Daylighting-Natural Light in Architecture -2

2 Environment

Change and variety . . . modelling . . . orientation . . . sunlight . . . colour . . .
view . . . health

Various aspects of the environment which affect the interior appearance
of buildings have been identified in the introductory chapter, and it is the
purpose here to illustrate these aspects in more detail.

CHANGE/VARIETY
Perhaps the most obvious and certainly the most important aspect of
daylighting is its capacity for change, leading to the infinite variety in
appearance of the daylit interior. Change is at the heart of daylighting,
the human body has a capacity for adaptation, particularly in vision, and
the need to exercise this response.
Perception reacts to a degree of change; it is the natural order of things
that the appearance of interior spaces alter with time; and if we have
confidence in their continuing reality, it is because change in their lit
appearance allows us to continue an exploration of the spaces we inhabit;
an entirely different measure of experience to the static qualities of spaces
lit entirely by artificial sources of light during the day; or where there is
no access to the daylight outside. There is a natural process of renewal in
the photochemical processes of the eye as it adapts to accommodate
changes in daylight
First there is the natural change from day to night, from first light until
dark and the need for artificial sources to take over when daylight fades.
Then there are the changes associated with changes of the weather; from
bright sunny days to dark and cloudy or rainy days, there is little doubt that
the human spirit soars when rising in the morning on a bright day, an
experience which is less likely to happen when it is dark and gloomy outside.
Closely associated with changes in the weather are those of the
changes of season, from the winter snows to summer sunlight; each
season will have its own character, which as human beings we
accommodate to in our own way; but what is important is that the
world outside, as experienced through the window, provides necessary
information of the variety of the exterior world; whilst leading to subtle
changes in the appearance of the interior.

MODELLING
Modelling of a shape derives from its physical form, whether round,
square or otherwise, coupled with the way in which light plays on its
surfaces. This is referred to as its modelling and when this derives from
daylight or sunlight, giving light from a single direction, this provides a
form which is perceived by the eye as having meaning, unambiguous.
This is a different experience again from the form of an object or space
resulting from a room lit by artificial light, where the overall light may be
received from a multitude of light sources.
The most usual daylight modelling is that derived from vertical
windows at the side of a room, giving light from a single direction; this
may be helped by windows from an adjacent wall which adds to the
modelling; as the light will still be from the same overall direction, but
adding to the total modelling.
Two examples might be used to emphasize this, the first, a Greek Doric
column where the light of day gives modelling to the entasis on the
rounded surfaces of the column; light which emphasizes its particular
rounded quality together with its verticality. The second example is the
original David statue by Michelangelo seen in its setting in the art gallery
in Florence, lit from daylight above, where the form changes in time as
the day goes by.
A more modern example of the use of overhead daylight to light a
statue is the Charioteer in Delphi (Case Study pp. 170–171).
Daylight by its nature gives meaning and aids our understanding of a
shape or space by its directional flow; a meaning which is emphasized
even further by the addition of direct sunlight.
Interior spaces are judged to be pleasant, bright or gloomy as a result of
the effects of modelling and interiors are judged by the way in which the
spaces and the objects within them are seen during the day to be natural,
or accord to our experience of the natural world.

ORIENTATION
The importance of orientation in a building must be considered at the
outset, when the architect is planning the location of the building on the
site, the aim being to ensure the maximum availability of useful natural
light and sunlight to the interior.
There may of course be severe restrictions where the building is set into
a rigid street pattern, or where there are severe external obstructions; but
even in these circumstances the best use of the daylighting available
should be considered. The architect will have the greatest flexibility to get
the building orientation right on a greenfield site, where he can plan the
site layout to take advantage of the sun path and the availability of the
daylight.
Taking an example from residential buildings in the northern hemisphere,
and using the simple fact that the sun rises in the east and sets in
the west, it would be normal to ensure that those rooms which might
benefit most from early morning light, such as a kitchen, morning room
or even bedrooms, are placed on the east side, whilst those more likely to
be used in the afternoon or evening such as living rooms face south or
west.
There will of course be debate about the desirability of selecting a
specific orientation for a particular use of room and it will be up to the
10 Daylighting: Natural Light in Architecture
The charioteer statue at Delphi, daylit (See
Case Study pp. 170^171)
London Metropolitan University
architect to discuss this with his client, and there may also be conflict with
the orientation of a room when associated with the ability to enjoy a
particular view.
As with all architecture a compromise will need to be established which
best fits the needs of the interior function. What is essential is that the
orientation of a building and the interior layout takes most advantage of
the daylight available and is a factor taken into consideration at the outset
of the building design.
Each architectural programme whether an office, school or church, will
have its own specific needs of orientation, and this is of special
significance where the interior function is one requiring the inhabitants
to sit in fixed positions, often the case in offices or classrooms.
Another aspect of orientation and one where the mere presence of
daylighting is reassuring, is the subconscious desire of people when
inside a building to keep in touch with the outside world, whether to
know the time of day or the nature of the weather. An example of this
might be taken from the modern shopping centre. The Victorians had got
it right when they introduced overhead daylighting from domes or barrel
vaults to their shopping arcades. But in the 1960s many of our early
shopping centres cut out daylight altogether, leading to people finding it
difficult to negotiate their way around or to find the exits.
In one large shopping centre built in Hong Kong in the 1970s where
daylight had been eliminated, visitors felt so disorientated that extreme
measures had to be taken; whilst at City Plaza, another shopping centre
of similar size where daylight had been provided over much of the
multistorey space, it was an immediate success.
There is little likelihood that any shopping centre built now would not
be daylit, there is a public demand for natural light in large open areas
used by the public during the day and whilst the individual shop may be
lit with artificial light to enhance the goods on sale, the public areas will
assist orientation by the provision of daylight. At night the whole
atmosphere will change, contributing to the variety we associate with the
high street shop with artificial light taking over after dark.


SUNLIGHT EFFECT
In his major work Sunlight as Formgiver for Architecture, Bill Lam asks the
question . . . The Sun: Problem or Opportunity? and then proceeds to
show how the answer can really be both, depending very much on the
location of the building. Clearly in hot climates where the sun is overhead
for much of the day the problem is not so much one of welcome, but of
exclusion.
In Britain where the sun is all too rare the answer must clearly be one
of welcome, and an early decison when an architect is planning the
orientation of his building is to encourage the entry of sunlight. Sunlight
adds to the overall level of light when it is available, and adds to those
other environmental factors such as variety and change, modelling and
the creation of delight. There is a different level of experience when
getting up in the morning to a sunlit world, as experienced from the
interior of a building, and it is important that an element of sunlight is
available for some part of the day.
Architects have used the sunlight effect in buildings to create a specific
atmosphere, as for example the shafts of light entering the south side of
our great cathedrals; and on a much smaller scale the use in houses of
daylight and sunlight entry from above to provide necessary functional
light to interior areas, where otherwise little natural light would be
available.
The impression of sunlight is also important seen from windows which
themselves admit no sunlight, but where the view of a sunlit landscape or
buildings may be enjoyed. Whenever sunlight is available there is a
strong desire to perceive it, and disappointment when it is unnecessarily
excluded.
There is of course the obverse side associated with heat gain and glare,
depending upon the orientation of the glazing, and whether people
working in a building are confined to a fixed position. The effects of
direct sunlight can be a disadvantage. Some control may be required in
certain circumstances at certain times of year, and as far as heat gain is
concerned this is best done beyond the window, and is of a sufficiently
flexible nature to be available only when required, or if fixed, not to
inhibit the view.
One of the methods adopted to control the glare effect is to use forms
of glazing which cut down light transmission; these need to be treated
with care to avoid the impression that the interior of a building is
permanently dim, and some glazing is available which reacts to the
external light available, only cutting down the light when the sunlight is
too bright, and might cause glare.
To sum up, the need for the admission of sunlight is important, the
architect must consider this as a first requirement in planning the location
and layout of the building, but in certain circumstances controls will be
needed.

COLOUR
Whilst the colour of daylight will vary from morning to evening, and with
changes in the sky and weather patterns; it is always regarded as the
reference by which colour is judged . . . daylight is regarded as ‘real colour.’
In early stores, such as Harrods, voids were opened in the roof to admit
daylight to sales areas below; whereas for some years this was ignored.
There were several reasons for this, not least being that it was considered
that means of artificial light were more suitable for display, to show off
the goods ‘in a better light.’
This tended to ignore the environmental advantages of daylight and
natural colour, and this has since been recognized in many new large
shopping areas, where the entry of daylight is encouraged for the
provision of environmental light to the store, but where for display
purposes artificial light may be introduced locally to enhance the product.
The old concept of ‘taking something to the light’, by which was meant
daylight, may be less of a necessity if the environmental light gives
natural colour; whilst from the point of view of the shop worker who
must remain in the same environment all day the advantage of natural
light is obvious.
The same applies to office buildings, where people tend to have to
stay in the same atmosphere all day; if workers are too far from a
window and the impression of natural light is greatly reduced, there is
a sense of dissatisfaction. This is recognized by management, ensuring
that for a part of the working day, for example during coffee breaks or
in the office dining room, there is access to daylight, a change of
environment.
It is generally recognized that vision is enhanced by good contrast,
and that the natural colour of daylight increases contrast; it is argued
that this permits lower illumination levels, whilst increasing visibility1.

IMPORTANCE OF VIEW
Although listed last amongst the environmental factors, the question of
view is of special importance. The view out from the window is our
contact with the world outside; it provides the information, which for
reasons already mentioned, allows us to experience the time of day,
changes in the weather, sunlight and the seasons.
At one level, a view satisfies the physiological need for the adaptation
and readaptation of the eye to distance, providing a visual rest centre. For
this reason any view is better than no view, whilst clearly some views will
be better than others. At a different level the importance of a view has
been recognized in research to show that a patient in hospital will recover
more quickly where a window with a view is available.
The content of a view is clearly of importance, and it is the information
it provides which will determine its success. A view out to a blank wall
may be better than nothing but a view out to open countryside, or a
garden will be a different order of experience.
Various views have been analysed in terms of the information
obtained, depending upon the height of the window. In tall buildings
the view may consist entirely of the sky when seen from the interior of
the space, whilst at lower levels the experience of the ground scene
becomes of more importance.
The quality of the exterior view will depend upon the surroundings of
the building, and the height at which it is experienced, but it is of
importance that where a view is available it should be exploited. There
will be instances in large building complexes where internal views from
one part of the interior to another may be had; these will provide the
visual rest centres to satisfy the physiological requirement, but unless
there are views to daylit areas they will lack the amenities of change,
variety and modelling which inform the natural scene outdoors.
The architect should take the question of view into consideration when
planning his building, and when planning the location and detail of the
windows. Some of the finest windows were those of the eighteenth
century in Britain where the refinement of detail of the glazing bar
ensured that the daylight was captured by the bar, led round it, not
impeding the view. This is less necessary today since the size of glass
available is such as to allow large areas of see-through glazing, with no
need for horizontal obstruction.
There are some architectural programmes where it is thought that a
view out may lead to a lack of concentration, as in a school classroom. It
was the author’s experience that classrooms in his school in the 1930s
had windows at high level, precluding a view out; a view which
prevailed until the new school building programmes of the 1960s. Other
building programmes, such as churches or factories, also tend to ignore
the need for a view, and it is perhaps understandable in a building used
only for a short space of time, that the question of view doesn’t figure
large in the architect’s priorities, and in the case of the daylit factory it
would be reasonable to suppose that there might be dangers associated
with lack of concentration when working with potentially dangerous
machinery if a view out were provided.
The question of ‘view-out’ is necessarily associated with ‘view-in’
raising the question of privacy, which in certain circumstances may be
deemed to be of importance. During the day this will generally not be a
problem, as the level of daylight outside will be greater than that within,
inhibiting the view-in but at night the situation will be reversed, and it
may be necessary to resort to some form of blind or curtain, which can
have the desirable effect of ensuring that the window is not seen as a
black hole from the interior at night.

HEALTH
Daylight has long been associated with health, and in Dr Hobday’s book,
The Healing Sun, he reminds us of the work of Vitruvius in the first
century BC with his ten books on architecture. Among the classic
principles of harmony proportion and symmetry, as Vitruvius set out,
he emphasized that architects should select healthy sites for their
buildings, and that careful design of buildings prevented illness. It was
clear that the healthy site was one which was oriented to permit the
introduction of natural light. Vitruvius was the first to study the
qualitative and quantitative aspects of daylight, proposing explicit rules
to assess whether an interior is well daylit.
We may have moved a great deal further than this now, but poor
daylighting and the lack of sunlight is said to be responsible for what is
described as ‘Seasonal Affected Disorder’ or SAD, which affects a large
number of people at certain times of the year due to the lack of sunlight.
It is not a coincidence that given the choice, people prefer to work in
daylight, and choose to locate close to a window. The presence of natural
light at times when it is available in a building, is an important
environmental consideration.
It is often forgotten that people are the major asset and expense of a
company. To get relative costs into perspective, the annual lighting costs
of a person in an office can be the equivalent to only 3–4 hours salary. If
staff are visually impaired through inadequate working conditions and
poor lighting, their productivity will deteriorate and output may decline
on a scale far greater than the gains which might occur from the
installation of more energy efficient (but less user friendly) lighting.
Poor lighting can affect workers’ health, badly designed or poorly
maintained lighting can cause stress and lead to various forms of
complaint, eye discomfort, vision or posture. Dry or itching eyes,
migraines, aches, pains and other symptoms, often known as Sick
Building Syndrome, can be caused by poor or inappropriate lighting
installations. A purely energy efficient approach to workplace lighting,
which pays little or no attention to user comfort, could turn out to be both
ugly and ineffective.
It would be a mistake to adopt energy efficiency as the principal
measure of good lighting, and whilst important, it should be balanced
against those other factors leading to a comfortable and pleasant
environment.