| 1. |
- Andrés Valiente, Blanca
(författare)
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A multi-scale approach for predicting the fire response of building barriers
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Building barriers are compartmentation elements in buildings that limit the passage of fire and smoke to adjacent spaces. They are key elements in the overall response of a building in a fire. The adequate fire response of building barriers is usually assessed by the fulfilment of standardized resistance to fire tests. However, building fire barriers might be exposed to very different fire scenarios than traditional standardized fire tests. The work presented in the thesis consists on an experimental and numerical methodology to use the material thermal properties obtained through reduced scale testing to model the fire response of building barriers in larger scales. The methodology is applied to gypsum-stone wool and steel stone-wool layered composites. The characterization of stone wool properties at micro-scale is conducted with thermogravimetric analysis, micro combustion calorimetry and bomb calorimetry. The thermal conductivity of stone wool is obtained with modified slug calorimetry. At a composite scale samples are exposed to different heating exposures using radiant panels (H-TRIS), reduced scale furnace and full-scale furnace. The different heat exposures allow for identifying thermal degradation phenomena. Heat transfer models are developed increasing in complexity to account for the different phenomena. Those include: heat transfer, heat and mass transfer, kinetic reactions to account for the combustion of the organic content of the stone wool, kinetic reaction to account for the calcination reactions in the gypsum and the paper lining burning. An analysis of the uncertainties linked to assumptions in the input parameters for thermal modelling in standard fire tests is also presented. Finally, the degradation of the mechanical properties of gypsum plasterboard in fire are studied by performing three-point bending tests to pre-heated samples.
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| 2. |
- Andrés Valiente, Blanca, et al.
(författare)
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Experimental and thermal analysis of wall assemblies exposed to standard and parametric fires
- 2015
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Ingår i: First International Conference on structural safety under fire and blast (CONFAB). - 9780993012129
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Konferensbidrag (refereegranskat)abstract
- The aim of this study is to assess the effect that different fire exposures have on the behaviour of gypsum plasterboard assemblies with known fire resistance rating. For this purpose a series of fire tests were performed on commonly used wall assemblies. Four different small scale samples were tested under ISO 834 and HCC standard fire curves. Additionally, one assembly was tested in an enclosure, with a pool fire used as a heat source. The results show that although there is a higher temperature exposure in HCC, the time criterion for standard classification is fulfilled in the small scale tests. A steeper rise of the temperature on the unexposed side for the HCC appears after 65 minutes in the worst case. In the pool fire test the highest temperature values measured on the unexposed side are closer to the values obtained in the HCC test, while the lower are below the ISO 834 results. 2D-heat transfer analysis was conducted on one of the assemblies tested. The aim was to evaluate if empirical thermal properties commonly assumed to model ISO 834 fire exposures are adequate for modelling other temperature-time exposures. The results show a need of further investigation on the thermal properties.
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| 3. |
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| 4. |
- Livkiss, K., et al.
(författare)
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Uncertainties in modelling heat transfer in fire resistance tests : A case study of stone wool sandwich panels
- 2017
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Ingår i: Fire and Materials. - : Wiley. - 0308-0501. ; 41:7, s. 799-807
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Tidskriftsartikel (refereegranskat)abstract
- Modelling fire performance of building fire barriers would allow optimising the design solutions before performing costly fire resistance tests and promote performance-based fire safety engineering. Numerical heat conduction analysis is widely used for predicting the insulation capability of fire barriers. Heat conduction analysis uses material properties and boundary condition parameters as the input. The uncertainties in these input parameters result in a wide range of possible model outcomes. In this study, the output sensitivity of a heat conduction model to the uncertainties in the input parameters was investigated. The methodology was applied to stone wool core sandwich panels subjected to the ISO 834 standard fire resistance temperature/time curve. Realistic input parameter value distributions were applied based on material property measurements at site and data available in literature. A Monte Carlo approach and a functional analysis were used to analyse the results. Overall, the model is more sensitive to the boundary conditions than to the material thermal properties. Nevertheless, thermal conductivity can be identified as the most important individual input parameter.
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