The proportions of the atrium and the reflective capacity of the
enclosing wall surfaces are critical, and those atria which are wide in
relation to their height, will perform better than taller, narrower spaces in
ensuring that daylight reaches the lower levels. Having said this, the
elongated atrium, which can act as an internal street at the low level, has
proved successful in providing the impression of a daylit interior, even if
due to its height the measured level of daylight at the lowest level will be
much reduced.
In order to optimize the daylight at the lower levels one method is to
set back the floor plans at the higher levels to maximize the direct view of
the sky at the lower; but this has planning limitations and economic
implications for the building owner.
Summarizing the advantages of atrium design
First, the human advantages: by getting daylight into the centre of deep
plan buildings, this provides the occupants with a sense of orientation,
information on the time, weather and the world outside the building;
together with a sense of space and expansive views which may
compensate for the lack of external views from the building.
Second, the environmental advantages: there is a potential for savings
of energy, assistance with the problems of ventilation, and a reduction in
the need for air-conditioning. Depending upon the orientation and detail
of the rooflight there may be a need for some solar shading.
On balance the advantages outweigh the disadvantages, as over the life
of the building the cost of the people who work there greatly exceeds
those of its construction, and the work environment is crucial.
Glazing
There is now a large amount of alternative glazing for windows, and it
is necessary for the architect, in conjunction with his services
consultant, to write a detailed performance specification; this must
include the orientation of the window, its thermal and acoustic
characteristics, together with its capacity for solar shading. This is of
course in addition to the main function of the window which is the
admission of daylight and the introduction of the view to outside.
Further factors which may need to be taken into account, are whether it
is thought desirable to have windows which open or are fixed, and its
relationship to ventilation.
But here our concern is with the types of glazing which are available.
As already stated the main purpose of a window is for the admission of
daylight, and associated with this the view to the exterior.
Glazing types which reduce the impression of daylight significantly,
darken both the interior, and the view, whilst the view from the outside
towards the building makes the fac ̧ade look black. It is only when
comparisons are made between the view through a clear glass window
and one with a modifying glass that reduces the daylight, that the results
create disappointment... it is true to say that it is human nature to
appreciate the natural environment, with all its variations of colour, light
and shade.
This is particularly true of residential properties where some form of
dark glass has been applied to the fac ̧ade, giving the impression of a dull
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