Daylighting: Natural Light in Architecture

The specific aims and objectives of the study included the following:

Is the level of daylight to the open plan studios adequate?

Is the level of daylight improved by increasing the amount of glazed

area provided within the walls of the studio abutting the atrium

area?

Does the level of daylight achieved within these areas meet with

current guidelines and/or legislation?

The approach adopted by the lighting designers was by means of direct
measurement in a 1/50 model provided by the architects. The model had
been accurately constructed in order to ensure the the window openings
related closely to the proposed openings in the ‘real’ building. It was also
important that the internal finishes within the model matched where
possible the proposed surface finishes, with regard to the reflection
factor, which have a significant effect on the lit environment.
The model was placed under the artificial sky at the Bartlett School of
Architecture, which was hired for the study, so that daylight factor
measurements might be obtained. The artificial sky consists of a
hemispherical array of compact fluorescent luminaires, which can be
individually programmed and controlled to provide a luminance
distribution which matches that of the CIE overcast sky. Measurements
of illuminance at specified locations can be provided by individual
sensors or cells positioned within the model, compared with a reference
cell located externally to the model allowing daylight factors (DF) to be
calculated.
The scale model was placed in the artificial sky, and measurements of
illuminance were taken at appropriate locations in each of the spaces
under consideration, which, when compared to the reference cell,
allowed the daylight factor at each grid point to be calculated.
From these measurements an average daylight factor for each group of
measurements was calculated as the arithmetic mean of the individual
daylight factor readings for each test session.
In the case of the open-plan studios measurements were taken with
and without the solid wall abutting the atrium area. By conducting two

Calculations 57

Photographs of the physical 1/50th scale model

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