The sufficient conditions for a binary liquid solution to behave as a minimum flash-point solution and the equations to determine the minimum flash-point composition and minimum flash-point are proposed here. Since these sufficient conditions and the associated equations were derived based upon the derivative of flash point with respect to composition (solution composition effect upon flash point), such a derivative equation was derived, initially, based upon the flash point-prediction model proposed in a previous study and then verified by the application of experimental data. Subsequently, this derived composition effect upon the flash-point equation for a liquid solution was applied to derive both the sufficient conditions and equations referred to above, with such conditions and equations both being verified by comparison of predicted results with experimentally derived data. The results reveal that these derived conditions are satisfactory for the identification of the status of a liquid solution as being a minimum flash-point solution and the proposed equations satisfactory to successfully estimate the value of the minimum flash-point composition and the minimum flash point. (C) 2003 Elsevier Science Ltd. All rights reserved.