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This study deals with the investigation of impact of temperature and ultraviolet (UV) radiation on spruce wood (Picea abies(L.) H. Karst.) and fir wood (Abies albaMill.) colour changes. Samples of investigated woods species were loaded by temperatures of 110, 130, and 150°C and UV radiation (with 253.7 nm wavelength and 40 W m-2intensity) during 72, 168, 336 and 672 hours. Colour changes were evaluated in the CIE Lab colour space. Theneural network for prediction of both colour coordinates and total colour difference of spruce and fir wood was trained by data regarding exposure conditions (temperature, UV radiation and time) and by obtained results. Coefficient of determination (R2) of the neural network was above 0.99 for training, validation and testing. Average colour coordinates (±standard deviation) of the spruce and fir wood before exposure were L* = 80.08 ± 3.70,a* = 7.55 ± 2.13, b* = 21.56 ± 1.79, L* = 80.46 ± 1.91, a* = 6.84 ± 0.97, and b* = 18.90 ± 1.26, resp. Total colour differences after thermal loading were in the interval from ΔEab* = 3.76 ± 1.95 (spruce wood at 110°C) to ΔEab* = 45.37±1.46 (fir wood at 150°C). Total colour differences of both wood species exposed by UV radiation were approximately in intervals from ΔEab* = 12 to 13 (after 72 h) up to ΔEab* = 16 to 20 (after 168 to 672 h). Obtained results proven that both temperature and UV radiation have significant impact on the colour changes of the investigated woods.

Fire-retardant (FR) treated wood-based panels, used commonly in furniture and construction, need to meet stringent fire safety regulations. This study presents a novel treatment for imparting fire resistance to wood composites by applying separate solutions of phytic acid and sodium silicate onto wood particles before the hot pressing at 160 °C. A scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) analysis revealed that phytic acid and sodium silicate were uniformly distributed throughout the wood particles, and the formation of silica gel resulted in the aggregation of elemental silicon. Fourier-transform infrared spectroscopy (FTIR) displayed that phytic acid caused the thermal degradation of hemicelluloses, which led to a brownish outer appearance of the FR-treated composites. Fire performance was assessed using both limiting oxygen index (LOI) and a cone calorimeter. These techniques showed a higher LOI value and a significant reduction in heat-release rate (HRR), total heat release (THR), smoke-production rate (SPR), and total smoke production (TSP). In addition, cone calorimeter and thermogravimetric (TGA) analyses consistently showed increased char residue in treated wood composites. Moreover, internal bond strength (IB) and modulus of elasticity (MOE) of the wood composite were not significantly changed compared with those of the untreated composite. Surprisingly, in the FR-treated composite, the 24 h-thickness swelling, and the water uptake were slightly decreased. Consequently, this new treatment has the potential to increase the fire retardancy of wood composites, such as particleboard, without deteriorating the key mechanical properties. Validerad;2023;Nivå 2;2023-05-22 (hanlid);Funder: Slovak Research and Development Agency (APVV-16-0223); VEGA agency (VEGA 1/0678/22); KEGA agency (KEGA 016STU4/2021); Swedish wood industry; OP RDE (CZ.02.1.01/0.0/0.0/16_019/0000803) Biobased fire protection of wood panel for exterior conditions by using phosphorylated lignin from wheat straw Advanced research supporting the forestry and woodprocessing sector’s adaptation to global change and the 4th industrial revolution

Aim of this study was to evaluate the effect of aluminium hydroxide and borates, separately or combined with ammonium polyphosphate (APP), upon the technological and fire properties of medium density fibreboard (MDF). Fire resistant MDF was fabricated in the laboratory from Scots pine (Pinus sylvestris L.) fibres bonded with a high molar ratio melamine-urea-formaldehyde resin. Overall, 24 h-swelling and water absorption properties of the treated boards were improved or remained unchanged compared to untreated ones. On the contrary, the internal bond strength (IB) of the fibreboards was significantly reduced up to 48%. The fire properties of the fibreboards were assessed by the determination of limiting oxygen index and cone calorimetry. As expected, the tested fire-retardants improved the fire resistance of the boards. Furthermore, the combination of aluminium hydroxide with ammonium polyphosphate considerably upgraded the fire retardancy while the incorporation of borates into APP showed much weaker effects.

This study is aimed to investigate of an impact of electrical cables installed on Norway spruce (Picea abies(L.) Karst.) wood board surface on main ignition parameters (mainly critical heat flux, ignition temperature, thermal response parameter and thermal inertia). Ignition parameters have been determined by dependence of ignition times (raised to the power of -1, -1/2 and -0.547) on heat flux. Initiation times have been measured for three configurations of spruce wood boards with surface dimensions of 100 x 100 mm ± 1 mm (the first configuration: board without cables on surface, the second configuration: board with three electrical cables on surface -spacing between cables was equal to their diameter and the third configuration: board with five electrical cables -spacing between cables was equal to their diameter) at five heat fluxes (30, 35, 40, 45 and 50 kW·m-2). Obtained results proved that installation of the electrical cables on the spruce wood board surface has a significant impact on the ignition parameters. The critical heat flux (8.5 kW·m-2), apparent thermal inertia0.20 ± 0.02 kJ2·m-4·K-2·s-1and ignition temperature 324 ± 105°C of spruce wood board increased up to 18 ± 3 kW·m-2(critical heat flux), 0.68 ± 0.03 kJ2·m-4·K-2·s-1(apparent thermal inertia) and 475 ± 27°C (ignition temperature) by theinstallation of electrical cableson the surface of spruce wood board.

The main objective of this research was to analyse the limitations of iCT - industrial computer tomography for measuring the wood pores characteristics as a new non-destructive method which is primarily intended to measure and inspect complete components primarily made of plastics or light metal. The subject matter of this paper are wood samples of paulownia (Paulownia tomentosa) and ash (Fraxinus excelsior) before and after thermal treatment. Porosity, pore volume and distribution of pores on the wood samples before and after the heat treatment were measured by iCT Metrotom 1500. The total porosity of the samples before thermal treatment was 5.28 % (paulownia) and 14.90 % (ash), while after thermal treatment, porosity increased to 9.50 % (paulownia) and to 30.78 % (ash). Changes in the porosity of the samples before and after heat treatment show an increase in porosity of 3.87 % (paulownia) and 15.88 % (ash).

Polymeric materials, which are currently very often used in various industries, are often transported and stored in the form of granules before processing. This method has several advantages, but in most studies the test samples are modified to different shapes and dimensions. This paper is therefore focused on the initiation of selected granular plastics. Samples of five polymeric materials were exposed to an external heat flux from 20 kW.m−2 to 40 kW.m−2. A spark initiator was used to ignite the released gaseous products of thermal decomposition of the polymer sample. FTP (flow-time product) method was applied to the obtained parameter - time to ignition, from which other initiation parameters were determined. The critical heat flux was determined in the range of 5.0 kW.m−2 - 11.8 kW.m−2. Despite the relatively small thickness (4 mm), the samples behaved as thermally thick. During the measurement, thin surface layer melted, and the rest of the polymer remained in its original granulated form. Ignition temperatures were calculated according to the Stefan-Boltzmann’s law between 273 °C - 402 °C.

This study deals with the Fire Growth Rate Index (FIGRA) as a key fire characteristic of electrical cables (determined by a cone calorimeter) that allows to estimate their reaction to fire class. Three power (supply) electrical cables (reaction to fire class B2ca) were tested by a cone calorimeter using different heat fluxes of 20, 30, 40 a 50 kW·m−2. The cables were three-wire (cross-section of each wire was 1.5 mm2) with a nominal voltage of 0.6 kV (alternating current), resp. 1 kV (direct current). The cable sheaths were made of an ethylene copolymer filled with aluminum hydroxide. The beddings were made of an ethylene copolymer filled with a mixture of aluminum hydroxide and calcium carbonate. The conductor insulations of one electrical cable were made of crosslinked polyethylene and the conductor insulations of the other two electrical cables were made of an ethylene copolymer filled with aluminum hydroxide. FIGRA was determined per unit length and unit area of electrical cables. FIGRA increased with increasing heat flux. At a heat flux of 50 kW·m−2, all the electric cables examined showed a very similar FIGRA (from 0.19 to 0.21 kW·m−1·s−1 and 18.4 to 21.2 kW·m−1·s−1, respectively). Conversely, at a heat flux of 20 kW·m−2, the investigated cables showed greater FIGRA variance (in the range of 0.11 to 0.16 kW·m−1·s−1 or 10.8 to 16.2 kW·m−1·s−1).

The objective of the work was to improve the leaching resistance of fire-retardant (FR) modified wood by the incorporation of a thermoset resin. Here, Scots pine (Pinus sylvestris L.) sapwood was impregnated with melamine formaldehyde (MF) resin and hydrophilic FRs guanyl-urea phosphate/boric acid by a vacuum-pressure treatment. Resistance to leaching of FR-modified wood was evaluated, after conducting an accelerated aging test according to European standard EN 84. Inductively coupled plasma analysis showed that the incorporation of MF resin significantly reduced the leachability of FRs. Scanning electron microscopy/energy-dispersive X-ray spectrometry revealed that the mechanism of water resistance was by doping the FRs into MF resin microspheres. Fourier transform infrared spectra showed the chemical functionality changes of FR-modified wood such as the formation of methylene bridges by drying the modified wood specimens. An increase in the thermal stability of FR-modified wood was confirmed by thermal gravimetric analysis. Excellent fire performance of FR-modified wood after leaching was affirmed by the limiting oxygen index and cone calorimeter tests. Validerad;2021;Nivå 2;2021-05-21 (alebob);Finansiär: Slovak Research and Development Agency (APVV-16-0223); Czech Republic’s funding office (CZ.02.1.01/0.0/0.0/16_019/0000803); Swedish wood industry

The Fischer-Tropsch process is a chemical reaction that enables liquid hydrocarbons to be produced from coal, natural gas, or biomass (e.g. wood). The heat of combustion and effective heat of combustion are important data for fuel used to produce energy. The usefulness of a particular fuel for society is usually evaluated on the basis of the energy returned versus the energy invested (EROI) = energy recovered/energy invested. The subject of the research was the product of a Fischer-Tropsch synthesis from a synthesis gas, which was produced through the liquefaction of sawdust from spruce wood. The synthesis took place in the reactor FIX BED at a temperature of 220 to 350 degrees C and a pressure of 2 to 3 MPa (the hydrogen to carbon monoxide ratio was approximately 2:1). The Fischer-Tropsch fuel that was produced had a heat of combustion of 27.79 M.g(-1), effective heat of combustion 25.14 M.kg(-1) and an EROI coefficient of 2.39. Web of Science 65 6 904 895

Heat release rate (HRR) is the principal fire characteristic of materials. There are three known methods for the measurement of HRR (based on oxygen consumption, mass loss rate, and combustion products temperature rise). The method based on oxygen consumption is considered to be the reference. However, this method is expensive and for a large part of laboratories and universities unavailable. The simplest method is based on combustion products’ temperature rise. However, this method has a fundamental problem with the temperature dependence of the heat capacity of combustion products and the thermal inertia of the measurement system. This problem has been solved by training neural networks to predict molar heat capacity and the amount of substance (chemical amount) flow rate of combustion products in the cone calorimeter exhaust duct. Data were obtained for six different wood species: birch (Betula verrucosa Ehrh.), oak (Quercus robur L.) spruce (Picea abies (L.) H. Karst.), locust (Robinia pseudoacacia L.), poplar (Populus nigra × P. maximowiczii L.), and willow (Salix alba L.) woods at heat fluxes from 25 to 50 kW m−2 have been used for neural network training. Data from three other wood species iroko (Milicia excelsa (Welw.) C.C. Berg), pine (Pinus sylvestris L.), and paulownia (Paulownia tomentosa (Thunb.) Steud.) woods have been used for testing of trained neural network. The average percentage ratio of the predicted to the true value of HRR (during the test) has been 103.8%. In addition to that, some key average fire characteristics of wood have been determined: critical heat flux 20.7 kW m−2, effective heat of combustion 14.01 MJ kg−1, and the average value of molar heat capacity of combustion products 0.045 kJ mol−1 K−1.

Water is the most frequently used substance for extinguishing of wildfires. Ones of the most commonly used additives enhancing the extinguishing efficiency are foaming agents. This article deals with the influence of foaming agents on germination of coniferous species. Foaming agents Moussol-APS F-15 and Sthamex F-15, foaming solutions of various concentrations were used for the tests. Germination of seeds of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris) was observed. The percentage of germinating seeds was recorded every 7 days. The results were evaluated in the form of graphs. When the concentration levels of foaming solutions ranged from 0.1 vol% to 0.25 vol%, their influence on germination of both coniferous species seeds varied from negligible to slightly positive. Subsequently, the negative effect increased considerably and with concentrations exceeding 1 vol% - 1.5 vol% the germination of samples reached zero values. While foaming solutions of Sthamex F-15 showed less significant influence on germination of the Scots pine seeds, seeds of the Norway spruce were less influenced by foaming agent Moussol-APS F-15. Based on obtained results it is possible to recommend minimisation of foaming agents amounts, eventually application of substances with less negative effect on plants germination for extinguishing of wildland fires, in order to gain restoration of affected area as fast as possible. Key words: foaming agent, germination, wildfire (wildland fire), foaming solution

This scientific study deals with investigation of the heat of combustion and effective heat of combustion of selected electrical cables. Two different electrical cables for rated voltage of 0.6/1 kV were investigated. Both cables were power three-core with cross-section area of each core of 1.5 mm2. The cores of both cables were made of a bar cooper wire. Insulations of conductors of both cables were made of silane cross-linked polyethylene without any inorganic filler, while the bedding and outer sheath were made of polyethylene-based copolymer (the beddings were filled with two fillers - aluminium hydroxide and calcium carbonate, while the outer sheath were filled only with aluminium hydroxide). Reaction to fire class of both cables was B2ca, s1, d0, a1. The main difference in the investigated cables was that the core of one of them was wrapped in a glass mica tape (this cable showed circuit integrity maintenance under fire conditions during 180 minutes). The heat of combustion and effective heat of combustion were determined by the oxygen bomb calorimeter according to the ISO 1716:2018 standard. The highest effective heat of combustion showed the insulation of wires (for both cables 42.47 ± 0.03 MJ/kg), lower value showed outer sheath (interval form13.61 to 15.26 MJ/kg) and the lowest value was determined for bedding (interval from 4.69 to 6.39 MJ/kg). The effective heath of combustion per unit of length of both investigated cables lies in the interval from 1.37 to 1.38 MJ/m. Therefore, there is no significant difference in effective heats of combustion of the electrical cables investigated.

The aim of the research was to determine the fire risk of selected flammable liquids (alcohols). Four alcohols, methanol, ethanol, propanol, and butanol, were chosen for the research. Flammable liquids were examined in a cone calorimeter at 0 and 5 kW.m−2 heat fluxes. Both, the cone calorimeter and test procedure, were in accordance with ISO 5660-1:2015. The fire risk was evaluated mainly on the basis of heat release rate, effective heat of combustion and carbon monoxide yield. Comparison of the achieved parameters of selected alcohols shows that the fire risk of the investigated alcohols increases with increasing the molar mass of alcohol and applied heat flow.

Formaldehyde is a toxic chemical commonly found in the environment. Owing to its increased usage, its incidence has also increased, and there is a need to determine the concentration of formaldehyde for the pollution control purposes. In general, spectrophotometric methods are easy to perform, low-cost, selective and sensitive, but every spectrophotometric method has its advantages and disadvantages, which are an important factor when selecting the method for determination of formaldehyde. Therefore, the aim of the research described in this paper was to compare the current spectrophotometric methods and to summarize their advantages and disadvantages.

This study focuses on the energy potential and combustion process of torrefied wood. Samples were prepared through the torrefaction of five types of wood: Ash, beech, oak, pine and spruce. These were heated for 2 h at a temperature of 300 °C under a nitrogen atmosphere. Torrefied wood was prepared from wood samples with dimensions of 100 × 100 × 20 mm3. These dimensions have enabled investigation of torrefied wood combustion in compact form. The effect of the external heat flux on the combustion of the samples was measured using a cone calorimeter. The observed parameters, include initiation times, heat release rate and combustion efficiency. The results show that increasing the external heat flux decreases the evenness of combustion of torrefied wood. At the same time, it increases the combustion efficiency, which reached an average value of approximately 72% at 20 kW m−2, 81% at 30 kW m−2 and 90% at 40 kW m−2. The calculated values of critical heat flux of the individual samples ranged from 4.67 kW m−2 to 15.2 kW m−2, the thermal response parameter ranged from 134 kW s0.5 m−2 to 297 kW s0.5 m−2 and calculated ignition temperature ranged from 277 °C to 452 °C. Obtained results are useful both for energy production field and for fire safety risk assessment of stored torrefied wood.

This paper deals with the recognition of selected burning liquids by convolutional neural networks (CNNs). Three CNNs (AlexNet, GoogLeNet and ResNet-50) were trained, validated and tested (in the MATLAB 2020b software) for the recognition of selected liquids (ethanol, propanol and pentane) using photographs of the flames they produce. For training, validation and test photographs of the liquids under investigation burning in a 106-mm-diameter vessel were used. The accuracy of all the CNNs under investigation during the tests was above 99%. In addition the trained CNNs were tested using photographs of the flames generated by the liquids under investigation burning in a vessel with a diameter of 75 mm. The accuracy of the trained CNNs in this additional test ranged from 37 to 42% (GoogLeNet) through 62–73% (ResNet-50) up to 51–80% (AlexNet) – the results varied dependent upon the relative size of the flame in the photograph under analysis (in most cases an increase in the relative size caused an increase in accuracy). The accuracy of the AlexNet can be improved from 80% to almost 96% using an algorithm. The principle of the algorithm is the analysis of 10 photographs of the same liquid in the same vessel (taken over a few seconds) followed by the recognition based on an identical classification for at least 6 out of 10 photographs. An accuracy of 96% is sufficient for the rapid recognition of burning liquids in practical applications. Supplementary Information The online version contains supplementary material available at 10.1007/s10973-021-10903-2.

This article deals with the combustion process of biodiesel produced from waste vegetable oil. The main fire-technical properties related to its thermal degradation during pool fire were observed. As a test device, a cone calorimeter with modified specimen holder was used. The measurements were obtained by applying an external heat flux of 20 and 25 kW m−2 and using a spark initiator. On the basis of the measured results, the biodiesel combustion was divided into six consecutive phases described by the heat release rate, CO production, CO2 production and smoke production rate. Mean heat release rate and maximum average heat release energy peaked at 315 kW m−2, respectively at 391 kW m−2 (external heat flux of 20 kW m−2) and at 420 kW m−2, respectively at 504 kW m−2 (external heat flux of 25 kW m−2). The flash point of biodiesel reached a lower value compared to oils. The CO/CO2 ratio in the flue gas showed virtually the same combustion efficiency throughout the whole experiment.

The presented study deals with the fire risk of electrical cables. Samples of three-core electrical power cables and two-core electrical control cables were investigated. The influence of the mutual spacing between the cables and the thermal conductivity of the material under the cables (underlying material) on fire risk was assessed in the study. The fire risk was determined using a cone calorimeter (at a heat flux of 50 kWm−2) and an oxygen bomb calorimeter. The fire risk was assessed based on parameters quantifying the released heat, toxicity and amount of combustion products and flashover category. The heat release rate, total heat release and the effective heat of combustion increase with increased spacing between the cables and decreased thermal conductivity of the underlying material. The carbon monoxide yield increases with the increase in the thermal conductivity of the underlying material. The influence of the spacing between cables on the carbon monoxide yield (in the interval 0–1800 s) depends on the thermal conductivity of the underlying material. At low thermal conductivity, the carbon monoxide yield decreases as the spacing decreases, with the opposite trend (with some exceptions) at high thermal conductivity. Smoke yield decreases with increasing thermal conductivity of the underlying material and also increases with increased spacing between cables. Neither the thermal conductivity of the underlying material nor the spacing between cables has an influence on the flashover category of the cables investigated.

Pri rôznych rozmeroch trhlín môže dochádzať k zmenšeniu reziduálneho prierezu a tým aj mechanickej odolnosti. V tomto článku je analyzovaná rýchlosť uhoľnatenia drevených prvkov s rôznymi trhlinami. Vzorky sú vystavené tepelnému toku v kónickom kalorimetri. Cieľom článku je popísať experiment drevených vzoriek s trhlinami a analyzovať výsledky získané pomocou numerickej analýzy. Z predbežných analýz vyplýva, že trhliny môžu mať signifikantný vplyv na uhoľnatenie dreva v mieste trhliny a v prípade viacerých trhlín v priereze na celý prierez.

This paper deals with the fire risk of a selected halogen-free electrical cable. The research was objected to a three-core power electric cable for a fixed installation CHKE J3x1.5 (cross section of each copper core was 1.5 mm2) with a declared class of reaction to fire B2ca, s1, d1, a1. The electrical cable was manufactured and supplied by VUKI, a. s., Slovakia. The fire risk of the electric cable was evaluated based on the heat release rate, total heat release, smoke release rate, total smoke release and effective heat of combustion. These parameters were measured using a cone calorimeter at 50 kW m−2 (specimens and cone emitter were placed horizontally during the test). The measured electrical cable showed a maximum heat release rate of nearly 150 kW m−2, a maximum average heat emission rate of almost 100 kW m−2, a total heat release of almost 130 MJ m−2, a maximum smoke release rate of almost 2.5 s−1, a total smoke release of more than 800 m2 m−2, an effective heat of combustion (cable as a whole) of nearly 9 MJ kg−1 and an effective heat of emission (polymeric parts of the cable) of 26.5 MJ kg−1.

Electric cables can contribute to the spread of fire through the insulating layer. This paper focuses on their properties characterizing the initiation of fire. Samples of ethylene-based cable insulation were tested using a cone calorimeter by exposing them to external heat flows of six different values (25 kW m−2 – 50 kW m−2). Time to initiate flame burning was observed. The critical heat flux (depending on the method of calculation was in the range 2.94 kW m−2 – 4.59 kW m−2) and the thermal response parameter (342 kW s−0.5 m−2) was calculated from the time of initiation and external heat flow dependence.

A charring rate is a key parameter for the calculation of fire resistance of timber structures and for fire investigation. Charring rates are calculated from the char depth, and the time material is exposed to the heat load. The presented study deals with the calculation of the char depth of Norway spruce (Picea Abies (L.) Karst.) and Scots pine (Pinus Sylvestris L.) wood from the mass loss during the test on a cone calorimeter. The samples were loaded with the heat fluxes of 20, 30, 40 and 50 kW m−2 during a period of 10, 20 and 30 min. The samples were extinguished after the stated time intervals and subsequently the char depth was measured. The mutual orientation of the grain and the incident heat flux was parallel. A strong linear relation was found between the char depth and the ratio of the mass loss to density. The average charring rate decreases with the increasing time and increases with the increasing heat flux. The average charring rate of spruce wood was in the interval from 0.73 to 1.5 mm min−1. The average charring rate of pine wood was in the interval from 0.67 to 1.3 mm min−1.

This study deals with heat of combustion of selected fast-growing woods. The study also investigates the impact of heat flux on fire risk of the selected fast-growing woods. The hybrid poplar J-105 (Populus nigra × P. maximowiczii), white willow (Salix alba L.) and black locust (Robinia pseudoacacia L.) woods were measured. The heats of combustion were determined by a bomb calorimeter. Fire risk was evaluated with a cone calorimeter at different heat fluxes. The net heat of combustion occurred in the interval from 17.68 MJ kg−1 (black locust) to 18.02 MJ kg−1 (hybrid poplar). Fire risk was assessed on the basis of the critical heat flux, maximum average rate of heat emission, carbon monoxide yield, smoke yield and time to flashover. The hybrid poplar had the lowest critical heat flux (12.8 kW m−2), and the white willow had the highest critical heat flux (17.4 kW m−2). The maximum average rate of heat emission and the smoke yield increased with the increasing heat flux. On the other hand, carbon monoxide yield decreased with the increasing heat flux. The differences between the times to flashover of the measured wood species were not significant.

The decomposition stages of spruce wood sawdust were analyzed by means of sequential differential calorimetry. Two stages of decomposition were identified and activation energy of one stage was calculated using the Kissinger method. The DTA was conducted by means of SEDEX safety calorimeter. Sample was analyzed under three heating rates of 10, 20 and 45 °C/h in temperature range from room temperature to 400 °C. The calculated activation energy for the last and most clear decomposition peak was 122.63 KJ/mol. The results are comparable with the data calculated by J.V. Rissanen et al., who calculated activation energy for Spruce hemicellulose as 120 KJ/mol.

This study is concerned with the investigation of the impact of heat flux on the fire hazard and the effective heat of combustion of sunflower seed hull pellets. Pellets produced by pressing common sunflower seed hulls (Helianthus annuus L.) were investigated. The samples were dried on water content of 0 mass% at a temperature of 103 ± 2 °C. The fire hazard and the heat of combustion have been determined via the cone calorimeter and by the testing procedure per ISO 5660-1:2015 at three heat fluxes (25, 35 and 50 kW m−2). The peak heat release rate increases with the increasing of the heat flux from 446 (at a heat flux of 25 kW m−2) to 601 kW m−2 (at a heat flux of 50 kW m−2). The carbon monoxide yield lies in the interval from 82.50 (at a heat flux of 25 kW m−2) to 154.15 g kg−1 (at a heat flux of 50 kW m−2). The effective heat of combustion decreases with the increasing of the heat flux from 15.84 (at a heat flux of 25 kW m−2) to 14.58 MJ kg−1 (at a heat flux of 50 kW m−2).

Drying fissures occur in some timber structures what can lead to an issue for a mechanical resistance of these structures. There is no proposal to quantify the effect of various fissures and gaps on the charring of timber structural members. Therefore, this contribution deals with the numerical and experimental analysis of selected dimensions and number of fissures. The numerical analysis was conducted in a software based on FEM. There were created models with local fissures and simplified “smeared” models. The samples were tested in a cone calorimeter. There were two types of samples. The charring depth was measured from a split cross-section for the first group of samples. Temperatures were measured by means of thermocouples for the second group of samples and the charring depth was calculated based on these temperatures. The aim of this paper is to compare values of the charring rate and depth for the samples with different fissures. In terms of results, the bigger fissures or larger quantity of fissures should be considered by means of advanced design methods, or by increased value of the charring rate. However, the smaller fissures can be neglected.

Worldwide, wood-based materials are massively exploited in many industries. As a renewable material with significantly lower environmental impact compared with conventional materials is very likely that their production will grow in the future. This paper deals with the determination of parameters characterizing the initiation of not only solid wood as the original raw material but also of other composites produced from it. Specifically, the parameters are: critical heat flux, thermal response parameter, initiation temperature and apparent thermal inertia. These parameters are calculated based on the dependencies between external heat flux and time to initiation suggested in the literature. During the measurement, samples of selected materials were dried to zero humidity and subsequently exposed to thermal radiation of varying intensities using a cone emitter. The results of these measurements were evaluated by graphs. Calculated values of initiation parameters are listed in a summary table and can be used for further calculations in the area of personal and property fire protection.