HEALTH

Recent research studies developed in the USA have demonstrated that there is no generally accepted evidence that low levels of illumination will damage the eye, any more than indistinct sounds damage the ears or foul smell damage the nose.The result states that the need for wearing glasses arises only from organic causes, not from inadequate illumination levels.Common complaints by visually poor conditions are eyestrain, muscular aches and pain: more general reactions are fatigue and headaches.

 

Eyestrain normally occurs when trying to overcome a difficult viewing condition and the strain is only temporary and does not damage the eye.Eye damage can only be caused by over-exposure to light.

 

As well as the ability to stimulate vision, daylight acts on the body in many other ways.Years ago the photo-biological techniques in medicine came into question because of the controversy surrounding the safety of some lamps. The most prevalent notion is that light is for seeing and has no effects on people, other than ultraviolet light, which is harmful.The most controversial issues in lighting are the statistical relationships between fluorescent lighting and malignant melanoma, a particularly dangerous form of Skin Cancer.

 

Daylight also regulates metabolic processes in the human body, and keeps the body’s resistance to unfavourable agents. Psychologists also advise that the light indoors has a considerable influence on the state of mind and affect the psychological, psycho-emotional health of human beings. Researchers have now come up with suggestions that there is a layer of the retina which has no function in vision, but serves as a receptor for light-waves, which is then carried along non-visual connected fibres of the optical nerve to the master endocrine glands in the brain that controls the entire metabolic system.

 

Daylight is also believed to be involved in setting of the “biological clock” and that lack of light for long periods, particularly such as during the winter seasons can also manifest itself as Seasonal Affective Disorder (SAD) where a general depressive mood may set in at the onset of Winter.

 

Daylighting cannot be considered in isolation.The LT method (Lighting and Thermal method) is a manual procedure to estimate energy use in non-domestic buildings.It estimates annual primary energy use for lighting, heating, ventilation and cooling: these conditions to which daylighting is associated.It is useful to know the implications for energy conservation of the designer’s early decisions. The energy consumption will also depend upon other parameters such as artificial lighting levels and plant efficiencies. The plan from, the facade designs and the arrangement of internal areas all play a crucial part. The integrated energy use analysis through the LT method, which is an energy tool, was mainly developed to address the problem concentrating on the following points:

 

• Local Climatic Conditions
• Orientation of Facade
• Area and Type of Glazing
• Obstruction due to Adjacent Buildings
• The inclusion of an Atrium
• Occupancy and Vacation Pattern
• Lighting Levels
• Internal Gains

 

The energy used is usually read off graphics, which are derived by a mathematical model.The model evolutes the heat conduction through the external envelope and ventilation heat loss or gain.The model then evaluates the solar gains (Fig. 7)

 

The heat gains from solar, casual pains from occupants and equivalent are then subtracted from the gross heating load to establish the net heating load.

 

The original version of the LT method was prepared for the EC Architectural ideas – working in the City.