Numerical Study on Sample Thickness Dependence of Fire Response Properties of Polymeric Materials (Charring and Non-charring) in Standard Cone Calorimeter Test
01 Nov 2019-pp 929-939
TL;DR: In this paper, the effect of sample thickness on fire response parameters of polymeric materials was investigated for both charring and non-charring polymeric polymers, and it was shown that properties such as peak mass loss rate, time to peak mass losses, average mass loss rates, and time to ignition vary with sample thickness.
Abstract: In standard cone calorimeter test fire response properties like time to ignition, peak mass loss rate, time to peak mass loss rate, average mass loss rate and burn out time are of interest. The ASTM 1354 [1] recommends sample thickness of less than 50 mm for the test. However, for thinner samples conditions on the unexposed side of the sample should represent actual conditions in real-life application as the test results may be affected by these conditions. Therefore, in this work, a numerical study is carried out to predict the effect of sample thickness on the fire response parameters of polymeric materials. Polymeric materials are broadly classified as charring (thermoset) and non-charring (thermos-plastic). A representative material in each category, namely CPVC (Chlorinated Polyvinyl Chloride) for charring polymer and PMMA (Poly Methyl Metha-Acrylate) for non-charring is studied. It was noted that properties like the peak mass loss rate, time to peak mass loss rate, average mass loss rate and time to ignition vary with sample thickness for both charring and non-charring polymer. These property values become constant for sample thicknesses beyond a certain value. The variation in properties is dependent on the condition on the backside of the sample. When an aluminium block was assumed to have been placed below the sample, the property variation was different from when an adiabatic condition was assumed. The fire response properties for charring and non-charring materials also exhibited different trends.
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TL;DR: In this article, the pyrolysis gas products of chlorinated polyvinyl chloride (CPVC) are first discussed based on thermogravimetry-Fourier transform infrared spectra-mass spectrometry (TG-FTIR-MS) analysis.
Abstract: The pyrolysis gas products of chlorinated polyvinyl chloride (CPVC) are first discussed based on thermogravimetry–Fourier transform infrared spectra–mass spectrometry (TG–FTIR–MS) analysis. The results of TG–FTIR preliminarily show that CPVC pyrolysis can be divided into two stages: the main gas products or functional groups are hydrogen chloride (HCl), chlorinated compounds, alkanes, alkenes and aromatic compounds in Stage I, while alkanes, aromatic compounds and alkenes in Stage II. By coupling MS, the main products can be further refined into hydrogen chloride and benzene in Stage I, while homologues, derivatives and polycyclic aromatic compounds of benzene (xylene and ethylbenzene, chlorobenzene and 1-chloronaphthalene, naphthalene and fluorene and so on) in Stage II. Moreover, compared with the pyrolysis gas products of PVC, chlorine is not completely converted into hydrogen chloride, and some of it is converted into other chlorinated compounds. Based on the above results, the possible reactions from molecular structure during CPVC pyrolysis are also put forward. Furthermore, the CPVC combustion properties and smoke production in cone calorimeter experiment are analyzed by the measured mass loss rate, heat release rate, smoke and CO/CO2 production rate.
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References
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TL;DR: In this article, the authors provide guidance in the use and interpretation of cone calorimetry for those directly involved with such measurements, and discuss the fire scenario with respect to applied heat flux, length scale, temperature, ventilation, anaerobic pyrolysis and set-up represented by the cone.
Abstract: There is little consensus within the fire science community on interpretation of cone calorimeter data, but there is a significant need to screen new flammability modified materials using the cone calorimeter. This article is the result of several discussions aiming to provide guidance in the use and interpretation of cone calorimetry for those directly involved with such measurements. This guidance is essentially empirical, and is not intended to replace the comprehensive scientific studies that already exist. The guidance discusses the fire scenario with respect to applied heat flux, length scale, temperature, ventilation, anaerobic pyrolysis and set-up represented by the cone calorimeter. The fire properties measured in the cone calorimeter are discussed, including heat release rate and its peak, the mass loss and char yield, effective heat of combustion and combustion efficiency, time to ignition and CO and smoke production together with deduced quantities such as FIGRA and MARHE. Special comments are made on the use of the cone calorimeter relating to sample thickness, textiles, foams and intumescent materials, and the distance of the cone heater from the sample surface. Finally, the relationship between cone calorimetry data and other tests is discussed. Copyright © 2007 John Wiley & Sons, Ltd.
1,116 citations
TL;DR: In this paper, a review of the progress that has been made to the understanding of chemical and physical processes, which occur during combustion of solid fuels, is presented, and the effects of bubble formation on the transport of volatiles during thermal degradation of non-charring fuels, described through a one-step global reaction, have been modeled.
434 citations
TL;DR: In this paper, the onset of piloted ignition of combustible polymers is predicted by a gas phase combustion energy density of 1.9 MJ/m 3 that describes the lower flammability limit of fuel vapor-air mixtures.
121 citations
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01 Jan 2016
TL;DR: This chapter outlines features and details of today’s preferred instrument for measuring bench-scale HRR—the cone calorimeter.
Abstract: Chapter 27 describes the history and development of techniques for measuring heat release rate (HRR). This chapter outlines features and details of today’s preferred instrument for measuring bench-scale HRR—the cone calorimeter. Other cone calorimeter measuring functions are
95 citations