Fire suppression mechanisms of solid fires with water mist

The LDV/APV system was employed to determine the water mist characteristics discharged from a single pressure nozzle. Small scale tests on the behavior of solid fires with different fuel characteristics suppressed by water mist were carried out in a 3 m × 3 m × 3 m enclosure. Results show that fuel surface cooling is the key mechanism for extinguishing solid fires with water mist. Under the same suppression condition, the charring solid fires are more easily to be extinguished than fires without char. However more water is needed to cool down the charring solid fuel in order to prevent re-ignition. The relationship between mist flux and extinguishing time satisfies the marginal utility decreasing theory, which indicates that there exists an optimum mist flux to get the maximum efficiency.