Rapid estimation of the heat release rate of combustible items

Heat release rate (HRR) from a fire is the most important parameter to describe the potential hazards posed from a fire. Indeed, the environmental consequences of a fire in a confined space depend in large measure on the HRR. Typically, the HRR curves of combustible items are determined in laboratory experiments. For the aim of a rapid hazard assessment, it is infeasible to perform fire experiments on every combustible item inside a given building due to the costs and the time required. Therefore, approximations should be adopted. In this work, we propose a simple method to estimate the HRR curve of a generic combustible item or group of items, through a conventional HRR curve (t-squared growth, peak HRR and linear decay). The conventional curve is drawn considering two main elements: the exposed surface and geometry of the combustible items and a categorization of the constituent materials of the combustible items. Indeed material type and geometry of the combustibles influence the fire growth, while exposed surface and material type are of importance when considering peak HRR. Results are compared with full-scale experiments available in the literature, showing the validity of the approach. The method can be usefully adopted to estimate HRR curves of single as well as multiple combustible items especially in existing activities, where data can be collected from an inspection of the premises aimed at a rapid fire hazard assessment.