Lighting systems and their design..mau --jmi-2014

LIGHTING SYSTEMS AND THEIR DESIGN

Presentation by:

Mohammed Azmatullah

Guided By:- Ar. Mariam Ahmad Mam

M.Arch , Building Services, III-SemFaculty of Architecture and Ekistics

Jamia Millia Islamia, New Delhi.

Lighting systems and their design

INTRODUCTIONA n e s s e n t i a l s e r v i c e i n a l l t h e i n d u s t r i e s ,The power consumption by the industrial lighting variesbetween 2 to 10% of the total power depending on the typeof industry.

Lighting is an area, which provides a major scope to achieveenergy efficiency at the design stage, by incorporation ofmodern energy efficient lamps, luminaires and gears, apartfrom good operational practices.

The aim of lighting is to create an adequate visualenvironment.

Thus, there are two components of the visualenvironment –1. one is a usually furnished room with

surfaces reflecting light to a greater orlesser extent , - this is a basically passivecomponent- and –

2. the other is light, which (as an activecomponent) makes the room visible.Lighting systems and their design 2

The lighting design should take into consideration the following aspects:1. ILLUMINATION LEVEL (right quantity of light)2. PROPER PLACEMENT OF LUMINAIRE ( proper location)3. WITH EFFICIENT INTEGRATED CONTROLS

Lighting design can be governed on the basis of following criteria’s:

LIGHTING DESIGN / ILLUMINATION PLANNING

Light defines space, enhances color and reveals the intricacies of texture and form.

2. LIGHTING QUALITY AND QUANTITY

A. Illumination levels

B. Adaptation levels

4. SPACE AND WORKPLACE CONSIDERATIONS

A. Flexibility

B. Appearance of the space and luminaires

C. Color appearance

D. Luminance of room surfaces

E. Flickering of light

F. Direct and reflective glare

1. LIGHT DISTRIBUTION

A. Task and ambient lighting

B. Day lighting integration

C. Light pollution and light trespass

3. LIGHTING ON PEOPLE AND OBJECT

A. Modeling faces and objects

B. Surface characteristics

C. Points of interest

D. Sparkle

Lighting systems and their design 3

Concept of lighting as a system

Lighting design requires consideration of • the amount of functional light provided, • the energy consumed, • the aesthetic impact

Architectural lighting design focuses on three fundamental aspects of the illumination of

buildings or spaces.

• The first is the aesthetic appeal of a building, an aspect particularly important in the

illumination of retail environments.

• Secondly, the ergonomic aspect: the measure of how much of a function the lighting plays.

• Thirdly is the energy efficiency issue to ensure that light is not wasted by over-illumination,

either by illuminating vacant spaces unnecessarily or by providing more light than needed for

the aesthetics or the task.


http://en.wikipedia.org/wiki/Retail

http://en.wikipedia.org/wiki/Ergonomic

http://en.wikipedia.org/wiki/Energy_conservation



http://en.wikipedia.org/wiki/Over-illumination



http://en.wikipedia.org/wiki/Aesthetics

Various types of lighting systems used

Generally there are 3types of lighting system

1.Accent lighting2.Ambient lighting 3.Task lighting

Many call LIGHTING as the 4th element of architecture.


Ambient lighting provides an area with overall illumination. Also known as general lighting, AMBIENT ILLUMINATION for orientation and general tasks in the space, like Walking etc.

Ambient lighting is often provided by traditional pendant typefixtures, down lights, chandeliers, or ceiling mounted fixtures etc.

LIGHT QUANTITYIlluminationLumenFoot-candleEfficacy

LIGHT QUALITYColor temperatureColor renditionGlare

Ambient lighting :-

Ambient Lighting:

Task lights can’t light the balance of the room, and thus some other type of lighting system is needed to produce the ambient illumination in the room.


Accent lighting

directional lighting .It can also be used to highlight the texture of abrick or stone wall, window treatments oroutdoor landscaping.

To be effective, accent lighting requires as least3-times as much light on the focal point as thegeneral lighting surrounding it.

Accent lighting is usually provided by recessedand track lighting or wall-mounted picturelights

ACCENT ILLUMINATION to highlight specialobjects of interest or to guide occupants.Accent lighting is mainly decorative, intendedto highlight pictures, plants, or other elementsof interior design or landscaping.

LIGHT QUANTITYIlluminationLumenFootcandleEfficacy



Task lighting:- Task lighting, or directional lighting, is aimed at a specific task; It can be provided by recessed and track lighting, pendant lighting and undercabinetlighting, as well as by portable floor and desk lamps.

Task lighting should be free of distracting glare and shadows and should be bright enough to prevent eye strain.

2) TASK ILLUMINATION for local, moredemanding tasks,

Task lighting is mainly functional and isusually the most concentrated, for purposessuch as reading or inspection of materials.

LIGHT QUANTITYIlluminationLumenFootcandleEfficacy


Task lighting systems independent from the space’s generallighting systems (serving specific task) are found in building typesfor instance, the display lighting in retail stores is a form of tasklighting. Similarly, task lights are used in industrial manufacturingand assembly, health care, residential lighting, and many otherinterior lighting applications.Options include– indirect luminaires mounted atop cabinetry or workstations– Suspended luminaires– Recessed luminaires


http://en.wikipedia.org/wiki/Task_lighting

http://en.wikipedia.org/wiki/Task_lighting

http://en.wikipedia.org/wiki/Reading_(activity)

http://en.wikipedia.org/wiki/Inspection

Good task light should provide about 50 to100 foot candles to the workspace

Well distributed over the work areashadow-free.

Adjustability is very important; you should beable to direct the light where you need it.

The task light should be designed to avoidglare.

It should be energy-efficient.

Most people prefer warm white toneutral white. Warm white is normallyassociated with a correlated colortemperature between 3,000 and3,500 kelvin.

Task Lighting Tips• Your light should be located to the side of

the task – not in front of it – to avoid glare.• If you’re right-handed, place your light on

the left side of your work area – and vice-versa, for lefties. Helps reduce the chanceof shadows.

• The light source should not shine in your (oranyone’s) eyes; adjust it downward, ontothe task surface and/or the task at hand(such as a document you are reading).

A recommended ratio between localized tasklighting and ambient lighting is 5:1.

Regarding Task lighting


http://en.wikipedia.org/wiki/Color_temperature





http://en.wikipedia.org/wiki/Kelvin

Informational lighting (Guidance Lighting)

The light in your closet, the light by yourdoorbell, and night lights, as well as pathlighting and motion lights, are all goodexamples of informational lighting.

It can be beautiful as well as functional, andcan create dramatic statements.Lights inset on stairs can create pathways thatenhance architecture.

Decorative lighting

Light strips, pendants, chandeliers, andsconces are all examples of light fixturesthat draw attention to themselves and addcharacter to the place being lighted.Many are also used for general lighting.


Key Light, Fill Lighting:-

• Multi-directional or diffuse light Reduces shadowson an object caused by the key light.

Single point source of light Provides highlights andcasts shadows providing contrast and producingdefinite focus.


Techniques used in controlling Directionality of light

• Occurs when light strikes a surfaceat a sharp angle, nearly parallelto a rough surface.

• Enhances any variations in surfacedepth, revealing texture.

• Will also emphasize flaws andunevenness in surfaces.

Grazing:-

Uplight:

Places a light source below anobject.Produces shadows that arereversed from how an object isshadowed in daylight.Creates an eerie, unnaturaleffect because it replaces themore familiar overheadorientation of the light source.

Light source is used not toilluminate an object itself, but itsbackground.Applicable when one aims toreveal the outline of an objectagainst a brighter surface and tocreate separation between theobject and its background.

Silhouette:

• Occurs when lightstrikes a surface at a

wide angle.

• Provides even lightingon a vertical space,increase luminances ofwall surfaces, andextend the space.

Wall Washing:


• Candlepower Distribution Curve: A curve, generally polar,represents the variation of luminous intensity of a lamp orluminaire in a plane through the light center.

Visual Edge: The line on an isolux chart thathas a value equal to 10% of themaximum illumination.

Rotational symmetricalLight distribution same in all planes. Usually Circular or ‘Bowl shaped’ luminaire

Planar symmetricalLuminaire distribution is confined to two vertical planes separately.Typical distribution for Fluorescent Lamp luminaires and Road Lighting

AsymmetricalAsymmetry present in one of thePlanes of measurement.

importance/ relevance of visual edge the designing of lighting systems

isoluxcharts help

the lighting

• Isolux Chart: A series of lines plotted on any appropriate setof coordinates, each line connecting all the points on asurface having the same illumination.

Lighting design curves/charts:


The image above is a candle powerdistribution curve, which providesinformation on how light is emittedfrom a lamp or light fixture.

The diagram represents a sectioncut through the fixture and showsthe intensity of light emitted ineach direction.

The portion of the graph above thehorizontal 90°-270° line indicateslight that shines above the fixture(indirect), while the portion of thegraph below represents lightshining down (direct).

The straight lines radiating from thecenter point identify the angle ofthe light emitted while the circlesrepresent the intensity. Forinstance, point A above shows thatthe intensity of light at 80° isapproximately 110 candlepower.

Point B shows that at 30° you willget about 225 candlepower.

The image is a candle power distribution curve,which provides information on how light is emittedfrom a lamp or light fixture


Lighting Luminaire components definition

•Baffle: An opaque or translucent element that serves to shield a light source from direct view at certain

angles, or serves to absorb unwanted light.

•Ballast: An auxiliary device consisting of induction wires wound around a metal core and sometimes

includes a capacitor for power correction. It is used with fluorescent and HID lamps to provide the necessary

starting voltage and to limit the current during operation.

•Lamp: An artificial source of light (also a portable luminaire equipped with a cord and plug).

•Capacitor: An electric energy storage device which when built into or wired to a ballast changes it from

low to high power factor.


•Class “P” Ballast: Contains a thermal protective device that deactivates the ballast when

the case reaches a certain critical temperature. The device resets automatically when the case

temperature drops to a lower temperature

•Cone Reflector: Parabolic reflector that directs light downward thereby eliminating

brightness at high angles.

•Dimming Ballast: Special fluorescent lamp ballast, which when used with a dimmer

control, permits varying light output.

•Lens: Used in luminaries to redirect light into useful zones.

• Louver: A series of baffles used to shield a source from view at certain angles or to absorbunwanted light. The baffles usually are arranged in a geometric pattern.

•Pattern Control: A blade, in the air passage of an air handling luminaire, which sets thedirection of air flow from the luminaire.



Luminaires designed for general illumination of large areasconstitute the majority of lighting installations and themajority of the energy consumed for lighting. These lightingsystems consist of a luminaire layout pattern that providesuniform lighting throughout the space.

Open direct systems do not employ shielding at all. These systems include surface- and pendantmountedstrip fluorescent fixtures and suspended open industrial and commercial luminaires.Unless equipped with reflectors, these systems radiate light in all directions. Open direct lightingsystems are often very efficient, with high CU values, but they may cause visual discomfort and disabilityglare.

Shielded Direct Lighting Systems

Shielded systems use some form of lens, louver, or baffle toprevent direct viewing of the lamps at normal angles of view (seeFigure 2). Surface and suspended luminaire types includeindustrial HID downlights, baffled industrial fluorescent luminaires,fluorescent wrap-around lens luminaires, and commercialfluorescent lens luminaires.

Recessed systems include HID downlights and a wide range of fluorescent “troffers” using lenses, louvers, orbaffles to control glare.


Parabolic Louvered Recessed Troffers

An increasingly popular commercial general lighting fixtureis the recessed parabolic troffer, which uses specularparabolic louvers to control the luminaire’s lightdistribution, providing sharp cut-off glare control.Depending on the spacing between the louvers, theseluminaries can be classified as large-cell and small-cellparabolic luminaires. Large-cell luminaires are generallymore efficient, with relatively high CU values, while smallercells can offer better glare control. Many standard sizes areavailable, including 2’x 4’, 2’x 2’, 1’x 4’ The extent of glarecontrol depends on the specific louver design.

Standard Lensed Troffers

Standard lensed troffers typically have higher efficiency and CU values than parabolic louveredtroffers, but provide less precise glare control. Many lens types can be used (i.e., patternedprismatic, batwing, linear batwing, and polarizing), though final photometric performance alsodepends on a number of other factors such as reflector type, number of lamps, lamp type, andballast type.


Indirect Lighting Systems

Lighting systems that radiate light up to a reflectingceiling are called indirect lighting systems. Thesesystems generally employ luminaires suspended fromthe ceiling, though cove lights and lights mounted towalls and furniture can also be used. Indirect lightingsystems using well-designed and properly spacedluminaires can provide excellent illumination,uniformity, and freedom from glare. Their successdepends on maintaining a high ceiling reflectance incombination with nearly uniform brightness. In thisway, a maximum amount of light is reflected down tothe work plane, yet light patterns are less likely tocreate reflected glare in VDT screens.

Indirect Lighting Luminaire

Cove Lighting System

Recent designs in fluorescent indirect lightingsystems use lenses or imaging reflectors toachieve high luminaire efficiency, by producinga broad batwing light distribution whileallowing for close-to-ceiling mounting. Thesedesigns can increase an indirect system’s CU tonearly that of traditional lensed troffersystems.

Other new designs in indirect lightingluminaires, especially for cove andcoffer installations, increase theeffectiveness of traditional striplights and eliminate socket shadows.


These systems combine the benefits of bothtraditional direct lighting and indirect lightingsystems. Combing the high CU of directillumination with the uniformity and glarecontrol of indirect lighting can be an idealsolution for many spaces. The appropriatebalance of direct and indirect light isdependent on the nature of individualapplications.

Direct/Indirect Lighting Systems

Architectural Luminaires

Architectural lighting systems, which are generally used in building spaces such as lobbies andcorridors include recessed downlights, wall washers, track lights, and wall sconces. Since theseluminaires are employed mainly for highlighting high-quality spaces, aesthetics is a principalconsideration in their design and selection. Nevertheless, there are many opportunities to utilizeefficient lighting in these applications.


Recessed Low-Wattage HID Downlights

New HID downlights, equipped with high-CRIcompact metal halide and white high pressuresodium lamps, can replace traditionalincandescent downlights in high-quality and/orlow-ceiling spaces, thereby achievingsignificant energy savings and extended lamplife.

Recessed Compact Fluorescent Downlights

The popular compact fluorescent down light is now available in a variety of configurations, andsome units include dimmable lamps designed for use with electronic ballasts. In general,compact fluorescent lamps replace incandescent down lights on a 1 watt for 3 watts basis. Arelatively recent development, the 1’x 1’ parabolic down light for compact fluorescent lamps isextremely efficient, allowing replacement of incandescent lamps on a 1 watt for 4 watts basis.


Track-Mounted Lighting Task Lights

Several interesting recent designs in trackluminaires using compact fluorescent andlowwattage HID lamps offer significant energysavings over standard incandescent trackluminaires Track lighting systems provideflexibility in design and make it possible toaccommodate changing displays.

Task lights work in conjunction with generallighting systems to meet diverse needs ofindividual occupants for specific visual tasks.Compact fluorescent lamp technology hasspecial relevance for task lighting applications.In VDT applications where high levels ofambient light often interfere with visibility, tasklighting may be especially important for non-VDT tasks, particularly when those visual tasksare difficult to perform because of lowcontrast, high speed, and/or worker age.


Decorative Luminaires

A renaissance in decorative lighting fixtures in the form of pendants, wall sconces, chandeliers,exterior lanterns, and landscaping lights occurred in the 1980s. In most instances, decorativelighting luminaires are used to provide general or ambient lighting in areas where a morecustomized appearance is desired. Although decorative lighting is still most often used inrestaurants and hotels, an increasing number of applications exist in offices, retail stores,apartment buildings, and other commercial spaces. Many decorative luminaires employ efficientlight sources, increasing opportunities for using less energy.

Many traditional applications for incandescentwall-mounted sconces and brackets can bereplaced with similar-appearing luminairesdesigned specifically for compact fluorescentor HID lamps. See Figure 10 for an example.

Compact Fluorescent Pendants and Chandeliers

Luminaire designs continue to evolve for compact fluorescentdecorative chandeliers and pendants used in applications oncelimited to traditional incandescent fixtures.


Combined diagram for spotlights

Light distribution curve

Isolux diagram


Color:Color is defined with a variety of metrics but the 2 most common are:

1. Correlated Color Temperature (CCT).2. Color Rendering Index (CRI).

Correlated Color Temperature (CCT):

• Represents the relative whiteness of a lightsource, whether the source appears warm, cool orneutral.

• Measured in Kelvin (°K).• Acceptable range of CCTs for indoor environments

is between 2500°K and 5000°K, with the highervalue representing a cooler source.

Color Rendering Index (CRI)

CRI rating indicates how well anobject’s colors are rendered by asource.It is a comparison of 8 specific testcolors under an ideal light source inquestion.When color rendering is important, asource with a high CRI (e.g. 3500°Kfluorescent with a CRI of 85) shouldbe selected.

Correlated color temperature and the ambient temperature Lighting systems and their design 26

Quantity (Illuminance):glare

• Light Level or Illuminance, is the total luminous flux incident on a work plane, per unit area.The work plane is where the most important tasks in the room or space are performed.

• There are recommended minimum illuminance for each place or task that must be followed,Standards.

• Direct glare is caused by excessive light entering the eye.• Direct glare can be minimized with careful equipment selection and placement.• In interior applications, indirectly light the walls and ceiling A limited amount of direct light

can provide accent and task lighting.

• In exterior applications, use fully shielded luminaires that directs light downwards towardsthe ground or a building façade.


how we can select the proper lamp type for a certain application.???The answer will be as follows:

1. Efficacy, Life, Lumen DepreciationAll of these have an effect on life cycle cost. If a lamp's lumen output declines rapidly during its life, theprudent designer initially provides more lumens than is required so that as the lamp declines with age, asufficient amount of light is still available. In other words, if seven luminaires are required to provide theright amount of light for a space initially, we might put eight luminaires in our design so that the space isover lit at first, but the installation will still provide enough light later on as the lamps provide less than theirrated lumen output due to ageing. Comparing the rate of lumen depreciation from one type of lamp to thenext thus becomes an important part of the cost analysis.

2.PATTERN OF DISTRIBUTIONIt is sometimes desirable to have diffuse light rather than highly directional light since the latter may causeharsh shadows. An area source or a linear source (such as a fluorescent lamp) generates more diffuse lightand softer shadows than a point source.

3. ControllabilitySome lamps are more easily dimmed than others. One must consider if simple on/off control is acceptable, ifinexpensive dimming is desired, or if it is reasonable to incur the larger expenditures to get higher qualitydimming.

4. Color RenditionOne of the key areas of concern for the architect, interior designer and lighting engineer is the lightedappearance of the space. Most light sources are available in a variety of spectral power distributions, yielding avariety of color-rendering indices (CRI) and color temperatures. The lighting designer must be thoroughly familiar

with these concepts in order to properly achieve the desired effect with the chosen lamps.Lighting systems and their design 28

5. Distribution ControlLight distribution from a small lamp can be controlled more easily than light emitted from a large lamp. Thisis simply because it is easier to shape a reflector around a small lamp than a large one. Some lamps are assmall as 10 mm in length, and others are as large as 1 m long. The pattern of light from the former can becontrolled very precisely whereas the best we can hope to do with the latter is to throw light in one generaldirection or another. We idealize a small light source with the concept of a "point source." The smaller thelight-emitting element of a lamp, the more closely it resembles the ideal of a mathematical point source.

6. Air Conditioning LoadAll artificial lighting adds an additional heat load to a building. Lamps with a higher efficacy will put less heatinto a space for a given amount of light output. The most thermally efficient form of lighting is diffusedaylight, followed by direct sunlight, low-pressure then high-pressure gaseous discharge.The worst of all is incandescent lamps.

7. Consistency and Reliability of Supply VoltageHigh-pressure gaseous discharge lamps are more sensitive to voltage variation than low-pressure lamps. Ifthe arc is extinguished due to a dip in voltage, the high-pressure lamp may require up to 15 minutes toreturn to full light output.

8. Ambient Temperature and HumiditySome lamps, notably fluorescents, are very sensitive to temperature and humidity. These lamps are difficultto start when the ambient temperature is low, and once started may not produce full light output.9. CostSome lamps are quite cheap to purchase, initially. However, these tend to have low efficacy and relativelyshort lives. One must consider not only the initial cost, but the cost to operate the system over its entire life,including energy costs and the requirement to pay a worker to change the burned-out lamps frequently.Fluorescent lights and LEDs are often a cost improvement on incandescents for this reason alone, evenwithout energy savings.


A 100 watt incandescent bulb produces 100 watts of heat (actually power). From an energy point of view, it puts out 100 Joules of energy every second.

What temperature rise this causes depends on a lot of factors, room size, air flow, etc.

specific heat capacity of dry air is 1.00 kJ/kgCDensity of air at 30C is 1.2 kg/m³

Take a small closed room, 4 m x 4 m x 3 m or 48 m³ with 1 100w bulb.48 m³ x 1.2 kg/m³ = 58 kg of air

100J = 1000 J/kgC x ∆T x 58 kg∆T = 0.0017 deg C, very small change in temp.

but this occurs every second, so in an hour, we would have a 6 degree C rise. or 11 deg F

So in a small enclosed room, one 100w bulb will cause the temp to go up 11 degrees F per hour. Actually a lot.

Add a few more bulbs and it goes up a lot more. But make the room larger or open a door, and it goes up a lot less.


Free-standing or portablesuch as Table lamp fixtures, standard lamp fixtures, and office task light luminaires.

1- Recessed light : the protective housing is concealed behind a ceiling or wall, leaving only thefixture itself exposed. The ceiling-mounted version is often called a downlight.Cans, downlighting , uplights placed on the floor, Troffer light (recessed fluorescent lights ), Covelight ( recessed into the ceiling in a long box against a wall), Torch lamp (floor lamp).2- Surface-mounted light : the finished housing is exposed, not flush with surface.3- Pendant light : suspended from the ceiling with a chain or pipe.4- Sconce : provide up or down lights; can be used to illuminate artwork, architectural details;commonly used in hallways or as an alternative to overhead lighting.5- Track lighting fixture: individual fixtures can be positioned anywhere along the track, whichprovides electric power.

Fixed :-


6- Under-cabinet light : mounted below kitchen wall cabinets.

7- Emergency lighting or exit light : connected to a battery backup or to an electric circuit that has emergency power if the mains power fails.

8- High- and low-bay lighting : typically used for general lighting for industrial buildings and often big-box stores.

9- Strip lights or industrial lighting : often long lines of fluorescent lamps used in a warehouse or factory.

10- Soffit : can be general or a decorative wall-wash, sometimes used to bring out texture on a wall, though this may also show its defects as well. The effect depends heavily on the exact type of lighting source used. Lighting systems and their design 32

Direct Lighting

• When luminaires direct 90 to 100% of their outputdownward.

• The distribution may vary from widespread tohighly concentrated, depending on the reflectormaterial, finish and contour, and on the shielding orcontrol media employed.

• Troffers and downlights are two forms of directluminaires.

• Can have the highest utilization of all types, but thisutilization may be reduced in varying degrees bybrightness-control media required to minimizedirect glare.

• Reflected glare and shadows may be a problemwith direct lighting unless close spacings areemployed.

Lighting systems and their design33

Reflector:polycarbonateprismatic, glassprismatic, opalglass or grey spunaluminium

Semi-direct Lighting• The distribution is predominantly downward (60 to 90%) but with a small

upward component to illuminate the ceiling and upper walls.• The same as for direct lighting except that the upward component will tend

to soften shadows and improve room brightness relationships.• Care should be exercised with close-to-ceiling mounting of some types to

prevent overly bright ceilings directly above the luminaire.

Semi- Indirect Lighting

• Lighting systems that emit 60 to 90% of their outputupward.

• The characteristics are similar to those of indirectsystems except that the downward componentusually produces a luminaire luminance that closelymatches that of the ceiling.

• However, if the downward component becomes toogreat and is not properly controlled, direct orreflected glare may result.


Lighting systems and their design35

diffused

indirect


Soffit lighting is used todirect more light to wallsurfaces and to horizontalsurfaces, such as kitchen andbath countertops, wall desks,music centers, and computercenters.

Cove lighting directs light(usually fluorescent) ontoceiling surfaces and indirectlyreflects light into the centerof a room. The soffit shouldhide the fixture from viewfrom any position in the room.

Valance lighting directs light upward tothe ceiling and down over the wall orwindow treatment. Valance faceboardscan be flat, scalloped, notched,perforated, papered, upholstered,painted, or trimmed with molding.

Cornice lighting directs all lightdownward. It is similar to soffit lighting.except cornice lights are totally exposedat the bottom.

General Diffuse Lighting• When downward and upward components of light from luminaires are about equal (each 40

to 60% of total luminaire output).• Direct-indirect is a special category within this classification for luminaires that emit very

little light at angles near the horizontal. Since this characteristic result in lower luminances inthe directglaze zone, direct-indirect luminaires are usually more suitable than general-diffuse luminaires that distribute the light about equally in all directions.

• General-diffuse units combine the characteristics of direct lighting and those of indirectlighting.

• Brightness relationships throughout the room are generally good and the upward lightreflected from the ceiling softens shadows from the direct component.

• Pendant-mounted luminaires designed to provide a general-diffuse or direct-indirectdistribution are frequently installed on or very close to the ceiling.

• Such mountings change the distribution to direct or semidirect since the ceiling acts as a topreflector redirecting the upward light back through the luminaire.


Indirect Lighting

• Lighting systems which direct 90 to 100% of the light upward to the ceiling and uppersidewalls.

• In a well-designed installation, the entire ceiling becomes the primary source of illumination,and shadows will be virtually eliminated.

• Also, since the luminaires direct very little light downward, both direct and reflected glarewill be minimized if the installation is well planned.

• It is also important to suspend the luminaires a sufficient distance below the ceiling to obtainreasonable uniformity of ceiling luminance

• Since the indirect lighting the ceiling and upper walls must reflect light to the work plane, it isessential that these surfaces have high reflectances. Care is needed to prevent overall ceilingluminance from becoming too high and thus glaring.


Downlights,aimed (recessed or surface mounted)

• Downlights have a rotationally symmetric beam that is downwards.• They are offered with narrow-beam symmetric light distribution.• The cut-off angle of narrow-beam downlights means they are largely free of glare.• This gives a luminaire with the widest beam possible while simultaneously having an

optimised light output ratio.• The use of a diffuser reduces the luminance in the luminaire and thereby improves the visual

comfort and the evenness.

Criteria for Downlights:

Choice of lamp determines light colour, functional life, efficiency, light intensity,

•Emission angle determines the beam of light and is defined by the reflector and the lamp,

•Cut-off angle limits glare and increases visual comfort,

•Light output ratio is increased by optimised reflector technology.


Applications of Generallighting- direct, aimed:•Entrance areas,•Arcades,•Passages,•Atria.

Normal

Wall-mounted down lights, with their diffuse beam in the room, provide good visual comfort. They can also be mounted on the ceiling.

Shielded Wall-mounted down lights with half-shielded face offer good visual comfort and illuminate the

floor area in particular.

Criteria for wall mounted down lights:

•Choice of lamp determines light color, functional life, efficiency, light intensity,

•Uniformity: optimized reflector for even illumination of areas,

•Cut-off angle increases visual comfort and limits glare and light pollution.

Uplight, diffuse

Recessed floor luminaires with diffuse light intensity distribution are used for marking paths or emphasizing architectural lines.Applications of General lighting - direct, diffuseEntrance areas,Overhanging or cantilevered roofs,Floor lighting on access driveways, paths and public squares.


Reflectors


Advances in materials science have resulted in several key new materials capable of precisely and efficiently redirectingincident light rays.While these types of reflector materials are advantageous for some luminaire designs, in other cases, optical performancerequirements dictate the use of standard painted reflectors that produce diffuse, scattered, or wide-spread distribution ofthe incident light.Appropriate use of reflector materials (specular or diffuse) will maximize luminaire efficiency while maintaining the desiredlight distribution.

DIFFUSE REFLECTOR

SPECULAR REFLECTORS

Reflector finishes can be chosen to coordinate with interior design elements, enhance the

tones of the lamp source as well as impact performance and ceiling brightness.

Specular Finish

Provides a clear image and a high

level of beam control.

Diffuse Finish

Allows light to be reflected evenly in

all directions, creating uniform

illumination.

Painted Finish

Provides a highly reflective finish that

is durable and easy to clean.

CLEAR

Produces the highest performance of

controlled reflected light.

GOLD

Provides warm tones, ideal for incandescent

and H.I.D. sources.

WHEAT

Provides warm appearance, ideal for

compact fluorescent sources.

BLACK

Absorbs light and minimizes glare.

CLEAR DIFFUSE

Creates a smooth appearance and even

illumination.

GOLD DIFFUSE

Provides a warm, soft, uniform illumination.

WHITE

Most economical choice and blends into

white ceilings.

BLACK BAFFLE

Ideal for reducing glare at the ceiling line.

WHITE BAFFLE

Blends into white ceilings, helps minimize

glare.



Design parameters


Direct Glare.Caused by a view of the light source, often with high contrast to the surroundings.

• Glare is associated not just with lamps, but also with daylight, especially when one isexposed to low angle, direct sunlight.

Be concerned– more about the glare caused by lamps, lenses and other overly birght sources of manmadelights– less about glare of sunlight and small point sources– most concerned about sources of glares in relation to the stationary tasks when buildingoccupants cannot easily relocate themselves or their tasks


• In exterior applications, use fully shielded luminaires thatdirects light downwards towards the ground or a buildingfaçade.

Reflective Glare• Have long been associated with gloss-coated paper, pencil paperwork and computer CRT

(cathode ray tube) screen.• Indirect lighting, by creating a diffuse and uniform illumination has been advocated as

solution.• Can create specular reflections that can cause glare reducing comfort or disabling the

worker’s vision in particular areas.• Reflective glare - when system has been optimized to reduce glare – then consider:• modifying the task to eliminate remaining glare problem such• as use of flat screen CRT or active matrix.• Use of ink rather than pencil• Use of matte-coated or uncoated paper rather than gloss coating paper.• Changing finishes of polished floors or shiny conference room tables.


Where to place the lighting ?

It can, in the case of lighting close to the wall (“grazing” rather than “washing”—see diagram) reveal defects in the workmanship.


GENERAL LIGHTING

DINNING AREA

ACCENT TASK LIGHTINGLighting systems and their design 48


Working area kitchen


Given the wide choice of different lamps andluminaires available, there is an almost infinite set ofdifferent arrangements of electric lights within a roomthat will provide a certain illumination level.The primary concern in lighting layout is to avoid glareon activity surfaces.

Good and bad lighting locations, causing or avoiding glare


Uniform VS Task lighting



System selection


Step 1 – the analysis of quality and quantity of light

Step 2 – Consider colour appearance

55Lighting systems and their design

Decide the colour of ‗white light‘that best suits the application. Thisis referred to as colour appearanceand can be different for each typeof lamp or can vary among modelsof the same lamp type. Choosingthe most appropriate colour‗white‘ can enhance the objectsbeing lit or the ambience of thespace

Choose the most efficient light source that candeliver the desired lighting characteristicsrequired for the application. While theefficiency of the light source is a key componentof an energy effective lighting solution, it is onlyone of a number of selection criteria. Take a lowpressure sodium lamp as an example; it is a veryefficient light source but its poor colourrendering characteristics make it unsuitable formost applications.


Step 3 – Consider colour rendering


Step 6 – CONSIDER luminaire position and maintenanceEnsure that the luminaires aremounted to provide effectiveillumination and are in accessiblelocations without the necessity ofhiring or buying special equipment tomaintain them. The luminaires shouldbe easy to clean and lamps should beeasily accessible for replacement.

Choose a wide or narrow light distributionpattern depending on the application. Anoffice normally requires wide and evenlight distribution with good uniformity,whereas a narrow distribution suitswarehouse aisles.


Step 7 – Consider controls and use of daylight

Lighting controls should provide theright quantity of light as and whenrequired. Lighting can be controlledby time, occupancy and daylightavailability. There are a number ofways to add controls to existinglighting installations andopportunities to maximize the use ofdaylight in buildings.

The Layered Approach to Lighting Design


Layer #1 -The Ambient or General Lighting Layer

1. Generally the relatively uniform lighting of the space.

2. Includes uniform down lighting, indirect lighting (up lighting and wall washing), and some

special techniques, but can also be the decorative lighting

3. Called “ambient lighting "if lower than task levels


Layer #2 -The Task Layer

•Generally limited to “task lighting "of the HORIZONTAL WORK SURFACE at work locations.•Tends to help create drama.•Usually produces 50 fc or more within a small area.


Layer #3 -The Display or Focal Layer

•Generally limited to accent lighting and similar effects, primarily through VERTICAL ANDOTHER NON-HORIZONTAL SURFACE ILLUMINATION.•Tends to create drama, with greater drama the result of greater contrast between thebrightness created by Focal Lighting and Ambient Lighting.•Usually involves key displays at 100 fc or more.


Principles of Wall washing

Fixtures at least 24”out from wall and about 1/4 wall height out from wall Fixtures apart 1 to 1.5 times the distance from the wall If you don’t need at least three -you shouldn’t be wall washing

The higher the wall the further out to locatewall washers


Accent Lighting Technique

Should be located at about 30 degrees off vertical relative to focal point

Do not get too close to wall -normally 24”minimum away

Use 30-60-90 triangle to determine optimum position

Only use lighting systems capable of hitting above 40 degrees (off vertical) in special situations.

PAR36For high ceilings use a low voltage 6”recessed luminaire and a 50 watt PAR36 low voltage lamp


Layer #4 -the Decorative or Traditional Layer

•In general, adds the decorative luminaires called for by the architecture/interior design style, period, theme.•Is usually expected to contribute to the ambient illumination. In many designs, the decorative lighting will BE the ambient lighting.•Usually reduces contrast (drama).



References • Lighting Design Basics, May 26-27, 2008 By-James R Benya, PE, FIES, FIALD, LC,BENYA LIGHTING DESIGN

• Lighting technologies

• EFFICIENT LIGHTINGSTRATEGIES

• Home Office

• BUILDING TECHNOLOGIES PROGRAM OFFICE OF ENERGY EFFICIENCY AND RENEWABLE ENERGY • U.S. DEPARTMENT OF ENERGY

• ARTIFICIAL LIGHTING, lecture notes, Dr. Habil. András Majoros

• Recessed

• Natural Lighting Systems-Based on Dielectric Prismatic Film, By Daniel

• Ambient bright light in dementia: Effects on behaviour and circadian rhythmicity J. van Hoofa,, M.P.J. Aartsb, C.G. Rensec, A.M.C.Schoutensc

• Net Zero Energy Buildings

• California Energy Commission’s Public Interest Energy Research Program

• Lighting Design Basics With a Green Touch-James

• Crestron

• IEEE Guide for Direct Lightning Stroke Shielding of Substations

• Benya Lighting Design

• Holophane

• Elements of lighting Design

• Philips

• Osram

• US department of energy

• Lighting System Considerations and Design Options for Application

• Advance lighting Guidelines

• NPC Experiences

• Clear advantage lighting

• NYC design + construction

• Lighting System Design – Design Methods Dr. Sam C M Hui

• PG&E's energy efficiency programs and other servicesLighting systems and their design 67