presentation on lighting design by tooba imlak

8/13/2019 Presentation on Lighting Design by Tooba Imlak

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Presented by:

Tooba Imlak



Why Is Lighting Important

Basic Lighting Terms

Lighting Design Considerations

Different Methods Of Calculation

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Light plays an essential role in our ability to perceive the world

around us; the lighting system plays a critical role in how we

perceive a space and can even influence how we act in that space.

Lighting can affect performance, mood, morale, safety, securityand decisions.

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LIGHT

LUMINOUS FLUX

LUMINOUS INTENSITY

ILLUMINANCE

LUMINANCE

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The part of the electromagnetic spectrum that can be perceived

by the eye.

Region of visible light extends from 380 to 760 nanometers

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Quantity of light emitted by a lightsource.

Unit is in lumen, LM.

Quantity of light radiated to

particular direction, radiated per

unit angle (Steradian)

Unit of luminous intensity is onelumen per Steradian (Candela)

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Quantity of luminous flux fallingon a unit area of surface.

E=F/A , unit is lux

Luminance or Brightness is aluminous intensity of a surfacein a given direction per unit ofprojected area of the surface.

Unit of luminance is cd /m² orlumen/ m².

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Acceptable minimum standards of light levels are set by the

I l luminating Engineers Society (IES).

For Example:

• Corridors, Passage ways: 100 Lux

• Stairs, Lifts: 150 Lux

• Kitchen: 500 Lux

• Restaurants: 300 Lux

• Parking Areas: 30 Lux• General Offices: 500 Lux

• Theatre & Concert halls: 100 Lux

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One of the most important considerations in selecting a light source

is how much light it will generate.

Two measurements are needed because, like most devices, lamps

lose some light output over their rated life

I NITIAL LUMENS

Initial lumens is a term defined as the amount of light output

from a lamp when it is new.

MEAN LUMENS

Any light source will decrease in light output the longer it isoperated. To properly light a facility for the useful life of a lamp,

an "average" lumen output is calculated known as mean lumens.

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The efficacy of a lamp refers to the number of lumens leaving the

lamp compared to the number of watts required by the lamp (and

ballast).

It is expressed in lumens per watt.

The H igher The Lumen Per Watt Rating Of A Lamp The Better -

- M eaning Greater L ight Output For A F ixed Wattage I nput.

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It measures the degree that perceived colors of objects,

illuminated by a given light source, conform to the colors of

those same objects when they are lighted by a reference

standard light source.

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The higher the color rendering index, the less color shift or distortion

occurs.

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This is a measurement of "warmth"

or "coolness" provided by the lamp,

expressed in Kelvins .

People usually prefer a warmer sourcein lower illuminance areas, such as

dining areas and living rooms, and

a cooler source in higher illuminance

areas, such as grocery stores.A "Warm" color light source actually

has a lower color temp.

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Incandescent

High-pressure Sodium

Compact Fluorescent

Full-size Fluorescent

Mercury Vapor

Metal Halide

LED

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There are important factors with respect to lighting quality .

Some of them are discussed here:

• Glare,

•

Uniformity of Illuminance• Color Rendition ( as discussed above)

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Glare is a sensation caused by luminance in the visual field that

are too bright. Discomfort, annoyance, or reduced productivity can result.

Glare can be reduced by not exceeding suggested light levels and

by using lighting equipment designed to reduce glare. For eg lens

or louver.

proper fixture placement can reduce reflected glare on worksurfaces or computer screens

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The uniformity of illuminance is a quality issue that addresses

how evenly light spreads over a task area.

• Inadequate light levels in some areas

• Visual discomfort when tasks require frequent shifting of view from

under lit to over lit areas

• Bright spots and patches of light on floors and walls that cause

distraction and generate A low quality appearance

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Calculation by Lumen Method :

The average illuminance produced by a lighting installation or the

number of luminaries required to achieve a specific averageilluminance, can be calculated by means of utilization factors. The

average illuminance E, over a reference surface s can be

calculated from the "LUMEN METHOD" formula.

E = ___F x n x N x MF x UF.___

Area of Surface (S)

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E = ___F x n x N x MF x UF.___

Area of Surface (S)

where:

• F is the initial bare lamp flux (lumens)

• n is the number of lamps per luminaire

• N is the number of luminaires

• Uf , is the utilization factor for the reference surface (s)

• MF is the maintenance factor (Dirty: 0.7 , Normal: 0.8 , Clean:0.9)

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A Software Project Launched By Dial GmbH

It Started In 1994 In Dial, Ludenscheid, Germany

Lighting Design Tool Which Is Continually Updated And Adapted To

The Requirements Of The Planners

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presentation on lighting design by tooba imlak

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