Daylighting: Natural Light in Architecture

SUMMARY

The CIE have published a set of guidelines for lighting design for energy
conservation, which if adhered to will ensure the creation of a lit
environment that is appropriate, energy conscious and that should satisfy
both EEC and UK lighting directives. These are as follows:

1. Analyse the task in terms of difficulty, duration, criticality and loca-
   tion, to determine the lighting needs throughout a space, taking into
   account the visual differences among people due to age and other
   factors.


2. Design the lighting so as to provide the necesssary illiumination on
   the task in accordance with current recommendations.


3. Select the most efficient lamps appropriate to the type of lighting to
   be specified, taking into account the need for colour rendering.


4. Select luminaires that are efficient, having light distribution charac-
   teristics appropriate for the tasks and the environment, and not pro-
   ducing discomfort glare or serious veiling reflections.


5. Use the highest practical room surface reflectances, so as to achieve
   the best overall efficiency of the entire lighting system.


6. Integrate the lighting with the heating and air-conditioning systems,
   as dictated by climatic conditions, to save energy for cooling and
   heating purposes.


7. Provide a flexible lighting system, so that sections can be turned off
   or the lighting reduced when not needed.


8. Coordinate , when appropriate and when space permits, daylighting
   with electric lighting, ensuring that this does not introduce glare or
   other brightness imbalance in the environment.


9. Establish an adequate maintenance programme for periodic cleaning
   of the luminaires and room surfaces and for lamp replacement.^1
   These guidelines specifically exclude mention of the aesthetic require-
   ments of the project, and it must be up to the architect and his lighting
   designer to ensure that in satisfying the guidelines, this is not at the
   expense of the lit appearance planned for the space.

44 Daylighting: Natural Light in Architecture

(^1) CIE. The Commission International de L’Eclarage