CH 9 - Lighting Systems Notes_StudyGuide

CH 9 - Lighting Systems Notes_StudyGuide - HA 355...

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HA 355 – Hospitality Facilities Operations 1 Chapter 9 - Lighting Systems I. Definitions/Concepts What is light? – visible radiated energy traveling in various wave lengths Visible Light Waves ** The lower end of this spectrum (violet, indigo, blue, green) is produced with shorter wavelengths violet is the shortest, red is the longest How do we see colors? Colors are reflected wavelengths of light All objects absorb color except for one wavelength reflected back When light shines on a surface, some of the colors in the light are absorbed and disappear, others are transmitted or reflected. The TRANSMITTED OR REFLECTED LIGHT IS WHAT GIVES OBJECTS THEIR COLOR Color Rendition – a light source’s ability to provide a perceived color similar to that which results from sunlight; a lamps CRI is from 0-100 * Daylight and incandescent lighting have a CRI = 100 How do we measure it? - Definitions Lumen (lux) – measure of the total output of light from a source How bright is it measured in lumens Illuminance – light that strikes a surface; measure horizontal plane and vertical plane You can get raccoon eyes from light shining down on you, therefore you need vertical illuminance for facial recognition Measured in FOOTCANDLES Footcandle (fc) - 1 footcandle is a light intensity of 1 lumen per square foot Lux = 1 lumen per square meter Fall 2005
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HA 355 – Hospitality Facilities Operations 2 Chapter 9 - Lighting Systems Footlambert – measure of brightness of surface; we see whatever light is reflected back up to us from a surface Typical illuminance levels in our everyday surroundings: Full moonlight: .005 - .01 fc Bright sunlight: 5,000 - 10,000 fc Overcast day: 50 - 200 fc Bright cloudy day: 500 - 2,000 fc Office lighting: 50 - 150 fc Other Definitions Lamp: light bulbs Luminaire : lamp (table lamp) or candelabra, overheadlight a fixture! Main function is to deliver the light produced by the lamps to a space in a way that is visually appealing and comfortable Consist of the following: Lamps, lamp sockets, ballasts, reflective material, lenses, housing Fixture: Another term for luminaire Ballast: fluorescent – converts electricity into usable form for fluorescent lamp Use for luminaries that use electric discharge lamps; mounted above luminaire Base: part of lamp that goes into some sort of socket (hell yea) Pin-type and screw There are two metal contacts at the base, which connect to the ends of the electrical circuit. They are attached to two stiff wires, which are attached to a metal filament. II. Light Sources - Natural and Artificial A. Natural - from the sun most common and least expensive Pros: Cons: Free Hot solar heat gain High illuminance level No Control Good color (renders true colors) Goes away at night; might not be when Psychologically pleasing you want it Avoid eye strain
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This test prep was uploaded on 02/19/2009 for the course H ADM 355 taught by Professor Rudy during the Spring '06 term at Cornell.

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CH 9 - Lighting Systems Notes_StudyGuide - HA 355...

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