Plus, also keep in mind that the runway needs to be of a length where a 15kt tailwind is operationally acceptable.
And you have to have the airport analysis stating that a 15kt tailwind is acceptable, and a light-enough takeoff weight to be able to make a 15-kt tailwind takeoff, since such a tailwind will be very weight limiting. At my first dispatch job, we had one airplane (a BAe146-100) with a 15-kt tailwind limitation, at 1 airport (Aspen, CO, USA).