Diameter of the Knockout drum $=40$ inches.

Level transmitter LT$100$B $100\%$ range $=55$ inches of water column. The max flowrate through the bottom when the discharge valves ar fully open is $2\mathrm{.}3$ cubic feet$/$minute$.$The low level trip is set at $10\%.$ The low alarm limit is set at $45\%$ What is the process safety time $($in minutes$)$ for the alarm?

Please enter answer with $2$ decimals.