Relieving rates in ethanol/water and ethylene glycol/water mixtures were investigated using dynamic models of an emergency relief scenario due to an external heat source. A commonly used shortcut method was compared to two rigorous calculation methods one using ideal conditions and another using non-ideal conditions. In several cases, the shortcut method provides a reasonable estimate compared to the rate predicted by the more rigorous methods. However, in many cases the shortcut method over or under-predicts the required relieving rate sometimes by a significant amount. Several discrepancies are also noted between non-ideal and ideal conditions. This study demonstrates that each multi-component mixture must be carefully considered before sizing emergency relief systems and devices. (C) 2016 Elsevier Ltd. All rights reserved.