B4 A general lighting scheme is to be proposed for a store room, which is 12 m (L) x 8 m(W) x 3 m (H). The required illuminance at working plan level, which is 0.85 m above floor, is 300 lux. A recessed type of luminaire containing 2 nos. of 28 W LED tubes is to be used for the room. The output lumen of each 28 W LED tube is 3000 lumens. The room reflectances are: 0.7 ceiling, 0.5 walls and 0.2 floor, and the Light Loss Factor (LLF) of the luminance is 0.85. The utilization factor of the proposed luminaire can be obtained in the following table: SHR max = 1.5 Reflectance: Cw F 0.70 0.50 0.20 0.30 Utilization factors, UF Room Index (RI) 0.75 1.00 1.25 1.50 2.00 2.50 3.00 4.00 5.00 0.43 0.51 0.56 0.60 0.65 0.68 0.71 0.74 0.76 0.37 0.45 0.50 0.54 0.60 0.64 0.67 0.71 0.74 0.33 0.41 0.46 0.50 0.56 0.60 0.64 0.68 0.71 0.10 (a) Determine the room index; and hence the utilization factor (to 2 decimal places) of the proposed luminaire. (b) Calculate the minimum number of the luminaire used for the store room. (C) Suggest and sketch the lighting layout of the store room. Show that the Space to Height ratios of your suggested lighting layout complies with the requirement of Uniformity. B4 A general lighting scheme is to be proposed for a store room, which is 12 m (L) x 8 m(W) x 3 m (H). The required illuminance at working plan level, which is 0.85 m above floor, is 300 lux. A recessed type of luminaire containing 2 nos. of 28 W LED tubes is to be used for the room. The output lumen of each 28 W LED tube is 3000 lumens. The room reflectances are: 0.7 ceiling, 0.5 walls and 0.2 floor, and the Light Loss Factor (LLF) of the luminance is 0.85. The utilization factor of the proposed luminaire can be obtained in the following table: SHR max = 1.5 Reflectance: Cw F 0.70 0.50 0.20 0.30 Utilization factors, UF Room Index (RI) 0.75 1.00 1.25 1.50 2.00 2.50 3.00 4.00 5.00 0.43 0.51 0.56 0.60 0.65 0.68 0.71 0.74 0.76 0.37 0.45 0.50 0.54 0.60 0.64 0.67 0.71 0.74 0.33 0.41 0.46 0.50 0.56 0.60 0.64 0.68 0.71 0.10 (a) Determine the room index; and hence the utilization factor (to 2 decimal places) of the proposed luminaire. (b) Calculate the minimum number of the luminaire used for the store room. (C) Suggest and sketch the lighting layout of the store room. Show that the Space to Height ratios of your suggested lighting layout complies with the requirement of Uniformity