In this work we have analyzed experimentally the mass flow rate (m) over dot of the lateral outflow of cohesionless sand beach and granulated sugar through circular orifices of diameter D and rectangular and triangular slots of hydraulic diameter D-H made in vertical walls of bins. Such experiments were also performed in order to determine the influence of the wall thickness of the bin, w. Geometrical and physical arguments are given to get a general correlation form) embracing both quantities, D (or D-H) and w. The angle of repose is also an important factor characterizing these gravity flows. (C) 2013 Elsevier B.V. All rights reserved.