A gas is leaking at 3.5ft3/min in a room of 2.9m by 6.9ft by 15.7m. How long would it take (in seconds) for 22% of the room to reach the LFL, if the gas has a LFL of 2.51%?

First find the volume of the room: convert m to ft first: 15.7m * 3.28084ft/m = 51.5092 ft 2.9m *3.28084ft/m = 9.5144 ft Calculate the volume of the room: V= 9.5144 ft* 6.9ft*51.5092 ft= 3381.5580 ft^3 find the 22% of the room: 3381.5580 * 0.22= 743.9428 ft^3 Find the flow of gas that has LFL, 3.5 ft^3/min* 0.021 = 0.0735 ft^3/min Then divide the volume by flow rate: 743.9428 ft^3 / (0.0735 ft^3/min) = 10121.67 minutes or 168.69 hours