A dynamic pressure pump transmits $100$ lit$/$s of water from a tank where the suction level is $3$ m above pump level, to another tank. The suction pipe is $20$ cm diameter, $\backslash ("$ f$^\{\backslash$prime $\backslash$prime$\}=0\mathrm{.}04\backslash ).$ The pump runs at $2000$ rpm at a total head of $6$ m $.$ The vapor and atmospheric pressure are $0\mathrm{.}3$ and $10\mathrm{.}3$ m water. Calculate: the maximum permissible length of the suction pipe.