Effect of natural and artificial light in designing modern building

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Introduction

Lighting has been one of the major modes of expression of the architects in the past decades. The character of interior spaces can be enhanced by controlling the admission of daylight by means of the form of a building and the size, position and aspect of opening in its fabric.

In the former decades, lighting after dark was provided by incandescent sources, torches, candles, oil lamps and latterly by gas. The present standard opportunities for expression were limited. The advances that have taken place in lighting technology during the last few decades have had a great influence on the way we live. According to Merritt and Ricketts 2000, electric light is readily available at the touch of a switch; it can be altered in intensity and, with the right equipment, it can be redirected, refocused and its colour altered, or it can be piped remotely form its source and redistributed whilst its duration can be controlled. The effectiveness of lamps has shown constant improvement and the range of types has been developed to satisfy growing and changing human requirements (Merritt and Ricketts 2000).

A symbiotic relationship between light and structure exists in that the unity of the building derives from their successful interrelationship. In the first instance, the perception of structure is gained from the light which falls upon its surface and edges (Cheung, 2010). One can only experience structure and consequently the spaces within and without a building as a result of light. Secondly, one sees the light itself entering upon the structure, either entering through it, by means of windows, or support from it if it is artificial.

According to Cheung 2010, a very clear relationship exists between the manner of the daylight and the structural system for the building since an important aspect of the structural strategy will be the environmental criteria of heat, light and sound. Light remains a major consideration and the advantages of natural light must be set against the need to overcome its possible disadvantages through structural and environmental solutions (Cheung, 2010). This paper explores the effects of natural and artificial light in designing modern buildings.

Use of Lighting in Interior and Exterior Design

As with all aspects of architecture, lighting may be analysed and its relative importance changed depending upon time, the building’s function and its location. Lighting design is essential to the success of any building. This hardly needs stressing since the way the interior of a building is perceived depends upon the way in which it is lit. Light is as much a building material as the structure of which it is made, since light, when reflected from a structure’s surfaces and edges, provides the information upon which we act (Horowitz et al., 2003). It is light that can make a building bright and airy or dull and gloomy; it is light that enables us to perform, and without it the building would cease to function. Whilst an understanding of the role of daylight is fundamental, knowledge of various forms and properties of artificial light not only at night but during the day is essential.

The interior of a building at night does not necessarily have to imitate its daylight appearance. In work places, it may be thought that conditions should be strictly controlled as far as possible, night and day, to create a standard environment, but this is not the case in the majority of buildings, where peoples’ emotional needs suggest that a change of appearance after dark may be beneficial.

Types of lighting

Light sources are grouped under two major categories; natural light and artificial light. Natural Light

The use of natural light presents the design with the possibility of forming an effectively lit space whilst at the same time reducing energy consumption. In many cases, the existing building will dictate the degrees of natural light or daylight that can enter the interior spaces, as the layout of windows, (their sizes, glass type and orientation) will affects the amount of light entering (Kim and Koga, 2004). However, daylight also enters a space via light wells, courtyards, atria and roof monitors. Clearly the climate, and especially the sky conditions, will have an impact on the quantity and quality of light, so its use needs planning in conjunction with artificial sources (Velds, 2002).

Artificial Light

Artificial light is constant in quantity, colour and direction but is often static. It needs translation, reflection and careful control. The function of the building will determine the amount of artificial and natural lights required (Ivan, 2010). Kim and Koga 2004 asset that some buildings or areas of buildings will demand a high level of light to serve the visual needs of the occupants, whilst other areas may be satisfied by the lower levels.

History of lighting in modern house, cities and buildings

The strategy for early twentieth century structures was developed by the imperative of day lighting, the structure itself and its configuration which was designed to serve the function of the space (Kim and Koga, 2004). This was particularly evident in the roof forms developed for the early factories. Designed to maximize the entry of natural light and minimize the adverse effects of sunlight and sky glare (Ivan, 2010). At the time such structures were designed in the 1940s, artificial light was both expensive and crude and little was done to integrate the lighting with structure; it was an add-on and often conflicted with the overall integrity of the design. Light fittings and other services hung below the ceiling, eliminating much of the benefit of the daylight (Khan and Abas, 2005).

With intense development of artificial lighting both sources and fittings) in 1960s and its greater efficiency, relative costs were reduced and design turned to structure where the need for daylight strategy seemed less necessary. This resulted in some buildings where daylight was excluded altogether or used only for environmental purposes, with the main functional light relying on a totally artificial lighting strategy (Khan and Abas, 2005). There were even those who felt that the building could be heated by the lighting system. It appeared that the qualities inherent in a daylight structures may have been forgotten.

Lighting designers took advantage of the secondary structures to accommodate their equipment, primarily using them to conceal the electrical distribution, then support the lighting equipment and finally to conceal the equipment by recessing light fitting within the ceiling space. Initially the main structure was used to support the equipment, but this required careful co-ordination with the main support structure (Ivan, 2010). An obvious development was to make the secondary ceiling the main support for lightning fittings and to solve the problems of dimensional co-ordination at the design stage of the ceiling and the light fittings together.

To this end suspended ceilings were designed not only to conceal the pipe and ductwork, but to integrate all the services within the ceiling space, including the lighting. Lightning often took the form of individual recessed fittings, or lines of light, the shape or form reflecting the nature of the source, fluorescent suggesting lines, filament and other compact sources suggesting circles (Velds, 2002).

The advantage of lighting in expressed structures lies in the ease of installation, maintenance and subsequent replacement or adjustment of equipment; the disadvantages lie in the somewhat obtrusive nature of the equipment, which in some circumstances overwhelms the purpose of the space itself (Merritt and Ricketts 2000). Kim and Koga 2004 say that various gantry systems have been designed to give homogeneity to the overall appearance of the lighting system, but it is necessary to emphasize that what to one architect is an honest expression of building function may be to another an unwelcome intrusion defeating the primary function of providing light to the space (Kim and Koga, 2004).

With the current technology and higher demands, lighting has taken a different forma altogether. Whilst it is essential to satisfy the visual needs of those using the building, it should be done in as energy saving manner as possible (Khan and Abas, 2005). When considering the energy aspects of the different lighting systems to be evaluated, it should never be forgotten that the chosen system must satisfy both the emotional as well as the visual needs of the occupants.

The most important contribution to energy conservation is to minimize the use of natural light during the day. The introduction of daylight through windows, where the daylight is designed to contribute a substantial element of the daytime lighting, is a basic design decision affecting the whole design of the building (Kim and Koga, 2004).

As with suspended fittings, any type of light distribution can be arranged, depending upon whether the track is ceiling mounted or suspended. Most lighting equipment designed for track mounting is in the form of spotlights, and the rich variety of this type of fitting will ensure that any type of distribution is possible (Lataille, 2003).

Impact of Artificial light on the Interior of the building

Merritt and Ricketts 2000 assert that since systems rely on the reflective capacity of those surfaces to which the concealed source give light, there is an important relationship between the light source itself and the colour, texture and reflective capacity of the source lit. They further emphasise that the dimensional relationship between the lamps, the surface to be lit and the building structure is crucial. If this is not right there will be too great a contrast of light level across the surface and it will appear unevenly lit. An example of this might be in the design requirement to light a ceiling from around its edge, where the light source must be placed below the ceiling (Merritt and Ricketts 2000).

The great advantage of fibre optics, or as it is now more generally called, ‘remote source lighting’, is that the light from a single high intensity source can be placed at a distance and concealed to power a number of light sources where they are required and where maintenance might prove to be a problem; only a single lamp will require replacement (Gevorkian, 2009). Remote source lighting is essentially insufficient since there are light losses in the transmission of light down the fibres, but this method of concealed lighting has its uses in displaying lighting and in providing light of a decorative nature (Horowitz et al., 2003).

Impact on the mood, Feelings and visual identity

It is a matter of common observation that up to a point, the more light that is available, the better people see. During the day, people tend to place themselves close to a window to obtain the advantage of daylight, whilst at night people stretch switch on electric light, and is means of control is available individuals set this to give a light level appropriate to their visual needs. There is a tendency for lighting codes and regulations to concentrate on the level of illumination required to satisfy the needs of vision. The level is clearly important, but this alone ignores peoples’ needs for the overall perception of a space.

Daylight helps people relate the indoors to the outdoors. Colours appear brighter and more natural in daylight or natural light. The variations in light over the course of a day and in different weather conditions stimulate visual interest. Like most other living things, people need full spectrum light, which is a main characteristic of daylight (Lataille, 2003). Without the natural or artificial light, people tend to lose track of time, are unaware of the weather conditions, and may feel disoriented.

It is clear according to Gevorkian 2009 that the more difficult the task to be done is, the more light needed. Although it is possible to perform at very low levels of light because of the human eye’s ability to adapt, if complex work is to be accomplished efficiently such levels would be inadequate. The higher levels equate with more difficult tasks (Gevorkian, 2009). Visual acuity, or the ability to discern detail, is directly related to the illumination level on the object, but relates also to the contrast between the object and its immediate background or surroundings.

Environmental impact of lighting- i.e. CO2 emission, risk of fire etc.

Conversely, as Lataille 2003 states, artificial lighting has resulted to various accidents and pollutions in the interior of the building. Active methods of controlling the internal environment of buildings have changed over the centuries and vary from one building to the other. Artificial illumination has a long history that dates from flickering light of fires and candles to that of oil lamps, gas lightening and electricity. Gas and electricity lightening has created a stronger and more controllable light but, like candles and lamps, it has had the major disadvantage of polluting the atmosphere and leaving soot deposited within the room (Lataille, 2003). The development of gas and electricity lightening transformed interiors, creating a bright and clean source of illumination.

Excessive lighting might also lead to glare. Glare is a result of excessive contrast or of light coming from a wrong direction. The contrast between the bright outside environment viewed through a window and the darkness of the interior space creates glare. Glare results in discomfort and eye fatigue caused by repeated adjustments of the eye to one lightening condition after another (Merritt and Ricketts 2000). Direct sunlight or reflected sunlight from bright, shiny surfaces can be disturbing or even disabling, and it should never be permitted to enter the field of view of a building occupants. The two methods of avoiding glare and reducing brightness contrast are sensitive interior design and daylight light controls.

Different Theory of lighting in our modern buildings

On hitting a dense surface, light, whether sunlight or artificial light, is directly reflected, diffusely reflected, absorbed or transmitted in some combinations thereof. According to Chiras 2006 and Crowley et al. 2003, most of the light reflect and absorbed are wasted and so the need for sustainability. Sustainability can also be defined as economic and social development that meets the needs of the present without compromising the ability of future generations (Crowley et al., 2003). Minimization of wastage on natural resources (example sunlight) makes architectural designs economically friendly. For the buildings to qualify as environmentally friendly, the lighting and heating system used in the building should be in such a way that there are no harmful emissions to the atmosphere and minimized dumping of waste materials into the environment (Chiras, 2006). These phenomena are important when considering the effect of light. Lighting designer, Dray Gordon points out that a common mistake when providing light for building is to select the lighting equipment first. Selecting luminaries is the last step in the process. What is important is not what makes the light, but which objects and surfaces receive it. The key successful lighting designs is to decide what one wants to light first, and then work backwards to determine the solution.

Impact of Natural light on the Exterior of the building

There is a concern with how new sources and higher levels of light affects the appearance of buildings both inside and outside. This would mean some questions posed on the psychological and physical environment created by light in the buildings (Edwards and Torcellini, 2002). A widespread application of higher lighting levels will undoubtedly be accompanied by changes in light sources, lighting equipment and application method, but nothing necessarily revolutionary. There will be a tendency to wider use of the more highly loaded lamps, the very high output, and the high output types; and colour-corrected mercury.

Any variable solution to the above problems according to Boyce et al. 2003, must be conceived in the broadest possible way. Many designs and construction professionals have been working for years to create environmentally conscious lighting systems. In London, most conventional practitioners’ modern design and construction find it easier to make buildings as if nature and place did not exist (Boyce et al. 2003). Fossil fuels make buildings differently, lighting them, cooling them and heating them. An ecologically aware architect would design those design differently. Boyce et al. 2003 emphasizes that all practitioners should immerse themselves in the life of each place, tapping into natural and cultural history, investigating local energy sources and the available of sunlight. The intention would be therefore to design a building that creates aesthetic, social, economic, and ecological values for the surrounding human and natural communities and resulting into more positive effects (Boyce et al. 2003).

Depending on the light intensity, angle at which it hits the exterior parts of the building, light has various effects on the building. In majority of the cases and depending on the material used in building, light accompanied with heat has caused various corrosions, tear and wear of building materials (Edwards and Torcellini, 2002). Various materials have also been oxidized in the presence of light and hence change in colour and appearance. The example is various building built in the early years which have lost their appearances and the paint due to light (Crowley et al., 2003).

Impact of Natural light on the Interior of the building

Horowitz et al. 2001, state that, natural light do not have much effect on the interior of a building as compared to the exterior. The light waves majorly affect the area of impact and the effects are spread to other interior areas. The natural lights only have direct effect on the interior of the building suppose the ventilations are left open (Horowitz et al., 2003).

Natural light penetrates to the room through ventilations and other openings. High lighting levels affects both air conditioning and heating of the room. When large areas sources are used, the adaption of the eye remains at a high level and quality lighting is obtained. When a small areas source are used to obtain the high levels of illumination, the eye is sees a field of view that is constantly changing from high brightness to low brightness. With the normal motion of the eye the variation between the high brightness areas and low brightness areas produces an undesirable effect on the eye adaption.

As McColl and Veitch 2001 states the impacts of both artificial and natural light on human health can be grouped under three categories; light operating through visual system, radiation and light operating through circadian system. He also says that exposure to ultra-violet light, visible or infrared radiations produced by light can harm both skin and eye. The damages are not common for artificial light sources meant for light although cases are witnessed sometimes (McColl and Veitch, 2001). Light enables vision but when excess can have various effects on the eye. Light operating through circadian system has impacts on sleeping patterns and is believed to be connected to the breast cancer developments (Horowitz et al., 2003).

Under certain day lighting conditions the sky brightness through a window wall becomes too bright for quality illumination. Consequently, some types of control are necessary. In fact, in deigning day lighting for higher levels of illumination the choice of the day lighting controls is much more critical than in designing for lower levels of illuminations.

Day lighting controls fall into two basic categories: fixed controls and variable controls. Fixed control (natural controls) are those with which the occupant has no choice of the amount of illumination coming from the room. This type of control can be either natural or artificial. The natural control may be orientation of the forestation so that sunlight does not enter the room.

Many fixed controls are not integral parts of the forestation. This type of control may be an overhand that is opaque, louvered or translucent. It may also be a horizontal or vertical lowered wall. The fixed day lighting control is generally employed for reasons other than daylight utilization. In the case of overhang construction, it may provide shielding from excessive heat loads, and at the same time provide exterior corridor for inclement weather conditions. The importance of green architecture cannot be over emphasized as its advantages have been seen and experienced in areas where it has been practiced. It is therefore imperative to focus and stress on green architecture as its merits are great.

Impact of Artificial light on the Exterior of the building

Most of the time, the exterior parts of a building do not experience the effects on artificial light. However, in busy cities, vehicles produce light but the effects on the exterior parts of the building are minimal (McColl and Veitch, 2001). As Huang 2007 states, the external lighting systems of a house do not or have very minimal direct effects on the building unless other secondary factors brought by lighting. The secondary effects include animals that use the light for climbing the walls of the buildings or feeding on the walls due to the presence of light at night (Huang, 2007).

The choice of building materials in reference to the effects of light on the building has been proved to affect the lighting system of the buildings and have impacts on the building occupants. Certain construction material like (polyvinyl chloride) PVC, which is a common ingredient in doors, windows, floors and wall coverings, contains heavy metals that are carcinogenic and endocrine disrupting (Alimoglu and Donmez, 2005). The materials are further dangerous when illuminated by either natural or artificial light or heat. Suppose illuminated by artificial light, these materials seep-off and accumulate in tightly sealed buildings making the air that the people in those buildings breathe harmful (McColl and Veitch, 2001).

The developments of low-wattage fluorescent lights that do not emit heat, the floor area of these structures are widened to the point where natural illumination has been replaced completely with the artificial. This is advantageous both to the designers and the occupants. Additionally, the affordability of these new buildings and the fossils fuels used to drive the generators that powers them, explains, in large part, why passive environmental control is phased out (Judith & Fellmann, 2009). Of course, air-conditioning also provides comfort in the summer, and issue that future environmentally conscious architects would have to address with more aggressive strategies to cool buildings passively. As a result, various architects have been simultaneously exploring new environmentally sensitive practices to make better energy efficiency, air quality, and occupant health (Huang, 2007).

Conclusion

In a nut shell, lighting system is important for sustenance of human beings both in seeing and in doing actions. Life would be impossible or unbearable without light be it natural or artificial. According to Alimoglu and Donmez 2005, light has impacts on both the health and activities of human beings. Light enables the performance of visual tasks, controlling the body’s systems, effects perception and mood, and enables other chemical reactions in the body. However, it is important to note that lighting system have also various effects on the building and the occupants, both positive and negative (Alimoglu and Donmez, 2005). Improperly installed lighting system has had various effects on the building, occupants and the surrounding. The lighting systems have contributed to various air pollution, eye and skin diseases in areas where they have not been properly installed. The use of natural light is of greater benefit than artificial light. Natural light apart for allowing visual, has also minimal or no pollution to the environment. Similarly, natural light is beneficial to the human skin as it enhances the production of various vitamins through the skins (Merritt and Ricketts, 2001).

LaGarce 2002 asserts that construction companies have incorporated ways of saving energy in their designs, as well as ways of reducing emission of harmful gases or effects into the building and its occupants (LaGarce, 2002). With the modern methods of lighting like electricity and gas, carbon dioxide emissions into the environment can be reduced significantly (Chiras, 2006). One method that construction companies have incorporated in buildings when installing lighting systems is energy saving. They have employed the use of solar energy which is far more economical than electricity. Other energy saving features in today’s green architecture include well- distributed lighting fixtures and demand controlled ventilation (Merritt and Ricketts, 2001). The lighting takes advantage of daylight such that there is no need of putting on power during the day.

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