... Herewith a first classification Table 1 is possible for the first letters: 1. Maintenance factors are crucial Maintenance factors are an important consideration in the planning of lighting installations. The larger the room, the smaller the utilization factor for each light. The highest of these surfaces, the C surface (for ceiling cavity) , is an imaginary horizontal plane at the level of the luminaires having a reflectance equal to that of the ceiling cavity. 14 The Lighting Handbook Glare – glare limitation Direct glare Light distributions of luminaires are categorized by a three character code. It is used to calculate the number of luminaires required for the target illuminance on the working plane or the illuminance achieved by a specified number of luminaires. Room Surface dirt depreciation LDD = .77 Table 1 Multiplying factor floor RSDD = .95 Table 4 24 months irt Level Medium aintenance Category V CU = .56 ampsxture 4 umens/ lamp 3150 Table A 50 FC Page 9-28 IES Cleaning Schedule: D M Coefficient of Utilization L/fi L Design Level Unfortunately, some LED luminaire manufacturers are misreporting or inflating claims of LED luminaire efficacy and lifetime characteristics. The Society of Light & Lighting Code for Lighting states that: “The lighting scheme should be designed with an overall maintenance factor calculated for the selected lighting equipment, environment, and specified maintenance schedule.” The lighting industry saw similar problems during the early years of CFL replacement bulbs. The reflectance factor table in the system helps you determine the reflectance factors. Utilization factor(UF) is the proportion of the luminous flux emitted by the lamps which reaches the working plane. The utilisation factor method is used for an estimated calculation of lighting installations. maintenance factor (RSMF) is the proportion of the illuminance provided by a lighting installation in a room after a set tim ecop a r dw h u h e nt r omw as cl. Title: Coefficients of Utilization Author: Ward Harrison and Earl A. Anderson Created Date: 9/21/2005 10:00:00 AM Utilization factors are, in practice, only calculated for general lighting systems with regular arrays of luminaires and for three main room surfaces. Switching to the LED luminaire is easier for the end user if the form factors are the same. ... darker the room and as lower the direct part as lower the room utilization factor; this means that more light has to … Take into account the size of the room and the brightness of each light you consider installing in the room, to ensure there is adequate lighting. Utilization factor is affected by the size of the room. accepted form factor. 4. Factors …