SPACING of bars in a flat slab shall not exceed 2 times the slab thickness.2. Critical section for shear in case of flat slabs is at a distance of d/2 from the periphery of the column/the capital / the drop panel, where d is the effective depth.When the drop PANELS are used, the thickness of drop panel for determining area of REINFORCEMENT shall be the lesser of the FOLLOWING: (a) Thickness of drop, and (b) Thickness of slab plus one quarter the distance between edge of drop and edge of capital.4. The minimum percentage of the reinforcement is same as that in solid slab i.e., 0.12 percent if HYSD bars used and 0.15 percent, if mild steel is used.5. Minimum LENGTH of Reinforcement At least 50 percent of bottom bars should be from support to support.