An industrial building has floor area of 5 m by 8 m and is 3 m high with a door 1 m wide and 2 m high. Leakage of transformer oil from a pump occurs and is ignited. What is the maximum area of spill in (m^2) if flashover is to be avoided. Assume the construction materia to be lightweight concrete and perform the calculations at a characteristic time of 10 minutes after ignition.