A packed column is used to scrub $\mathrm{SO}_{2}$ from air using water. The gas flow rate is $500 \mathrm{scfm} / \mathrm{ft}^{2}$ and the column operates at $90^{\circ} \mathrm{F}$ and $1 \mathrm{~atm}$. If the column contains No. 1 plastic Intalox packing, what is the maximum liquid flow rate (per unit cross section of column) that could be used without flooding?