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This article deals with the activation energy of ignition calculation of plastics. Two types of polyamide 6 and one type of polypropylene and polyurethane were selected as samples. The samples were tested under isothermal conditions at several temperatures while times to ignition were observed. From the obtained data, activation energy relating to the moment of ignition was calculated for each plastics. The values for individual plastics were different. The highest activation energies (129.5 kJ.mol−1 and 106.2 kJ.mol−1) were achieved by polyamides 6, while the lowest was determined for a sample of polyurethane.

This scientific study deals with a complex research of initiation process of selected natural materials. The first chapter deals with research of the influence of density and thermal modification of spruce wood (Picea abies(L.) Karst.) on the critical heat flux density for the pilot ignition. In this chapter the thermally modified and unmodified samples of a spruce wood were investigated. The thermally modified samples were prepared according to temperature program for the ThermoWood - Thermo-S (maximum temperature during the thermal modification was 190 °C) and ThermoWood - Thermo-D (the maximum temperature during the thermal modification was 212 °C) production. Critical density of heat flux was determined on a cone calorimeter test by procedures in accordance with ISO 5660-1:2002. The obtained results showed that the thermally modified spruce wood in comparison with the thermally unmodified one had higher critical density of heat flux. The second chapter is aimed on determination of ignition activation energy of pure cellulose, cellulose impregnated by water solutions of KHCO3and (NH4)2HPO4with concentrations of 5, 10 and 15 wt. % and on determination of ignition activation energy of dust from beech wood (Fagus sylvaticaL.). The activation energies were determined in accordance with isothermal, dynamic and non-isothermal model-free methods. The obtained results showed that the ignition activation energy of cellulose impregnated by water solutions of KHCO3and (NH4)2HPO4have lower activation energy than the pure cellulose. The obtained data on the activation energy of beech wood dust showed that the activation energy depends significantly on the degree of conversion. Chapter three deals with the research of inclination of selected vegetable oils (Linseed, Sesame and Sunflower oil) applied to cotton to self-ignite. The propensity towards spontaneous combustion of the mentioned oils was investigated by Mackey test and Accelerating Rate Calorimetry. The results showed that the ratios of oil mass to the mass of the carrier, on which oil is applied, had significant impact on the propensity of vegetable oil to the spontaneous combustion. The highest propensity to spontaneous combustion of the investigated materials showed the Linseed oil.

This article deals with evaluation of the spontaneous-ignition activation energy of the Teak wood (Tectona grandis L.f.) and the Oak wood (Quercus robur L.). Spontaneous-ignition activation energy was calculated from dependence of ignition time to inverse value of thermodynamic temperature. This dependence was measured in the hot-air (Setchkin) furnace according to ISO 871:2006 standard by modification of the test procedure. The modifications of test procedure lay in measurement of the time to ignition of sample loaded by various temperatures (at spontaneous ignition temperature and at temperatures above this value). The mass of investigated samples was (3 ± 0.05) g and its moisture contents was 0 wt %. The dimensions of sample was (20 x 20) mm, the third dimension was adjust to achieve required mass of sample. The activation energy of spontaneous-ignition for Teak wood was 78.23 kJ.mol-1 and for Oak wood was 59.24 kJ.mol-1. The spontaneous-ignition temperature for Teak wood was 460 °C and for Oak wood was 450 °C. Thus despite slight difference between spontaneous-ignition temperatures of investigated materials the difference between activation energy of spontaneous-ignition is significant.

This paper deals with the assessment of the influence of heat treatment of Norway spruce wood (Picea abies L.) on its thermal stability and burning process. Three types of samples were used for the research. The first group was comprised of untreated samples. The second group was comprised of samples heat treated according to the ThermoWood—Thermo-S thermal programme (maximum temperature during heat treatment is 190 °C), and the third group was modified according to the ThermoWood—Thermo-D thermal programme (maximum temperature during heat treatment is 212 °C). The influence of heat treatment on the burning process was assessed based on the heat release rate, effective heat of combustion and the yield of carbon monoxide. The influence of heat treatment on the thermal stability was assessed based on the resistant residue weight. Heat release rate, effective heat of combustion, yield of carbon monoxide and resistant residue weight were determined with a cone calorimeter for different heat flux densities. The results obtained prove that the spruce wood heat treatment has an important influence on the decrease of the maximum heat release rate and the increase of resistant residue weight. The results obtained further prove that the heat treatment has only a modest influence on the increase of the carbon monoxide yield, and its influence on the effective heat of combustion significantly depends on the heat flux density.

This article evaluates the fire risk of petrol utilising a novel testing procedure that enables the measurement of heat release rate (HRR), specific mass loss rate and carbon monoxide (CO) yield of flammable liquids in a cone calorimeter. The testing procedure is a modification of the procedure described in ISO 5660-1:2002. The modification includes the use of a sample pool enabling the testing of flammable liquids. Pure petrol samples were tested. They were ignited with a spark igniter, without the use of a cone heater. The cone heater was removed before testing to avoid its heating by the flame and consequent heat radiation onto the tested sample surface. The average HRR was 612 kW m−2 and the maximum HRR was 842 kW m−2. The total CO yield related to mass loss was 58.6 g kg−1 and related to the effective heat of combustion was 1.48 g MJ−1. The immediate CO yield increased significantly with an increase in testing time (an increase in the depth level of liquid below the upper edge of the pool). Dependence equations of HRR and specific CO production rate (SCPR) on the specific mass loss rate were calculated from the obtained data. Substituting the specific mass loss rate of petrol (55 g m−2), which burns in an infinite diameter pool, the HRR (1,581 kW m−2) and SCPR (3.99 g m−2 s−1) were calculated for petrol pool fire under real conditions (at pool diameter larger than 1.5 m). The calculated SCPR accounted for a CO yield of 72.55 g kg−1.

In the presented paper is assessed fire risk of pellets made from spruce wood (Picea abiesL.) without bark, processed by hot pressing without the use of additional chemicals. Fire risk was assessed on the basis of heat release rate (HRR), the specific carbon monoxide production rate (SCPR) and the time dependence of the induction period of spontaneous ignition on temperature. HRR and SPCR were determined on the cone calorimeter test performed according to ISO 5660-1:2002 standard. Samples were loaded by 20 kW/m2heat flux during the test. The maximum HRR was 229 kW/m2and average HRR was 55 kW/m2. Maximum SCPR was 0.37 g/(m2s) and the average SCPR was 0.16 g/(m2s). The dependence of the induction period of spontaneous ignition on temperature was determined by a modified test performed according to ISO 871:2006 standard. Modification of the test procedure was based on measurement of the induction time period of the spontaneous ignition on temperature, and temperatures higher of 20, 40, 60, 80 and 100 °C than spontaneous ignition temperature. The obtained data proved an exponential dependence of the induction period of spontaneous ignition on temperature.

Electricity is the most important form of household energy and one of the most important forms of energy for industry and transport. Electrical distribution in construction and transport is almost exclusively implemented using electrical cables. One of the unresolved problems associated with electrical cables is the release of smoke and the resulting reduction of visibility in case of fire in the area. In this study, a new approach was developed to assess the reduction of visibility in an area affected by an electrical cable fire. This approach is based on the determination of the critical ratio of smoke volume (in the smoke layer and exhausted from the fire compartment) to the length of the burning cable, through which the visibility of reflective and illuminated signs was reduced to a lower limit value (a standard of 10 m). The input data for this approach was the extinction area of the smoke released from one meter of burning cable and the length of the cables in the area. This approach was used to test two power cables (CHKE-V J3x1.5 and CHKE-R J3x1.5) and one signal cable J-H(St)H 1 &times, 2 &times, 0.8 with the B2ca, s1, d1, a1 fire reaction class. The smoke extinction area of the examined cables was determined using a cone calorimeter at a heat flux of 50 kW/m2. The obtained data showed that in order to maintain a visibility of 10 m for reflective signs, the critical ratio of smoke volume to length of burning cable was 7.5 m3/m. For illuminated signs, the critical ratio was 2.8 m3/m. The relationship between burning length and visibility allows the calculation of visibility in the fire compartment affected by cable fire only from cables length.

This article deals with comparison of the behaviour of spruce wood and polyolefins (polyethylene PE and polypropylene PP) during the test on the cone calorimeter. Samples were tested on the cone calorimeter at heat flux of 20 and 40 kW/m2. An evaluation of the behaviour of examined materials was based on the determination of the maximum and the average heat release rate, yield of carbon monoxide (CO), and relative comparison of tendency to fire propagation in a flashover phase. The tendency of materials to fire propagation in the flashover phase was evaluated based on the Pearson ́s correlation, the Spearman ́s correlation and the Kendall ́s correlation coefficient of HRR-CO and CO2-CO. Spruce wood showed better properties in comparison with PE and PP in all evaluated parameters (the maximum and the average heat release rate, the yield of CO, and also the resistance to fire propagation in the flashover phase. Additionally, spruce wood showed significantly lower sensitivity of dependence of the maximum and also the average heat release rate on external heat flux.

The oxidative self-heating process of vegetable oil with high content of unsaturated fatty acids was investigated by the means of sequential scanning calorimetry in safety calorimeter SEDEX. The oil was applied on the cotton, and was put to the standard pressure sample vessel, which was modified for air inlet. The behavior of sample was studied under three rates of air flow. First experiment was carried out in the temperature range between approximately 30 and 350°C at a heating rate of 45°C/h. Second scanning was carried out in the temperature range from 30 to 200°C at heating rate of 10°C/h.

On the base of experimental observations of mass loss rate in dependance of time in isothermal condition in circulating air atmosphere was determined the moment of lignocellulosic materials ignition. Experiment was performed in an electrically heated hot-air furnace according to ISO 871 standard (Setchkin furnace) in conjunction with precision scales. Experiment was performed with ignition source. The ignition source was kanthal wire. Experiment was performed at one temperature, three positions of samples in the oven and various air-flow speeds. Pure cellulose as a model compound was impregnated by water solution of KHCO3 and (NH4)2HPO4.

The presented paper deals with determining the influence of the flow rate of oxidising atmosphere on the flame spread along the surface of the organic settled dust layer. We determined the rate of the flame spread on the surface of the organic settled dust layer (whole grain rye and spelt flour) with absolute moisture of 10 % wt., for the flow rates of oxidising atmosphere 1, 3, 5 and 10 cm/s. Pure oxygen was used as an oxidising atmosphere. The obtained results suggest that there exists a power relationship of the flame spread rate along the surface of organic settled dust layer to the flow rate of the oxidising mixture. The method described is suitable for the relative comparison of the organic settled dust layer from the point of its ability to spread the flame and the influence of the air flow rate on this process.

The combustion process (efficiency and toxicity of combustion generated emissions) depends on the chemical composition and physical characteristics of materials, the oxidizing agents, and the temperature. This article will determine the influence of temperature (450 and 600 °C) and the volume of oxygen concentration (9, 15, and 21%) in an oxidizing atmosphere on the main emissions of burning White Birch wood (Betula verrucosa Ehrh.) The examined samples weighed 3 ± 0.05 g; the average density was 540 kg/m3; and the absolute humidity was 8%. The samples were thermally loaded in a Setchkin furnace specially modified to enable the thermal sample in an atmosphere with an adjustable oxygen concentration and the withdrawal of fire emissions by means of UniGas C440 analyzer probes and BERNATH ATOMIC Modell 3006 analyzers. At 450 °C, the concentration of oxygen in the oxidation mixture did not significantly influence the maximum concentration of carbon monoxide (CO) and the total organic carbon (TOC) in the fire emissions. At 600 °C, the decrease of the oxygen concentration in the oxidation atmosphere caused a significant increase of the maximum concentration of CO and TOC in the fire emissions. However, the generally accepted presumption of a maximum concentration increase of CO in the emissions as a result of the oxygen (O2) concentration decrease in the oxidation atmosphere has not been confirmed. The highest concentration of CO and TOC were measured in the initiation phase or closely after it.

This paper deals with monitoring of the thermal decomposition of pure cellulose in a modified electrically heated hot air furnace, which allows simultaneous measure of weight loss, released gases (CO, CO2, CxHy, H2, NO, NO2 and O2) at a given temperature or a selected heating rate and the selected airflow speed. The measurements were made under isothermal conditions in the temperature range 230-340 ° C and air flow at speeds 30, 20, 10, 0 mm.s.

Influence of Retardants to Burning Lignocellulosic Materials The paper deals with monitoring retardant changes of lignocellulosic materials. Combustion of lignocellulosic materials and fire-technical characteristics are described. In assessing the retarding effect of salt NH4H2PO4, fire-technical characteristics as limiting oxygen index (LOI) were measured, and by using thermoanalytical TG and DSC methods. High-temperature process of cellulose degradation at various flame concentrations was studied.

The presented article deals with the assessment of combined impact of temperature and flow of oxidising atmosphere, its oxygen concentration and heat flux on the ignition time of isotactic polypropylene (PP). The ignition time was determined in a specially adapted hot air Setchkin furnace at temperatures (450 and 600 °C), density of heat flux (12.4 and 26.4 kW m−2), flows of oxidation mixture (6 and 8 L min−1) and volume oxygen concentrations (3, 9, 15, 21, 27, 33, 39, 45 and 50 %). Obtained data allows us to assume that the temperature influence on PP induction period of ignition increases with decreasing flow rate of oxidising atmosphere. At the flow of oxidising mixture equal to 6 L min−1 and temperature of 600 °C, oxygen concentration had only a negligible impact on the the induction period of ignition in the analysed period. From the presented results, the induction period of ignition depends on the temperature and also on the flow rate of oxidising mixture and oxygen concentration in it. In addition, heat flux has a significant influence on the induction period. However, the quantification of the heat flux influence was not possible with the applied experimental device.

The present article deals with a fire risk assessment for bio ethyl te rt-butyl ether (ETBE). The fire risk has been assessed based o n the heat release rate (HRR) and the carbon monoxide (CO) yield, using a cone calorimeter in accordance to testing procedure doc umented in ISO 5660-1:2002, which has been modified in order to enable the testing of flammable liquids. The research f ocuses on bio-ETBE used as bio component in automobile petrol (analytically pure ETBE was not a subject of this research). T he sample weight used for a single testing was 100g at 745.1 kg.m -3 density. The sample was ignited with a spark igniter, a voiding additional heat radiation effect from the cone emitter. The f ollowing values were measured under the testing conditions: maximum HRR (2796 kW.m -2 ), average HRR 876 kW.m -2 , average specific mass loss rate (SMLR) 23.08 g.m -2 .s -1 and the CO y ield 10 g.kg -1 . Equations for the statistical dependence of HRR and specific CO production rate (SCPR) on SMLR were compiled from the obtained values. Further, the SMLR for ETBE burning in an infinite size pool 165.42 g.m -2 .s -1 was calculated. Substituting the calculated SMLR values (for pool fire in an inf inite size pool) into the statistical dependence equations, HRR 6356 kW.m -2 and SCPR 2.57 g.m -2 .s -1 were calculated for pool ETBE f ire under realistic conditions (pool diameter exceeding 3.5m). The calculated SCPR accounted for a CO yield of 15.54 g.kg -1 .

Under the fire conditions, the resistance of cable distribution is required for a fixed period, depending on the intended use of the cable. To increase the fire resistance of cables a fireproof coating may be applied. Article deal with the behavior of the fireproof coating during elevated temperature. Concretely, the aim is monitored a coating weight change under the conditions of dynamically increasing temperature and with or without using air-flow. It is also monitored the change in weight, depending on the isothermal temperatures in dynamic air atmosphere.