AbstractOne of the elements used to compute the dryout heat flux of a debris bed is the capillary pressure/saturation curve. This relationship describes the pressure difference between liquid and vapor phases in a porous bed as a function of saturation. It is used in the calculation of the liquid and vapor pressure drops in the debris and in the calculation of channel depth. The first complete correlation of capillary pressure/saturation data was reported in 1941 by Leverett. Leverett demonstrated that the data for unconsolidated sand in the 45- to 180-µm range could be non-dimensionalized using the liquid surface tension, bed permeability, and void fraction. At the time, the primary interest was in geologic materials and further work on unconsolidated particulate was limited. The presented measurements of capillary pressure are designed to check the range of validity of the Leverett correlation. For beds with narrow particle size distributions, the Leverett correlation is found to be adequate. For beds composed of broad size distributions, the capillary pressure curve changed significantly.