In the air duct system shown in the figure, air enters the main duct at A. The recommended Fan velocities in the main duct sections and branches are 10 m/s and 7 m/s, respectively. Using the velocity method, propose the correct 3 m/s duct diameters for main duct segments (AB, BC, CD) and branches (BE, CF). Also calculate the pressure drop in each run (ABC, ACF, ABCD) of the system. The loss coefficients are: Entrance 0.35, Tee (branch) at B 0.25, Tee (through) at B 0.20, Tee (branch) at C 0.30, Tee (through) at C 0.27. Each outlet has a pressure drop of 5 Pa. [12 marks, CLO 3] K = 0.25 for 90 elbow (ABE, ABCF, ABCD) A 1m/s 30 m- 30m B -15 m- C * 20m 60 m 15m