has a wider beam whereas the micro-prismatic has a sharper cut-off at 60° and a more intense downward beam.

An asymmetric optic is available for wall washing, for a whiteboard or display, for example.

Tech spec
  • Luminaires C80-RR LED
  • Optical control Micro-prismatic
  • ArrangementThree continuous rows
  • Average illuminance (Eh) at desk height
  • 425 lx
  • Electrical load
  • 3.4 W/m2 at 100% output
  • Pros
  • Clean appearance

This option uses recessed 600 mm x 600 mm panels with micro-prismatic optical control. The Modul-R luminaire is DALI controlled and can vary the CCT from 2,500K to 7,000K with an Ra >90.

The advantage of this type of scheme is that it can be fully automated to vary the illuminance and CCT throughout the day. The whole space is brightly lit and the ceiling and walls are fairly uniform.

Currently, there is a lot of research being done concerning improving the ability of children to learn by varying the colour temperature and illumination level throughout the day. Glamox recommends a high CCT and illuminance at the beginning of the day to boost alertness and then use a warmer CCT and lower illuminance during rest periods and at the end of the day.

Tech spec
  • Luminaires Modul RC tunable white, 600 x 600 panel
  • Optical control Micro-prismatic panel
  • Arrangement
  • 3 x 3
  • Average illuminance (Eh) at desk height
  • 520 lx
  • Electrical load
  • 7.4 W/m2 at 100% output
  • Pros
  • Variable CCT throughout the day

One of the best ways to achieve a comfortable, well-lit environment is to use suspended direct/indirect luminaires. This method ensures that the ceilings are well lit and the space looks light and airy. It also produces good vertical illumination on the students’ faces whilst minimising glare.

This technique works best with bright white ceilings. Dark wood ceilings would look good but wouldn’t reflect enough light downwards to the desks.

The C20-P4 LED luminaire is just 30mm in height. 60% of the light is emitted upwards in a fairly wide beam via a clear, smooth, wipe-clean lens. The 40% downward light is controlled by a micro-prismatic lens which has a 60° cut-off.  

A useful feature is that you can control the upward and downward light separately using DALI control.

Tech spec
  • Luminaires C20-P4 LED
  • Optical control Clear upper and micro-prismatic directed down
  • Arrangement
  • 3 rows of 2
  • Average illuminance (Eh) at desk height
  • 565 lx
  • Electrical load
  • 4.4 W/m2 at 100% output
  • Pros
  • Light and airy