Measurement of the Smoldering and Flaming Heats of Combustion of Vegetative Fuels

Published

June 30, 2025

Author(s)

Isaac Leventon, Karen De Lannoye, Ryan Greene

Abstract

T The combustion of vegetative fuels or biomass has important applications in energy generation, wildfire spread, and structural fire safety. It is critical to be able to accurately quantify the energy content of these fuels (i.e., their respective heats of combustion [kJ/g]) and where this energy is released during burning (i.e., in the gas-or solid-phase due to flaming or smoldering combustion). In this study, a microscale combustion calorimeter (MCC) is used to perform repeated experiments on vegetative fuels and the chars that they produce to uniquely measure the heat of combustion of flaming combustion (∆Hc,gas) and the heat of combustion of char oxidation (∆Hc,char). CHNS-O elemental analysis is also performed on both virgin fuel samples and char residue of selected fuels, to quantify the relation between measured heats of combustion and molecular composition. Species of interest tested in this study include (a) sticks, stems, and/or leaves of grasses and trees, (b) peat (commercial and natural samples, obtained from multiple sources), and (c) solid and engineered wood samples (i.e., western red cedar and oriented strand board, OSB). Initial results demonstrate up to 65% variations in ∆H c,gas measured for these different fuels (consistent with values reported in the literature) and a factor of 2.1 to 2.9 increase in ∆H c,char versus ∆Hc,gas for a given fuel. The relative amounts of energy released (per gram initial sample mass) in the gas-phase and the condensed-phase can be calculated based on measured ∆H c,gas, ∆Hc,char, and residue yields. The fraction of total fuel energy content released in the condensed-phase due to char oxidation varied substantially: between 21 % and 58 % for all fuels tested here and, on average, 50 % for peat samples and 33 % for each of the other vegetative fuels

Proceedings Title

Interflam 2025

Conference Dates

June 29-July 3, 2025

Conference Location

Egham, GB

Conference Title

Interflam

Pub Type

Conferences

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Citation

Leventon, I. , De Lannoye, K. and Greene, R. (2025), Measurement of the Smoldering and Flaming Heats of Combustion of Vegetative Fuels, Interflam 2025, Egham, GB, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=960103 (Accessed November 23, 2025)