Towards the third stage of the lighting profession

Abstract

The notion of stages of the lighting profession is examined to identify the main themes that have directed the objectives of the lighting profession. It is proposed that the objective of the first stage was provision of uniform illumination over a horizontal plane, and that of the second stage has been to provide illuminance suited to human need, based on visual performance. This brings us up to the current era, and it is the author’s opinion that the second stage has failed to achieve its objective. While codes and standards pay lip service to visual performance, the reality is that for the vast majority of situations where lighting standards are applied, the aim is to meet user expectations for the spaces they occupy to appear adequately lit. The metrics currently used to specify, measure, and calculate lighting levels are inappropriate for this purpose. The concept of mean room surface exitance is proposed as a basis for lighting standards. Procedures for calculation and measurement lead to some startling conclusions. Familiar notions of lighting effectiveness and efficiency are turned upside down, and an entirely different way of thinking about interior lighting design is revealed. The essential difference is a switch from assessing light incident on planes to assessing light arriving at the eye. Such a change of thinking may be seen as a precursor for the third stage of the lighting profession.

The Productivity Paradox in Green Buildings

“…However, Cuttle [23] is clear that while this level of light may be sufficient for "performance" it is inadequate for "appearance". Furthermore, using the level of light on a working plane is not a representative measure with which to assess appearance since perception of lighting is based on the light that "exits" all surfaces in a room (luminence) rather than the light level that "arrives" at a certain point in a room (illuminance).…”

“…These assumptions have been challenged for many decades [22] but more recent research has demonstrated the flaws in assuming that the appearance of lighting in a space can be measured by a level of light on a working plane and that more light necessarily results in improved appearance or performance [23]. This research exposes that there were no empirical studies carried out to justify the basis for commonly recommended light levels in offices; they were based on "reason rather than research" [23] (p. 77).…”

“…This research exposes that there were no empirical studies carried out to justify the basis for commonly recommended light levels in offices; they were based on "reason rather than research" [23] (p. 77). The empirical work that has been carried out [24] indicates that, under normal conditions, 11 lux is a satisfactory level to perform office tasks such as reading and for ordinary purposes.…”

“…This, by its very nature, leads to a less precise way of measuring both IEQ and productivity. For example, the requirement for a lighting level of 400 lux on a working plane could be reduced tenfold providing that other lighting indicators are achieved [23]. A similar finding was made by Healey and Webster-Mannison [33] in their survey on qualitative factors that influence thermal comfort: "the common theme among respondents was that as long as one was able to work at a satisfactory rate and without major distraction, there was no problem with the indoor conditions" [33] (p. 173).…”

Lighting Design in Europe: Aligning the Demands for Lower Energy Usage with Better Quality

“…Simply following them will not produce good quality lighting. Boyce [12] explores methods which may bridge the gap between indifferent and good quality lighting such as proposals by Cuttle [13][14][15][16][17][18][19] and proposes that if none of these are accepted and adopted in the future, then good quality lighting will only be available to those who can afford the services of a creative, experienced and talented lighting designer.…”