Fire Protection Of Wooden Storage Containers For Explosive And Pyrotechnic Products

Analysis of the emergency storage facilities for explosive and pyrotechnic products is conducted. It is established that one of the greatest risks is their flammability. Since the explosive and pyrotechnic products are stored in wooden containers, there is a need for their fire protection. To determine the efficiency of fire resistant containers for packaging explosive products it is designed operating range of testing method. This method is necessary to establish mass loss, measuring the growth temperature and response time of the squibs. The results of the efficiency of the fire retardant treatment of wood and organic coated coating showed that when exposed to high–temperature destruction of the construction detonation of the squibs didn\u27t happen.Tests to determine the quality of the fire retardant treatment of wood coatings showed that the temperature on the inner surfaces of the untreated sample was more than 760 ºC, samples with fire retardant coatings – no more than 128 °C. The conclusion of the feasibility of using fire–retardants is not based on inorganic and organic binders for the treatment of wooden structures.Method of determining the fire protection is used to assess the efficiency of the fire protection of wooden structures. Method comprises determining the ratio of the sample rate of burnout, the temperature increment and the ignition time of untreated and treated samples. As a result of the firing testing it is established a speed burnout reduction of samples of the container with treated coatings compared with untreated coatings is decreased by 2,4-4,4 times and respectively fire protection efficiency factor of treated samples of the container compared to untreated is increased by1.8-4.1 times

Justification of the wood polymer material application conditions

The production of heat-insulating materials based on wood was analyzed in this paper. The expediency and efficiency of using wood waste were established. A study of the operational properties of the sample obtained from wood shavings polymerized with mixtures of polyester and epoxy resins was carried out. It was proven that the process’s primary regulator is the material’s density and porosity. Also, an increase in humidity and wetting reduces heat-insulating indicators. Based on thermophysical dependences, the thermal insulation properties of the samples were calculated. Moreover, it was established that the thermal conductivity does not exceed 0.21·10–6 m2 /s, and the thermal conductivity of the sample – 2.85·10–3 W/(m·K). Therefore, these products can be classified as heatinsulating materials. A through-thickness compressive strength study showed that the wood shavings and polyester resin material are more fragile, and the strength limit was reduced by more than 1.2 times compared to the epoxy resin-based material. The moisture absorption results showed that a heat-insulating product made of shavings polymerized with polyester resin. Moisture absorption was 5 % after 90 days of exposure to water. On the other hand, the heat-insulating products made of shavings with epoxy resin of 4.41 % showed their resistance to moisture absorption

DEVELOPMENT OF NEUTRON IRRADIATION TEST BENCHES TO STUDY THE PHYSICO-CHEMICAL STABILITY OF FM-1 SILICOME FLUID

In this work the special neutron irradiation test benches were constructed on the basis of working neutron sources. The energy spectrum and flux density of neutron radiation were determined. The benches were used to study physical-chemical stability of FM-1 silicon fluid

Modeling a Thermal Conductivity Process Under the Action of Flame on the Wall of Fire­retardant Reed

Creating environmentally friendly flame-retardant materials for natural inflammable roof structures will make it possible to control the processes of thermal stability and physical-chemical properties of a protective coating over its life cycle. There is therefore a need to study conditions for the formation of a thermal conductivity barrier and for the establishment of a mechanism that inhibits heat transfer to the material. It was experimentally determined that reed, non-treated with a flame-retardant agent, was ignited under the action of burner in 5 seconds, with the flame spreading throughout the entire surface, which resulted in its complete burning and the loss of mass. The study that we conducted into the influence of a coating on the transfer processes of a high-temperature flame to a material, established the fire protection process mechanisms, which imply the inhibition of such an action. It was proven that this process includes the decomposition of flame retardants under the action of temperature, with heat absorption and release of incombustible gases, the formation of ash-like products at the surface of a natural combustible material, as well as thermal insulation. That made it possible to determine conditions to protect reed from fire by forming a barrier to thermal conductivity. Experimental study has confirmed that a sample of fire-retardant reed withstood a thermal influence; the action of a heat flow lead to the swelling of the impregnation and the coating, which lasted for 120 seconds. We estimated the maximum possible penetration of temperature through the thickness of a coating and established that when reed, protected by the impregnating composition, was exposed to a flame of the burner, temperature at the inner surface was less than 147 °C with the mass loss not exceeding 2.9 %. Even greater efficiency was demonstrated by samples that were treated with the coating; the temperature did not exceed 140 °C, with a 2.5% mass loss. We also established that the coefficient of thermal conductivity, when protected from fire, reaches 1.6 W/(m∙°C) for the impregnating composition, and 1.2 W/(m∙°C) for the coating, respectively

Establishment of Fire Protective Effectiveness of Reed Treated with an Impregnating Solution and Coatings

An analysis of techniques for determining the fire protective effectiveness of reed was performed; the need to develop reliable methods for studying the process of ignition and flame propagation around the surface of the building structure, required to create new types of fireproof materials, was established. Estimation of ignition time and time of passing the surface area by the flame front revealed the unreliability of the actual values of the flammability index. The method for determining the process of ignition and propagation of flame of fire protected materials was substantiated and, taking into account the permanent conditions of heat and mass exchange in the course of testing, the setup was developed. Determining the flammability index implies the impact on sample of the heat flux of the electric radiation plane and the sample ignition by the burner. In also involves determining the thermal coefficient of the plant, measurement of the maximum temperature of combustion products and the time of its achievement, ignition time and the time of passing the surface sections by the flame front, the length of the burnt part of the sample and calculation of flammability index.The conducted research into the process of ignition and flame propagation along the reed surface using a given technique showed that the raw sample under thermal influence ignited at second 52, the flame propagated across the whole sample over 100 s. The fire protected sample, treated with the impregnating solution based on the mixture of inorganic and organic substances, specifically the mixture of urea and phosphoric acids and natural polymer in the amount of 47.1 g/m2, ignited at second 595, flame propagation along the surface occurred only at the first section, the maximum temperature of flue gases was 114 °C, flammability index decreased to 0.42.The results of determining the flammability index showed that under the influence of high temperature flow on the coating in the amount of 46.2 g/м2, ignition and flame propagation did not occur, flammability index was 0. Due to intense swelling, there occurred a slight increase in temperature in the vent pipe. A decrease in the flame retardant in the composition by two times at the same consumption resulted in an increase in flammability index for the roofing impregnating solution up to 5.8, and for the swelling coating up to 0.96, respectively. The above results make it possible to establish the ratio of flame retardants and polymers in these compositions and their required quantit

Influence of Dry Mixtures in a Coating on the Effectiveness of Wood Protection From the Action of a Magnesium Flame

We carried out an analysis of the occurrence of fires and explosions on objects of storage of explosive products and established that one of the greatest risks is a fire hazard. Since the storage of such products involves the use of wood, both in building structures and packaging products, it is important to establish effectiveness of fire protection at high temperatures and influence of components that are part of the composition, and their role in ensuring fire resistance and fire protection mechanisms. This makes it possible to develop effective methods and means for extinguishing fires in such classes and take into account their peculiarities. We proposed a composition to counteract a high temperature. The basis of its mixture consisted of fire retardants (ammonium polyphosphate), gas formers (melamine), carbohydrates (pentaerythritol), and high-temperature fillers based on mineral substances. Studies showed that charring depth under the action of magnesium flame for untreated wood samples was larger than 16÷20 mm. Instead, after the fire protection treatment of wood with dry mixtures coating, the charcoal depth did not exceed 5÷6 mm. This allows us to conclude that the fire protection of wooden structures and the use of dry mixtures for the localization of magnesium flame is appropriate.Extinguishing of the magnesium flame with samples of dry mixtures coating with the addition of aluminosilicate microspheres, perlite, basalt scales, metallurgical sludge and ashes in the amount of 10 % showed the intensity of the supply of powder in the extinguishing of magnesium flame in the range of 0.034÷0.041 g/(cm2·s), which is significantly lower than the sodium chloride supply rate. The results of determination of the efficiency of extinguishing magnesium flame with dry mixtures coating indicate the ambiguous effect of fillers on the change in supply rate during flame extinguishing. The greatest effect is demonstrated by the mixture with the addition of basaltic scales, its supply rate is the lowest when extinguishing the magnesium flame and is 0.034 g/(cm2·s

Research of the Mechanism of Protecting Wood with Intumescent Coating

The object of research is intumescent coatings for wood, which, under the influence of high temperatures, are capable of forming a coked cellular material layer on the wood surface, which prevents the passage of temperature to the material. One of the most problematic areas in the application of these coatings is the unknown efficiency of the application and their performance characteristics. The effectiveness of wood fire protection in building structures and wood products is determined by the level of their ability to withstand thermal effects and is determined by the schedule of components under the influence of temperature with the absorption of heat and the formation of non-combustible gases. Thermal destruction of protected wood was carried out and volatile destruction products were identified, and a change in the components was obtained, namely, during thermal decomposition of fire-protected wood, the amount of combustible gases decreases and the amount of inert gases increases in the reverse order. To establish the effectiveness of wood protection with the given coating, it is necessary to conduct research on the wood flammability. In the course of the study, standardized equipment in accordance with DSTU 2289 was used. It was experimentally established that the treated wood is characterized by a low weight loss (2.2 %) and a flue gas temperature of less than 200 °C, and also belongs to hardly combustible materials. This is due to the fact that the coating, when exposed to high temperatures, forms a significant swelling coefficient and contributes to the formation of a heat-insulated coke layer, which prevents the wood from burning out, and the passage of high temperature to the material. Thanks to this, it is possible to obtain wood with indicators that do not spread a flame on the surface, and with a moderate smoke-forming ability. Compared with similar known inorganic-based coatings, characterized by low adhesion to wood with fluctuations in temperature and humidity, it provides such advantages as lower coating consumption and its weather resistance

Defining Patterns of Heat Transfer Through the Fire-protected Fabric to Wood

Under the thermal action on wood when applying a protective screen made from fire-retardant fabric, the process of temperature transfer is natural. It has been proven that depending on the thermal properties of the coating of fire-proof fabric, this could lead to varying degrees of heat transfer. Therefore, it becomes necessary to study the conditions for establishing low thermal conductivity and establishing a mechanism that inhibits heat transfer to wood. Given this, a mathematical model has been built of the process of heat transfer to wood when it is protected by a screen made of fire-proof fabric. According to the experimental data on determining the temperature on the non-heated surface of the fabric and the resulting dependences, the density of the heat flow transmitted to wood through fire-proof fabric was determined. Thus, with an increase in the temperature, the density of the heat flow to the surface of the wood through a protective screen made of fire-proof protected coating based on "Firewall-Attic" increases to a value above 16 kW/m2, which is not sufficient for ignition of wood. Instead, the density of the heat flow through the protective screen of fire-proof fabric protected by the "Firewall-Wood"-based coating did not exceed 14 kW/m2. This makes it possible to argue about the compliance of the detected mechanism of formation of heat-insulating properties in the protection of wood and the practical attractiveness of the proposed technological solutions. Thus, the peculiarities of inhibition of the process of heat transfer to wood through a protective screen made of fire-proof fabric under the action of a radiation panel imply the formation of a heat-insulating layer of coked cellular material when decomposing the coating. Thus, on the surface of the fire-proof fabric, a temperature above 280 °C was achieved and, on an untreated surface of the fabric, it did not exceed 220 °C, which is insufficient for the ignition of wood

Modeling the Process of Moisture Diffusion by a Flame-retardant Coating for Wood

Description of performance of fire-protective coatings during operation of a wooden construction structure is a separate and complex task that covers both stages of the protection process: both moisture protection and further heat transfer that occurs when the coating swells. It has been proven that they imply creating a layer at the surface of the material, which prevents the penetration of moisture to wood when the swelling of a wooden structure and the destruction of the coating begins. Due to this, it becomes possible to determine the effect of flame retardants and the properties of protective formulations on the process of decelerating the rate of moisture absorption of wood. When using fire-retardant coatings for wood, as it is indicated by the research results, typical processes imply the formation of a protective layer under the impact of temperature and a decrease in humidity, which slow down the moisture diffusion processes. It seems likely that such a mechanism of a fire-retardant coating is a factor in regulating the degree of formation of a weather-resistant protective layer and the effectiveness of heat and moisture insulation of the material. We have modeled the process of moisture transfer by a fire-retardant coating; the diffusion coefficient was determined and the estimation dependences were derived, which made it possible to obtain a change in the dynamics of moisture when drying a fire-retardant coating. Based on the derived dependences, the moisture diffusion coefficient of a fire-retardant coating was calculated, which amounts to 0.163·10-9 m2/s. The results from determining the mass loss of the coating sample during drying indicate the ambiguous effect of the nature of a protective agent on the change in humidity. In particular, this implies the availability of data sufficient for the qualitative implementation of the process of inhibition of moisture diffusion and the identification, on its basis, of the point in time that gives rise to a drop in the coating efficiency. The features of inhibiting the process of moisture transfer to wood, which was treated with a fire-retardant coating, include several aspects. Specifically, the use of water-insoluble flame retardants and other components, as well as a polymer binder, characterized by the formation of a heat-insulated layer at the wood surfac