Research On Timber Yard Log Piles Water Mist Fire Extinguishing

The timber yard which is responsible for logging, making woods and transferring woods is the final mountain landing, it hoards a large number of log piles. The timber yard is the collecting and distributing center of timber, it not only takes charge of the final processing in timber production process but also allocates process flow to the market. Once the timber yard fire can’t be restrained timely, it will change into forest fire which causes major disruption in property security, economic benefit and ecological benefit. Traditional fire extinguishing methods in the timber yard are water spray, dry powder fire extinguishers and halon fire extinguishers. Water particles produced by water spray have larger relative superficial area, it is labeled by fire extinguishing speed fast, environmental protection, but the characteristics of high water consumption with chils flame temperature directly and goes through the flame; dry powder fire extinguisher has high fire extinguishing efficiency, but the storage temperature is unfavorable and exorbitant, they affect the body health after being used; halon fire extinguishers have been banned by the world because they damage Atmospheric ozone layer even they have fine characteristics of high fire extinguishing efficiency, non-conductive, no residue. At the end of20century, the emerging water mist fire extinguishing technology is widely used in city building fire because it has the characteristics of no pollution, less water consumption, the advantages of small damage to protect the object and so on, but it just enters the preliminary experimental research stage in the lumber yard log piles firefighting.Based on the characteristics of water mist fire extinguishing technology, carrying out the burning experiment in timber yard log piles and log fire extinguishing experiment under water mist. Comparing the combustion characteristic of log piles under water mist and observing the fire extinguishing effect of log piles under water mist. The text explores the changes of temperature, carbon dioxide, oxygen and carbon monoxide concentration in typical burning space inside and outside of the water mist fog cover.At last, the text analyzed the correlation of temperature field by using mathematical statistics software-SPSS and the correlation about concentration of carbon dioxide, oxygen, carbon monoxide in logs produced inside and outside of the water mist fog cover. Based on the research on combustion characteristic of timber and timber yard log piles, water mist fire suppression mechanism, combined with water mist fire extinguishing properties, the characteristics of temperature and flue gas produced by log piles under the effect of water mist, exploring water mist nozzle used in timber yard log piles pressure parameters and installation optimization setting.The experimental results show the highest temperature could be1000℃when timber yard log fire spreads to the stable combustion phase; the effect of water mist control fire sprawling is remarkable when log just enters spreading stage; the experimental results show the surrounding temperature is lower than the temperature of it’s bottom, middle and top; the front temperature has positive correlation with the back’s and left’s, so the right’s is to top’s,middle’s and following’s; the pressure of nozzle determines the flow and droplet size distribution and affects the effect of water mist spray directly, when gas and liquid pressure ratio is2corresponding spray effect is best. when nozzle is placed in the ground, installation number of alpha is N=1/8.5m3, installation angle between56.3°and78.94°, the fire extinguishing is optimal.