OPEN ACCESS
This work proposes an experimental and numerical method to determine char-layer and temperature in pine wood at high temperatures. The elevated temperature in the wood is due to an anaerobic heating process. A thermal unit and electro-ceramic resistance are used during experimental tests to simulate elevated temperatures in wood profi les. Wood samples have been manufactured for experimental tests. To ensure greater efficiency in the heating process, it is necessary to insulate the wood samples. A numerical method that predicts the thermal degradation of wood exposed to high temperatures is used. A non-linear thermal and transient analysis is conducted using the finite element method. Numerical results are obtained to determine temperature fi elds and char-layer in wood profi les under same con-ditions. The char-layer is calculated for pine wood profi les (Pinus pinaster) through this study. This parameter is important in safety design because it determines how cross-section size decreases to criti-cal external conditions. These methodologies could be used to assess the performance time of wood material, during exposure to high temperatures or in fi re conditions.
char-layer, heating process, high temperatures, pine wood
[1] Schaffer, E.L., Charring Rate of Selected Woods Transverse to Grain. Research paper FPL 69. Forest Products Laboratory: Madison (WI), 1967.
[2] White, R.H., Charring Rates of Different Wood Species. PhD Dissertation, Madison University of Wisconsin, Madison (WI), 1988.
[3] White, R.H., Erik, V. & Nordheim, E.V., Charring rate of wood for ASTM E119 exposure. Fire Technol, 28(1), pp. 5–30, 1992. doi:10.1007/BF01858049
[4] Konig, J. & Walleij, L., One-dimensional charring of timber exposed to standard and parametric fires in initially unprotected and postprotection situations. Swed Inst Wood Technol Res, 48, 1999.
[5] Gardner, W.D. & Syme, D.R., Charring of glued-laminated beams of eight australiangrown timber species and the effect of 13 mm gypsum plasterboard protection on their charring. N.S.W. Technical report no. 5. Sydney, 1991.
[6] Collier, P.C.R., Charring rates of timber. Study report, Branz, New Zealand, 1992.
[7] Pun, C.Y., Seng, H.K., Midon, M.S. & Malik, A.R., Timber design handbook. FRIM, Malayan Forest Records no. 42, 1997.
[8] Fonseca, E.M.M. & Barreira, L., Charring Rate Determination of Wood Pine Profiles Submitted to High Temperatures. Third International Conference on Safety and Security Engineering, ed. M. Guarascio, C.A. Brebbia & F. Garzia, WIT Press: Italy, pp. 449–457, 2009. ISBN: 978-1-84564-193-1.
[9] Poon, L. & England, J.P., Literature Review on the Contribution of Fire Resistant Timber Construction to Heat Release Rate – Timber Development Association, Warrington Fire Research Aust. Pty. Ltd., Project No.20633, version 2b, pp. 1–78, 2003.
[10] Weng, W.G., Hasemi, Y. & Fan, W.C., Predicting the pyrolysis of wood considering char oxidation under different ambient oxygen concentrations. Combustion and Flame, 145, pp. 723–729, 2006. doi:10.1016/j.combustflame.2005.12.016
[11] Frangi, A., Erchinger, C. & Fontana, M., Charring model for timber frame floor assemblies with void cavities. Fire Safety Journal, 43, pp. 551–564, 2008. doi:10.1016/j.firesaf.2007.12.009
[12] White, R.H. & Dietenberger, M.A., Fire Safety, Chapter 17, Wood Handbook: Wood as an Engineering Material, Forest Products Laboratory, USDA Forest Service, 1999.
[13] [EN 1995-1-2] prEN 1995-1-2. Eurocode 5: Design of Timber Structures, Part 1–2: general-structural fire design, CEN, Brussels, 2003.
[14] Njankouo, J.M., Dotreppe, J.C. & Franssen, J.M., Fire resistance of timbers from tropical countries and comparison of experimental charring rates with various models. Construction and Building Materials, 19, pp. 376–386, 2005. doi:10.1016/j.conbuildmat.2004.07.009
[15] Hakkarainen, T., Mikkola, E., Ostman, B., Tsantaridis, L., Brumer, H. & Piispanen, P., InnoFireWood-Innovative Eco-efficient High Fire Performance Wood Products for Demanding Applications, VTT, SP Tratek, KTH, 2005.
[16] Barreira, L. & Fonseca, E., Cálculo da Espessura Carbonizada em estruturas de Madeira Quando Submetidas à Ac玢o do Fogo, II Conferencia Nacional de Metodos Numericos em Mecanica de Fluidos e Termodinamica’08, Proceedings, Aveiro, 2008.
[17] Janssens, M.L., Modeling of the thermal degradation of structural wood members exposed to fire. Fire and Materials, 28, pp. 199–207, 2004. doi:10.1002/fam.848
[18] Spearpoint, M. & Quintiere, J., Predicting the burning of wood using an integral model. Combustion and Flame, 123, pp. 308–325, 2000. doi:10.1016/S0010-2180(00)00162-0
[19] Bamford, C., Crank, J. & Malan, D., The combustion of wood, Part I. Proceedings of the Cambridge Philosophical Society, 42, pp. 166–182, 1946. doi:10.1017/S030500410002288X