Ignitability of materials in transitional heating regimes

Abstract

Piloted ignition behavior of materials, particularly wood products, during transitions between heating regimes is measured and modeled in a cone calorimetry (ISO 5660) heating environment. These include (1) effect of material thickness, density, moisture content, and paint coating variations on thermal response characteristics, (2) effect of fire retardant treatment concentration on smoldering and flashing prior to flaming ignition, and (3) effect of cone irradiance on inducing convective heat loss of the material. Thermophysical properties of volumetric heat capacity or thermal conductivity as functions of temperature and moisture content are obtained from available independent sources. Values of ignition temperature or adjustments to thermal conductivity are derived from a least-squares fit of cone irradiance as a nonlinear function of time to ignition. Independent measures of ignition temperature and thermal conductivity for redwood are in very close agreement with derived values. For 16 additional materials, which span a wide range of flammabilities, the reasonable values for material properties of heat capacity, thermal conductivity, surface emissivity, and ignition temperature are provided for use in mathematical fire models, such as the Fire Dynamic Simulator from NIST-BFRL.

Citation

Dietenberger, Mark A. 2004. Ignitability of materials in transitional heating regimes. In: Proceedings of the Wood & Fire Safety 5th International Scientific Conference. Slovak Republic: Faculty of Wood Sciences and Technology, Technical University of Zvolen: 31-41.