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LAMPS (Chapter 3)

LAMPS (Chapter 3). Lamp efficacy, life, and color Incandescent Incandescence (Additional information) Light emitted from a heated object Uses a tungsten filament enclosed in a glass bulb, usually filled with a mixture of nitrogen and argon gases Operates at 4800 o F

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LAMPS (Chapter 3)

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  1. LAMPS (Chapter 3) • Lamp efficacy, life, and color • Incandescent • Incandescence (Additional information) • Light emitted from a heated object • Uses a tungsten filament enclosed in a glass bulb, usually filled with a mixture of nitrogen and argon gases • Operates at 4800oF • Tungsten has the highest melting point of all metals (6170° F) and has a high conductivity • Efficacy (some additional information) • Efficacy = Lumens/Watt • Life • Color • Special lamps • Lamp Shape and size

  2. LAMPS (Chapter 3) • Fluorescent lamps • Fluorescence (Additional information) • Conversion of ultra-violet light into visible energy • Efficacy • Life • CRI • Color • Operation • Lamp types and bases • Preheat • Instant start • Rapid start • High and very high output • Lamp designations • Ballasts • Special fluorescent lamps • Compact • Energy efficient fluorescent lamps • Cold cathode • Neon

  3. LAMPS (Chapter 3) • High intensity discharge (HID) • What is it? • Production of light by passing an electric arc through a conductive vapor • HID efficacy and life • Mercury • Color • Efficacy • Life • Sodium • High pressure • Low pressure • Color • Efficacy • Life • Metal Halide • Color • Efficacy • Life • CRI • Comparisons • Other types • E-lamp • A compact high-tech induction reflector lamp • LED • Special semi-conductor chips (diodes) that emit light when connected in a circuit

  4. LIGHTING NUMBERS (Chapter 7) • Terms and accents • How much light? • Luminaire photometrics • Luminaire (Additional information) • Complete lighting unit consisting of lamps, parts that position and protect lamp, and means of connection to power supply. Also referred to as a fixture • S/MH (spacing-to-mounting height ratio [spacing between two adjacent luminaires/mounting height of the luminaire); also called spacing criteria (SC)] • Coefficient of utilization (CU) • CU values are influenced by (Additional information): • Room surface reflectances • Size and shape of a room • Location of luminaires • Design of luminaires • Light loss factor (LLF) (Additional information) • Ratio of illumination of a given area after a period of time to the initial illumination on the same area • Usually two main factor are taken into consideration for calculating LLF (additional information): • Lamp lumen depreciation (LLD): A factor used to account for reduced lumen output due to aging of lamp sources. • Luminaire dirt depreciation (LDD): A factor used to account for reduced illumination due accumulation of dirt on luminaires. May be obtained by consulting the Maintenance Category of the luminaires. • LLF = LLD*LDD • Cavity ratio (CR) (Additional information) • A number that indicates the proportions of a cavity (space) calculated from its length, width, and height. Room, floor, and ceiling cavity ratio have to be determined. • RCR • FCR • CCR

  5. LIGHTING NUMBERS (Chapter 7) • Footcandle calculations • Example calculations • Reflectances • Coefficient of utilization • CU values are influenced by (Additional information): • Room surface reflectances • Size and shape of a room • Location of luminaires • Design of luminaires • Lighting quality numbers • VCP • ESI • CRF • VDT

  6. L Perimeter = 2x(L+W) W

  7. LIGHTING DESIGN (Additional information) • Determination of CU • Divide the space into cavities: (1) Ceiling cavity (2) Room cavity (3) Floor cavity • Determine cavity ratio: CR = 2.5*cavity ht.*cavity perimeter/cavity area • Example: • Room cavity ratio = [2.5*5.5*(29.33+14+29.33+14)]/410.62 = 2.9 • Reflectances • Find out wall, ceiling, and floor reflectances based on surface colors • Find out effective ceiling and floor cavity reflectances • Effective ceiling cavity reflectance: Combined reflectance effect of all surface areas above plane of luminaire • Effective floor cavity reflectance: Combined reflectance effect of all surface areas below work plane • Use actual reflectances when CR = 0 • Adjust CU if effective floor cavity reflectance is more than 30% or less than 10%

  8. LIGHTING DESIGN (Additional information) • Choosing a luminaire • Choose one that has a CU table available • Use lamps with high efficacy • Determine number of lamps and find out initial lumens, life, and replacement protocol • Spacing criteria (SC or S/MH) • Fixture spacing should have an acceptable uniformity of illumination. Use recommended SC factor to determine both across (side-to-side) and along (end-to-end) spacing. • Formula to be used for lighting design • Illuminance = (No. of luminaires*lamps per luminaire*lumens per lamp*CU*LLF)/Area • No. of luminaires = (Illuminance*Area)/(Lamps per luminaire*lumens per lamp*CU*LLF)

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