Luminaires – Module 3 Functional Aspects

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Luminaire Module 3 - Functional Aspects

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Luminaires – Module 3 Functional Aspects

  1. 1. Luminaires – An Overview:Facts, Basics and Considerations Target Audience: Facility managers, Procurement managers, Technical managers, Maintenance managers and General Lighting enthusiasts Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012
  2. 2. Luminaire Overview – ObjectivesThe purpose of this outline is to provide an overviewand to familiarize the decision maker with the keyconsiderations when evaluating a lighting solutionLuminaire Overview Topics:a. Luminaire classificationb. Luminaire technical aspectsc. Luminaire functional aspects Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 2
  3. 3. Module 3Luminaire Functional Aspects Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012
  4. 4. Luminaire – IlluminationThe optical system of a given luminaire is paramount formeeting the desired illumination. The reflector shape, type,and material are key for light quality in matters of intensity anddirection.This section will discuss the following: Illumination basic terms Photometrics, curves & distribution Luminaires and Reflectors efficiency and DLOR (Downward Light Output Ratio) materials, type and reflection louvers and light diffusion Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 4
  5. 5. Illumination - Basics The Inverse Square Law of light states that:the power of the light on an object is inversely proportional tothe square of the distance (d) from the source … E ~ /d² E – illuminance intensity on a surface. measured in lux. 1m 2m 3m 4m E= 100 lux E= 25 lux E= 11 lux E= 6 lux (100/1²) (100/2²) (100/3²) (100/4²) Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 5
  6. 6. Illumination – angle & intensity Intensity measured at 180 pointing towards the ceiling Intensity at 150 Intensity at 90Intensity values are incd/1000 lm (lumen) Intensity at 30cd – candela, luminous Intensity measured at 0 pointingintensity system unit towards the floor Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 6
  7. 7. Photometric distribution – polar intensity diagram Polar luminous intensity graph: The diagram illustrates the distribution of luminous intensity, in candelas, of the luminaire. The photometric curve provides a visual guide to the type of light distribution produced by the luminaire e.g. wide, narrow, direct, indirect etc. 150 180 150 The diagram showsIntensity values in the illuminationcd/1000 lm against vertical and 120 120 horizontal angles of the luminaire. For 90 90 example, the 100 luminous intensity 200 at 0˚ horizontal 60 60 300 angle and 30˚ 400 vertical angle is 30 0 30 300cd. Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 7
  8. 8. Photometric curve types and applicationsThe reflector has a key role in defining the light distribution pattern of a luminaire Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 8
  9. 9. Photometrics and IES files Luminaire photometrics is illustrated by an IES fileAn IES file visually illustratesseveral dimensions/rotationAny quality luminaire wouldcome with an IES file which canbe viewed by a softwareprogram rotating it.Commonly used software is IESviewer byhttp://www.photometricviewer.com Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 9
  10. 10. Reflector – Quality and Quantity IlluminationThe reflector and the optical system of a given luminaire isparamount for meeting the desired illumination. The reflectorshape and type, material are key for light quality in matters ofintensity and direction. Direct lamp light Reflected lamp light Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 10
  11. 11. Reflectors & Lamp size: Efficiency & DLOR T8 vs T5 FluorescentAs a rule of thumb the smaller the lamp the more efficient the reflector would be.DLOR – Downward Light Output RatioT8 fluorescent diameter is 8/12”, while T5 fluorescent diameter is of 5/12”.The illustration clearly shows that T8 obstructs some of its own light.It is estimated that 5%-10% of T8 light is being obstructed compared withT5. Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 11
  12. 12. Reflectors & Lamp Size: Efficiency & DLOR Quartz MH vs. Ceramic MHQuartz MH Ceramic MHbulb: ~ 9”, 23 cm bulb: ~ 3”, 7 cm Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 12
  13. 13. Reflector – Size mattersSmaller Reflector is considered more advantageous due to thefollowing arguments:• Less material required, eg. cheaper BOM & cheaper logistics• More efficient by design• Higher precision of light orientation illumination• Better quality materials are utilized, due to smaller size• Smaller size design usually more architectural in nature Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 13
  14. 14. Reflectors: Material, Type & ReflectanceType Material ReflectanceSpecular Commercial grade aluminum Up to 0.7 Aluminum with quality coating 0.8-0.9 (based on coating & color) Glass or plastic w’ aluminum 0.85-0.89 coating Multi coated polyester film 0.95-0.98Spread Brushed aluminum 0.5-0.6 Peened aluminum 0.7-0.8Diffuse White pain on steel ~ 0.8 (up to) Glossy white plastic ~ 0.9 (up to) Specular Spread Diffuse Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 14
  15. 15. Luminaire – light shielding qualitiesAmong luminaire qualities is light shielding. Improved light screening with lowcut design is a desirable attribute for a luminaire .Shielding Angle : an angle beyond which light is not visibleCut off Angle : 90 -shielding angle Low cut profile Cut off angle Shielding angle Shielding angle Luminaire A Luminaire B Luminaire “B”, has same cut off angle as “A”, while having low cut profile Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 15
  16. 16. Luminaire – light reflection & diffusingLuminaire louvers facilitate light reflection and diffusion aimingto provide pleasant and quality light spread.Ray of light at angleless than shieldingangle is diffuselyreflected Shielding angle Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 16
  17. 17. Luminaire – parabolic reflectors & diffusingLuminaires with parabolic louvers enable orientation anddiffusion of light along desired direction. Shielding angle Reflected light rays are oriented along desired direction Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012 17
  18. 18. The EndLuminaires by Light-Ref.com Light-Ref.com The unbiased lighting reference source http://www.light-ref.com © 2012

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