New Correlations for Predicting Flammability Limits of Pure Materials and Mixtures

Flammability limits are one of the most important parameters to characterize material hazards. Currently, numerous methods or correlations, either stoichiometry or energy based, have been developed to evaluate flammability limits. In this work, a thermal theory is proposed to understand the dual role (quenching and heating) of each component in a mixture. Excess heating potential (EHP) is directly related to the heat of combustion, and hence the connection between flammability limits and energies can be established from an energy balance. In addition, the idea of oxygen calorimetry is found to be useful for understanding and correlating flammability limits. Here, both EHP and oxygen calorimetry are applied to develop new correlations and then to predict flammability limits of pure chemicals accurately. Since the thermal balance behind these correlations is universal, they can also be used to estimate flammability limits of complex material mixtures effectively.