light_architecture-corporate interiors

• Light is that part of the electromagnetic spectrum that is perceived by our eyes.

• It is preferable to provide uniform illumination over the entire workplace by combining both natural and artificial lighting.

LIGHT

By:Akshay Bhatia

Illumination

Quantity of

illumination

Quality of

illumination

Light sources

Characteristics

of light sources

Incandescent

lamps

Fluorescent

lamps

High-intensity

discharge lamps

Ballasts Luminaries

Efficiency

Directing light

Lighting Fundamentals

• Luminous flux (Light Output)

• Illuminance (light level)

• Luminance (brightness)

• Consideration of lamp

Quantity of

illumination

Luminous flux is the quantity of the energy of the light emitted

per second in all directions. The luminous efficiency is the

ratio of the luminous flux to the electrical power consumed (lm/W). It is a measure of a light source's economic efficiency.

The unit of luminous flux is

lumen (lm)

Luminous flux (light output)

Luminous intensity is the ability to emit light into a

given direction. This is a useful

measurement for directive lighting elements such as reflectors. It is represented by the luminous intensity distribution curve (LDC).

The unit of luminous intensity is candela

Luminous intensity

This definition determines the

amount of light that covers a surface.

It decreases by the square of the distance (inverse square law). Eg. If distance is 2x, brightness will be 1/4 and if distance is 3x, brightness will be 1/9.

B = lumen/4p(d)^2

Illuminance

Luminance L is the luminous

intensity emitted by the surface area of 1 cm² (or 1 m²) of the light source.

It specifies the brightness of a

surface and is essentially dependent on its and Colour)

The human eye does not see illuminance; it sees luminance.

Luminance

Relation between them

Luminous flux Luminous intensity

Luminance Illuminance

A range of lighting levels is recommended for each type of interior/activity. (minimum-medium-maximum)

General office - 300-500-750 (lux)

Deep plan office - 500-750-1000 (lux)

Computer work stations - 300-500-750 (lux)

Conference room - 300-500-750 (lux)

Executive office - 300-500-750 (lux)

Computer and data

preparation room - 300-500-750 (lux)

Filing rooms - 200-300-500 (lux)

Value of illuminance recommended by NBC-2005

The appropriate type and quantity of lamps and light fixtures may be selected based on the following:

Fixture efficiency

Lamp lumen output

Reflectance of surrounding surfaces

Room size and shape

Availability of natural light

Lamp consideration

• Glare

• Uniformity of illuminance

• Colour rendering

Quality of

illumination

Glare is a sensation caused by

luminance in the visual field that are too bright. Discomfort, annoyance, or reduced productivity can result.

A bright object alone does not necessarily cause glare, but a bright

object in front of a dark background, however, usually will cause glare.

Controls

◦ using lighting equipment designed to reduce glare.

◦ A louver or lens is commonly used to block direct viewing of a light source.

◦ Indirect lighting

Glare

Direct glare

GlareIt is a visual sensation caused by excessive and uncontrolled brightness.

Reflected glare

Cause:• Luminaires without glare control• Very bright surfacesCure:• Luminaires with limited luminance levels

Cause:• Reflective surfaces• Incorrect luminaire arrangement• Incorrect workstation positionCure• Matching luminaire to workstation (layout)• Indirect lighting• Matt surfaces

The uniformity of illuminance is a

quality issue that addresses how evenly light spreads over a task

Although a room's average illuminance may be appropriate, two factors may compromise uniformity.

◦ improper fixture placement

◦ fixtures that are retrofit with reflectors that narrow the light distribution.

Uniformity of illuminance

Light source

• Efficiency

• Colour temperature

• Colour rendering index

CHARACTERSTICS

Light sources

Some lamp types are more

efficient in converting energy into visible light than others.

The efficacy of a lamp refers to the number of lumens leaving the lamp compared to the number of watts required by the lamp

It is expressed in lumens per

watt. Sources with higher efficacy

require less electrical energy light a space.

Efficiency

This is a measurement of "warmth" or "coolness" provided by the lamp.

Color temperature refers to the color of a blackbody radiator at a given absolute temperature, expressed in Kelvins.

A blackbody radiator changes color as its temperature increases ( first to red, then to orange, yellow, and finally bluish white at the highest temperature.

Colour temperature

Color rendering describes how a light source makes the color of an object

appear to human eyes. The Color Rendering Index (CRI) is a scale from 0 to 100 percent indicating how

accurate a "given" light source is at rendering color when compared to a "reference" light source.

The higher the CRI, the better the color rendering ability.

Color rendering

Color rendering index

Colour rendering groups CIE general colorrendering Index(Ra)

QUALITY

1A Ra > 90 Wherever accurate color

rendering is required

1B 80 < Ra < 90 Wherever good color rendering is required

2 60 < Ra < 80 Wherever moderate color rendering is required

3 40 < Ra < 60 Wherever color rendering is of

little significance

4 20 < Ra < 40 Wherever color rendering is of

no importance at all

• Standard Incandescent Lamp

• Tungsten-Halogen Lamps

Incandescent

lamps

Light sources

Light sources

Incandescent lamps are one of the oldest electric lighting technologies available.

Colour temperature- 2500 k-3000 k

Efficiency- 6-20 lm/W

Life- 1000 hrs

Colour rendering- 1A

Luminous flux- 200-40,000 lm

Standard Incandescent Lamp

Colour temperature- 2800 k-33 00 k


Life- 2000-3000 hrs

Colour rendering- 1A


Tungsten-Halogen Lamps

• Full-size fluorescent lamps

• Compact fluorescent lamps(CFL)

Fluorescent

Lamps

Light sources

Standard Incandescent Lamp

Full-size fluorescent lamps are available in several shapes, including straight, U-shaped, and circular configurations. Lamp diameters range from 1" to 2.5".



Life- 7500-15000 hrs

Colour rendering- varies

Luminous flux- 1000-5400 lm

Full-size fluorescent lamps

Reductions of tube diameters have facilitated the development of compact fluorescent lamps.


Efficiency-

◦ 36-65 lm/W (with ballast)

◦ 50-90 lm/W (without ballast)

Life- 7500-15000 hrs

Colour rendering- 1A, 1B

Luminous flux- 250-2900 lm

Compact fluorescent lamps(CFL)

• Mercury Vapor

• METAL HALIDE LAMPS

• HIGH PRESSURE SODIUM LAMPS

High-

intensity

discharge

lamps

Light sources

Clear mercury vapor lamps, which produce a blue-green light, consist of a mercury-vapor arc tube with tungsten electrodes at both ends.



Life- 7500-15000 hrs

Colour rendering- 3


Mercury Vapor

These lamps use metal halide additives inside the arc tube along with the mercury and argon. These additives enable the lamp to produce more visible light per watt with improved color rendition.



Life- 2000-10,000 hrs

Colour rendering- 1A, 1B OR 2


METAL HALIDE LAMPS

The high pressure sodium (HPS) lamp is widely used for outdoor and industrial applications. Its higher efficacy makes it a better choice than metal halide for these applications, especially when good color rendering is not a priority



Life- 10,000-28,000 hrs

Colour rendering- 3 OR 4


HIGH PRESSURE SODIUM LAMPS

LED (Light Emitting Diodes)

LEDs (Light Emitting Diodes) use a fraction of the electricity of standard incandescent bulbs and have become the best energy-saving light sources. LED’s are long-lasting, reliable and produce a comfortable white light, which is essential for secure uniform lighting

Pros:

LED lamps last up to 20 years

LED lamps reach full brightness immediately

LEDs do not radiate infrared or ultraviolet light or contain mercury

LED lamps have no start up problems because of cold temperatures

LED is the most efficient light source available till now.

Ballasts

All discharge lamps (fluorescent and HID) require an auxiliary piece of equipment called a ballast.

Ballasts have three main functions:

◦ provide correct starting voltage, because lamps require a higher voltage to start than to operate

◦ limit the lamp current to prevent immediate destruction,

Ballast

There are three main types of fluorescent circuits:

◦ rapid start: Users notice a very short delay after "flipping the switch," before the lamp is started.

◦ instant start: The instant start system ignites the arc within the lamp instantly.

◦ Preheat: The filament needs some time to reach proper temperature, so the lamp does not strike for a few seconds.

Types of Fluorescent Circuits

The main function of the luminaire is to direct light using reflective and shielding

materials.There are several different types of luminaires. The following is a listing of some of the common luminaire types:

general illumination fixtures such as 2x4, 2x2, & 1x4 fluorescent troffers

downlights

indirect lighting (light reflected off the ceiling/walls)

spot or accent lighting

task lighting

outdoor area and flood lighting

Luminaries

A luminaire, or light fixture, is a unit consisting of the following components:

lamps

lamp sockets

ballasts

reflective material

lenses, refractors, or louvers

Luminaries

Each of the above luminaire types consist of a number of components that are designed to work together to produce and direct light. The components used to direct the light produced by the lamps.

Reflectors:

Lenses

Louvers

Directing light

Reflectors are designed to redirect the light emitted from a lamp in order to achieve a desired distribution of light intensity outside of the luminaire.

In most incandescent spot and flood lights, highly specular (mirror-like) reflectors are usually built into the lamps.

Reflectors

Lenses made from clear ultraviolet-stabilized acrylic plastic deliver the

most light output and uniformity of shielding media.

they provide less glare control than

louvered fixtures. Lenses are usually much less expensive

than louvers.

Lances

Louvers provide superior glare controland high visual comfort compared with lens-diffuser systems.

The most common application of louvers is to eliminate the fixture glare

reflected on computer screens.

Deep-cell parabolic louvers provide a good balance between visual and luminaire efficiency.

Small-cell parabolic louvers provide the highest level of visual comfort, they reduce luminaire efficiency to

about 35-45 percent.

Louvers

General

Different light provisions

Localised Private

Light has a triple effect:

1. Light for visual functions: glare-free and convenient.

2. Light creating biological effects: Stimulating or relaxing

3. Light for emotional perception: Creating scenes and effects

Different type of light fixtures:

Direct

Distribution of lightingOne of the primary functions of a luminaire is to direct the light to where it is needed.

Indirect Direct-Indirect Diffused

90 to 100 percent of the light is directed downward for maximum use.

90 to 100 percent of the light is directed to the ceilings and is reflected to all parts of a room.

Portions of the light are directed upward and downward.

Light is projected in all directions.

Highly directional

Dark ceiling

Limited flexibility of work-station layout

Energy efficiency on the task level

Direct lighting

Diffuse lighting conditions

Room gains in height

Glare-free

Workstations can be positioned anywhere

Low energy efficiency

Indirect lighting

Pleasant room impression

High user acceptance

Good contrast ratios

Flexible workstation layout (indirect component > 60 %)

Direct-Indirect lighting

direct/indirect solution

Workstations can be positioned anywhere

Glare-free

Gives impression of daylight in room

Diffused lighting

Natural light

Light tubes or light pipes are physical structures used for transporting or distributing natural or artificial light for the purpose of illumination.

they are also often called tubular daylighting devices, sun pipes, sun scopes, or daylight pipes.

Light pipe

Collector

The Sky Vault Collector capture daylight without heating the building interior.

Diffuser

Sky Vault Series Diffuser Assemblies provide precise control over daylight collected by our optical domes and Spectra light Infinity Tubing. Each is factory-assembled to make field installation quick and easy.

Extension Tubes

Extension tube or pipe for transport of light to another location, minimizing the loss of light.

Dimmer

Thank you

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