ESTIMATION OF THE TIME OF REACHING FIRE AND EXPLOSIVE CONCENTRATIONS IN THE ROOM WHEN A PROPANE-BUTANE CYLINDER IS DEPRESSURIZED

The study was conducted in the context of military aggression, where the use of propane-butane by the population of Ukraine for cooking and heating has become particularly relevant due to periodic power outages. This situation creates additional threats, as the fire and explosion hazard of gas cylinders, particularly their depressurization due to critical pressure and temperature increases, is determined by several key factors. Incidents related to gas explosions regularly occur worldwide, causing significant material damage, infrastructure destruction, and, most importantly, human casualties. The authors conducted a detailed analysis of the influence of the adiabatic coefficient and system pressure on the nature of gas leakage from the cylinder. The range of parameters under which the leakage is supercritical was determined. The use of the dependence for supercritical gas leakage from a gas cylinder is justified , as it is the most appropriate for calculating leakage parameters within the operating range of propane-butane cylinders (pressure above 0.174 MPa). The analysis showed that when the coefficient changes from 1,13 to 1,15, the change in ( 0,5) Q/ S is no more than 1% , which allows the use of an averaged coefficient value without significant errors. A key result of the study is the establishment of the dependence of the mass flow rate of gas from the cylinder on the hole area and pressure in the event of possible depressurization. It was found that with a hole area of 1 mm2, the gas flow rate ranges from 0,0012 to 0,0028 kg/s. This indicates that with small hole areas, gas leakage will be insignificant, and the user may not notice it due to low flow rates. At the same time, the time to reach a fire and explosive concentration critically depends on the hole area and can range from 20 seconds to 10000 seconds. For a hole area of 1 mm2, the time to reach an explosive concentration is between 10 and 20 minutes. Gas ignition (explosion) in a room is possible if the gas concentration in the room is within the range between the Lower Flammability Limit (LFL) and Upper Flammability Limit (UFL). The obtained results are important for developing effective preventive measures and monitoring systems aimed at preventing gas explosions and minimizing their consequences.