FIRE RESISTANCE OF STEEL AIR DUCTS WITH COMBINED FIRE PROTECTION SYSTEM

Abstract

The results of research of fire resistance of steel air ducts with the combined system of fire protection in the conditions of fire influence according to the standard temperature regime according to DSTU B V.1.1-4 are resulted. Steel air ducts were investigated, in the design of which two fire protection systems were used, in which passive fire protection material material (fiberglass "IPS-T-1000") and reactive fire protection material materials ("Endotherm HT-150" and "Endotherm 250103") were used. The research method is applied, which is based on the provisions of DSTU B V.1.1-16. The essence of this technique is that the samples of steel ducts are installed in the vertical support structure of the furnace and exposed to fire. According to the obtained experimental data, the integrity and thermal insulation capacity of air ducts are evaluated. According to the results of the research, the peculiarities of temperature distribution on the unheated surface of air ducts in the conditions of fire influence and characteristics of fire resistance of steel air ducts with the combined fire protection system are determined. It is shown that the temperature is most important on the unheated surface of the duct near the place of its compaction in the vertical enclosingstructure. The temperature on the surface of the duct at a distance of 325 mm from the enclosing structure is several tens of degrees lower than the temperature on the surface of the duct at a distance of 25 mm from it. The period of time to achieve the loss of thermal insulation capacity of air ducts and the class of their fire resistance, which is EI 45. The direction of further researches which are focused on revealing of dependencesbetween a time interval before achievement of loss of thermal insulation capacity and thickness of layers of the combined system of fire protection for steel air ducts is defined. This detection will determine the optimalparameters of the combined fire protection system for steel air ducts, acceptable to ensure their fire resistance for a wide range of duration of fire exposure at a standard temperature.