DEFINITION OF THE LENGTHENING VALUE OF USED T-TYPE FIRE PRESSURE HOSES BY CONDUCTING OF NATURAL EXPERIMENTS

Abstract

The phenomenon of changing of the geometric parameters of pressure fire hoses is manifested while their transport fire-extinguishing liquids. First of all, the length and diameter undergo changes. The lengthening of pressure fire hoses doesn't have a significant effect on the fire extinguishing process, but it is worth considering the energy costs that ensure such changes, when part of the fire pump power is spent not on transporting liquids and forming fire extinguishing jets, but on the "optional" lengthening of pressure fire hosesFor the experiments, were randomly selected latex pressure fire hoses with diameters of 51 mm and 77 mm and fire hoses with double-sided polymer coating with diameters of 51 mm (all T type ). The temperature was -10°С and +25°С, the liquid consumption was constant, the pressure values at the entrance of the PROTEK 366 handline nozzle ranged from 0.2-0.4-0.6-0.8 MPa. The biggest lengthening in 79 cm with a fire hose length in 1960 cm and 73 cm with a fire hose length of 1790 cm was fixed in case of using hoses with a diameter of 77 mm, a pressure at their inlet of 0.8 MPa, a temperature of +25°C and a water flow rate of 0 l/s. The force providing such tension was 2.04 kH. The lengthening slightly decreased with decreasing temperature. There was detected a slight unevenness of the stretching of pressure fire hoses along the length, especially when the stretching increased closer to their middle. There were no significant changes in the diameters of pressure fire hoses when they transported water. The obtained results indicate the dependence of the amount of their lengthening on the materials from which pressure fire hoses are made, as well as their diameter. Thereby, while designing new types of latex pressure fire hoses, manufacturer should take into account the geometric features of thread winding, primarily the density and diameter. The values of dynamic forces determined in the study, which cause the stretching of pressure fire hoses, can be used in practice if we will taking into account the forced energy losses for liquid transportation.