Development of a pyrolysis model for oriented strand board: Part II—Thermal transport parameterization and bench-scale validation

2021 ◽  
pp. 073490412110366
Author(s):  
Junhui Gong ◽  
Hongen Zhou ◽  
Hong Zhu ◽  
Conor G McCoy ◽  
Stanislav I Stoliarov
Keyword(s):  
Heat Flux ◽  
Mass Loss ◽  
Loss Rate ◽  
Oriented Strand Board ◽  
Mass Loss Rate ◽  
Radiant Heat ◽  
Heat Fluxes ◽  
Controlled Atmosphere ◽  
Radiant Heat Flux ◽  
Pyrolysis Model

Oriented strand board is a widely used construction material responsible for a substantial portion of the fire load of many buildings. To accurately model oriented strand board fire response, kinetics and thermodynamics of its thermal decomposition and combustion were carefully characterized using milligram-scale testing in part I of this study. In the current work, Controlled Atmosphere Pyrolysis Apparatus II tests were performed on representative gram-sized oriented strand board samples at a range of radiant heat fluxes. An automated inverse analysis of the sample temperature data obtained in these tests was employed to determine the thermal conductivities of the undecomposed oriented strand board and condensed-phase products of its decomposition. A complete pyrolysis model was formulated for this material and used to predict the mass loss rates measured in the Controlled Atmosphere Pyrolysis Apparatus II experiments. These mass loss rate profiles were predicted well with the exception of the second mass loss rate peak observed at 65 kW m−2 of radiant heat flux, which was underpredicted. To further validate the model, cone calorimeter tests were performed on oriented strand board at 25 and 50 kW m−2 of radiant heat flux. The results of these tests, including both mass loss rate and heat release rate profiles, were predicted reasonably well by the model.

scholarly journals Determination of Mass Loss Rate and Smoke Generated of Jordanian Hardwood Timber under Different Flaming Combustion and Limited Ventilation Environment

2020 ◽  
Vol 15 ◽  
Keyword(s):  
Heat Flux ◽  
Mass Loss ◽  
Optical Density ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Heat Fluxes ◽  
Wood Products ◽  
Specific Optical Density ◽  
Flaming Combustion ◽  
Natural Wood

Natural wood has been used in structural applications for decades. Smoke from wood fires, additives and wood-protective coatings is a cause of death and serious injury in limited ventilation compartment. Ventilation restrictions in modern day designs complicate the combustion process and increase incomplete combustion products due to a reduction in the amount of oxygen available for fuel oxidation. Jordanian hardwood samples have been examined, tested and evaluated according to their mass loss rates, specific optical density, mass optical density, transmittance, and visibility using qualitative research used to realise the dynamics of fire phenomena. Four types of natural wood were tested under different heat fluxes with different Flaming combustion in a Smoke Density Chamber (SDC). The samples studied were Beech, Oak, Rhamnus, and Abies. The samples have been exposed to 25 and 50 kW/m2 heat fluxes in a limited ventilation compartment. Twelve samples were tested, each with dimensions of 75 x 75 mm and 10 mm thickness. An evaluation of the tested parameters, such as mass loss rate (MLR), specific optical density, transmittance, visibility and mass optical density (MOD have been carried out to determine their effectiveness as predictive parameters. Main results shows Beech has the lower values of specific optical density despite it has higher values of MLR% and MOD compared to other samples studied. Also, the mass loss rate (MLR %) increases with the heat flux even with different flaming conditions. In the opposite, there is a strong dependence for the mass optical density (MOD) on the heat flux and flaming conditions. Key conclusions have been drawn up that could be used in wood products and future works. The main objective of this work is to model the fire dynamic behavior in the pre-fire time. The results of this study can provide the bases for ventilation process and considerations of using natural woods in Jordan for different applications.

Pyrolysis and ignition delay time of poly(methyl methacrylate) exposed to ramped heat flux

2018 ◽  
Vol 36 (3) ◽  
pp. 147-163
Author(s):  
Chunjie Zhai ◽  
Fei Peng ◽  
Xiaodong Zhou ◽  
Lizhong Yang
Keyword(s):  
Heat Flux ◽  
Surface Temperature ◽  
Methyl Methacrylate ◽  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Ignition Time ◽  
Heat Fluxes ◽  
Critical Surface ◽  
Poly Methyl Methacrylate

Usually, the constant heat flux is used in the previous studies of polymeric pyrolysis. However, the ramped heat flux may be more realistic under a fire condition. For further understandings of polymer pyrolysis in the early stage of fire, the influences of ramped heat flux on pyrolysis of poly(methyl methacrylate) were experimentally and theoretically investigated. Linearly and quadratically ramped heat fluxes were controlled by the output power of a radiative heater. Surface temperature, mass loss rate, and ignition time were experimentally obtained to explore the thermochemical stability of poly(methyl methacrylate) under ramped heat fluxes. A one-dimensional model was used to predict the pyrolysis process, where kinetic parameters were evaluated by a genetic algorithm. Finally, ignition criteria including critical surface temperature and critical mass loss rate were revisited. We observed that the two ignition criteria give similar ignition time when the heat flux increases fast.

scholarly journals The Effect of the Heat Flux on the Self-Ignition of Oriented Strand Board

2017 ◽  
Vol 25 (40) ◽  
pp. 123-129 ◽  
Author(s):  
Siegfried Hirle ◽  
Karol Balog
Keyword(s):  
Heat Flux ◽  
Heat Flux Density ◽  
Loss Rate ◽  
Oriented Strand Board ◽  
Mass Loss Rate ◽  
The Self ◽  
Significant Information ◽  
Initiation Phase ◽  
Panel Methods ◽  
Time To Ignition

Abstract This article deals with the initiation phase of flaming and smouldering burning of oriented strand board. The influence of heat flux on thermal degradation of OSB boards, time to ignition, heat release rate and mass loss rate using thermal analysis and vertical electrical radiation panel methods were studied. Significant information on the influence of the heat flux density and the thickness of the material on time to ignition was obtained.

scholarly journals Effect of the Cone Heater Scale Compliant with the ISO 5660 Standard on Spatial Uniformity of Radiant Heat Flux

2020 ◽  
Vol 34 (5) ◽  
pp. 27-33
Author(s):  
Sanghoon Ryu ◽  
Sun-Yeo Mun ◽  
Cheol-Hong Hwang
Keyword(s):  
Heat Flux ◽  
Heat Release ◽  
Cone Calorimeter ◽  
Large Deviation ◽  
Mass Loss Rate ◽  
Radiant Heat ◽  
Radiant Heat Flux ◽  
Spatial Uniformity ◽  
Measurement Results ◽  
Physical Quantities

Physical quantities such as mass loss rate, heat release rate, and total heat release are often measured through a cone calorimeter (a representative bench-scale apparatus) and are primarily considered as values per unit area. Hence, the uniformity of radiant heat flux supplied by the cone heater to the specimen is very important with respect to the measurement results’ validity. In this study, on the basis of the ISO 5660 standard, the uniformity of radiant heat flux at the specimen surface was evaluated for the cone heaters used with the cone calorimeter. It is observed that a normal cone heater (NCH) compliant with the ISO 5660-1 standard satisfies the requirement of uniformity within a range of ± 2% in the central 5 cm × 5 cm area, but it has a large deviation of approximately 13% at the position corresponding to the edge of the specimen. In addition, the duration of NCH usage does not significantly affect the distribution of radiant heat flux. Furthermore, it is observed that a large cone heater compliant with the ISO/TC 5660-4 standard can supply moderately-uniform radiant heat flux over the entire surface area (10 cm × 10 cm) of the specimen.

scholarly journals An experimental study on crib fires in a closed compartment

2017 ◽  
Vol 21 (3) ◽  
pp. 1431-1441 ◽  
Author(s):  
Bhisham Dhurandher ◽  
Ravi Kumar ◽  
Amit Dhiman
Keyword(s):  
Heat Flux ◽  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Flame Temperature ◽  
Great Influence ◽  
Gas Temperature ◽  
Compartment Pressure ◽  
Burning Behavior ◽  
Length Width

An experimental investigation on burning behavior of fire in closed compartments is presented. Fire experiments were performed in a closed compartment of interior dimensions 4 ? 4 ? 4 m (length ? width ? height) with ply board cribs as fire source. The parameters including the gas temperature, mass loss rate, heat flux, flame temperature, and compartment pressure were measured during the experiments. Experimental results indicated that the providing sudden ventilation to the closed compartment had great influence on the behavior of fire. The mass loss rate of the burning crib increased by 150% due to sudden ventilation which results in the increase in heat release rate by 198 kW. From the perspective of total heat flux, compartment pressure, and gas temperatures closed compartment with sudden ventilation were more hazardous.

Critical heat flux and mass loss rate for extinction of flaming combustion of timber

2017 ◽  
Vol 91 ◽  
pp. 252-258 ◽  
Author(s):  
Richard Emberley ◽  
Tam Do ◽  
Jessica Yim ◽  
José L. Torero
Keyword(s):  
Heat Flux ◽  
Mass Loss ◽  
Critical Heat Flux ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Flaming Combustion

Influence of model assumptions on charring polymer decomposition in the cone calorimeter

2018 ◽  
Vol 36 (3) ◽  
pp. 181-201 ◽  
Author(s):  
Luc Murer ◽  
Sarah Chatenet ◽  
Gaelle Fontaine ◽  
Serge Bourbigot ◽  
Olivier Authier
Keyword(s):  
Heat Flux ◽  
Mass Loss ◽  
Cone Calorimeter ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Constant Volume ◽  
Radiative Heating ◽  
Gaseous Products ◽  
Time To Extinction ◽  
Polymer Decomposition

This article addresses the one-dimensional modeling of a charring polymer decomposition in the cone calorimeter used to reproduce at bench scale the radiative heating from a fire. The rate-controlling phenomena are first discussed in a preliminary analysis of dimensionless numbers. Then, the role of three critical assumptions is highlighted by simulations: (1) transport of the gaseous products within the material or instantaneous release of gaseous products, (2) volume variation or constant volume, and (3) absorption of applied heat flux at the exposed face or through the thickness. Their influence in thermally thick regime is shown in particular on mass loss rate and time to extinction. Under the conditions tested, the influence of internal transport by convection on mass loss rate and time to extinction is minor. The assumption of constant volume appears to have a moderate influence on the mass loss rate and time to extinction. Variations of optical properties affect the numerical results by an increase of the maximum peak of mass loss rate and a decrease of time to extinction. Finally, the effects of applied heat flux and initial material thickness on the mass loss rate and time to extinction are important. With a higher heat flux or a smaller thickness, the decomposition is earlier, faster, and more intense.

scholarly journals Experimental Study of Oriented Strand Board Ignition by Radiant Heat Fluxes

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 709
Author(s):  
Ivana Tureková ◽  
Iveta Marková ◽  
Martina Ivanovičová ◽  
Jozef Harangózo
Keyword(s):  
Heat Flux ◽  
Critical Heat Flux ◽  
Elevated Temperatures ◽  
Oriented Strand Board ◽  
Ignition Time ◽  
Radiant Heat ◽  
Heat Fluxes ◽  
Composite Panel ◽  
Substantial Part ◽  
Ignition Times

Wood and composite panel materials represent a substantial part of the fuel in many building fires. The ability of materials to ignite when heated at elevated temperatures depends on many factors, such as the thermal properties of materials, the ignition temperature, critical heat flux and the environment. Oriented strand board (OSB) without any surface treatment in thicknesses of 12, 15 and 18 mm were used as experimental samples. The samples were gradually exposed to a heat flux of 43 to 50 kW.m−2, with an increase of 1 kW.m−2. At heat fluxes of 49 kW.m−2 and 50 kW.m−2, the ignition times are similar in all OSB thicknesses, in contrast to the ignition times at lower heat fluxes. The influence of the selected factors (thickness and distance from the heat source) was analysed based on the experimentally obtained data of ignition time and weight loss. The experimentally determined value of the heat flux density was 43 kW.m−2, which represented the critical heat flux. The results show a statistically significant effect of OSB thickness on ignition time.

Sign in / Sign up

Export Citation Format

Share Document