Question

8.) Assume that we have the barrel-vaulted ceiling shown below in Figure 1 and bisected by the x, y, and z plane lines. The length of the barrel-vaulted ceiling (along the y-plane line) is 40 feet. The inside width of the barrel-vaulted ceiling along the x-plane line is 20 feet. Reflectances are 80% for the ceiling surface and 50% for the wall surfaces at the ends of the ceiling (ceiling wall surfaces above the x-plane line). What is the average ceiling cavity reflectance given the above information? Assume luminaires will be hung such that the bottom of the fixture is even with the x-plane line. Wed Figure 1 – Barrel vaulted ceiling

Answer 1

a The length of the leared-vaulted culing is 40 ft. The inside width - of leaseocel - vaulted t ceiling y 2017, a Reflectances of surface from ceiling (es, - 8%) and that of surface from wall (esy = 50%). ac L = 404, w = 2011; Os, 2 0.80, ºsz20.50 . The arual As of the swefaces are , is, for barred As, = TIW x) = ax20x40 = 4000 = 12575€ ?" 257 16² part of ceiling Is jou end and As2 = 72 = 1 x20² = 314th. of ceiling areage now fall caretty refactance ' A = L x W gt ! =40x20 ft2 Surface i love my vein om een los i =800 ft2 ana of the 800 HP - Pac =- [1257*(1-0) + 314+ (1-0) + 80942 open surface loce = 0.56 a onerage eiling careely. I