Monitoring the Thermal Degradation of Two Spruce Species, (Picea abies L., Picea rubens Sarg.), Cherry (Prunus avium), and Oak (Quercus spp.) Under the Influence of Radiant Heat

Wood, in the form of cladding or furniture, is often placed in close proximity to heat radiant sources. This research focused on samples, which are Norway spruce (Picea abies L.), Red spruce (Picea rubens Sarg.), cherry (Prunus avium), and oak (Quercus spp.). The aim of this paper was to observe the effect of the distance of the selected wood samples from the radiant heat source on the process of thermal degradation of wood. Additionally, this research aimed to identify significant effects of wood species and sample distance on this process. A hot-plate device, an electric plate heated according to a temperature–time curve, was used as the initiating source. Samples were placed directly on the plate, as well as at two different distances from the plate (12 and 32 mm). During the experiment, the temperature history on the heat-exposed side of the sample, its mass loss, and the formation of a charred layer were monitored. Additionally, the progression of thermal degradation and related effects (smell, smoldering, and charring layer) were visually observed. The highest level of degradation was observed in the spruce sample placed directly on the plate, which started to smolder after 540 s of exposure to radiant heat at 291.2 °C.