Light and Architecture-Masters Thesis

Light And Architecture

L e b a n e s e U n i v e r s i t y 2 0 1 1

Masters Thesis Supervised by: Dr Samir El Tawil – Presented by: Maria Akl

Maria Akl – M2 LIGHT AND ARCHITECTURE 2

Light And Architecture Masters Thesis

Presented by: Maria AKL

Supervised by: Dr. Samir El Tawil

Presented to : Dr. Shadia Senno Dr. Mosbah Rajab Dr. Nahed Ghazal Dr. Samir El Tawil

Lebanese University Faculty of Fine Arts and architecture

Branch III 2010-2011

Date: May 5, 2011

Maria Akl –M2 LIGHT AND ARCHITECTURE 3

TABLE OF CONTENT:

FOREWORD AND ACKNOWLEDGEMENT..........................................................5

I- INTRODUCTION....................................................................................................6

II- HISTORICAL REFERENCE OF LIGHT IN ARCHITECTURE .................... 10

III- LIGHT ................................................................................................................. 15

1- A DEFINITION OF LIGHT ............................................................................................15

a-‐ Tone: ..................................................................................................................................................15

b-‐ Intensity: ..........................................................................................................................................16

c-‐ Focus: .................................................................................................................................................16

d-‐ Natural effects of light:...............................................................................................................16

e-‐ Light as material: ..........................................................................................................................17

2- EFFECT LIGHT HAS ON MOOD AND PSYCHOLOGY......................................................18

a-‐ Brightness contrast: ....................................................................................................................22

b-‐ Subjective impressions ..............................................................................................................24

c-‐ Degrees of stimulation: ..............................................................................................................26

3- EFFECT LIGHT HAS ON SPACE ....................................................................................26

a-‐ Forming functional zones .........................................................................................................26

b-‐ Defining spatial borders............................................................................................................29

c-‐ Emphasizing architectural features......................................................................................32

4- SHADING VERSUS LIGHTING ......................................................................................35

IV- WINDOWS......................................................................................................... 40

1- TYPES OF OPENINGS: .................................................................................................42

a-‐ Sidelighting systems....................................................................................................................42 Historical evolution: ................................................................................................................................... 42 Types of systems: ........................................................................................................................................ 44

b-‐Toplighting Systems:....................................................................................................................48 Historical evolution .................................................................................................................................... 48 Types of systems.......................................................................................................................................... 49


c-‐atrium and glazing.........................................................................................................................52

V- ARCHITECTS AND THE LIGHT ..................................................................... 53

1- LE CORBUSIER............................................................................................................53

2- LOUIS KAHN ..............................................................................................................55

3- NORMAN FOSTER ......................................................................................................57

VI- LIGHT IN LEBANON........................................................................................ 59

1- SOCIAL, CULTURAL AND ECONOMIC FACTORS .......................................................59

2- HISTORICAL EVOLUTION OF WINDOWS ....................................................................61

a-‐ rectangular window ....................................................................................................................61

c-‐ small openings ...............................................................................................................................63

c-‐ Triple Arched Window ...............................................................................................................64

d-‐ The bay window............................................................................................................................65

3- OURRENT SITUATION IN LEBANON ...........................................................................65

Lebanese rules and regulations...................................................................................................66

Commentary ........................................................................................................................................67

VII- MUSEUMS AND THE LIGHT........................................................................ 69

1- TYPES OF MUSEUM LIGHTING....................................................................................70

2- LIGHTING DESIGN TECHNIQUES.................................................................................71

3- CONSIDERATIONS TO BE TAKEN................................................................................73

a-‐ Glass display cabinet ...................................................................................................................73

b-‐ Surface reflectance ......................................................................................................................74

c-‐ Contrast.............................................................................................................................................74

4- CASE STUDIES ............................................................................................................75

a-‐ National Etruscan Museum ‘Pompeo Aria’, Marzabotto, Italy ..................................75

b-‐ Archaeological Museum of Delphi ........................................................................................76

VIII- CONCLUSION ................................................................................................. 78

IX- BIBLIOGRAPHY ............................................................................................... 80


Foreword and acknowledgement

The Masters thesis is the crown work of all the knowledge, research and information that I have accumulated throughout my four previous years in University, these years that have brought me much more than I expected them to, both academically and socially.

Therefore I would like here to say THANK YOU to all those who have made this possible.

First and foremost, I would like to thank each and every one of my

professors at university, who have held me by the hand and led me across the architectural path all the way HERE. A special thank you to Dr Shadia Senno, Dr Mosbah Rajab, Dr Nahed Ghazal and Dr Samir El Tawil who have supervised this thesis step by step.

I would also like to immensely thank our University director, Mr. Ali el Ali,

whose efforts are what are still keeping our university going, and our head of department, Mr. Wassim Naghi, who is constantly working on improving our department and who has never denied any of us help should we ever ask for it.

A big thank you to all my classmates and friends in university, who made

this ride not only educational, but also fun, and my parents and family who always encourage me.


I- Introduction

It is pretty curious how the world evolved in the past few decades.

Photography, means of transportation, Internet, media and other technologies

assured the fact that all countries are today open to what is going on in other -

even far- parts of the world. Hence any new development that happens in one

place only takes hours, minutes even, before reaching the other end of the

globe.

This universalisation is not only about technology, it is also applicable on

ideas, techniques, materials, visions, concepts and different other prospects. It

allows us to always be updated to any new happenings and breakthroughs, and

share our own with the rest of the world.

As a result of the stated above facts, we today exchange architecture. It is

no longer a definition of the region it is in, vernacular architecture is fading away

more and more with every day, replaced by the bright ideas of leading architects

around the world, new technologies and techniques that make construction


faster, easier and more efficient; new visions and concepts that redefine the

very meaning of architecture from being a “space” to satisfy a need, into being a

functional piece of art, every aspect of which serves a certain purpose. Studies

are made for the betterment of this functionality, on different fields that affect

architecture one way or another. Hence topography, soil study, weather study,

energy consumption, isolations ….etc have all become a necessity to envisage

before the conception of any project. A project is then the outcome of the sum of

all these fields put together; it is the optimal solution an architect reaches in

order to satisfy at the same time the needs and the constraints. Those

constraints are no longer those taken from a physical point of view of the land

and project itself, but nowadays, with the expansion of the fields of psychology

and human study, those aspects now play an important role in the conception of

an architectʼs design.

Henceforth the built and the living are not divided from each other, but one

is part of the other, and the architect has to envisage how the building will affect

the person psychologically, will it change his mood, does this feeling the person

gets walking in serve the purpose of the architecture? In parallel, the architect

should wonder how will human presence affect the architecture of the project,

and he should use this presence to enrich the project not impoverish it. He

therefore has to look into the smallest details of what he is creating: The

volumes of the interior, the colors, the lights, the height of the ceiling, the

materials used for the interior as well as the exterior, the openings and

windows, the types of lamps, paints, furniture… etc.

My interest however has always been the light. It is amazing how the

natural light can affect our mood: we feel gloomy on a rainy cloudy day, we feel

exhausted if we stay too long in the hot summer sun… Also the sun, and the

light in general, affect how we see things, depending on the intensity, the focus,

the color…etc It can change shapes and add or subtract emphasis from one


point or another, it affects how we see volumes whether it was in interior space

or the exterior.

Seeing and reading about architecture of residential and other buildings

abroad, in some parts in Europe and USA, amazed me at how much the effect

of natural light in the first place and artificial in the second place, is taken into

consideration. How complicated is the study of the very window in order to give

the interior the ambiance the architect has in mind.

On the other hand, driving around in Lebanon, and looking at the

residential buildings with their repetitive rectangular aluminum windows of

standard dimensions, opposes harshly these “poetic” (so to speak) ideas. Even

non-residential buildings barely take light into consideration: office buildings

mostly are all about the glass exterior glazing, that does or does not help the

function of the interior, whether it was from the point of view of light, or heat, or

even how it serves the aesthetics.

This stirred my curiosity, how does light really affect the interior and

exterior of a project? How does it change the atmosphere and how should it be

used correctly in order to define the wanted spirit of a room? How should be

used to mold our perception of an architectural shape and the entities inside it?

And how can we, in Lebanon, put to practical use the knowledge about light and

its effects in our buildings and constructions.

Therefore Iʼm writing this essay about the use of light in architecture to

discuss different points that will help me reach a better understanding of the

effect of the light and how to use it correctly in order to benefit from the interior

of architecture in general and museums in particular.

The general plan of the thesis paper will take the following path: The main

ideas to be discussed start with a general introduction of the history of the use


of light in architecture and its importance for humans, and an introduction of the

properties of light.

The different effects of light are thoroughly discussed, the effect on human

mood and the psychology of light on one hand, and the effect of light on space

on the other hand.

Windows are very important, they are the opening through which the light

comes in, hence their shape and materials are of crucial importance in the

process of making the light that enters the premises, thatʼs why the types and

properties of windows are cited, and the influence of different materials and

construction techniques on those windows. In addition to that, the effect of the

sunʼs location to how the sunrays penetrate the given window into the room are

also of importance to try and narrow down and specify exactly how the sun and

natural light affect the interior space and its architecture; that includes light itself

and the shading, the effect of which is just as important, so both will be further

discussed in the thesis.

The situation in Lebanon is brought up, first a historical outlook on old

houses, followed by a general analysis of the current situation, observation of

residential and non residential buildings, paired with an analysis of the problem

from the legal and social point of view.

Finally, the use of light in museum and the optimal solutions for a best

result of interior space and exposition of works will end the essay, with some

views of world renown architects about light and its relation to architecture.

The aim of this thesis is not to simply state already established facts about

light, but to try and find a better understanding of the relation between light,

architectural space and humans, and see how to best apply it in our community

as a whole (residential or not) and in museums in particular.


II- Historical reference of light in architecture

Light has played an important role and functions in architecture throughout

the time. Architecture is the story of how the human being adjusted to the

elements he is presented with, and many times was this architecture affected by

his belief systems.

From the times of the Menhir and worshipping light, to Egyptian

architecture and its ornamented light, the precise light of Classical Greek archi-

tecture. All through the time, light has been used to serve different functions.

In Ancient Egypt, the Divine Father

was the sun god Ra, the supreme ruler of

all creation. The religious beliefs related to

the sun influenced and informed the town

planning and the architecture of ancient

Egyptian cities. The Pharaonic city of Iunu,

referred to by the Greeks as Heliopolis or

ʻthe city of the sun,ʼ represented the

geographical center of the sun cult that


existed in ancient Egypt. The layouts of Egyptian temples such as Karnak were

usually informed by the movements of the sun and accommodated seasonal

variations.

The Greek expressed a respect for the sun and its many powers; this is

clearly visible in the architecture of places of worship and social gatherings. The

ancient Greeks typically oriented the front façade of their temples towards the

east. Important religious ceremonies took place in the eastern section of the

temple, which was illuminated by the early morning rays of the sun. The Greek

vernacular architecture was mainly based on a play between light and shadow.

Buildings were built with thick walls that transferred warmth of the winter sun, or

the coolness of the summer nights inside. The walls were painted white to usher

light into the interior.

Socrates wrote about the sun in his book, Xenophonʼs Memorabilia, saying:

“Now in houses with a south aspect, the sunʼs rays penetrate into the

porticos in winter, but in the summer, the path of the sun is right over our heads

and above the roof, so that there is shade. If then this is the best arrangement,

we should build the south side loftier to get the winter sun and the north side

lower to keep out the winter winds. To put it shortly, the house in which the

owner can find a pleasant retreat at all seasons and can store his belongings

safely is presumably at once the pleasantest and the most beautiful.”

In Roman times, the light that is distilled as it

passes from the outside to the interior of their

architecture (for example the Pantheon), the divine light

of spaces devoted to the liturgy, the protective light that

inclines people to meditation in Romanic architecture

are what characterized it. In the Pantheon, The oculus

on top of the dome of the main rotunda captures the sun

rays that heat and illuminate the rotunda, which is an


obvious example of the importance of sunlight in roman architecture.

That wasnʼt the case for only places of worship, Many Roman houses had

ʻheliocaminusʼ in their houses. Resembling the modern sunrooms, the

heliocaminus was a separate space within the house where solar heat could be

trapped and then distributed to other quarters of the house as needed. The

Romans are the ones who first started the technology of glass window, which

were used to warm their houses by trapping the solar heat. They also used

solar energy in large public buildings such as public baths.

Also we knew the humanized light of the Renaissance, the sublime light of

the Baroque period and the fluid light that allows us to use glass enclosures in

contemporary architecture, which almost manages to eliminate the difference in

light between the interior and the exterior.

The supernatural light through stained glass windows in gothic times was

one of the most breath-taking phenomena. People would appreciate the

buildingsʼ dominant scale from the exterior. But once they entered, they would

discover a mystical world where sunlight behind stained glass brought scenes

from the Bible to life in front of their eyes. In a world without film or television, a

dark room full of brightly back-lit stained glass windows would rival fire and the

night sky as the most visually exciting things anyone in the middle ages had

ever seen.

During the mid-eighteenth century, the early years of the Industrial

Revolution, in Western Europe a huge number of people migrated from rural

areas to the city to look for work in the growing number of factories, causing

enormous economic and social changes. Demands for housing were growing

rapidly due to the growing amount of people; this caused the appearance of

overcrowded and unsanitary ghettos in many cities in Great Britain and in other

countries of Western Europe. Buildings were built back-to-back, in narrow


streets with very little exposure to sunlight, with open sewers and a density of

population, this led to the appearance of many diseases such as cholera,

tuberculosis and other deadly diseases.

This was described by Charles Dickens in Oliver twist, he said:

“There exists the filthiest, the strangest, the most extraordinary of the many

localities that are hidden in London, wholly unknown, even by name, to the

great mass of its inhabitants. To reach this place, the visitor has to penetrate

through a maze of close, narrow, and muddy streets, thronged by the roughest

and poorest of waterside people, and devoted to the traffic they may be supposed to occasion.”

Awareness of the importance of light in peopleʼs lives grew when Dr Niels

Finson received the Nobel Prize in 1903 for proving that sunlight can cure

tuberculosis. In the beginning of the 20th century, architecture changed by the

birth of a new architectural school that rejected the old ways of buildings. The

Modern Movement gained popularity after World War II through the work of

CIAM (Congrés International de lʼArchitecture Moderne) that put principles that

were the basis of rebuilding the new European cities, ruined after the end of the

war. The work of Le Corbusier, Walter Gropius, and Mies van der Rohe followed

principles of CIAM and the Modern Movement in architecture. This new

architecture emphasized straight lines and simple, economic forms. It focused

on the use of large windows to maximize natural light and fresh air.


Artificial light is quite different, invented light that comes from a fixed and

constant source of emission and, therefore its effect does not vary and it

obviously implies consuming energy and, far too often, it also involves visual

“noise”.

And as with good architecture, good lighting, illuminates, clarifies,

stimulates. Bad lighting, like bad architecture, dazzles, confuses and produces

weariness.

Film directors used to say that a good lighting director was just as

important as a good actor for making a film. He said that a badly lit good

expression or gesture is almost worse that a well lit bad gesture and vice versa.

Architects know, or should know, that it is of prime importance to get the

lighting right, whether it is natural or artificial light: the right light enhances and

improves a space, bad lighting degrades it. The best lighting is almost always

one that you do not notice. You sometimes enter a place and you cannot

perceive it or appreciate what it contains, because the light blinds you. Other

times, you go to an exhibition and the reflections of the poor lighting do not

allow you to appreciate what is on display. And not to forget what is told in the

cops and robbers films when they wanted to interrogate somebody, they shined

a bright light in his face to weaken or destroy his physical and mental defenses

and he would end up confessing.


III- LIGHT

1- a definition of Light All sources of light have their own particular qualities, some of which are

the result of the light source itself and the some the result of external influences,

such as the weather and the landscape.

The light from the sun, for example, is constantly changing, depending on

the time of day, the time of year, the weather …etc

The quality of any light (whether natural or artificial), can be defined in three

simple ways:

a- Tone:

The tone of a light is defined by its colors temperature. The temperature of

light is synonymous with its color, in the sense that they are both the product of

a specific wavelength. The primary colors of natural light make up the spectrum

of colors that can be seen when the light is split by a prism; at one end of the

scale is ultraviolet (the blue end) and at the other is infrared (the red end of the

visible spectrum).

We light we see is a mixture of all these and is described as “white”, but all

light sources have their own color; meaning that they emit a distinct wavelength

pattern, depending on what they are designed to do.


b- Intensity:

The brightness of the light is fundamental to the quality of the atmosphere

in a room. That is not to prelude the use of very bright lights, and if used, these

lights are to be carefully controlled. Generally, a number of dim lamps will create

a more interesting atmosphere than a single bright lamp, even if they add up to

the same amount of light. So basically the intensity is not only the physical

amount of light in a certain space, but also how this light is translated in the

space.

c- Focus:

Whether the light is direct or not is the result of exterior influences on the

light that is emitted from the lamp.

The “bulb” of the standard lamp is frosted and throws a diffuse light all

around, producing a bland featureless light. However, if a crown-silvered lamp is

combined with parabolic reflector, the design diffuses a very tightly focused

beam, producing a dramatic light capable of giving life and shape to a room.

The number of designed lamps is incredible and each of them has its own

controlled width of beam, and different lamps are to be used in different places

and serve various functions (emphasis, illumination, etc)

d- Natural effects of light: The atmosphere we experience in the outside world in the combination of

the tone and the contrast produced by the conditions. We can begin to study

those natural conditions by analyzing the tone, intensity and focus.

The quality of sunlight at noon in the Sahara desert is harsh and bright, with

intense shadows. By contrast, in a deciduous wood on a wet day in the northern

hemisphere, the light is muted and soft with very little obvious shadow, the

whole effect being diffuse and vague.


Humansʼ mood is strongly influenced by these conditions, the feeling tend

to vary in a certain way about a place or scene, depending on the quality of the

light.

The search for understanding the relationship between light and mood was

of primary importance to the impressionist school of painters at the turn of the

century. They sought to represent light with pigment, capturing atmosphere

through color. Studying their work has brought important information about the

color of light and its effect on mood.

e- Light as material: Architects thoughts always seek the material of finished product while they

work out the puzzles of the volume or proportion of space. Different materials,

including stones, brick, steel, glass, wood, tile, plaster, paper and cloth render

different qualities in architecture. Light is an equally and sometimes more

influential element in determining the result. It can even highlight or damage the

value of architectural materials themselves.

Lighting fixture is an important tool for architectural lighting design that

distinctively offers specific function. Each fixture has a different purpose

according to the architectʼs intention. Be it spots or lamps or chandelier, these

fixtures are the architectʼs accessories to producing the space.

However, the fixtures should stay behind the scene, the goal of light is to

create a miraculous situation whereby the right amount of light is floating in the

air comfortably.

The ideas for lighting design usually do not come out of the blue. Because

architecture is a mean of various space functions, a function of light is also

hidden for each of these segmented spaces. Liberal ideas full of creativity

should be employed after thoroughly examining how the space should function.


2- effect light has on mood and psychology “Light affects our bodies in two ways. In the first, light impinges on the retina

of our eyes and, through our vision system, affects our metabolism and our

endocrine and hormone systems. In the second, it interacts with our skin by way

of photosynthesis and produces vitamin D. Daylight serves as a catalyst for the

secretion of hormones from the pineal gland namely serotonin and melatonin.

The level of melatonin determines the energy and activity levels in our bodies. At

darkness or low light levels, melatonin secretion increases and drowsiness

occurs. Daylight suppresses the production of melatonin and fosters an alert

state of mind by secreting serotonin. People who live and work in window-less

environments or in places lacking adequate light may be at risk of having their

internal clock continually disturbed. Melatonin is an important anti- oxidant and

can neutralize some agents. Serotonin, a hormone first discovered in 1933, is the

neurotransmitter identified in many psychiatric disorders. During long periods of

high stress, serotonin is used up, exceeding its replenishment rate. Prolonged

stress lowers serotonin levels in the brain and a stress-induced depression may

take place. The less serotonin available in the brain, the more severe is the depression and related symptoms.” (1)

So light has a direct effect on our mood and feeling, from a scientific

medical point of view. Light acts on the production of cortisol, serotonin, and

melatonin, three important hormones that affect our internal clock and our mood

states, among many other effects. It is important to keep these hormones in

proper balance. Low levels of serotonin (the daylight hormone) cause

depression. Light therapy, be it artificial or natural, has been found to be an

effective antidepressant but only when the light is bright enough.

Light not only affects the psychological state of the person, but also has a

direct effect on what he feels in a certain ambiance.

(1) Mohamed Boubekri; Daylight, Architecture and Health: building strategies, England,

Elsevier (Architectural Press) 2008


An architectural space accompanied by a satisfactory function of light has

the power to move people. The crux of architectural lighting is how it can cater

not only to the biological, but also to the psychological needs of humans. The

way architectural spaces are perceived generally vary from a person to another,

but there is something known as an emotional impact, which is rather common

among people. However, different studies have shown that the light color and

intensity may affect people differently according to their age and gender: a study

showed that young adults (of around 23 years old) preserve a negative mood in

a warm (red tones) atmosphere, while older adults (65 yeas old) the cool (blue

tones) conveyed the same negative effect when it came to cognitive

performances.

Light, its color and intensity, vary according to the function of the local it is

in. Thus, a hospital room, a classroom and a living room of a residential home

should have different lighting whether it was artificial or natural (variation of

opening types and spaces). Hence, Light is often used by architects as a

metaphor, a mood-giver or a carrier of a meaning in and of itself.

The chapel of Notre-Dame-du-Haut at Ronchamp, France, by Le Corbusier

is a boldly expressive free-form structure in which the symbiotic association

between the form and the interior natural light identifies the essence of the

building, making it the central element of the design concept. Through

irregularly sized and shaped windows piercing the southern thick masonry wall

of the chapel and from three light towers emerging through the roof much like

wind catchers, light enters the space from multiple directions, bouncing off richly

textured surfaces, and through colored glass that imparts unequalled poetic and

spiritual qualities that have made the building one of the icons of modern

architecture.”


Notre-dame-du-haut Chapel, Ronchamp, France

In the Chapel of Light by the Japanese

architect Tadao Ando in Japan, light enters

from behind the altar through a cruciform cut

in the concrete wall that extends vertically

from floor to ceiling. Light emerges through

the crucifix as an abstract and universal event

in contrast to the darkness of the concrete

wall. The effortless simplicity of the space is

contrasted only by the intense brightness of

the luminous crucifix, making it the

centerpiece of the chapel and of the spiritual

experience sought by those who frequent it.

The effect of light on architecture this became a main concern to

researchers, who started looking into the relationship between light and the

mood of the occupants, not only in religious places, but in any social place,

because anywhere, a human experiences mood changes according to dramatic

change in light.

Psychologists and behaviorists believe that even in places where the

change in lighting is not as dramatic, small changes in light may also affect a


personʼs mood or his emotional state. Apparently, the presence or absence light

can produce a positive or negative effect.

The sensations that come along with good lighting are excitement, alertness

and dominance. However, with poor lighting comes dullness, boredom and

submissiveness. These states affect the social behavioral responses of the

occupants and their ability to make proper decisions. When people are in a

good mood, they tend to perform better in a work place and vice versa.

Most research on the effect of light and mood has focused on the artificial

electric light. Unlike electric light, daylight is a more difficult field to study due to

its dynamic and constantly changing aspect and its properties that are not static

(as are those of artificial light). This changing character of daylight that varies

from one minute to another makes experiments rather difficult, however there is

a general natural preference for daylight over artificial light. This could be

related to its spectral quality (the spectrum of daylight being the fact the white

daylight is in fact the compilation of 7 colors – those of the rainbow) that triggers

hormonal and physiological progresses. These progresses affect our

psychological wellbeing. That however is not a proven fact, but whatever the

reasons are, the fact remains that most people prefer natural lighting to artificial

one.

The individual impressions of a space depend on the relationship of

surfaces that are lit to those left in the dark, and on the focus of the surround or

background, i.e. the emphasis on a space or another.

It is through the wits of the architect that the manipulations of light,

brightness and contrast, focus and color, will give the desired emotional impact

of an interior, though different degrees of stimulation.

The degree of brightness contrast evokes emotions in the same way as

background music. It affects:


• The performance of task

• The behavior of people at work or play

• The amount of containment and pleasure, and emotions in general.

This brightness and contrast hence affect the way the person perceives the

architectural space and how this space will affect him.

a- Brightness contrast:

Low contrast environment, everything is of equal emphasis

Mid contrast environment, combination of emphasis


High contrast environment, high bright and dark areas

Very high contrast environment – extreme high bright and dark areas


b- Subjective impressions

These are 6 different ways to light the same space and see how light

different effect and the feelings/impressions it conveys to the occupants.

Picture 1: direct lighting on the table gives a strong contrast, is too harsh

for lighting faces and It gives a strong impression of confinement and haziness.

Picture 2: shows lighting on all the walls, with low intensity. This lighting

promotes the impression of spaciousness and increased height, at the same

time gives a pleasant impression to the occupants of the room.

Picture 3: lighting of cove above, low intensity. This lighting is pleasant for

near and distant faces and promotes a quiet impression.

Picture 4: direct lighting on table and lighting of small wall. It promotes a

relatively strong feeling of pleasantness and gives the impression of length to

the room.

Picture 5: direct lighting on table, and lighting of cove above. It gives a soft

subdued effect and is pleasant for near faces, it also promotes the feeling of

spaciousness.


Picture 6: lighting of cove above, and lighting of walls flat, shadow free. It

gives a strong feeling of pleasantness and clarity and promotes the

spaciousness of the room.

Other types of subjective impressions are shown below:

Impression of

spaciousness: the room

appears larger or

smaller.

Impression of

perceptual clarity:

the room appears

public or private.

Impression of

pleasantness: the room

appears friendly or

sociable.


c- Degrees of stimulation:

Environmentalists use the terms High-load and Low-load to describe the

degrees of stimulation or arousal. The more stimuli that must be processed by a

person, the higher is the load.

Environments that are complex, crowded, asymmetrical, novel, unfamiliar,

surprising or random are High-load, where as environments that are simple,

symmetrical, conventional, unsurprising and organized are Low-load. High

levels encourage participations and increase enjoyment where as low level help

a person feel contented, comfortable, focused and relaxed.

Although individuals react differently to the same environment, there is a

high degree of similarity in peopleʼs reactions to light.

3- effect light has on space Light plays a central role in the design of a visual environment, the

architecture, people and objects are all made visible by the lighting, since it is

what enables “what we see”.

Our perception of architecture will be influenced by light:

• Light defines zones and boundaries

• Light expands and accentuates rooms

• Light creates links and delineates one area from another

The challenge of a qualitative lighting design is to develop a design concept

that combines the technical and aesthetic requirements of complex guidelines.

a- Forming functional zones

Distinct contrasts between individual zones and their surroundings remove

them from their special context, whether itʼs with the use of natural daylight

(windows) or artificial light. Also the same technique can be used outside to

form exterior functional zone, or inside, to form interior ones.


Interior:


exterior:


b- Defining spatial borders

Horizontal

floor illumination emphasizes objects and pedestrian surfaces.

Indirect lighting of a ceiling creates diffuse light in the room with lighting

effect being influenced by the reflectance and color of its surface.


Examples of defining horizontal spatial borders

Vertical:

• Vertical borders are emphasized by illuminating wall surfaces.

• Uniform light distribution emphasizes the wall as whole.

• Bright walls create a high level of diffuse light in the room.

• Vertical illumination is used to shape the visual environment.

• Room surfaces can be differentiated using different levels of illuminance to

indicate their importance.


• Uniform illumination of the surfaces emphasizes them as an architectural

feature.

• Grazing light gives the wall structure by adding patterns of light.

• A decreasing level of brightness across a wall is not as effective as uniform

wall lighting at defining room surfaces.

• Lighting effects using gazing light emphasis the surface textures and become

the dominant feature.

Examples of defining vertical spatial borders


c- Emphasizing architectural features

• The illumination of

architectural details

draws attention away

from the room as w

whole towards

individual components.

• Columns appear as

silhouettes in front on

an illuminated wall.

• rooms can be given a

visual structure by

illuminating the

architectural features.

• Narrow-beam down lights

emphasize the form of the

columns.


• Grazing light accentuates

individual elements or

areas and brings out their

form and surface texture.

• Grazing light can cause

highly three-dimensional

features to cast strong

shadows.

• By using different levels or illuminance, different part of a room can be placed

in a visual hierarchy

Some example of emphasis of architectural features:


Some types of lighting


4- shading versus lighting “Shadow design is now being called for on the lighting scene. When

spreading a white drawing of architectural design, we must reverse the

colors in our minds and picture a blackened drawing. We must start from

darkness (as opposed to the statement “in the beginning there was light”)

and carefully add the figures of light to space. To design shadows is to design light for no space exists without shadows.”(1)

Shading is an almost essential part of passive building design. there are

many different form of solar shading and different uses for it. A part of it is

essential to:

a- Reduce the solar heat gain to the room It is of greatest importance to the south elevations, that are most exposed to

the sun. The shading is hence necessary to limit the amount of light coming in

the room on one hand, and the amount of solar heat on the other. The shading

system used hence has to be controlled manually of automatically, to allow the

most of light and heat to come in during cold and cloudy days when light and

heat is needed, and limit them during hot sunny days.

b- Reduce glare Glare usually results from a direct view of the sun, or by reflection from

outside sources as well as inside sources (items inside of the building). Glare is

annoying and gives a feeling of unease and irritability, hence it has to be

controlled by shading the sun or the source of reflection and allowing only light

to come into the room (not the sun rays themselves)

c- Allow a level of privacy

Some buildings and especially residential buildings, need a level of privacy for

the inside, hence curtains for example are used.

(1) Designing with light and shadow: Kaoru Mende + lighting planners associate Inc.


However, the use of curtains minimizes the income of light from outside and

sometimes requires the use of artificial light in days where it shouldnʼt be

needed.

So the best solution is the use of some translucent material, which lets

through the maximum amount of daylight but breaks the internal image as seen

from the outside.

There are many ways to provide this shading, and they are an important

part of the design phase, since they are placed on the windows and seen in the

elevations. The solar shading systems are now an important industry, high tech

and of many aesthetic choices.

In the picture above, we see a movable shading device (such as blinds).

These are only opened when there is a surplus of light and shade is needed.

They donʼt affect the lighting in days with poor daylight.


In the picture below however, we see an example of fixed lightshelf. The first

illustration shows the amount of light coming in without the lightshelf, it is too

much for the room and causes glare and surplus of light. The second illustration

shows the effect of the lightshelf in sunny days: it allows part of the light to

come in while reflecting another part into the back of the room. And finally the

last illustration shows the action of the light shelf in cloudy days: it allows all of

the sky light and there are no harmful sunrays.

This is only a couple of example of shading devices; lightshelf systems will

be further explained in more details in the next chapter.

This shading is an intrinsic part of lighting design. However, some more

particular form of shading may be used, not just to immerge the room in the


exact quantity of light required by its function, but to play a game of shadows

and thus give the room the ambiance that the architect had planned for it. In this

kind of shading, the shadow plays an important role and the architect has to

carefully plan the imagery drawn by the shadows in the interior according to the

sun position and the styles, types and forms of the window he is using (the

frame, the bars or lack of in the window, etc..). The shadowing hence is the one

that would give the interior the ambiance required and would masterfully

become the art inside the room (if used correctly)

A simplification of the shadow-play concept is shown in the illustrations

below (these are cut plans of a room with the window on the right):


This clearly shows how the sunʼs position affect the way in which the rays

reach the interior and what wall theyʼd illuminate more, as well as how the

framing of the window casts a shadow on the wall. This shadow as well varies

throughout the day and time of year. If the architect chooses to make the

shadow an important part of his design, heʼd have to study the sunʼs rotation

during the day and the year. This will change according to what elevation the

window is on (north having very little direct sun rays, while south has a

considerably large amount).

The choice of the frames of the window, its height, width, and elevation from

the ground, as well as the divisions (if any) inside the window itself, all influence

the way the light reaches its destination and more importantly, the shadow the

window casts. It thus becomes a matter of “vide et plein” i.e. solid and void.


IV- Windows

Daylight is inextricably linked to windows and openings within the exterior

envelope of a building. The two cannot be separated under typical design

approaches, although it is technologically possible to bring in daylight without

windows through the use of light pipes and other strategies.

Windows play several roles and have more than one effect on a room and

its occupants. The changing character of daylight adds a dynamic qualitative

dimension to the ambiance of the room that is not easily achievable with an

electric illuminant. Windows allow diffuse daylight and sunlight inside a room

while providing views to the outside, thereby adding a sense of openness,

spaciousness, and orientation. Because of the technological advances of the

last five decades, we are able to design buildings with large glass façades that

permit daylight to enter and allow views to the outside.

The importance of the connection with the outside world can be observed in

the behavior of people who live and work in windowless spaces. They appear to

use twice as many visual materials to decorate their workstations than do their


counterparts who have windows. Landscape scenes and nature-related themes

seem to be the prevalent content of these visuals, an indication of a need to

connect with the natural world. Attention to the outside world proved an

important ingredient to relieve a sense of enclosure.

The window is an opening in a wall or side of a building admitting light and

often air to the interior. Early windows were developed before the introduction of

glass, so initially windows were left open to the external atmosphere, or filled by

some form of closure to minimize the heat loss at night. The more sophisticated

buildings would have had thin slabs of marble, mica or oiled paper for this

purpose.

In mediaeval times wooden shutters were installed on the interior, and these

were left open or closed to regulate the light and air. With the introduction of

glass, used first in small panes in Roman architecture, the window as we know

it today had its beginnings. The concept of small panes of glass, divided by

bronze or later lead divisions, as used in early buildings dies hard and window

manufacturers still offer these as alternatives to fully glazed windows in new

domestic work, however inappropriate they may appear.

Windows can broadly be divided into two main types, first the window set in

the side walls of a building, and second the opening light set into the roof,

generally known as roof lights, the first allow the light coming from the sun to

come inside the room, called sunlight, and the second lets the light coming from

the sky, called skylight to come in. A successful daylighting strategy is one that

maximizes daylight levels inside the building but optimizes the quality of the

luminous environment for the occupants. Daylighting design is not only about

maximizing light levels. Excessive sunlight in an interior can be extremely

uncomfortable for its occupants. The key word in daylighting design is control,

not only of light levels but also of the direction and the distribution of light.


1- types of openings:

a- Sidelighting systems

Historical evolution:

The daylight penetration from side windows will depend upon the ceiling

height, and in early buildings where the ceiling heights were low, the penetration

of daylight into the building was severely limited . . . with the design of the

important houses of the seventeenth and eighteenth centuries the ceiling

heights were raised and daylight was able to reach further into the interiors.

However as buildings became grander, even this was not enough, and the

concept of the rooflight was developed to introduce daylight into interiors far

from the side windows.

The horizontal window is perhaps the most well known of all, starting as it

did in mediaeval times, limited by the construction methods of the day. It is still

much used in todayʼs domestic architecture. Provided the horizontal window is

placed high in the wall the daylighting will penetrate well into the space, but

other features of the window need to be considered.

A logical development of this type is where the horizontal window extends

the entire length of the external wall, a device used in nineteenth century

industrial buildings to provide even and sufficient light for machine operators.

This type of window required new structural techniques to overcome the need

for vertical support to the structure above.

Yet a further example is the clerestory; found mainly in tall buildings such as

churches, generally associated with other forms of window at lower level to

provide the main daylight. Clerestories are placed at high level to assist in

getting daylight further into the interior and to light the roof structure.


A logical development of the extended horizontal window is the floor to

ceiling window; as structural techniques were perfected, this type of window has

become almost universal in some types of architectural program such as the

office. The 1930s saw the innovation of the wrap around corner window, as

further structural techniques were made possible.

Finally and in no chronological order comes the vertical window. Vertical

windows were popular from the fourteenth century, having perhaps their most

glorious period in the eighteenth century, when the Georgian window with its

sophisticated detailing was almost universal.

London city hall orange operational facility


Tall windows, set apart by masonry at intervals, provided a simple

structural solution and this formed the pattern of development in residential and

other building types for several centuries.

The window can be said to be the most important architectural feature of a

building; this is the first experience that a visitor will have when seeing the

building for the first time, and architects have naturally considered the form of

the window and its relationship to the exterior to be vital.

Types of systems:

Side windows: Side windows are divided to low windows and high windows

(clerestory). Traditional side windows light mostly the area closest to the

windows and the rest of the room is less lit, or even dim when the room is deep.

The light is distributed depending on the sky conditions: when the skies are

overcast the daylight is more diffuse than when the skies are clear; the shadows

are, however, much softer. Other factors affect the spread of daylight in the

room, such as the orientation of the window, its location on the wall, the height

of the window and its width. A single side window may cause high discomfort

glare because of the contrast between the brightness of the window and the

darker background surrounding the window frame. A more balanced daylight

distribution may be obtained by bringing daylight from two different sidewalls,

resulting in a deeper, more balanced daylight distribution and a reduction in

glare.


Clerestory system: A clerestory is also a side window but one that is

placed high in the wall. It is usually contained in a part of the building that rises

clear of the roof. Generally, it doesnʼt provide views towards the exterior but

permits a deeper penetration of daylight into the room than a standard side

window and gives less discomfort to the occupants of the room. Like a standard

side window, a south-facing clerestory will produce higher daylight illumination

than one that faces north. East- and west-facing clerestories present the same

problems as east and west windows: difficult shading and sometimes high heat;

however, because the frame of the window is higher, the penetration of the

sunlight is easier with clerestory. The area of the illuminated interior area

depends on how high the clerestory is, and its dimensions (height and width).

The higher the window, the deeper the light penetrates into the room.

Combined side-systems: Combined side-systems that include a side

window and a clerestory provide a more balanced distribution of daylight than

does a typical side window or a clerestory window alone. Since daylight levels

are additive, we can combine the daylight distribution from the side window with

that from a clerestory window.


Lightshelf system: A lightshelf is a device designed to capture daylight,

particularly sunlight, and redirect it towards the back of the room by reflecting it

off the ceiling. As a result, this strategy can lead to a more even distribution of

light throughout the room than is found in a room with only a side window. A

lightshelf divides the window into a lower part that mainly serves the role of

providing a view and an upper window that serves to redirect the daylight

towards the back of the room away from the window plane. As a by-product, a

lightshelf can also provide shade from direct sunlight and reduce glare from

the sky. A lightshelf works best under sunlight conditions. The upper surface of

the shelf is made of a highly reflective material to maximize reflection; it should

not, however, be made of a highly polished surface, in order to prevent glare

and shiny spots on the ceiling. Medium polished surface materials are

recommended.

The design of a lightshelf should be integrated with the fenestration of the

building and planned during the early design stages. Its size and depth depend

on window size and façade orientation. A lightshelf may be combined, exterior

only, or interior only. It can be horizontal or oblique. Exterior lightshelves are

more effective in providing shade than interior ones but reflect less light towards

the back of the room. Oblique lightshelves reflect light more deeply into the

room but provide less shading than a horizontal lightshelf.

Variable area lightshelf system: A variation of the static lightshelf system,

the variable area lightshelf is designed to be a dynamic system whereby the

position of the lightshelf moves to optimize sunlight penetration according to

time of day or season


A highly reflective film moves between two positions to optimize reflection

inside the space. This system can be automated for higher efficiency.

Prismatic systems: Prismatic glazing is designed to change the direction

of incoming sunlight and redirect it by way of refraction and reflection. As a ray

of light hits the prism, its direction is changed. Part of the light is then directed

towards the ceiling to be later reflected, while the other part comes inside the

room directly. Prismatic glass is commonly used inside electric lamps to

distribute light. However, its application as a daylighting system to control light

distribution in building interiors has been limited and its performance is yet to be

researched further. In principle, the prismatic panel can be placed in the upper

portion of a side window to deflect a portion of the incoming light deeper into the

room. In the case of double or triple glazing, the prismatic panel can be

sandwiched between glass panels to minimize dust and maintenance.

refraction of an incoming sunray

within the prism provoking a change of direction and improving sunlight penetration towards the back of the room.


b-Toplighting Systems:

Historical evolution

While rooflights could properly have been said to have started with the

central courtyards or atria of the Roman house, these were open to the sky and

rain; and despite providing daylight to the surrounding dwelling space, would not

have modified the exterior climate in the manner of

a roof light.

The rooflight by definition permits daylight to

enter from above through a glazed opening in the

roof protecting the interior from wind and weather.

The early rooflights were perceived either as domes

such as that at Chiswick House with ordinary

windows in the sides allowing in the daylight, but by

the nineteenth century structural techniques had

developed sufficiently to allow fully glazed barrel

vaults or glazed domes to be placed above areas of

building remote from the side walls and the

proximity of windows. Examples of nineteenth century shopping malls still exist

today where these overhead lights permit daylight to reach deep into the interior

of buildings.

Much innovation was used in the nature of these rooflights, and it is of

interest to study the section of the Soane Museum, to see the many different

shapes and sizes of overhead light Soane devised to introduce daylight to the

different spaces, in what was at the time his private house.

By the twentieth century the use of rooflights had been reduced almost

entirely to industrial buildings.


Types of systems

Skylight system: A skylight system is one of the simplest toplighting

strategies. It usually provides a horizontal or slanted opening in the roof of a

building and is designed to capture sunlight when the sun is high in the sky and

diffuse light from the zenithal area of the sky vault, and introduce it into the

portion of the room under the skylight. This daylighting approach can be used

only for the top floor of a multi-story building or for single-story buildings.

Several skylights uniformly distributed across the ceiling lead to a uniform

distribution of daylight. A skylight gives daylight distribution of an inverted V-

shape, where daylight is maximal underneath the skylight and progressively

lessens as we move away from that area. The reflector shown in Figure 6.18 is

used to deflect light from the area beneath the skylight in order to obtain a more

even distribution of light throughout the room. When several skylights are used,

and under diffuse sky conditions, the recommended spacing between them is

equal to their mounting height in order to obtain a fairly uniform distribution of

daylight throughout the space.

Roof monitor and saw-tooth systems: Roof monitors and saw-tooth

systems are toplighting strategies that differ primarily in their shapes. Under

these systems, light is captured through vertical or sloped openings in the roof.

These openings can be designed to capture sunlight at certain times of the day

or of the year, depending on the requirements of the building. Roof monitors can


be single-sided or two-sided. Single-sided roof monitors and sawtooth systems

provide a directional effect inside the room, especially if the elements are

spaced far apart. Two-sided roof monitors provide a more uniform distribution of

daylight and less directionality, particularly under overcast sky conditions.

Types of rooflight:


Light pipe system: A light pipe system

is a toplighting strategy designed to bring

daylight into the lower floors of a multi-story

building. This apparatus can be relatively

simple or sophisticated and elaborate. The

typical components of a light pipe system

are a solar collector that gathers sunlight, a

concentrator that focuses solar energy onto

a smaller area, a transport system, and a

distribution system. The solar collector may

be a simple stationary mirror or a

sophisticated computerized heliodon that

tracks the sunʼs movement. Another

possible component of a light pipe system is

a solar concentrator that is made of a

concentrating mirror or lens that focuses the energy collected from a large

collector onto a smaller area so that it can be transported efficiently. The higher

the concentration ratio of the mirror or the lens,

the smaller the cross-section of the

transporting mechanism needs to be. The

transport system can be a simple opening

shaft through the various floors of a building as

shown in, or it can be a prism or fiber optic

system that channels light in whatever

direction is needed. Light is transported within

the fiber optic walls by being inter-reflected

within the walls of the fiber.


c-atrium and glazing

The word atrium started as the central court of a roman house, admitting

light and air to the surrounding space. Today, it is described in the “CIBSE

LG10 daylight and window design” as the following:

“An interior light space enclosed on two or more sides by the walls of a

building, and daylit from a roof of transparent or translucent material and,

sometimes, from glazed ends or sides. It permits the entry of light to the other interior spaces, linked to it by glazed or unglazed openings”.

The atrium allows the daylight into central areas, modern atriums are most

commonly covered by a glazed skylight that monitors the light that reaches the

inside while keeping out the rain and reducing the need of air-conditioning.

Atrium has many advantages: it gets daylight into deep plans, giving a

sense of orientation, information of time, weather and keeping the occupants

connected with the outside of the building. Also, atria save energy by helping

the ventilation and admitting daylight.


V- Architects and The Light

Lao-Tse had said: architecture is not four walls and a roof, it is the air

that remains within, the space that these enclose.

Many great architects understood the importance of light and different

windows in their design and made it their first point of concern in order to better

embody their architectural ideas.

1- le Corbusier Le Corbusier had said: Architecture is the wise, correct and magnificent play

of volumes collected together under the light.

Le Corbusier not only brought the “Five Points of a New Architecture,” but

he also utilized light to its extents in the process. Light played a key role to

validate all of Corbusierʼs design and make it effective. He raised his structure


on pilotis, to give the building a sense of floating that is created through the

cooperation of light and shadow beneath on the lower level.

Extending pilotis and using frames as structure allows architecture to open

up and to become a free plan allowing natural daylight into the interior spaces.

Daylight is also utilized through roof top terraces and ribbon windows creating a

free façade. These aspects are evident when investigating structures of

Corbusier.

The weekend house, Villa Savoye, in Poissy, France, adequately

demonstrates each of Corbusierʼs five points. In the living room, ten meters of

full height glaze opens to a roof terrace allowing for the glass to slide open.

Natural daylight is essential to display the form within the structure. On the

exterior of the villa, the use of a white façade draws attention to the already

intrinsic nature of the form showing contrast.

At the “Unite dʼHabitation”, located in Marseilles,

France, light shows up in different fashions. As a

machine for living and known as the “vertical garden

city,” this unconventional apartment complex allows

for individual units, often different in appearances, to


be joined together. These two-story units are arranged in a fashion so that each

can display frontage and a private balcony on both sides of the building. Full

height glazing allows light to reach deep into the plan, which is protected from

overheating by a concrete “brise-soleil”. There is still a roof top terrace creating

indescribable space.

2- louis Kahn

Louis Kahn also uses light as a key factor when designing a structure. A

center for biological research, the Salk Institute in La Jolla, California, keeps site

context as an important aspect by angling each part of the towers toward the

Pacific Ocean in forty-five degree geometry. Focused around a central

courtyard each laboratory invites natural daylight to penetrate interior spaces

through this angle. In the center of the courtyard is a central water channel

leading to a reflecting pool ensuring not to miss-guide the viewer from the

Pacific Ocean. Acting like ancient ruins, Kahn wanted the sun to follow the

building throughout the day allowing

natural daylight within by using screens.

Also, at the Kimbell Art Museum in

Fort Worth, Texas, light is the sole factor

of the design. The play of light and shade

on masonry forms create subtle changes

to different spaces within the galleries.

Day lighting is essential, but the control of

natural light is at the utmost importance.

There is a need to illuminate the interior,

but also to keep harmful ultraviolet rays from

damaging the precious artwork. The structure of


the museum is the maker of light through reflection. The roof is vaulted and

splits down the center using reflectors to cascade light down the walls. At mid-

day, the roof illuminates silver.

Louis Kahn also expressed light through designs that are bold in geometric

forms. One of his early buildings the Yale Art Gallery in New Haven,

Connecticut, he focused on the distribution of light in a low interior space. His

solution was a ceiling formed of joined tetrahedrons and serves as space for

lighting conduits, which Kahn said, is good for illuminating the room as a whole

without minimizing the chance for specific illumination.

Understanding the importance for various sources, type and intensity of

light, Kahn design the library at Phillips Exeter Academy to take advantage

light's many properties. Kahn provided three distinct areas of light for the each

of his important spaces. The areas for reading in the Light received natural light

that was skillfully designed to enhance without bothering the ability to read,

Glare is bad in the library; wall space is important. “Little spaces where you can

adjourn with a book are tremendously important”, Kahn wrote about the Exeter

Library.


Kahn believed the potential of learning was just as great from looking out

the window as from reading a book, however he also understood the need to

limit the outside distractions, both of people and of light. At the perimeter he

allowed the light to bring the reading area to life, yet he controlled the glare at

the reading carrels, through window height and the use of sliding shutters. In

areas of more serious study, he limited the windows to a source of light from a

clerestory. Because the rays of direct sunlight are harmful to books, Kahn used

dim fluorescent lighting in the place of books, offering only enough to allow the

user to find a book. As a result of ever-changing external conditions, the interior

space comes alive with a constant income of light and shade. The room exists

in the kingdom of shadows, that is, between the silence of ideas and the light of

material reality.

3- norman Foster Norman Foster is another great architect to master the use of light in

architecture. The Hong Kong and Shanghai Bank, located in China, is tiered

and steps each layer of the tower allowing daylight into the spaces and atop the

roof terraces. The lower ten stories are dedicated to an atrium with a mirrored

ceiling that receives sunlight from a giant reflecting sun scoop outdoors

originally made to track the sunʼs path. Due to this aspect of so much natural

daylight within the structure, ample lighting is given to the underground level

due to a translucent floor installation.


The Willis, Faber and Dumas Headquarters office building in Ipswich,

United Kingdom, revolutionized skeleton construction and the use of iron and

glass. Without window mullions, ample daylight can enter interior spaces and

create a spacious atrium at the heart of the building. The solar-tinted glass wall

around the perimeter is uninterrupted exposing each façade.


VI- Light In Lebanon

The sun in Lebanon is an important factor, given the fact that itʼs a sunny

country generally speaking. The sunny days prevail in number in comparison to

cloudy ones, thus making daylighting a given element in architecture. Lebanese

windows have thus been modeled by the geographic properties of the sun the

the country in a way to increase heat and light inside during the winter days,

and reduce them during the summer.

Natural elements suck as the sun arenʼt however the only criteria that

affected the evolution of windows architecture in Lebanon. There were as well

social, cultural and economic factors.

1- social, cultural and economic factors Lebanon has always been, throughout the history, the crossroad of different

civilizations and cultures. These diverse currents kept introducing new forms

and concepts that would meddle with the local customs thus creating what is

known as Lebanese architecture. The west provided Lebanon with technology

and some socio-cultural aspects, while the Arab identity is what molded the

Lebanese identity, whether it was in social behavior or architecture.


Lebanese society with the different classes that arose was clearly shown in

the architectural aspect of Lebanon. Classes where known by their residence:

rectangular houses, with little decorative features, were the housing of the poor.

Middle classes would occupy the “beirutie” house, or the mansion.

Elements that today constitute what is known as Lebanese architecture are

taken from different times and cultures. Columns of the Roman, arch-shaped

windows from the Italian and roofing tiles from Venice, all were introduced by

artists or architects brought to the country by emirs and rich families, thus

shaping new fashions and forms as well as decorative patterns. Other elements

such as “moucharrabieh” came as a result of religious customs that would seek

to protect the woman from the curious eye; Islamic culture also narrowed the

window and introduced the pointed arched window.

During the second part of the 19th Century, as major cities in Lebanon

especially Beirut became trade centers; the presence of foreigners living on a

permanent basis revolutionized the concept of the window. The small protective

character gave way to the big exposing window not only to see but to be seen.

The new facades with large openings giving a view towards the sea or the street

were definitely an evident rupture with the past.

Around the 1850ʼs, cities in Lebanon became important commercial centers

that were home to a great number of foreigners. This changed the concept of

the window from being small, for the protection, to becoming big exposing

windows that would allow to see as well as to be seen. This era presented new

facades with large openings, that was clearly a leap from the past.

According to their religion, the Lebanese had different preferences in

architecture. However, ornamentation was always used, it was a symbol of

good wealth. The more original and innovative the ornament details, the richer

was the house and the higher was the social class. With the appearance of


rental houses, this however deteriorated: there was a mass production of

ornamentation and later on collage on the facade, which replaced the unique

designs and elaborate work on details that masons did before.

2- historical Evolution of windows

a- rectangular window It is the simplest and most common shape of windows. It changed and

evolved through the history affected by climate and foreign style. It is used in all

house types and went from small, thick openings constructed roughly to

become an ornamental element with a lot of details.

The first elaborate form of vernacular architecture was the rectangular

house, remains of which can be seen in all Lebanese regions. Dating from

5000BC, the windows in this type of houses was defined by thick masonry

walls, it was limited in size (depending on its climatic zone) and in number.

Evergreen trees were used on the outside to provide shade, and later shelves

were introduced to cast shade in the summer and stop the rain from reaching

the interior in winter. Wooden shutters were sometimes also used. The

orientation of these windows was a result of the natural setting.

“Depending on the climatic regions, openings in rectangular houses differed in size and location. On the coastal region, where solar gain and humidity are factors to consider, windows are places were maximum ventilation can occur in contrast to the high-‐ mountain region where window size and number is kept to a minimum. North-‐side open-‐space is usually rendered for outdoor summer activities during the day in all climatic regions. Whereas in the inland region, window openings seldom occur due to the characteristic feature of grouping houses therefore minimizing external climatic exposure. In the Beqa'a, the grouping of closed rectangular houses predominates; the detached house is rare . Also in the high-‐mountain, region variations of reducing heat loss conditions in north walls include backing the building into a sloped hillside or providing a berm (the level area separating ditch from bank on a hill-‐fort or barrow), both of which reduce the exposed north area to cold winds and heat loss.”(1)

(1) Windows as Environmental Modifiers in Lebanese Vernacular Architecture: Habib Melki


The major aim of this type of housing was the protection against the natural

climate. There was anther type of housing, called the “riwak house” it consists

in rooms connected with a gallery. The gallery was orientated north, giving

space for outdoor activity, its orientation gave it a natural cooling.

The windows are placed mainly within the riwak (gallery), putting to use the

shaded area as well as the cross ventilation, result of openings on opposite

walls of the room. The gallery has also an important social role, for the

gathering that happens within in and it connects all the parts of the house

together.


The liwan is a space that opens to the outside and continues by connecting to

the space in front of it. Often found in the high mountain region, the liwan is a

space used for circulation, social activities and

Storage space which is covered but always open to the outside. Cross-

ventilation was achieved by internal windows or vents between the rooms and

the central space, which originally was permanently open. Furthermore, the very

position of the central living space, be it the liwan or the central hall,

Throughout the development of different house typologies, rectangular,

gallery, and liwan, the rectangular window evolved mainly because of

environmental considerations. Whereas the features that influenced the

transformation of the rectangular window into the triple arched, in the central

house typology, were mainly socio-cultural and economic.

With the evolution of these typologies and the increase of use of interior

space (As opposed to the fact social gatherings, even within the family, used to

happen outside) it became important to use windows not only for heat gain but

also for natural ventilation and daylighting. Larger windows imply solar gain and

improved quality of daylight, this became very popular and soon curtains and

shading devices were introduced for situation with excessive sunlight.

c- small openings Throughout Lebanese

vernacular architecture,

small openings were used

for purposes that enhanced

environmental strategies of

natural ventilation and

daylighting.

Their position was


critical because they had to achieve their aims of adding daylight and balancing

ventilation, especially during winter.

The openings were located either on the upper part of selected walls

(above or next to the windows/doors), depending on orientation. The upper

openings increased in number and in some case were found on different

orientations for the purpose of daylighting, whereas ventilation openings were

placed depending on prevailing winds. The use of these openings was evidently

more flexible in the original rectangular house since the walls had similar

thickness whereas the vaulted houses in all typologies restricted their use to the

central part of the vaults. Within the gallery, liwan and central houses, these

small openings developed to become an ornamented feature within the façade.

c- Triple Arched Window

With the turn of the 20th Century and the wide use of sheet glass, people

began to feel the need for social expression through eclecticism and the

influence theyʼve experienced. Although the central hall type of houses

appeared at a later stage than the ones described before, itʼs the true Lebanese

house which attains the highest degree of identity.

The triple arch consists of three arches connecting above slender columns

and either tie to a wall or are supported by half columns. In some cases, the

number is extended to four or five arches. The total is a combination of a door

which opens to a balcony or a rail-protected protrusion, and two windows

forming a parapet. The arches were generally plane and open, until later

periods when glass came in use. Wooden frames were fitted into the columns

and arches with intricate designs and patterns of plane or colored glass.


d- The bay window

Typical to Arab architecture, the

musharrabiya, or bay window, was more

common in Islamic communities and served

as lookout for the harems. Resting upon

stone corbels, the structure was mainly

made of wood in a way to allow seeing

without being seen.

3- Current situation in Lebanon In recent days we can no longer clearly formulate a pattern of window

typologies in the modern architecture in Lebanon. There isnʼt one type of

windows spread across Lebanon, thereʼs a huge diversity in dimension, styles,

and even materials used.

The current universalisation of construction technique, of architectural

styles, ideas and concepts made the whole world one giant architectural scene.

Thus Lebanon is observing a loss of the native identity when it comes to the

construction, and especially the windows.

As exposed in the parts above, the vernacular architecture (ex: rectangular

houses), thanks to its instinctive nature, used to take the light strongly into

consideration, whether it was on the level of urban planning or the individual

residences. Today however, we notice a standard -seldom blind- copying of the


western windows, which is mostly a commercial, economical approach, mostly

seen in commercial buildings for sale or rent, where the façade is spotted with

aluminum windows and doors or the same shape and dimensions.

In buildings like these, the leading factors controlling the windows

orientation, size and shape are governmental rules and regulations that are far

from being environmentally conscious, or taking into consideration the effect of

daylight on mood and space.

Lebanese rules and regulations According to the construction law in Lebanon (revised in 2007):

Article 9, part 1 discusses the “legal” area that should be outside a window or

opening for that opening to be legal. The law defined that area to be 4.5mx5.5

m, given that rectangle touches the opening itself, or the balcony/terrace

adjacent to the opening (if any).

Some conditions are stated such as:

The depth of the room inwards from the opening shouldnʼt exceed 5 times the

height of the room.

The area of the room to lit shouldnʼt exceed 10 times the area of the opening

(thus a 2m2 opening is enough for a 20m2 room)

Article 9, part two states all the rooms that are legally exempt from having

openings from natural daylight, some of which :

Stairwells, hallways, maids rooms, kitchens of 8m2 or smaller, lobbies, clubs,

restaurants, cafes, libraries etc.


Article 9 part three mentions rooms that require ventilation but not daylighting.

Commentary So as it was clear from the summary of the article, the Lebanese law has

one law and standard when it comes to daylighting, for all the facilities without

taking into consideration the function of said facilities and rooms. In the face of

the law, the minimum to light a living room is the same as the minimum to light a

hospital room, as the same to light a museum. Its is not a full law and doesnʼt

cover all the basics as they should be covered, by dividing the lighting according

to function. Not to mention that some of the rooms that donʼt require lighting are

absurd such as the maidʼs room, or the library. In fact the Arabic word for

“library” is ambiguous, it could also mean book store, but the law doesnʼt take

the trouble to make that clear and thus according to the law, a library doesnʼt

have to be naturally lit! Architects such as Louis kahn have thoroughly studying

lighting in libraries and the law allows to “keep it dark”.

Shy attempts are being done to correct the current situation by studies

carried out by the UNDP and building legislation authorities, but so far no results

are seen.

As a conclusion of the previous, the authorities and laws donʼt take into

consideration the difference in human needs when it comes to lighting,

depending on what the person is doing or isnʼt doing in the room to light, they

are mostly taking a general minimum of light requirement. The commercial

buildings of today are satisfied with this requirement, and that leaves them dimly

lit in the interior, especially that a 4.5x5.5 space is small when there are many

buildings around, more so when all of them are tall, or if the room in question is

on the first floor, be it residential or an office.


Lebanon is a country with a lot of sun but this natural resource is not fully

benefited from. Hence it is the architectʼs duty to take it into consideration and to

try to make his designs environmentally better, to take advantage of the

presence of the sun and day lighting (in a country where the electricity is not

even always available) and to give his projects the ambiance that would fit them

best, with the use of natural light. And above all, architects of Lebanon should

try as much as possible to restore the Lebanese national identity, with the use

of modern material and new sustainable technologies, especially that Window

design today has brought flexibility to concepts of orientation, shape and size

which makes the aim easier to achieve, and which opens new design

opportunities.


VII- Museums and The Light

Light has a special importance in museums, because the main function of a

museum is the display, hence the items shown should be clearly visible without

causing any irritation of the sight to the viewers or discomfort. On the other

hand, light should be illuminating the museum as a whole to allow circulation

and other functions.

So to summarize this, there are two types of light in the museum, Task

Lighting (the illumination of art and exhibited items) and Ambient Lighting (the

general use of light within the museum).

Museum visitors usually prefer to see objects that are displayed under

daylight. The daylight may be provided by side windows or rooflights and may

be highly controlled or partially controlled. The effects of daylight in a space are

much more noticeable from side windows than rooflights but is more difficult to

control to ensure avoidance of glare and poor viewing conditions. Highly

controlled rooflights may however fail to give a good impression of daylight and


it must be questioned whether they are worth the cost. An evaluation of energy

payback is needed.

1- types of museum lighting a- Ambient lighting

It defines the general experience of light within a gallery, the light that

illuminate the gallery as a whole, without taking in consideration the lighting of

the works. Many of the advantages attributed to natural light actually deal with

the psychological mood that it conveys within an interior space. The two most

important advantages of natural light are: the experience of not being confined

within an enclosed space and the changing quality of natural light over time.

b- Task lighting

It deals with illuminating works of art without regard for its effect on the

overall physical space.

When designing task lighting, two of its aspects is most important to take

into consideration: spatial distribution and the intensity of the light.

Spatial Distribution

Shadows and gloss on a surface are caused by directional sources such as

incandescent lamps. Both shadow and gloss are harmful for viewing any work

of art and most items that are usually exhibited in a museum, so many ways are

used to eliminate them: non-directional diffuse light is used, making surfaces

appear flat and matte, thus eliminating shadows. Veiling reflections caused by

non-directional sources (natural or fluorescent light through a diffusing daylight)

result in a loss of colorfulness. From a practical standpoint, many naturally lit

galleries use some diffusion to reduce the high intensity of direct sunlight and to

distribute light uniformly around a room. Diffuse daylights also hide ductwork,

light louvers, and other distracting elements hidden in the ceiling zone. But too


often, such diffusion also destroys much of the quality that we associate with

natural light.

Properly designed reflected light can provide general control and still

maintain directionality, although it is difficult to provide acceptable light

distribution in all directions at the same time.

Intensity

Humans generally prefer high light levels, while to conserve the pieces

exhibited lower light levels are favored. Therefore, the intensity of the light

directed at the works should be taken into consideration when designing the

light: it should be high enough not to cause discomfort for humans and favor

their well-viewing, yet low enough to preserve the objects.

There are many examples of artworks that have been damaged by daylight,

which has more potential for harm than most conventional artificial sources of

illumination. The museum designer must know both the dangers inherent in

various light sources and the visual advantages of the sources to find a proper

balance between aesthetic and conservation concerns. Ultimately, the

seemingly opposite requirements of good lighting and conservation must be

synthesized to find a solution that satisfies both goals.

2- lighting design techniques The overall light exposure permitted on sensitive objects is the sum of the

daylight and artificial light. With highly sensitive objects it is almost impossible to

use daylight. Where such objects are being displayed, especially in any large

museum, areas should be provided where a view out is possible. These areas

may contain less sensitive objects or may simply provide seating for the visitors.

Such an approach can also help reduce the incidence of ʻmuseum fatigueʼ.


With objects of medium sensitivity a highly

controlled approach may be adopted requiring

automatic shutter control of the louvers that

control the daylight, and of artificial light. A

more passive approach might be adopted

where by daylight may provide between 40%

and 70% of the total yearly lighting demand.

Such a system would normally have

differential louver controls on the daylighting

for summer and winter, and be relatively more

transparent in winter than summer.

Vertical space is usually the preferred space in museums particularly for

hanging paintings. Hence it is frequently found that vertical windows have been

blocked up or covered in museums that have been created from refurbished

buildings of other types. However, it is not just the lack of space that causes

problems with vertical windows: Objects displayed against windows have a very

bright background, thus the eye takes longer to adapt to them and a lot of detail

and color of the object is lost, it often appears more like a silhouette.


With lower levels of light, the use of a dark background reduces the

adaptation level of the eye, thus increasing the apparent brightness of the

viewed object. For instance, in the ʻTurner Watercolorʼ room at the Tate Britain

Gallery in London where the vertical illuminance on paintings is maintained at a

low reflectance, maroon background is used.

The choice of background reflectance and, indeed, color plays an important

role in the visibility of the objects. Backgrounds of high chroma (strong color

intensity) can impose their own color on a room. Photographs may exaggerate

this effect as the eye searches for a reference or ʻwhite balanceʼ within a room

in an effect sometimes known as ʻcolor constancyʼ. Neutral surfaces (except

white) tend to produce a gloomy, cold appearance. The best compromise is

usually a low chroma background with a reflectance of 20% – 60%, chosen

according to the necessity to reduce the adaptation level of the eye.

Galleries exhibiting modern art have a tendency to use a white background

where the reflectance may exceed 80%. This will often work with modern art

consisting of strong primary colors, such as the works of Andy Warhol, but not

necessarily so well with Picasso and, in particular, dark sculptures.

Care should be taken, however, if a design that was originally conceived

with highly reflective walls is to be replaced with walls of lower reflectivity. This

is because in schemes with high reflectivity the contribution of the reflected light

to the total amount of light is very high and a reduction in that reflectivity will

severely compromise the total amount of light in the room.

3- considerations to be taken

a- Glass display cabinet

High brightness sources, either artificial light or daylight, may produce

reflections in the glass of display cabinets thus affecting the visibility of objects

within the cabinet. They may be particularly noticeable if the objects within the


cabinet are poorly lit and it contains no additional light source. The perception of

the ʻveiling reflectionʼ depends on the balance between the brightness of the

reflection and the brightness of the object. The issue is quite complex, however.

A low reflectance surface in the background of the cabinet can reduce the

adaptation level of the eye and, in theory, improve the visibility of the object

reducing the adaptation level of the eye may make the veiling reflection visible.

Careful analysis is needed in each case.

b- Surface reflectance Surface reflectance can have a major impact on the level of illuminance in

the room. The more the surface is reflective, the more light fills the room, for a

lower quantity of light sources. The reflectance is increased by the color of the

surface, so a white room with white floors, ceilings and walls is of very high

reflectance and luminance.

The color of the surfaces and the materials used on the inside of the room

are thus of great importance in respect to the lighting of the interior and affect

directly the need for light sources, be in natural or artificial.

c- Contrast Diffuse illumination, where light comes equally from all directions, will allow

an object to be seen, but will do little to reveal the form or texture because of the

lack of shadows. The lack of shadow, and thus the lack of contrast, is then

harmful to the object seen (from the point of view that the object is not well

expressed under these circumstances). The gradation of the reflected light

(brightness) over the surface of an object reveals its 3D nature. Applying light at

an appropriate angle helps express the texture of the object.

Contrast is not just essential for seeing the object, but as expressed in

chapter III (2-a) it affects directly the way the interior itself is perceived, and how

the occupants of the room feel psychologically.


4- case studies

a- National Etruscan Museum ʻPompeo Ariaʼ, Marzabotto, Italy The new exhibition space of the ʻPompeo Ariaʼ National Etruscan Museum

in Marzabotto, has south facing vertical glazing that needs sun control with

regard to both thermal gains and daylighting. The service/ energy solution

chosen involved the use of an external wooden balcony, an observation point

towards the archaeological area that also connects to the new multimedia room.

Moreover, the balcony acts as an external shading system, designed to

allow solar gains in winter and avoid overheating during summer season.

Internal baffles and louvers, together with a curved ceiling, diffuse daylight and

allow a uniform illuminance inside the exhibition room and a more variable one

in corridors.

The following images show RADIANCE simulations of the proposed

solution under an overcast sky and a sunny sky on 21st March at noon.

Museums: energy efficiency and sustainability in retrofitted and new museum buildings: European

Commission directorate- General Energy and Transport - University College Dublin, Ireland 2004


b- Archaeological Museum of Delphi The museum at Delphi had two distinct types of gallery. In most galleries

the objects are not sensitive. The clerestory-lit galleries (e.g. the Apollo and the

Athenians) tended to suffer from sun patches on the objects, particularly from

the east-facing windows during the morning. The Siphnians room had a

traditional rooflight, with light penetrating through the roof into the roofspace and

then through diffusing glazing into the room.




There was no control. An even level of light was produced in the room with

poor contrast. In the vertical plane, the walls had a higher illuminance than the

large objects in the room (generally placed toward the centre of the room). The

clerestories were fitted with external shading, while east-orientated screened

rooflights, were added. The artificial lighting strategy incorporates a combination

of fluorescent and spot lamps with ceiling-reflected light.

The diffusing ceiling in Hall V (Siphnians Room) is being replaced by an

egg-crate based internal system, with external shading louvers allowing no

penetration of sunlight, reducing the luminance of the background while

maintaining the illuminance on the objects.




VIII- Conclusion

“And in the beginning there was light”

The importance of light has always been acknowledged, but not often is the

light carefully studied in architecture as to provide not only global illumination of

the interior, but to set a mood, an ambiance, and a vision.

As shown in the thesis, light has many roles and can have many different

uses. It has a direct effect on the wellbeing of humans from a physical and

psychological point of view, and affects the way the occupants perceive the

interior space, whether it was artificial or natural light.

It is common knowledge that artificial light is easily controlled and

manipulated to reach the desired effect, but natural light can also be

manipulated and control using a set of ways. The windows shapes, placements,

orientation, dimensions and shading devices placed on them help control the

light and balance it to the wish of the architect, as well as create a game of light

and shadow in the interior that can set a mood as much as interior decoration,

hanged paintings or walls color.

Many architects, old and new, have given great importance to the light.

Discussed earlier are some of the most light-oriented works by Louis Kahn, Le

Corbusier and Norman Foster.


Despite extensive work and studies done on the lighting systems and light

techniques, Lebanon seems to lack nowadays of correct lighting ideology. Both

in the mind of people and in the sets of laws, light takes a small, if any, portion

of the design phase, problem which should be worked on and attended to by the

architects, who should know better than to build only “commercially”

Finally one of the institution that require most study on the light are the

museums, because their main aim is to “show”. The main problem in museums

is that a great number of them are a restoration of old buildings and facilities

main function of which was not museum. Careful light study hence has been

done on them and the restoration shows a great deal of wit and use of modern

technologies.

To put more of an emphasis on the Lebanese situation, it is a very hard job

to fix all the problems of the modern constructions, aiming in majority on the

commercial outlook. Shouldnʼt however be denied the praise those few facilities

and buildings that respect light to a great extent, mainly in Beirut and the area.

The problem however is far from being solved. The start should be in the

legislations, this would point to the problem, awaken people to the importance of

light and incite them to take lighting into consideration not as an accessory, but

as a main element.


IX- Bibliography

Books:

[1] Between the silence and the light: John Lobell & Louis I. Kahn – Boston,

Shambhala (2008)

[2] Daylight, Architecture and Health: building strategies: Mohamed Boubekri - England, Elsevier, Architectural Press (2008)

[3] Daylighting: natural light in architecture: Derek Phillips- England, Elsevier,

Architectural Press (2008)

[4] Designing with light and shadow: Kaoru Mende & lighting planners

associate Inc. , Australia, Images Publishing Group Pty (2000)

[5] Energy and environment in architecture: Nick Baker and Koen Steemers -

London, Taylor & Francis Group (2000)

[6] Human Factors in Lighting, Boyce, P.R, London, Applied Science Publishers

(1981)

[7] Lighting Modern Buildings: Derek Phillips- England, Elsevier, Architectural

Press (2000)


[8] Museums: energy efficiency and sustainability in retrofitted and new museum

buildings: European Commission directorate- General Energy and Transport - University College Dublin, Ireland 2004

[9] Rehabilitation: Traditional Lebanese Architecture: Corpus Levant -

Leogravure, Beirut, (2004)

[10] The complete home lighting book: James Davidson - London, Cassel 1997

[11] The role of vitamin D endocrine system in health and disease: Reichel H., Koeffler, H.P. and Norman, A.W. - New England Journal of Medicine 320 (1989)

[12] Windows selection: Ian D. Collins and Eric I. Collins, London, Newnes-

butterworths, 1977

Articles:

[13] Effect of light on human mood: Hamzeh Karbasi -arefianatelier.com (2009)

[14] Energy Efficiency & Renewable Energy: United States Department of

Energy (2005). http://www.eere.energy.gov/buildings/info/design

[15] Light and architecture: Cesar Portela –cesarportela.com (2007)

[16] On light and dematerialization in architecture – John C. Klopf

klopfarchitecture.com (2000)

[17] Windows as Environmental Modifiers in Lebanese Vernacular Architecture:

Habib Melki (The 23rd Conference on Passive and Low Energy Architecture,

Geneva, Switzerland, 6-8 September 2006)

Light and Architecture-Masters Thesis

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