Principles of lighting in building

GAFFUR BOLIYA

SHUBHAM SHAH

MUKESH DHAMECHA

Principles of good lighting

• Directional lighting should be used wherever possible.

• Proper attention should be given to the colour of light as well as light distribution.

• Direct & reflected glare from light sources should be controlled.

• Lighting throughout the building should be correlated to prevent excessive difference between adjacent areas.

• Excessive contrast between the illumination levels of the object may cause visual discomfort.

Daylighting

• Daylighting is the practice of placing windows or other openings and reflective surfaces so that during the day natural light provides effective internal lighting.

• Energy savings can be achieved from the reduced use of artificial lighting.

Daylight Factor

• Df = Ei/Eo * 100

• Where,

• Ei = Illuminations indoor at the point taken

• Eo = Illuminations outdoor due to direct sunlight being executed

Components of day light factor

• Sky component

• Externally reflected component

• Internally reflected component

Sky component

• Direct light from a patch of sky visible at the point considered, known as the sky component

• : It is definesd as the ratio of that part of the daylight illumination at a point on a given plane, which is received directly from the sky as compared to the simulataneous exterior illumination on a horizontal plane from the entire hemisphere of an unobstructed clear design sky.

Externally reflected component

• Light reflected from an exterior surface and then reaching the point considered, known as the externally reflected component

• It is defined as the ratio of that part of the daylight illumination at a point on a given plane, which is received by direct reflection from external surfaces, as compared to the simultaneous exterior illumination on a horizontal plane from the entire hemishphere of an unobstructed clear design sky.

Internally reflected component

• Light entering through the window but reaching the point only after reflection from an internal surface, known as the internally reflected component .

• It is defined as the ratio of that part of the daylight illumination at a point in a given plane, which is received by direct reflection from internal surfaces as referred to simultaneous exterior illumination on a horizontal plane due to entire hemisphere of an unpbstructed clear design sky.

Principles of Design of windows

Taller opening gives greater penetrations as sky component is more for taller window.

Openings in deep reveals tend to minimize glare effects.Openings must be provided with chajjas.

A no. of smaller openings positioned along the same, adjacent walls will give better distribution of illumination than a single large opening.

Cont.

• Intensity of light can be controlled by making use of translucent glass planes.

• Cross lightning with openings on adjacent walls, tends to increase the diffused lightning within a room.

• If room is 7m or more across, openings on two opposite walls will give uniformity of internal daylight illumination.

Artificial Illumination

• When daylight is not sufficient to give the required levels of illuminations, daylight will have to be supplemented by artificial means of illuminations.

• Different types are

• Incandescent light bulb

• Fluorescent lamp

Necessity of Artificial lightning

• Due to reduction of daylight beyond design hours, that is, when dark cloudy conditions occurs.

• To provide lightning in innermost part of the building which doesn’t receive sufficient daylight.

• Where visual tasks may demand during the day higher levels of illumination.

Incandescent light bulb

• An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light which produces light with a wire filament heated to a high temperature by an electric current passing through it, until it glows 

• They are manufactured in a wide range of sizes, light output, and voltage ratings, from 1.5 volts to about 300 volts. 

Fluorescent lamp 

• A fluorescent lamp or a fluorescent tube is a low pressure mercury-vapor gas-discharge lamp that uses fluorescence to produce visible light. An electric current in the gas excites mercury vapor which produces short-wave ultraviolet light that then causes a phosphor coating on the inside of the bulb to glow.

• Because they contain mercury, many fluorescent lamps are classified as hazardous waste

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