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Povzetek: In comparison to non-combustible construction materials commonly used for taller buildings, timber elements can significantly alter the fire dynamics in a compartment. This fundamentally challenges many of the conventional fire safety strategies and design approaches for mid-rise and high-rise buildings. Consequently, many building industry practitioners are questioning the limitations of existing methodologies, while searching for additional ways to account for this different fire behaviour in the design, construction, and operation of timber buildings. In seeking to address these questions, this chapter describes the state-of-the-art and recent advances in understanding the fire behaviour in compartments with areas of exposed timber (e.g., engineered wood products), and protected timber elements that may contribute to the fire if their encapsulation fails. Relevant experimental findings and engineering approaches to date are summarised and discussed, and design guidance is provided in relation to the typical phases of realistic or ‘natural’ fires, namely the growth phase, the fully-developed phase, the fire decay, and the cooling phase. Critical fire phenomena and their impacts on the fire safety strategy are addressed, such as fire spread; active fire suppression; heat induced delamination and char fall-off; and self-extinguishment.
Ključne besede: timber, fire dynamics, fire safety, self-extinguishment, heat induced delamination, char fall-off
Objavljeno v DiRROS: 18.11.2025; Ogledov: 212; Prenosov: 83
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Povzetek: This study investigates fire-induced charring and thermal penetration in structural timber elements exposed to natural fire conditions, with a focus on the critical role of the cooling phase. A simplified 1D heat transfer model, based on Eurocode 5 temperature-dependent material properties, is implemented to simulate the thermal response of timber members subjected to Eurocode parametric fire curves. The analysis quantifies the char depth (300 °C isotherm) and the zero-strength layer, using both temperature-based (80-300 °C and 120-300 °C) and reduced mechanical properties approaches (tension and compression). Results show that, while the char depth predominantly develops during the heating phase, the zero-strength layer continues to grow during cooling, often reaching a thickness comparable to the char layer. The effective char depth (char depth + zero-strength layer) typically reaches its maximum towards the end of the cooling phase, representing the most critical condition for load-bearing capacity. The most severe conditions arise in low ventilation and high fuel load scenarios, characterised by long-duration fires rather than the highest temperatures. The findings highlight the need to explicitly consider the cooling phase in performance-based fire design for timber structures.
Ključne besede: timber structures, fire safety, charring, zero-strength layer, cooling
Objavljeno v DiRROS: 16.07.2025; Ogledov: 429; Prenosov: 281
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Povzetek: Photovoltaic (PV) systems play an important role in reducing society’s dependence on carbon-based energy sources, and their coupling with timber buildings is an interesting and expected solution for meeting sustainability requirements in the modern built environment. However, both PV systems and timber structures have unique fire safety challenges, and their combination may introduce additional risks. Therefore, relevant fire hazards associated with each of the technologies and their pairing are discussed. The findings highlight the importance of revising fire testing standards and developing tailored safety measures to identify and manage these risks.
Ključne besede: fire safety, timber buildings, photovoltaics, sustainability
Objavljeno v DiRROS: 17.03.2025; Ogledov: 835; Prenosov: 545
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Povzetek: Fire resistance tests rely on the use of standardized furnaces to apply specific thermal boundary conditions to assess the performance of construction materials and systems in fire conditions. However, these tests are very expensive and encounter challenges related to repeatability and uncertainties in establishing thermal boundary conditions. Moreover, their incapacitance to tailor experiments hinders advancements in understanding structural behaviour during fire exposure. In this work, a novel type of radiant panel, that operates on electricity, is introduced: the High-Intensity Fast-Response Electric radiant Panel (HIFREP). This innovation offers enhanced sustainability performance while ensuring more precise control over thermal boundary conditions. By eliminating the need for gas combustion, the panel can be used in a traditional structural testing lab to investigate non-combustible materials (e.g. concrete), without requiring extraction hoods and other provisions. The presented electric radiant panel system represents a significant step forward from fire resistance furnace testing.
Ključne besede: radiant panel, fire testing, heat transfer, radiation, heat flux, fire safety, thermal boundary conditions
Objavljeno v DiRROS: 19.12.2024; Ogledov: 806; Prenosov: 433
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Povzetek: In this study, the effects of natural fire exposure on the post-fire behavior of concrete beams are investigated. The study is based on laboratory tests where three reinforced concrete beams were subjected to fire exposure using an electric radiant panel. This panel enables a precise application of radiative heat exposure closely mimicking natural fire exposure in a safe manner. During the test, the deflections, deformations and temperature changes are measured for all three concrete beams. Additionally, finite element modeling (FEM) is applied to supplement these tests, demonstrating the performance of existing structural fire engineering calculation tools in evaluating the burnout performance of concrete beams. The results of the tests show that the electric radiant panel provide a novel approach for fire simulation which is effective in replicating natural fire conditions, by applying the heat flux as specified in the Eurocode Parametric Fire Curve in a highly controlled manner. The uniformity of the temperature field measured inside the beams and the consistent deformations observed during the heat exposure across all three tests underscores the accuracy of the fire simulation. Furthermore, post-fire assessments reveal that while the exposed beams suffered some reduction in load-bearing capacity, they retained a significant portion of their original strength that was consistent across all three beams. The numerical simulations conducted in this study demonstrate a high level of accuracy in predicting the behavior of the concrete beams during fire exposure. These simulations effectively mirrored the experimental results, validating that they are a valuable tool for assessing concrete structures' performance in fire scenarios.
Ključne besede: concrete beam, fire testing, numerical modeling, radiant panel
Objavljeno v DiRROS: 28.11.2024; Ogledov: 856; Prenosov: 337
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