  In the Hadron machine option, proposed in the context of the Future Circular
Colliders (FCC) study, the dipole field quality is expected to play an
important role, as in the LHC. A preliminary evaluation of the field quality of
dipoles, based on the Nb$_{3}$Sn technology, has been provided by the magnet
group. The effect of these field imperfections on the dynamic aperture, using
the present lattice design, is presented and first tolerances on the b$_3$ and
b$_5$ multipole components are evaluated.
