Tricks of the light

Tricks of the light

Are you aware that luminosity can influence your mood? Biological malfunction, tired and strained eyes, and road accidents are some of the possible negative effects caused by wrong use of lighting.

Jatupong Jaturawong, GE Lighting general manager, explained that colour temperature is a characteristic of visible light, which has important application in lighting. Artificial light replicates natural light, which we can gauge by the colour temperature, measured in kelvin (K). Colour temperature at 3,000K is warm white, 4,000K is cool white, 5,000K is daylight, and 6,500K is cool daylight, which replicates natural daylight. At noon, natural light measures upwards of 10,000K.

In office environments, colour temperatures at 4,000K and 5,000K are generally recommended.

"If you put the 3,000K type in the office, it will lead people to feel drowsy as the warm white is more suitable for residential buildings because it has a cosy mood," Jatupong said.

Light also has an influence on biological function. Everyone has a body clock, and every morning natural light will automatically reset our biological clocks. Studies show that if people have been in artificial light for three to four days without being exposed the natural light, they will become sick because their body clocks malfunction. This is why working in an office with a lot of windows is recommended.

Glare, the presence of bright light such as direct or reflected artificial light that causes a difficulty in seeing, is a matter that so far has not been of concern in Thailand, but it is an issue in many countries involved with the rights of consumers as it can cause health problems with the eyes.

There is no awareness of light pollution in Thailand yet, even if at night, outside lights can gleam into houses. Glare can also lead to eye fatigue and can cause accidents when drivers doze off, which is why road lighting in Europe is controlled by the cut-off angle of the lights. In Thailand, the Department of Rural Roads started endorsing cut-off angles of road lights a few years ago.

Lighting is both a science and an art. Besides beauty and comfort, users should be concerned for their safety.

Jatupong pointed out that incandescence is the conversion of heat to light, which requires the filament inside a light bulb to burn at a high temperature.

This conversion is very simple, but the disadvantages are that only 5% of the total energy consumed by the lamp is used to generate light, while 95% is wasted as heat, and its lifetime can be limited to about 2,000 hours.

A compact incandescent lamp of 1300lm at 100W produces the efficiency of 13lm per watt.

"Incandescent lamps are the most ancient, use the most energy... the only reason people use it is [because it is] the cheapest," he said.

Fluorescence is the conversion of ultraviolet (UV) light to visible light. Electrons flow through the fluorescent lamp and collide with mercury atoms, causing photons of UV light to be released. The UV light is then converted into visible light as it passes through the phosphor coating on the inside of the glass tube.

Compact fluorescent lamps comprise two types: the spiral shape and the U-shape. The spiral-shape lamp is more efficient than the U-shape because the electrons can run more smoothly.

LED stands out because they are robust and highly resistant to shock and vibration. Due to the solid-state nature of LED, there are no filaments to break, no moving parts to fail and no glass components. With LED, breakage during transportation, installation or operation is virtually eliminated. Environmental friendliness is also a factor as LED does not contain mercury.

"While fluorescent lamps have 10,000 hours of life, LED lamps have over 25,000 hours and it saves 10-15% power. And the price will decline," Jatupong said.

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