A storage room in an industry has a floor area of 30 m by 50 m and a height of 10 m. A garage door has a width of 3 m and a height of 3 m and the room has four windows that are 0.9 m by 0.9 m, situated at the height of 1 m from the floor. the fire load consists mainly of wooden pallents (1.2 x 1.2 m^2); the maximum amount stored is two pallet loads, side by side, which are 1.4 m high. the fire is assumed to attain maximum effect after 6 mnutes and firefrighters are assumed to arrived at the location 15 minutes after the fire starts. Design the size of smoke vents in the ceiling with the objective of avoiding falshover and only allowing the smoke layer to be 3 m thick. Assume a flow coefficient of 0.6 for the ceiling vents and assume the walls and ceiling to be of steel sheet, isolaed with mineral wool with kpc-3.3 * 10^3 W^2s/m^4K^2