Formulation of the problem. For the cities of Ukraine, the problem of preventing the occurrence of fires and minimizing their consequences is of particular importance. Reducing the number of fires and losses from them requires an improved system approach that will ensure the interaction of all interested bodies and organizations to solve the problem. Proceeding from the above we can state that there is a problem for the cities of Ukraine that the main directions of reducing the risks of fires on the objects of the city are developed. The goal of the work. To develop a methodology for reducing the risks of fire on the relevant objects of protection and minimizing their consequences in the event of a fire (damage to the objects from the fire and expenses of fire and rescue units for its elimination). Setting tasks and their solutions. According to statistical indicators of the state of fires in Ukraine, for example, in 2017, the main causes of the fires are: 1) arson; 2) malfunction of production equipment; 3) violation of the rules of fire safety in the installation and operation of electrical installations; 4) violation of the rules of fire safety in the installation and operation of heat-generating units and installations; 5) careless handling of the fire; 6) the wisdom of children with fire; 7) other reasons. The largest number of fires occurred in the residential sector, accounting for 73.8%. The main cause of these fires (up to 71.2%) is the careless handling of fire. Therefore, the main tasks to be solved and related to reducing the risks of fire on the relevant security objects will be as follows: Determine the effect of the fire risk value associated with the risk of fire, on the duration of free burning during the fire. Determine the direct damage from the fire for the object, depending on the duration of free burning. Determine the expenses of the fire and rescue units that are associated with the elimination of the fire. Determine the effect of the fire risk value on the total fire damage. Develop a methodology for reducing the risks of fire on objects of protection. Determination of the risk of a fire is performed on the basis of the statistics of the fire of the State DPSU of Ukraine in the Lviv region (information form F-701 as of December 31, 2017). The total number of fires on the objects of the Lviv region Nn = 3137, and No = 474521 - the total number of objects for the Unified State Register of Deputies of Ukraine, located on the area of the region (data of the Main Directorate of Statistics in the Lviv region). Then εо = 0,00661. After processing the obtained results by the method of mathematical statistics, dependence was obtained for determining the duration of free burning depending on the fire risk. To determine the direct damage from the fire for the object of protection, depending on the duration of free burning, we will use the dependence, where Co is the average cost per square meter of the area of the fire protection object, UAH / m2; SP - area of the object destroyed by a fire, m2. Determine the expenses of the Bf of the fire and rescue units, where Cn - the average cost of one minute of the operation of the PRP during the firefighting process during the time τz.p.p, UAH / min. The main directions were devised to develop the main measures to reduce the "risks of fire" at the protection objects. Conclusions and specific suggestions: Influence of the fire risk, which is connected with the risk of fire, on the duration of free burning during a fire is established, which makes it possible to carry out the analysis and predict the impact of the risk of a fire on the total fire damage and reduce the value of this risk. The work shows that the duration of the free development of a fire has a linear dependence on the fire risk within its classification. 3. It is shown that the area of the fire in the process of its localization increases and it is necessary to take into account when it is determined during the time of free development of the fire.
The methodology of determining the thermal balance during fires in closed room was developed. Thermal balance during a fire is primarily influenced by the temperature of the seat of fire. This temperature depends on the burning rate of combustion products, the area of the fire and its duration and the mass of gas in the volume of the room. The lower calorific value also has a significant effect on the of thermal balance. The value of the heat flow, which passes into the walls of the room at all stages of the fire, was estimated. Analytic expression for determining the heat absorption coefficient depending on the duration of free burning was obtained. The results of research show that the heat absorption coefficient φ is not a constant value – during the fire it changes its value and reaches a maximum (no more than 0.5). Increasing of the volume of the room leads to increasing of the heat loss (more heat goes into the environment), which reduces the thermal load on the building structures.
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