Calculation Methods for the Heat Release Rate of Materials of Unknown Composition

Abstract

The Heat Release Rate (HRR) is a critical parameter to characterise a fire. Different methods have been developed to estimate it. The most widespread techniques are based on mass balance. If the heat of combustion of the fuel is known, the measure of the mass loss allows its evaluation. If the burning material can not be identified, calorimetric principles can be used. They rely on oxygen consumption (OC) or carbon dioxide and carbon monoxide generation (CDG) measurements. Their asset comes from the observation that the amount of energy release per unit mass of O 2 consumed or per unit mass of CO 2 produced is relatively constant for a large number of materials. Thus, an accurate HRR can be obtained without knowing the composition of the burning fuel. The aim of this work is to assess this last statement and define how essential the knowledge of the chemistry to calculate HRR for complex materials such as polymers including fire retardants and/or nanocomposites, energetic materials or pine needles is. This assessment ends in an OC and CDG calorimetry comparison of several materials in order to investigate the propensity to determine whether converging or diverging HRR results when average energy constants are used.

Combustion Characteristics of Materials and Generation of Fire Products

“…Furthermore, for materials that have bound oxygen in their chemical structures, oxygen may be released as a product of combustion which will affect the OC methodology [110]. Thus, chemical structure plays an important role in the determination of heat release rate [111].…”

Distribution analysis of the fire severity characteristics of single passenger road vehicles using heat release rate data

“…In addition it is also noted that the procedures, standards and/or protocols varied between each experiment which likely lead to different effects on the fire spread, availability of air etc. Finally it is important to note that the various heat release rate measurement techniques, namely mass loss rate, convective calorimetry and species-based calorimetry, could result in variability in the heat release rate measurements (Biteau et al 2008) thus affecting the fire severity analyses.…”

Fire Performance of Sandwich Panels in a Modified ISO 13784-1 Small Room Test: The Influence of Increased Fire Load for Different Insulation Materials

“…The output heat release rate is calculated by a species evolution approach using oxygen consumption calorimetry (OC). This approach is based on Thornton's principle [18] which assumes that the energy released by the burning organic material is proportional to the amount of oxygen consumed by the combustion reaction [19,20] coupled to the measurements of effluent flow from the room. Due to the assumptions that had to be made to determine the velocity profile of the flow at the door, there is a potentially large uncertainty in the calculations.…”

“…(3), as reported elsewhere [20,34]. A correction for incomplete combustion is included, by taking into account the generation of carbon monoxide.…”