Krízový manažment - Ročník 22.; Číslo 1/2023
Permanent URI for this collectionhttps://drepo.uniza.sk/handle/hdluniza/837
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Item Analýza rizika iniciácie usadenej vrstvy prachu smreka vybranými iniciačnými zdrojmi(Žilinská univerzita v Žiline, 2023) Tureková, Ivana; Marková, IvetaThe article evaluates the minimal initiation temperature and hot surface temperature of the spruce dust layer using selected ignition sources. The influence of selected physical properties of wood dust, the size of the contact area between the ignition source and the combustible material, the ignition time, and the thermally degraded area are monitored. The article describes the behaviour of a 15 mm beech dust layer (Beech Fagus silvatica L.) under the action of three potential initiating sources: a hot surface, an electric spiral, and a smouldering cigarette. Prior to the experimental determination of the minimum ignition temperature, the dust moisture was determined and the sieve analysis was performed. The lowest minimum ignition temperature on the hot plate was 280 °C. The ignition mechanism of wood dust was comparable for all initiators investigated, differing in the ignition time and the area of the thermally degraded layer. The least effective was the initiating source of the smouldering cigarette.Item Vplyv tepelného toku a retardérov horenia na proces iniciácie drevných materiálov(Žilinská univerzita v Žiline, 2023) Harangózo, Jozef; Tureková, IvanaThe paper studies the effects of heat flow on the flammability of wood materials when flame retardants are applied. Beech and spruce wood samples were treated with phosphorus- and carbon-based flame retardants, namely NH4H2PO4 and KHCO3 salts. Retarders were applied by spraying them on the surface of the samples. After their thermal stabilization, the parameter time until the sample ignited when exposed to the action of a radiation panel set to a maximum power of 15 kW was investigated. The results were recorded at different distances of 50, 70, and 100 mm from the radiation panel. KHCO3 was identified as the retarder with the highest efficiency based on the obtained measurements. Thermal decomposition analysis indicated that the improvement in flame retardancy of the treated wood was achieved by dehydration of the polysaccharides and the formation of a protective char shield due to the cessation of heat and oxygen transfer.Item Sledovanie vplyvu tepelného toku a hrúbky drevených dosiek na čas zapálenie(Žilinská univerzita v Žiline, 2023) Marková, Iveta; Tureková, Ivana; Ivaničová, Martina; Jaďuďová, JanaOriented strand boards (OSB) and particleboards (PB) are wooden boards, commonly used in building structures or building interiors. The surface of boards may hence become directly exposed to fire or radiant heat. The aim of this paper is to evaluate the behaviour of uncoated particleboards and OSB exposed to radiant heat. The following ignition parameters: heat flux intensity (from 43 to 50 kW.m-2) and ignition temperature were used to observe the process of particleboard and OSB ignition. The time-to-ignition of particleboards and OSB with a thickness of 12, 15, and 18 mm were monitored and compared. The experiments were conducted on a modified device in accordance with ISO 5657:1997. Results confirmed the thermal degradation of samples. Heat flux had a significant effect on time-to-ignition. OSB had a higher ignition time than particleboards and the thermal degradation of OSB started later, i.e., at a higher temperature than that of particleboards, but OSB also had a higher mass loss than particleboards. The samples yielded the same results above 47 kW.m-2 .