For pump tests in hot water and other liquids, the required NPSH is less than with cold water. Cavitation erosion is less violent. Cavitation inception is delayed by thermodynamic effects, which depend on numerous parameters. The heat of vaporization is drawn from the surrounding liquid and this causes a drop in temperature in the cavity, connected with a lower pressure of vaporization. Adequate grouping of parameters allows comparison between fluids, test facilities, and even transposition of test results between different models such as ogives, Venturis and pumps. There are more numerous parameters which influence cavitation erosion and it was not yet possible to classify the amount and rate of erosion, like it has been done successfully with cavitation inception.