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


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An essential service in all the industries,
The power consumption by the industrial lighting varies between 2 to 10% of the total power depending on the type of industry.
Lightingisanarea,whichprovidesamajorscopetoachieveenergyefficiencyatthedesignstage,by incorporation of modern energy efficient lamps,luminaires and gears,apart from good operational practices.

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

  1. 1. LIGHTING SYSTEMS AND THEIR DESIGN Presentation by: Mohammed Azmatullah Guided By:- Ar. Mariam Ahmad Mam M.Arch , Building Services, III-Sem Faculty of Architecture and Ekistics Jamia Millia Islamia, New Delhi. Lighting systems and their design
  2. 2. INTRODUCTION A 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 varies between 2 to 10% of the total power depending on the type of industry. Lighting is an area, which provides a major scope to achieve energy efficiency at the design stage, by incorporation of modern energy efficient lamps, luminaires and gears, apart from good operational practices. The aim of lighting is to create an adequate visual environment. Thus, there are two components of the visual environment – 1. one is a usually furnished room with surfaces reflecting light to a greater or lesser extent , - this is a basically passive component- and – 2. the other is light, which (as an active component) makes the room visible.Lighting systems and their design 2
  3. 3. 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
  4. 4. 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. Lighting systems and their design 4
  5. 5. Various types of lighting systems used Generally there are 3types of lighting system 1.Accent lighting 2.Ambient lighting 3.Task lighting Many call LIGHTING as the 4th element of architecture. Lighting systems and their design 5
  6. 6. 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 type fixtures, down lights, chandeliers, or ceiling mounted fixtures etc. LIGHT QUANTITY Illumination Lumen Foot-candle Efficacy LIGHT QUALITY Color temperature Color rendition Glare 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. Lighting systems and their design 6
  7. 7. Accent lighting directional lighting . It can also be used to highlight the texture of a brick or stone wall, window treatments or outdoor landscaping. To be effective, accent lighting requires as least 3-times as much light on the focal point as the general lighting surrounding it. Accent lighting is usually provided by recessed and track lighting or wall-mounted picture lights ACCENT ILLUMINATION to highlight special objects of interest or to guide occupants. Accent lighting is mainly decorative, intended to highlight pictures, plants, or other elements of interior design or landscaping. LIGHT QUANTITY Illumination Lumen Footcandle Efficacy LIGHT QUALITY Color temperature Color rendition Glare Lighting systems and their design 7
  8. 8. 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 undercabinet lighting, 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, more demanding tasks, Task lighting is mainly functional and is usually the most concentrated, for purposes such as reading or inspection of materials. LIGHT QUANTITY Illumination Lumen Footcandle Efficacy LIGHT QUALITY Color temperature Color rendition Glare Task lighting systems independent from the space’s general lighting systems (serving specific task) are found in building types for instance, the display lighting in retail stores is a form of task lighting. Similarly, task lights are used in industrial manufacturing and assembly, health care, residential lighting, and many other interior lighting applications. Options include – indirect luminaires mounted atop cabinetry or workstations – Suspended luminaires – Recessed luminaires Lighting systems and their design 8
  9. 9.  Good task light should provide about 50 to 100 foot candles to the workspace  Well distributed over the work area shadow-free.  Adjustability is very important; you should be able to direct the light where you need it.  The task light should be designed to avoid glare.  It should be energy-efficient.  Most people prefer warm white to neutral white. Warm white is normally associated with a correlated color temperature between 3,000 and 3,500 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 chance of shadows. • The light source should not shine in your (or anyone’s) eyes; adjust it downward, onto the task surface and/or the task at hand (such as a document you are reading). A recommended ratio between localized task lighting and ambient lighting is 5:1. Regarding Task lighting Lighting systems and their design 9
  10. 10. Informational lighting (Guidance Lighting) The light in your closet, the light by your doorbell, and night lights, as well as path lighting and motion lights, are all good examples of informational lighting. It can be beautiful as well as functional, and can create dramatic statements. Lights inset on stairs can create pathways that enhance architecture. Decorative lighting Light strips, pendants, chandeliers, and sconces are all examples of light fixtures that draw attention to themselves and add character to the place being lighted. Many are also used for general lighting. Lighting systems and their design 10
  11. 11. Key Light, Fill Lighting:- • Multi-directional or diffuse light Reduces shadows on an object caused by the key light. Single point source of light Provides highlights and casts shadows providing contrast and producing definite focus. Lighting systems and their design 11 Techniques used in controlling Directionality of light • Occurs when light strikes a surface at a sharp angle, nearly parallel to a rough surface. • Enhances any variations in surface depth, revealing texture. • Will also emphasize flaws and unevenness in surfaces. Grazing:-
  12. 12. Uplight: Places a light source below an object. Produces shadows that are reversed from how an object is shadowed in daylight. Creates an eerie, unnatural effect because it replaces the more familiar overhead orientation of the light source. Light source is used not to illuminate an object itself, but its background. Applicable when one aims to reveal the outline of an object against a brighter surface and to create separation between the object and its background. Silhouette: • Occurs when light strikes a surface at a wide angle. • Provides even lighting on a vertical space, increase luminances of wall surfaces, and extend the space. Wall Washing: Lighting systems and their design 12
  13. 13. • Candlepower Distribution Curve: A curve, generally polar, represents the variation of luminous intensity of a lamp or luminaire in a plane through the light center. Visual Edge: The line on an isolux chart that has a value equal to 10% of the maximum illumination. Rotational symmetrical Light distribution same in all planes. Usually Circular or ‘Bowl shaped’ luminaire Planar symmetrical Luminaire distribution is confined to two vertical planes separately. Typical distribution for Fluorescent Lamp luminaires and Road Lighting Asymmetrical Asymmetry present in one of the Planes of measurement. • Isolux Chart: A series of lines plotted on any appropriate set of coordinates, each line connecting all the points on a surface having the same illumination. Lighting design curves/charts: Lighting systems and their design 13
  14. 14.  The image above is a candle power distribution curve, which provides information on how light is emitted from a lamp or light fixture.  The diagram represents a section cut through the fixture and shows the intensity of light emitted in each direction.  The portion of the graph above the horizontal 90°-270° line indicates light that shines above the fixture (indirect), while the portion of the graph below represents light shining down (direct).  The straight lines radiating from the center point identify the angle of the light emitted while the circles represent the intensity. For instance, point A above shows that the intensity of light at 80° is approximately 110 candlepower.  Point B shows that at 30° you will get about 225 candlepower. The image is a candle power distribution curve, which provides information on how light is emitted from a lamp or light fixture Lighting systems and their design 14
  15. 15. 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. Lighting systems and their design 15
  16. 16. •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 absorb unwanted 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 the direction of air flow from the luminaire. Lighting systems and their design 16
  17. 17. Lighting systems and their design 17 Luminaires designed for general illumination of large areas constitute the majority of lighting installations and the majority of the energy consumed for lighting. These lighting systems consist of a luminaire layout pattern that provides uniform lighting throughout the space. Open direct systems do not employ shielding at all. These systems include surface- and pendantmounted strip fluorescent fixtures and suspended open industrial and commercial luminaires. Unless equipped with reflectors, these systems radiate light in all directions. Open direct lighting systems are often very efficient, with high CU values, but they may cause visual discomfort and disability glare. Shielded Direct Lighting Systems Shielded systems use some form of lens, louver, or baffle to prevent direct viewing of the lamps at normal angles of view (see Figure 2). Surface and suspended luminaire types include industrial HID downlights, baffled industrial fluorescent luminaires, fluorescent wrap-around lens luminaires, and commercial fluorescent lens luminaires. Recessed systems include HID downlights and a wide range of fluorescent “troffers” using lenses, louvers, or baffles to control glare.
  18. 18. Lighting systems and their design 18 Parabolic Louvered Recessed Troffers An increasingly popular commercial general lighting fixture is the recessed parabolic troffer, which uses specular parabolic louvers to control the luminaire’s light distribution, providing sharp cut-off glare control. Depending on the spacing between the louvers, these luminaries can be classified as large-cell and small-cell parabolic luminaires. Large-cell luminaires are generally more efficient, with relatively high CU values, while smaller cells can offer better glare control. Many standard sizes are available, including 2’x 4’, 2’x 2’, 1’x 4’ The extent of glare control depends on the specific louver design. Standard Lensed Troffers Standard lensed troffers typically have higher efficiency and CU values than parabolic louvered troffers, but provide less precise glare control. Many lens types can be used (i.e., patterned prismatic, batwing, linear batwing, and polarizing), though final photometric performance also depends on a number of other factors such as reflector type, number of lamps, lamp type, and ballast type.
  19. 19. Lighting systems and their design 19 Indirect Lighting Systems Lighting systems that radiate light up to a reflecting ceiling are called indirect lighting systems. These systems generally employ luminaires suspended from the ceiling, though cove lights and lights mounted to walls and furniture can also be used. Indirect lighting systems using well-designed and properly spaced luminaires can provide excellent illumination, uniformity, and freedom from glare. Their success depends on maintaining a high ceiling reflectance in combination with nearly uniform brightness. In this way, a maximum amount of light is reflected down to the work plane, yet light patterns are less likely to create reflected glare in VDT screens. Indirect Lighting Luminaire Cove Lighting System Recent designs in fluorescent indirect lighting systems use lenses or imaging reflectors to achieve high luminaire efficiency, by producing a broad batwing light distribution while allowing for close-to-ceiling mounting. These designs can increase an indirect system’s CU to nearly that of traditional lensed troffer systems. Other new designs in indirect lighting luminaires, especially for cove and coffer installations, increase the effectiveness of traditional strip lights and eliminate socket shadows.
  20. 20. Lighting systems and their design 20 These systems combine the benefits of both traditional direct lighting and indirect lighting systems. Combing the high CU of direct illumination with the uniformity and glare control of indirect lighting can be an ideal solution for many spaces. The appropriate balance of direct and indirect light is dependent on the nature of individual applications. Direct/Indirect Lighting Systems Architectural Luminaires Architectural lighting systems, which are generally used in building spaces such as lobbies and corridors include recessed downlights, wall washers, track lights, and wall sconces. Since these luminaires are employed mainly for highlighting high-quality spaces, aesthetics is a principal consideration in their design and selection. Nevertheless, there are many opportunities to utilize efficient lighting in these applications.
  21. 21. Lighting systems and their design 21 Recessed Low-Wattage HID Downlights New HID downlights, equipped with high-CRI compact metal halide and white high pressure sodium lamps, can replace traditional incandescent downlights in high-quality and/or low-ceiling spaces, thereby achieving significant energy savings and extended lamp life. Recessed Compact Fluorescent Downlights The popular compact fluorescent down light is now available in a variety of configurations, and some 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. A relatively recent development, the 1’x 1’ parabolic down light for compact fluorescent lamps is extremely efficient, allowing replacement of incandescent lamps on a 1 watt for 4 watts basis.
  22. 22. Lighting systems and their design 22 Track-Mounted Lighting Task Lights Several interesting recent designs in track luminaires using compact fluorescent and lowwattage HID lamps offer significant energy savings over standard incandescent track luminaires Track lighting systems provide flexibility in design and make it possible to accommodate changing displays. Task lights work in conjunction with general lighting systems to meet diverse needs of individual occupants for specific visual tasks. Compact fluorescent lamp technology has special relevance for task lighting applications. In VDT applications where high levels of ambient light often interfere with visibility, task lighting may be especially important for non- VDT tasks, particularly when those visual tasks are difficult to perform because of low contrast, high speed, and/or worker age.
  23. 23. Lighting systems and their design 23 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, decorative lighting luminaires are used to provide general or ambient lighting in areas where a more customized appearance is desired. Although decorative lighting is still most often used in restaurants and hotels, an increasing number of applications exist in offices, retail stores, apartment buildings, and other commercial spaces. Many decorative luminaires employ efficient light sources, increasing opportunities for using less energy. Many traditional applications for incandescent wall-mounted sconces and brackets can be replaced with similar-appearing luminaires designed specifically for compact fluorescent or HID lamps. See Figure 10 for an example. Compact Fluorescent Pendants and Chandeliers Luminaire designs continue to evolve for compact fluorescent decorative chandeliers and pendants used in applications once limited to traditional incandescent fixtures.
  24. 24. Lighting systems and their design 24 Combined diagram for spotlights Light distribution curve Isolux diagram
  25. 25. Lighting systems and their design 25
  26. 26. 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 light source, whether the source appears warm, cool or neutral. • Measured in Kelvin (°K). • Acceptable range of CCTs for indoor environments is between 2500°K and 5000°K, with the higher value representing a cooler source. Color Rendering Index (CRI) CRI rating indicates how well an object’s colors are rendered by a source. It is a comparison of 8 specific test colors under an ideal light source in question. When color rendering is important, a source with a high CRI (e.g. 3500°K fluorescent with a CRI of 85) should be selected. Correlated color temperature and the ambient temperature Lighting systems and their design 26
  27. 27. 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 towards the ground or a building façade. Lighting systems and their design 27
  28. 28. how we can select the proper lamp type for a certain application.??? The answer will be as follows: 1. Efficacy, Life, Lumen Depreciation All of these have an effect on life cycle cost. If a lamp's lumen output declines rapidly during its life, the prudent designer initially provides more lumens than is required so that as the lamp declines with age, a sufficient amount of light is still available. In other words, if seven luminaires are required to provide the right amount of light for a space initially, we might put eight luminaires in our design so that the space is over lit at first, but the installation will still provide enough light later on as the lamps provide less than their rated lumen output due to ageing. Comparing the rate of lumen depreciation from one type of lamp to the next thus becomes an important part of the cost analysis. 2.PATTERN OF DISTRIBUTION It is sometimes desirable to have diffuse light rather than highly directional light since the latter may cause harsh shadows. An area source or a linear source (such as a fluorescent lamp) generates more diffuse light and softer shadows than a point source. 3. Controllability Some lamps are more easily dimmed than others. One must consider if simple on/off control is acceptable, if inexpensive dimming is desired, or if it is reasonable to incur the larger expenditures to get higher quality dimming. 4. Color Rendition One of the key areas of concern for the architect, interior designer and lighting engineer is the lighted appearance of the space. Most light sources are available in a variety of spectral power distributions, yielding a variety 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
  29. 29. 5. Distribution Control Light distribution from a small lamp can be controlled more easily than light emitted from a large lamp. This is simply because it is easier to shape a reflector around a small lamp than a large one. Some lamps are as small as 10 mm in length, and others are as large as 1 m long. The pattern of light from the former can be controlled very precisely whereas the best we can hope to do with the latter is to throw light in one general direction or another. We idealize a small light source with the concept of a "point source." The smaller the light-emitting element of a lamp, the more closely it resembles the ideal of a mathematical point source. 6. Air Conditioning Load All artificial lighting adds an additional heat load to a building. Lamps with a higher efficacy will put less heat into a space for a given amount of light output. The most thermally efficient form of lighting is diffuse daylight, followed by direct sunlight, low-pressure then high-pressure gaseous discharge. The worst of all is incandescent lamps. 7. Consistency and Reliability of Supply Voltage High-pressure gaseous discharge lamps are more sensitive to voltage variation than low-pressure lamps. If the arc is extinguished due to a dip in voltage, the high-pressure lamp may require up to 15 minutes to return to full light output. 8. Ambient Temperature and Humidity Some lamps, notably fluorescents, are very sensitive to temperature and humidity. These lamps are difficult to start when the ambient temperature is low, and once started may not produce full light output. 9. Cost Some lamps are quite cheap to purchase, initially. However, these tend to have low efficacy and relatively short 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, even without energy savings. Lighting systems and their design 29
  30. 30.  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/kgC Density 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. Lighting systems and their design 30
  31. 31. Free-standing or portable such 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 the fixture itself exposed. The ceiling-mounted version is often called a downlight. Cans, downlighting , uplights placed on the floor, Troffer light (recessed fluorescent lights ), Cove light ( 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, which provides electric power. Fixed :- Lighting systems and their design 31
  32. 32. 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
  33. 33. Direct Lighting • When luminaires direct 90 to 100% of their output downward. • The distribution may vary from widespread to highly concentrated, depending on the reflector material, finish and contour, and on the shielding or control media employed. • Troffers and downlights are two forms of direct luminaires. • Can have the highest utilization of all types, but this utilization may be reduced in varying degrees by brightness-control media required to minimize direct glare. • Reflected glare and shadows may be a problem with direct lighting unless close spacings are employed. Lighting systems and their design 33 Reflector: polycarbonate prismatic, glass prismatic, opal glass or grey spun aluminium
  34. 34. 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 output upward. • The characteristics are similar to those of indirect systems except that the downward component usually produces a luminaire luminance that closely matches that of the ceiling. • However, if the downward component becomes too great and is not properly controlled, direct or reflected glare may result. Lighting systems and their design 34
  35. 35. Lighting systems and their design 35 diffused indirect
  36. 36. Lighting systems and their design 36 Soffit lighting is used to direct more light to wall surfaces and to horizontal surfaces, such as kitchen and bath countertops, wall desks, music centers, and computer centers. Cove lighting directs light (usually fluorescent) onto ceiling surfaces and indirectly reflects light into the center of a room. The soffit should hide the fixture from view from any position in the room. Valance lighting directs light upward to the ceiling and down over the wall or window treatment. Valance faceboards can be flat, scalloped, notched, perforated, papered, upholstered, painted, or trimmed with molding. Cornice lighting directs all light downward. It is similar to soffit lighting. except cornice lights are totally exposed at the bottom.
  37. 37. 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 in the 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 indirect lighting. • Brightness relationships throughout the room are generally good and the upward light reflected from the ceiling softens shadows from the direct component. • Pendant-mounted luminaires designed to provide a general-diffuse or direct-indirect distribution 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 top reflector redirecting the upward light back through the luminaire. Lighting systems and their design 37
  38. 38. Indirect Lighting • Lighting systems which direct 90 to 100% of the light upward to the ceiling and upper sidewalls. • 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 glare will be minimized if the installation is well planned. • It is also important to suspend the luminaires a sufficient distance below the ceiling to obtain reasonable uniformity of ceiling luminance • Since the indirect lighting the ceiling and upper walls must reflect light to the work plane, it is essential that these surfaces have high reflectances. Care is needed to prevent overall ceiling luminance from becoming too high and thus glaring. Lighting systems and their design 38
  39. 39. 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. Lighting systems and their design 39 Applications of General lighting- direct, aimed: •Entrance areas, •Arcades, •Passages, •Atria.
  40. 40. 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, diffuse Entrance areas, Overhanging or cantilevered roofs, Floor lighting on access driveways, paths and public squares. Lighting systems and their design 40
  41. 41. Reflectors Lighting systems and their design 41 Advances in materials science have resulted in several key new materials capable of precisely and efficiently redirecting incident light rays. While these types of reflector materials are advantageous for some luminaire designs, in other cases, optical performance requirements dictate the use of standard painted reflectors that produce diffuse, scattered, or wide-spread distribution of the incident light. Appropriate use of reflector materials (specular or diffuse) will maximize luminaire efficiency while maintaining the desired light distribution. DIFFUSE REFLECTOR SPECULAR REFLECTORS
  42. 42. 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. Lighting systems and their design 42
  43. 43. Lighting systems and their design 43
  44. 44. Design parameters Lighting systems and their design 44
  45. 45. 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 is exposed to low angle, direct sunlight. Be concerned – more about the glare caused by lamps, lenses and other overly birght sources of manmade lights – less about glare of sunlight and small point sources – most concerned about sources of glares in relation to the stationary tasks when building occupants cannot easily relocate themselves or their tasks Lighting systems and their design 45 • In exterior applications, use fully shielded luminaires that directs light downwards towards the ground or a building façade.
  46. 46. 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. Lighting systems and their design 46
  47. 47. 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. Lighting systems and their design 47
  48. 48. GENERAL LIGHTING DINNING AREA ACCENT TASK LIGHTING Lighting systems and their design 48
  49. 49. Lighting systems and their design 49
  50. 50. Working area kitchen Lighting systems and their design 50
  51. 51. Given the wide choice of different lamps and luminaires available, there is an almost infinite set of different arrangements of electric lights within a room that will provide a certain illumination level. The primary concern in lighting layout is to avoid glare on activity surfaces. Good and bad lighting locations, causing or avoiding glare Lighting systems and their design 51
  52. 52. Uniform VS Task lighting Lighting systems and their design 52
  53. 53. Lighting systems and their design 53
  54. 54. System selection Lighting systems and their design 54
  55. 55. 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. This is referred to as colour appearance and can be different for each type of lamp or can vary among models of the same lamp type. Choosing the most appropriate colour ‗white‘ can enhance the objects being lit or the ambience of the space Choose the most efficient light source that can deliver the desired lighting characteristics required for the application. While the efficiency of the light source is a key component of an energy effective lighting solution, it is only one of a number of selection criteria. Take a low pressure sodium lamp as an example; it is a very efficient light source but its poor colour rendering characteristics make it unsuitable for most applications.
  56. 56. Lighting systems and their design 56 Step 3 – Consider colour rendering
  57. 57. Lighting systems and their design 57 Step 6 – CONSIDER luminaire position and maintenance Ensure that the luminaires are mounted to provide effective illumination and are in accessible locations without the necessity of hiring or buying special equipment to maintain them. The luminaires should be easy to clean and lamps should be easily accessible for replacement. Choose a wide or narrow light distribution pattern depending on the application. An office normally requires wide and even light distribution with good uniformity, whereas a narrow distribution suits warehouse aisles.
  58. 58. Lighting systems and their design 58 Step 7 – Consider controls and use of daylight Lighting controls should provide the right quantity of light as and when required. Lighting can be controlled by time, occupancy and daylight availability. There are a number of ways to add controls to existing lighting installations and opportunities to maximize the use of daylight in buildings.
  59. 59. The Layered Approach to Lighting Design Lighting systems and their design 59
  60. 60. 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 Lighting systems and their design 60
  61. 61. 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. Lighting systems and their design 61
  62. 62. Layer #3 -The Display or Focal Layer •Generally limited to accent lighting and similar effects, primarily through VERTICAL AND OTHER NON-HORIZONTAL SURFACE ILLUMINATION. •Tends to create drama, with greater drama the result of greater contrast between the brightness created by Focal Lighting and Ambient Lighting. •Usually involves key displays at 100 fc or more. Lighting systems and their design 62
  63. 63. 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 locate wall washers Lighting systems and their design 63
  64. 64. 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 Lighting systems and their design 64
  65. 65. 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). Lighting systems and their design 65
  66. 66. Lighting systems and their design 66
  67. 67. 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 services Lighting systems and their design 67