For any reaction mechanism and a given positive equilibrium a cone of possible velocities for the systems with detailed balance is defined for any non-equilibrium state N Q D B ( N ) = c o n e { γ γ r s g n ( w r + ( N ) − − w r − − ( N ) ) | r = 1 , … … , m } , where cone stands for the conical hull and the piecewise-constant functions s g n ( w r + ( N ) − − w r − − ( N ) ) do not depend on (positive) values of equilibrium reaction rates w r e q and are defined by thermodynamic quantities under assumption of detailed balance.