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- Försth, Michael, et al.
(författare)
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Characterization of the thermal exposure in the en 50399 cable test apparatus
- 2015
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Ingår i: Fire and Materials 2015, 2-4 Feb 2015, San Francisco, USA. - : Interscience Communications. - 9780000000002 ; , s. 23-37
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Konferensbidrag (refereegranskat)abstract
- The EN 50399 cable test is used for classification of cables within the European construction products regulation. Means to predict a cables performance in this test, based on material data and small scale test results is of great value for the development of new cable materials. A first step in developing a prediction tool should be to understand the heat exposure on the cables in the EN 50399 test apparatus. The heat load in e.g. the cone calorimeter is very well characterized whereas for EN 50399 only the burner power (20.5 kW) is known. In the cone calorimeter the heating is solely by radiation, whereas for the EN 50399 test a large fraction of the heat exposure depends on feed-back from the cable fire. This paper presents a measuring method for characterizing the thermal exposure inside the EN 50399 cable test apparatus without cables and with a cable rated Euroclass Dca. A new instrument for measuring thermal exposure simultaneously in several directions was developed for the purpose, and thereby the non-isotropic exposure on the cables at different position on the ladder could be investigated
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- Girardin, Bertrand, et al.
(författare)
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Characterization of thermo-physical properties of EVA/ATH : Application to gasification experiments and pyrolysis modeling
- 2015
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 8:11, s. 7837-7863
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Tidskriftsartikel (refereegranskat)abstract
- The pyrolysis of solid polymeric materials is a complex process that involves both chemical and physical phenomena such as phase transitions, chemical reactions, heat transfer, and mass transport of gaseous components. For modeling purposes, it is important to characterize and to quantify the properties driving those phenomena, especially in the case of flame-retarded materials. In this study, protocols have been developed to characterize the thermal conductivity and the heat capacity of an ethylene-vinyl acetate copolymer (EVA) flame retarded with aluminum tri-hydroxide (ATH). These properties were measured for the various species identified across the decomposition of the material. Namely, the thermal conductivity was found to decrease as a function of temperature before decomposition whereas the ceramic residue obtained after the decomposition at the steady state exhibits a thermal conductivity as low as 0.2 W/m/K. The heat capacity of the material was also investigated using both isothermal modulated Differential Scanning Calorimetry (DSC) and the standard method (ASTM E1269). It was shown that the final residue exhibits a similar behavior to alumina, which is consistent with the decomposition pathway of EVA/ATH. Besides, the two experimental approaches give similar results over the whole range of temperatures. Moreover, the optical properties before decomposition and the heat capacity of the decomposition gases were also analyzed. Those properties were then used as input data for a pyrolysis model in order to predict gasification experiments. Mass losses of gasification experiments were well predicted, thus validating the characterization of the thermo-physical properties of the material. © 2015 by the authors; licensee MDPI, Basel, Switzerland.
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- Girardin, Bertrand, et al.
(författare)
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Measurement of kinetics and thermodynamics of the thermal degradation for flame retarded materials : Application to EVA/ATH/NC
- 2017
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Ingår i: Journal of Analytical and Applied Pyrolysis. - : Elsevier BV. - 0165-2370 .- 1873-250X. ; 124, s. 130-148
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Tidskriftsartikel (refereegranskat)abstract
- The modelling of the behavior of a material exposed to fire is very complex and needs the coupling of fluid dynamics, combustion, heat and mass transfer, kinetics and so forth. A growing amount of studies and numerical models are reported in this field since the last decade. The aim of these models is to predict the fire behavior of wood, charring or non-charring polymers and even intumescent materials. However, these studies are seldom applied to formulated materials and especially flame retarded materials. In this study, an ethylene-vinyl acetate copolymer was formulated with a flame retardant (aluminum tri-hydroxide) and a synergist (nanoclays). A systematic approach for the characterization of the thermo-physical properties of the material as well as of its optical properties and the heat capacity of the decomposition gases is proposed and applied in this study. It is shown that it is possible to evaluate the input data required for pyrolysis modelling, even for multi decomposition steps materials. It is also shown that the diffusion of the gases inside the material had to be considered on the opposite of the classical assumption found in other studies. Indeed, using low mass diffusivity was the sole way to predict in the same time the temperature distribution and the mass loss rate of the material in a gasification experiments.
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