The paper presents a mathematical model for predicting outflow rates from a ruptured pipeline transporting compressed volatile liquids. The main focus of the paper is the methodology used to predict thermodynamic properties of interest. The model is validated using experimental data in the open literature. As the field scale outflow data does not include typical operating conditions the model is further validated at higher pressures and longer pipelines by comparing outflow rates calculated using a commercial pipeline simulation package, PROFES. The mathematical model predictions of mass flow rate and pipeline inventory agree well with the measured data and the more sophisticated pipeline model. The simple pipeline rupture model is a useful tool for consequence analysis as it has a fast runtime on a standard PC. A further advantage is it is more easily, without having to address all of the numerical issues that arise when using a more sophisticated pipeline model. This allows a safety engineer to focus on the potential hazard rather than driving the model. (C) 2003 Elsevier Ltd. All rights reserved.