Why is the water droplet size in a Water Mist System important?

Smaller droplet sizes result in a more efficient use of the water. Water Mist works by flashing of the droplets to steam, resulting in reduction of the Oxygen content of the remaining air and cooling of the fire by causing loss of energy (steam production) and continued application of the water mist droplets. Smaller droplets have more surface area which increases the heat transfer rate from the fire, the water flashes to steam rapidly. In addition to this heat absorption and resultant cooling, the steam displaces oxygen, at the fire, thereby accomplishing extinguishment. In general, High Pressure Water Mist Systems discharge water in smaller droplets than do either Intermediate Pressure or Low Pressure Water Mist Systems. Because of the use of Dual Media, the Securiplex FIRE-SCOPE2000 System produces a water mist in the 150 - 200 micron range which is in the same order of magnitude as most High Pressure Systems. We have been asked to propose a Water Mist System for a room containing ...  more