Guangzhou Baiyun District, a warehouse fire yesterday at 5 pm unexpected, almost all the goods of the warehouse were destroyed. Canton Fire Brigade dispatched 11 sets of the second fire, which lasted 5 hours to extinguish the fire, but fortunately no casualties.
The Street glue gun lying in the same warehouse Hill Street Political Department of the Guangzhou Military Region, all, and residential buildings only separated by a small road. Warehouse fire about 300 square meters, was divided into six, he stored pesticides, chemicals, auto parts, plastic products.
April 11 around 10:30 the night, firefighters extinguished the fire base. According to the relevant person in charge, after a preliminary investigation, plastic products in the warehouse store, a gas cutting tool to cut workers to use waste plastic, the not properly power, high temperature fire, the workers are illegal operations.
On the dangers of polyurethane foam and fire prevention.
Abstract: decoration materials on fire, releasing large amounts of toxic smoke, causing heavy casualties, glue stick the "culprit" is decorated with polyurethane foam. Therefore, the understanding of the fire hazard of polyurethane foam, research fire prevention measures are very necessary.
Key words: polyurethane foam fire hazard prevention measures.
First, the fire risk.
"PU" All known polyurethane, foam made of this material has superior insulation, thermal insulation and sound insulation. Polyurethane foam, plastic foam Common name (hereinafter referred to as polyurethane foam), is the production, extensive use of the best-selling life products. Polyurethane foam is a porous solid product, thermal conductivity is extremely poor and likely to cause heat buildup. The flash point of rigid foam 310 ℃, ignition temperature is 416 ℃, 1 per thousand burning foam can be released 3073.53KJ molar heat. Without flame retardant treatment of the finished product, the oxygen index of 20 or so; by fire-retardant treated between 23 and 27, the individual has up to 30 or so. Occurs at 200 ℃ thermal degradation, release of low molecular weight compounds such as CO and alcohols.
For flexible polyurethane foam, according to fire the determination of parameters of the results of differential thermal analysis, the initial decomposition temperature is 260 ℃ or more, intense decomposition temperature is 280 ℃, spontaneous combustion temperature above 330 ℃, easily result in spontaneous combustion and decomposition of the burning. Burning, will the decomposition of hydrogen cyanide, carbon monoxide and other toxic gases, cause you to inhale a few seconds after the poisoning death and burning a lot of smoke, reducing visibility space, people lose their ability to escape.
Second, fire characteristics.
Polyurethane foam fire fire and other combustible solids than the existence of different and unique personality. Main features:
1, easy to produce smoldering.
Experiments show that some of the standard polyurethane foam, even if stored in a separate case, also occur smoldering. Soft polyurethane foam in the still air, resulting in smoldering maximum temperature does not exceed 400 ℃, and the time to continue smoldering for several hours. Rigid polyurethane foam smoldering occurs only on the surface, the maximum temperature of about smoldering about 500 ℃.
2, fast combustion, flame and high temperature.
In the experiment using 150 × 50 × 15mm polyurethane foam sample size determination, the combustion rate of 1.5 ~ 2.0mm / s; burning strong radiant heat, flame temperature has been tested up to about 2000 ℃, heat value of 28 ~ 23MJ / kg, according to fire brigade combat experience showed that the accumulation of 500 kg ignited polyurethane foam, the battle has not yet commenced, all the gun not to burn the water, showing the burning ferocity.
Analysis, polyurethane foam burning speed, high temperature, mainly because the temperature under the action of polyurethane foam, with a rapid decomposition of the characteristics. Decomposition of a variety of small molecules of combustible gas, when its temperature reaches ignition, the limit concentration of combustion occurs when the overall violent explosive combustion, the combustion into the "flashover" state.
3, smoke big, strong toxicity.
Polyurethane foam combustion emit a lot of black smoke. This is due to smoke and contains both a breakdown product of combustion. Moreover, the polyurethane foam produced simultaneously at high temperature dehydrogenation and condensation effects. Dehydrogenation of carbon particles and the formation of a small number of compounds containing hydrogen products of combustion particles and mixed with each other; high-temperature pyrolysis of alcohols, aldehydes and other oligomer or small molecule Condensed droplets are mixed with the smoke, so smoke large, component complex.