(42S) Room Cavity Ratio, Luminous Intensity and Illuminance
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05-13-2019, 01:28 PM
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(42S) Room Cavity Ratio, Luminous Intensity and Illuminance
Blog entry: http://edspi31415.blogspot.com/2019/05/h...ratio.html
Room Cavity Ratio The room cavity ratio is used to assist in calculating lighting efficiency in determining where to place ceiling lights in an office room. The formula is: RCR = INT( ( 5 * H * ( L + W ) ) / ( L * W ) ) where: L = length of the room H = height difference between floor cavity and ceiling cavity W = width of the room HP 42S/DM42/Free42: Solver RCR Code: LBL "RCR" Example 1: Input: H = 5.5, L = 16.8, W = 13.7. Result: RCR = 3 Example 2: Input: H = 5.5, L = 16.8, RCR = 4. Result: H = 7.1650 Sources: Dilouie, Craig. "Lighting Design: Example of Role Surfaces Play in Lighting Efficiency" LightNOW https://www.lightnowblog.com/2010/06/exa...fficiency/ June 16, 2010. Retrieved March 31, 2019 "Room Cavity Ratio, RCR" Illuminating Engineering Society. https://www.ies.org/definitions/room-cavity-ratio-rcr/ July 5, 2018. Retrieved April 28, 2019 Luminous Intensity and Illuminance The follow equation relates the luminous intensity (measured in candelas, cd) and illuminance (measured in lux) of a light source. The equation assumes the light source radiates a spherical matter. E = I / R^2 E = illuminance I = luminous intensity R = radius of the sphere's light (meters) HP 42S/DM42/Free42: Solver ILSPH Code: LBL "ILSPH" Example: Example 1: Input: I = 10 cd, R = 2 m. Result: 2.5 lux Example 2: Input: R = 3.65 m, E = 30 lux. Result: I = 399.6750 cd Sources: Daryanani, Sital "Building Systems Design With Programmable Calculators" Architectural Record Books. McGraw-Hill Book Company: New York. 1980. ISBN 0-07-015415-5 Zumtobel "The Lighting Handbook" Zumtobel Lighting GmbH. Dornbirn, Austria. 6th Edition: 2018 https://www.zumtobel.com/PDB/Ressource/t...ndbuch.pdf |
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Messages In This Thread |
(42S) Room Cavity Ratio, Luminous Intensity and Illuminance - Eddie W. Shore - 05-13-2019 01:28 PM
RE: (42S) Room Cavity Ratio, Luminous Intensity and Illuminance - Luigi Vampa - 05-14-2019, 08:15 AM
RE: (42S) Room Cavity Ratio, Luminous Intensity and Illuminance - SlideRule - 05-14-2019, 02:46 PM
RE: (42S) Room Cavity Ratio, Luminous Intensity and Illuminance - Eddie W. Shore - 05-15-2019, 02:04 AM
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