Natural Lighting in Greek Interiors

As the Romans were aware of the thermal and luminance effect that Natural Light had on their dwellings and how they could orientate their interiors to the sun’s path in order to be able to use its natural substances at the appropriate time of the day and to the occupant’s advantage, the Greeks took a different course of action to be able to use natural light benefits in collaboration with their interior.

The orientation of the dwellings themselves were being designed to the east or west in order to allow the natural light to pierce the interior at its two most dominant peaks; the sunrise and the setting of the sun. The Greeks, in their temple interiors kept their cellas; the inner chamber of the temple at low exposure to natural light to keep the element of mystery. Although the focal point was kept at low light the intention was to use natural light to penetrate the statues that were placed in the interiors. This was their primary intention as when the natural light would reach the sculpture it would refine and show attention to the hidden details of the artwork itself therefore making the statues the dominant part of the interior.

To be able to foresee how natural light would affect the interior itself the Greeks made use of Helidons. Helidon is a device which can determine the sun angle that would penetrate the interior; to do so the helidon can be adjusted through three variables, the latitude, time of year and the time of day. As a device helidons are not theoretically clear in relation with the technological advances and knowledge one can access nowadays yet they were one of the first sun measuring systems that was utilized. This is a clear example of what techniques were used in the past in order to strategically use natural light in coordinate with the interior orientation. 

Helidon 

Reference Links ;

Daylight Design of Buildings: A Handbook for Architects and Engineers - Nick Baker, Koen Steemers - Google Books. 2015. [ONLINE] Available at:https://books.google.com.mt/books?id=Eg6AAgAAQBAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false. [Accessed 24th April 2015].

index. 2015. index. [ONLINE] Available at:http://www.auburn.edu/~lechnnm/heliodon/. [Accessed 24^th April 2015].

The Birth of Consciously Utilizing Natural Light

One of the key elements in my essay was to be able to pinpoint when civilization was aware of the effect that natural light was projecting onto buildings and how it affected the interior both positively and negatively. Through my research for the ideal sources for reliable knowledge I came across a particular book ‘The Daylight Design of Buildings’ by Nick Baker and Koen Steemers; in which I was able to find the answers regarding my queries of natural light’s historical context.   

 

Baker and Steemers (2002)

Baker and Steemers (2002) stated that it was Vitruvius the well-known Roman architect who formed the connection between natural light and the buildings themselves. By coming to the realization of this ideology that a strong stable well orientated and understood relationship should be formed between the sun’s luminance and the dwelling was the stepping stone that formed natural light’s history. In their book Baker and Steemers were quoting Vitruvius who firstly started to logically state that the type of buildings built for Italy differ from the ones in Spain and other countries; apart from the cultural aspect of his reasoning Vitruvius was referring to locations, due to the variation of latitudes and longitudes the sun’s path when colliding with the countries would have a different impact through the intensity of the light itself along with the thermal effects.

After being consciously aware Vitruvius started applying his knowledge to his work keeping in mind the occupant and the building’s needs; after he would design a particular building Vitruvius would suggest the orientation of the space in co ordination with the sun’s path so that the occupant would be able to utilize the natural light at its peak time in a positive manner.

Reference Link :

Daylight Design of Buildings: A Handbook for Architects and Engineers - Nick Baker, Koen Steemers - Google Books. 2015. [ONLINE] Available at:https://books.google.com.mt/books?id=Eg6AAgAAQBAJ&printsec=frontcover&source=gbs_ge_summary_r&cad=0#v=onepage&q&f=false. [Accessed 21st April 2015].

Metrics For Daylight Strategies

The Daylight Factor

As society came to terms and realization of the sustainable energy and benefits that natural lighting offer; it was essential to try and harness such a resource to its full potential. The concept of the daylight factor was established in the early twentieth century to assist architects and designers to be able to assess how daylight would interact with the dwellings and how they can use it to their advantage.

The Daylight factor represents the quantity of illumination that would be available indoors relative to the illumination present outdoors of the location under overcast skies; this factor is formed in a ratio. To calculate the factor a simple formula is used ; 

DF = (Ei/Eo) x 100 %

Ei stands for the indoor illumination and Eo represents the outdoor illumination. It is calculated as the above formula displays by dividing the horizontal work plane illumination indoors by the horizontal illumination outdoors on the roof of the building that is being questioned for its daylight intake and then multiplying the result by 100.

The higher the ratio the more natural light the location is exposed to. This helps the architects to evaluate where windows should be placed so that the interior is exposed to enough daylight. On the other hand if the building is already built the daylight factor helps designers to be able to manipulate the access points in order to have more exposure to daylight.

The illustrations below show how a building would be typically assessed using the daylight factor. The image on the left shows the ground level of the building and the amount of light that the floor would intake and the intensity of light that would integrate with the interior. The image on the right displays the first floor and the intensity of the light is also seen; even where access points are not integrated. 

 Another useful way to asses the daylight is through the use of luminance. By invoking a cross section of the building and analyzing its luminance a more dynamic overview of the exposure of natural lighting is gained. The study of daylight and its luminance can be calculated through daylight simulation programs such as; 

Radiance

§  Daysim

§  Desktop Radiance

§  IESve

§  DIALux

§  Relux

§  Ecotect

§  VELUX

§  LightCalc

Reference Links;

Daylight Site. 2015. DAYLIGHT ANALYSIS IN THE DESIGN PROCESS OF RESIDENTIAL BUILDINGS | The Daylight Site. [ONLINE] Available at: http://thedaylightsite.com/daylight-analysis-in-the-design-process-of-residential-buildings/. [Accessed 19 April 2015].

Daylight Factors | All Things Lighting. 2015. Daylight Factors | All Things Lighting. [ONLINE] Available at: http://agi32.com/blog/2014/03/05/daylight-factors/. [Accessed 19 April 2015].

Daylight factor. 2015. Daylight factor. [ONLINE] Available at:http://www.new-learn.info/packages/clear/visual/daylight/analysis/hand/daylight_factor.html. [Accessed 19 April 2015].

Daylight Factor | Daylighting Pattern Guide. 2015. Daylight Factor | Daylighting Pattern Guide. [ONLINE] Available at:http://patternguide.advancedbuildings.net/using-this-guide/analysis-methods/daylight-factor. [Accessed 19 April 2015].

Disadvantages of Daylighting

Although the various benefits that daylighting has to offer the side effects of using natural lighting as the key source of light in a space has also its disadvantages that are crucial to take into consideration when strategically applying a daylight design to a space.

If natural light is used excessively may it be from one side of the space or exaggerated overall the intensity of the light may cause glare discomfort. This occurs when a significant amount of light enters a space and a large difference is at play between the task being observed and the area that is lit with the entering light. If the occupant is exposed to excessive light for a short period of time the glare type at hand would be discomfort glare which means that the occupant would be exposed to direct light at a close range that the eye can handle for a short period of time. Indirect glare results from light being reflected off surfaces and causing discomfort to the eye off a surface. If the occupant is exposed for a long period of time disability glare would be developed resulting in the occupant to have vision impairment.   

diagram discomfort glare

diagram indirect glare

Another vital disadvantage that daylight causes is the thermal effect in the space itself. To have daylight accessing a space the entrance point is through transparent materials; glass. Due to the fact that the sun is a powerful natural source of heat and light to control the intensity of both aspects is not optional; therefore it is vital to be able to soften the intensity with the use of diffusers as if not the excessive amounts of heat and light would cause discomfort to the occupant and may be hazardous to one’s health.

To be able to lessen the disadvantages to the minimum it is vital to have light diffusers next to windows such as light shelves that would be placed underneath the window causing the sun to first hit the shelf and then reflect in the space with lower intensity. Another optional diffuser is through the use of materials in front of the windows such as light curtains that are able to soften the light and the heat yet still accessing the space.

diagram light shelves

Light shelves

curtians 

lourves 

It is vital as designers to carefully calculate the amount of daylighting that would be accessing the space to be balanced due to the consequences that may result in the future.  

Reference Links;  

What are the Advantages and Disadvantages of Daylighting?. 2013. [ONLINE] Available at:http://www.lightingandmaintenancesolutions.com/blog/business/advantages-disadvantages-daylighting/. [Accessed 04 April 2015]. 

 FacilitesNet Stuff 17.02.2009 Daylighting Advantages And Disadvantages - Lighting Coverage . 2015. [ONLINE] Available at: http://www.facilitiesnet.com/lighting/topic/Daylighting-Advantages-And-Disadvantages--19593. [Accessed 04 April 2015]. 

Windows for High-performance Commercial Buildings.  2013 - 2015. [ONLINE] Available at:http://www.commercialwindows.org/glare.php. [Accessed 04 April 2015].

A. Williams 04.09 NBS | National Building Specification | Building services: Dealing with glare: improving visual comfort. [ONLINE] Available at:http://www.thenbs.com/topics/BuildingServices/articles/glare.asp. [Accessed 09 April 2015].

Access Points

Other access points for daylight consist of clerestories and skylights. Clerestories were prominent in the Egypt era through the form of vertical slabs in the wall in order to allow limited daylight in to access; they also were prominent in the Romanesque and Gothic Era. 

The modern version of a clerestory which is a technical architectural word for windows above eye level are mostly used instead of a skylight; if one does not want to pierce the ceiling for daylight to access clerestory are used in a repeated manner to create an interesting pattern rather than just a placed window and allowing access for daylight.

modern clerestory 

 By having daylight access an interior through a high point within a room the space is immediately lit better as it has better coverage and a sense of space is also gained. Certain buildings are not built with eyelevel windows but use clerestories instead as natural lighting and thermal effect can be gained and the risk of glare is avoided.

skylight modern kitchen

Skylights are used quite frequently as a source of daylight. By having glass ceilings the illumination of the natural light accessing the room is able to spread evenly and balanced throughout the space.

Another form of skylight is the skylight tube; it consists of a hole being pierced into the ceiling and an aluminium vent that connect the hole with the space. By doing so; a concentrated amount of natural light accesses the tube and is reflected into the vent through the reflected material and is used similar to a spot light. 

skylight tube 

In the below photograph the difference that the skylight tube can be seen. By doing the tube it serves as a substantial replacement for a  spotlight and does not overpower the room with intense daylight. 

Reference Links; 

Solar Tube Skylight – Use of the Solar Tube Skylight 03.04.13 [ONLINE] Available at:http://www.solartubeskylight.com/category/use-of-the-solar-tube-skylight. [Accessed 09 April 2015].