  It is shown that the dipole pomeron model of single diffraction dissociation
-- contrary to the case of the supercritical pomeron -- is compatible with the
inequality $\sigma^{SD}\leq\sigma^{tot}$, imposed by unitarity, provided the
triple pomeron coupling satisfies certain conditions. With the adopted
approximation the model considered as a parcticular solution of the triple
pomeron decoupling problem. Explicit forms of such a coupling and a qualitative
comparison with the experimental data on single DD are presented. The modified
factorization properties of the model are also discussed.
