An Influence of the Peculiarities of the Concentration Field of Gaseous Fire Extinguishing Substances with High Boiling Point on Their Fire Extinguishing Properties

Behaviour of fluoroketone CF3CF2C(O)CF(CF3)2 as gaseous fire suppressant in various volumes was studied computationally and experimentally. It was showed that non-uniformity of the concentration field of fire extinguishing agent having high boiling point influences strongly its effectiveness: extinguishing concentration of the fluoroketone rises from 3.5 % vol. in the smallest volume (1 m3) up to 4.5 % vol. in 100 m3. Relatively uniform extinguishing medium was found in 1 m3 only. In bigger volumes a torus-like inhomogeneity with a reduced concentration of fire suppressant in the middle part of the room is formed. To compensate this effect it is necessary to increase the average concentration of the agent. More complex geometry of the experimental premise may cause appearance of long-term existing non-uniformity of extinguishing environment which is difficult to overcome by increasing the average concentration of fire suppressant or by increasing the discharge time. To obtain practically effective test results it is necessary to increase standard test chamber to 100 m3 (or more).