WOOD RESEARCH Volume 71, Number 2, 2026
JAKUB BACA and PETER RANTUCH

The influence of gypsum board claddings and fasteners on the thermal degradation of a timber substrate

This article deals with the influence of gypsum board cladding and mechanical fastening on the thermal degradation of a timber substrate exposed to external radiant heat flux. Test specimens consisting of spruce wood protected by either standard gypsum board or fire-rated gypsum board were exposed to a heat flux of 50 kW·m⁻² in a cone calorimeter. Temperature development was monitored using thermocouples placed at the gypsum board–wood interface and inside the timber element within a pre-drilled hole with a diameter of 1 mm. In addition, thermogravimetric analysis of the individual components of the tested assembly was performed. The results indicate that the dehydration of gypsum significantly slows down heat transfer to the timber substrate. Samples protected by fire-rated gypsum board showed a slower temperature increase, lower CO production, and a greater residual thickness of timber compared to samples with standard gypsum board. No significant effect of the screw on temperature development or residual timber thickness was observed.

WOOD RESEARCH Volume 70, Number 4, 2025
RENÁTA KUTLÁKOVÁ, PETER RANTUCH, JOZEF MARTINKA, MARGARÉTA TIBENSKÁ, TOMÁŠ ŠTEFKO, and IGOR WACHTER

CHARACTERIZATION OF IGNITION PROCESS OF THERMALLY TREATED WOOD BY CONE CALORIMETER

This study examines the influence of thermal treatment on the ignition properties of Norway spruce (Piceaabies (L.) H. Karst.) and sessile oak (Quercus petraea (Matt.) Liebl.) wood. Using a cone calorimeter both untreated and thermally modified samples (180°C for 6 h) were analysed to determine key fire modelling parameters: combustion efficiency, critical heat flux, ignition temperature, thermal inertia, and thermal response parameter. Obtained results reveal that thermally treated wood exhibits higher combustion efficiency than its untreated equivalent, with spruce generally outperforming oak. The effect of thermal treatment on other properties was species-dependent. Thermally treated spruce showed an increase in critical heat flux and a decrease in both thermal inertia and the thermal response parameter. Conversely, thermally treated oak displayed a reduction in critical heat flux and an increase in both thermal inertia and the thermal response parameter. These results highlight the complex, species-specific effects of thermal modification on the fire behaviour of wood.

WOOD RESEARCH Volume 67, Number 6, 2022
Chao Deng, Yang Liu, Junxian Xu, Xiangyu Li, Mingyu Wen, Xixin Duan, and Heejun Park

Fire retardant performance of sugi and hinoki treated with phosphorus and nitrogen fire retardant

In this paper, ammonium phosphate polymer (APP), guanidinium phosphate urea (GUP), phosphonic acid, and a small number of additives that confer flame retardant properties were prepared as a new composite flame retardant. Cedar (Cryptomeria japonica) and hinoki (Chamaecyparis obtuse) penetrate and absorb the solution into the inner wall of the wood by vacuum pressurization, thus obtaining fire-retardant woods. The flame retardant effects at different absorption amounts were investigated by thermogravimetric analysis and cone calorimetry. The absorption amounts of both kinds of wood above 0.095 g.cm-3 and 0.085 g.cm-3 respectively, met the flame retardant standard ISO-5660-1: 2015. Thermogravimetric analysis showed that the fire-retardant-treated wood increased thermal stability, accelerated carbonization, and lower the decomposition temperature to below 300°C.

WOOD RESEARCH Volume 62, Number 6, 2017
PETER RANTUCH, Ivan Hrušovský, JOZEF MARTINKA, Karol Balog, and Siegfried Hirle

Determination of the critical heat flux for floating flooring

The paper deals with the possibility of floating flooring ignition due to radiant heat. Samples of floating flooring with dimensions of 100 ± 1 mm x 100 ± 1 mm and thickness of 6 mm were thermally loaded by different densities of external heat flux. The flaming combustion was initiated either solely by means of radiant heat, or in combination with electric spark igniter. Cone calorimeter was used for the determination of the critical heat flux. Time to ignition for each sample was recorded and the obtained data were used for the calculation of the critical heat flux density.