The Study Of Typical Lining Material Fire Growth Under The Water Spray Action

Lining material is an important approach of fire spread while water spray is an effective way to control fire spread. For smaller droplet size and higher specific surface area and stronger capacity of absorbing heat comparing with water sprinkler, water spray has advantages of extinguishing fire within shorter time and requiring smaller water amount and avoiding to stain the protective place. There is little work conferring extinguishment of typical lining materials vertical fire spread by water spray in former literature. The function of water spray on typical lining materials vertical fire spread when sprayed horizontally was studied in this paper. Two typical lining materials: plywood lining and flexible polyurethane foams, were chosen in this investigation.The fire control and extinguishment of vertical fire spread when spray on the heating zone of the plywood lining material and the conversion from fire control to extinguishment were analyzed. The expression of critical water flow rate to control the fire spread was deduced theoretically and the factors influencing water flow rate were analyzed.The full-scale fire tests on plywood lining materials extinguishing by water spray were conducted in the ISO 9705 room. The influences of various rate of water application on fire spread were discussed and the critical rate of water application on warm-up area was gained in this paper. A formula to calculate the critical rate of water application was deduced in theory and the critical rate of water application in experiment was calculated.Full-scale fire tests on plywood lining materials extinguishing by water spray at different position were conducted in the ISO 9705 room. Parameters such as heat release rate, concentration of CO and temperature were recorded. The function of spraying on pyrolyzing zone and heating zone of the plywood lining material was discussed.Water droplet can't reach the wall unless it has enough muzzle velocity when it reaches the front of flame plane because of the flow resistance in fire zone. Motion of water droplet varying with different droplet sizes and different original velocities was discussed and the extreme length of droplet was gained. Relationship between droplet size and the time and the distance it passes through the flame zone were analyzed.Considering the different droplet sizes and different velocities, fire suppression mechanisms can be divided to surface and gaseous suppression. The difference of water spraying vertically and horizontally was analyzed by theory. It was found that when horizontally spraying to lining material, the surface suppression plays the major part. Then full-scale fire tests of which the results validated the theory analysis were conducted in the ISO 9705 room.The extinguishment of flexible polyurethane foams fire spread by water spray was investigated. The factors which effect critical rate of water application were analyzed. Full-scale fire tests of 2cm lexible polyurethane foams were conducted in the ISO 9705 room and the critical rate of water application were gained.