The main waste of wood sanding technology is wood dust. The formation of wood dust affects its behaviour. Wood dust can be in a turbulent form and behaves explosively or in a settled form where it becomes flammable. Dust particles are barely detectable by the naked eye, wood dust still presents substantial health, safety, fire and explosion risks to employees. This article deals with the evaluation of ignition temperature and surface temperature of deposited wood dust samples by 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 spatial arrangement during the ignition and the application time of the ignition source are analysed. The paper describes the behaviour of a 15 mm deposited layer of wood dust of spruce (Picea abies L.), beech (Fagus silvatica L.). oak (Quercus petraea Liebl.) caused by three potential ignition sources—a hot surface, an electric coil and a smouldering cigarette. Prior to the experimental determination of the ignition temperature, dust moisture content which did not significantly affect the ignition phase of the samples, as well as sieve analysis of tested samples were determined. The lowest minimum ignition temperature on the hot plate, as an important property of any fuel, because the combustion reaction of the fuel becomes self-sustaining only above this temperature, was reached by the oak dust sample (280 °C), the highest by the spruce dust sample (300 °C). The ignition process of wood dust was comparable in all samples, differing in the ignition time and the area of the thermally degraded layer. The least effective ignition source was a smouldering cigarette.

This article deals with the assessment of the hazards of dust waste generated by modern CNC (computer numerical control) technologies from the processing of resin-containing plastic composites. The change of the original material into dusty waste predicts the emergence of new hazardous characteristics such as flammability, explosiveness and adverse effects on employee health. The aim of this article is to determine the experimental measurement of dust particle size, its thermal degradation and safety characteristics. Sieve analysis showed that the representative sample contained a 93.8% weight of particles with a size of less than 0.4 mm. Three degrees of thermal degradation of industrial dust samples and heat production (exo reaction ∑ΔH = 9172.9 J/g) were determined by TG (thermogravimetry), DTA (differential thermal analysis) and DSC (differential scanning calorimetr) methods. The measurement safety characteristics such as the lower explosion limit, the maximum explosion pressure, the maximum pressure rise rate, and the calculated cubic constant confirmed that the dust is an explosive, and is determined as explosion class St1 (determined by Cubic constant).

Thermal Analysis of Granulometry Selected Wood Dust Particles

Occupational safety and health should be the subject of education, as it prepares students for their future occupation, and further adult education, including retraining. Nowadays, as society supports technical education via dual learning, this issue is becoming particularly necessary. Schools ensure students’ safety and health in education, training and other related activities as well as in the provision of school services. In order to secure this task the schools adopt preventive measures based on risk assessment associated with the school activities and environment. When establishing specific measures the school takes into account predominantly the possible threat to students in education of individual subjects, movement within school, and the participation of students in various school-organised events. Subsequently, the educational institution provides continuous education in this area for its students and employees and requires the observance of relevant legal standards by systematic control. It takes into account the age of students, their abilities, and their physical and mental maturity. The aim of this article was to find out how students at different age levels (students of secondary school and elementary schools) understand and observe the principles of safety and health which is a central prerequisite in preparedness for future occupation. In the conclusion part of this paper, we present some solution suggestions; highlight the importance of suitable curricula at schools and educational institutions. Education methods must reflect current, valid and enforceable safety and health regulations at work. It is therefore essential that risk assessment is included in the education process.

Particleboards (PB) and oriented strand boards (OSB) are commonly used materials 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 were used to observe the process of particleboard and OSB ignition: heat flux intensity (from 43 to 50 kW.m^-2) and ignition temperature. The time-to-ignition and mass loss of particleboards and OSB with thicknesses 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 thermal degradation of samples. Heat flux had a significant effect on mass loss (burning rate) and time-to-ignition. OSB had 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 higher mass loss than particleboards. The samples yielded the same results above 47 kW.m⁻². Thermal analysis also confirmed a higher thermal decomposition temperature of OSB (179 °C) compared to particleboards (146 °C). The difference in mass loss in both stages did not exceed 1%.

The article is dealing with wood dust particle size problem in consideration of their fire and explosion. The aim of the thesis is statistical evaluation of wooden particles of Palisander (Jacaranda Mimosifolia) and Oak (Quercus robur L.). The samples were taken from the operation of the production furniture, in which dust is formed during the technology. Measurement was carried out by laser analyzer. Measurements were carried out on samples in specific time interval. Values, which were acquired, were evaluated of characteristics of the Weibull Distribution and treated in statistical program. It has been found by means of measurement and evaluation that sample of Palisander (Jacaranda Mimosifolia) has finer grain than sample of Oak (Quercus robur L.), therefore the has greater assumption to the creation of fire and explosions in process at the wood processing. We note in comparison with other sizes of wood particles, that the percentages are comparable.