DETERMINATION OF THE OPTIMAL THICKNESS OF FIRE-RESISTANCE PARTICULAR AROUND FURNACES AND CHIMNEYS IN BUILDINGS WITH COMBUSTIBLE BUILDING STRUCTURES

Abstract

Introduction. Heating stoves, which account for 80% of the total heat produced in rural areas, are widely used in single-storey buildings, both in the existing housing stock and in new construction. Fires that occur in residential buildings often lead to death and injury. Among the causes of fires violations of fire safety rules during the installation and operation of furnaces, heat-generating units and installations are 29.2%. The article aims to research fire safety at the device of furnaces and chimneys in buildings with combustible constructions.
Methods. Some methods were used in the work, in particular, statistical, system, comparative, as well as the method of mathematical modelling of the heat transfer process in a multilayer flat structure to determine the temperature of the outer surface depending on the thickness and material of the chimney.
Results. The article analyses the fire hazard of furnace heating, which consists in the presence of high temperatures on the surface of the furnace elements (walls, pipes, pipes), which can be a source of ignition of combustible materials and combustible structures of buildings. The temperature on the surface of the elements of non-heat-burning furnaces depends on the type of fuel burned, the mode of the furnace fuel and can exceed 600 oC. The temperature in the fuel of heat-intensive furnaces can be over 1000 oC, and in the flue near the floor - 500 oC. The degree of heating of the side surfaces and the floor of the furnace, as well as the flues, depends on the thickness of the walls, the type and amount of fuel burned and the duration of combustion.
The temperature on the outer surface of the fire partition is calculated depending on the size and geometric shape of the chimney cross-section at a flue gas temperature up to 4500 C. This temperature is formed during the operation of boilers and furnaces in turbo mode. Researches were carried out for chimneys from various materials, in particular: from a ceramic brick of various thickness, from a ceramic brick and a layer of cement-sand plaster, from a ceramic brick and alteration from concrete, from a ceramic brick and alteration from mineral wool, from heat-resistant concrete and alteration from mineral cotton wool, steel.
Conclusion. To prevent a fire in the chimneys, it is necessary to regularly inspect the heater and chimney, to make the correct selection of the power of the heater. Based on the above analytical dependences, the optimal thickness of the fire-fighting partition around the chimney was determined, it was found that this thickness is significantly affected by the thermal properties of building materials from which the chimney and partition are made. It is shown how with the help of mathematical modelling of the heat exchange process, if necessary, you can set the temperature on the surface of the chimney of any building material. It is established that chimneys that have the shape of a cylinder are heated less than rectangular ones.