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Abstract: Recent high-profile fires involving combustible façades have exposed significant gaps in both the understanding and regulation of external wall systems. Modern façade designs frequently employ polymers as insulation and/or laminated composite materials that, while improving energy efficiency, can inadvertently create pathways for vertical fire spread. Thus, there is a need to establish fundamental principles for evaluating the fire spread performance of these systems. Drawing on notable incidents, it is shown how uncontrolled flame spread can defeat compartmentation strategies, compromise occupant egress, and overwhelm firefighting efforts. Extending on previous studies, a performance-based approach to fire spread is proposed, examining four levels of relevance: material properties, product characteristics, assembly configuration, and overall building context. Key factors include combustibility, ventilation effects, and real-world variables (e.g., building characteristics). Case studies of testing methods illustrate both utility and limitations in capturing metrics relevant to façade design. Ultimately, it is advocated that there is an urgent need for rigorous, tailored assessment protocols supported by professional competence, thereby ensuring that complex external wall systems can be designed and managed to balance fire safety with sustainability and safety objectives.
Keywords: fire safety, facades, external wall systems, fire spread
Published in DiRROS: 28.11.2025; Views: 45; Downloads: 27
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Keywords: nutrition claims, health claims, consumer understanding, multiple sort procedure, health claim typology
Published in DiRROS: 18.11.2025; Views: 125; Downloads: 56
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Abstract: Titania nanoparticles were synthesized by employing the hydrothermal method and using TiOSO4as a titanium source. By varying pH between 0.5 and 1.0 and adding isopropanol to the hydrothermal reaction mixture, different mixtures of anatase, rutile, and brookite were obtained. The samples were also doped with nitrogen at different N concentrations using, respectively, urea, ammonium nitrate, and tripropylamine as nitrogen sources. The samples were characterized by X-ray powder diffraction, field emission scanning electron microscopy, infrared spectroscopy, UV-Vis diffuse reflectance spectroscopy and according to their specific surface area. Additionally, their photocatalytic activity was measured in a gas-solid reactor system. The results show that low pH favours rutile formation, whereas a higher pH yields mixed phase titania polymorphs. Isopropanol addition also favours rutile formation, and boosted the photocatalytic activity of the resulted particles. Contrary to most data in the literature, rutile turned out to be the more active phase in the present investigation. Nitrogen doping, on the other hand, did not contribute to higher photocatalytic activity, but was rather detrimental to it.
Keywords: titanium dioxide, rutile, hydrothermal synthesis, photocatalysis, nitrogen doping
Published in DiRROS: 26.09.2025; Views: 287; Downloads: 113
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Abstract: Atmospheric pressure plasma jet was employed to improve adhesion between polypropylene (PP) column wall and monolith used in chromatography. Different treatment conditions for modification of PP tube were used and the effects of treatment were analysed with X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Modified surfaces had higher oxygen content and surface was covered with small grain like structures. To explore effects of modification on adhesion between PP tube and monolith tensile strength measurements were conducted. It was shown that appropriate treatment conditions significantly increased bonding strength. The improvement of adhesion was attributed to increased oxygen functional groups obtained from plasma.
Published in DiRROS: 05.09.2025; Views: 250; Downloads: 112
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Abstract: 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.
Keywords: timber structures, fire safety, charring, zero-strength layer, cooling
Published in DiRROS: 16.07.2025; Views: 362; Downloads: 247
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