This paper presents experimental results of pressure drop measurements for different solid ceramic sponges. In the experiments, the material, pore sizes and porosity were varied. Furthermore, this data is correlated using an Ergun-type equation. It was possible to obtain Ergun constants for sponges independently of the varied parameters. In the future, the presented pressure drop correlation will provide a simple method for determining hydraulic diameters for solid ceramic sponges with unknown geometric parameters (strut, window and pore diameter,....) based on pressure drop measurements. Furthermore a correlation is given to derive the hydraulic diameter from the ppi (pores per inch) number. (C) 2009 Elsevier Ltd. All rights reserved.