At present, building exterior wall insulation material is one of the important items of interior decoration material sampling inspection, which is related to its frequent fire accidents. For example, the CCTV building fire originated from the use of Non-Flame-Retardant organic thermal insulation materials. The incomplete combustion and pyrolysis of these materials will produce more smoke and poisonous gases, and most of them are suffocated by inhalation of smoke and poisonous gases. Therefore, the fire risk caused by the building exterior wall is very high, and it is easy to cause serious casualties. The author talks about the causes of the fire and preventive measures combined with the working experience. First, the analysis of the reasons for the fire of exterior wall insulation materials. First, the industry standards are not perfect and the product quality is uneven. At present, the production and use of external thermal insulation materials are chaotic. The organic thermal insulation materials currently used in the construction field mainly include EPS, XPS and PU. Their advantages are light weight, good thermal insulation and good thermal insulation. The defects of **** are poor fire safety, aging and flammability. The former two are widely used because of their low cost, while the latter is slightly superior in thermal conductivity, construction performance and combustion performance. The industry standard of exterior wall thermal insulation material is not perfect, and there are loopholes in the management of individual manufacturers. The exterior thermal insulation material produced can not meet the requirements of building fire protection design at all. The fire resistance grade and fire resistance limit can not meet the national standard. After the products are put into the market, congenital safety risks are buried for building fire accidents. Second, the construction period is long, and hidden dangers are numerous in the work site. For the construction industry, energy-saving and thermal insulation is the national policy, wall thermal insulation is an important means to achieve building energy-saving, so the application of building thermal insulation materials is very extensive. In reality, the construction period of high-rise buildings, large-scale stadiums and other buildings is generally two to three years, and various construction processes are cross-cutting, which makes management inconvenient. Individual managers neglect the investigation and remediation of potential fire hazards on site and the setting of temporary water for fire prevention, and concentrate all their efforts on catching up with the construction period and reducing the cost.
During a long period of two to three years, there are many combustible materials in the work site, which makes it difficult to detect fire hazards in time. External wall thermal insulation materials have the characteristics of rapid spread, hidden combustion, once the fire is difficult to control and so on. It is easy to cause heavy personnel and property losses due to carelessness of field personnel. Thirdly, the cost of qualified materials is high, and the construction units are second best. Ji Guangqi, a researcher at the Institute of Architectural Fire Prevention, Chinese Academy of Architectural Sciences, once said in a CCTV program entitled "Flammability and Worry of Building Thermal Insulation Material": "In fact, many thermal insulation materials, whether polyphenyl or rigid foam insulating paper, are not up to the standard, that is, B3 pole, all belong to flammable materials. It's easy to start a fire when it's almost on fire. Taking the extruded board as an example, the price of the extruded board which meets the fire protection standard is more than twice that of the flammable one. At present, thermal insulation materials are divided into four grades: non-flammable, B1 (non-flammable), B2 (flammable), B3 (flammable). There are two kinds of inorganic thermal insulation materials and organic thermal insulation materials. The former is non-flammable, but the thermal insulation effect is poor, only about 20% of the market share. The latter has good thermal insulation effect, but it is flammable and occupies 80% of the market. Therefore, it is necessary to add a certain amount of flame retardant in the materials. To make it up to the standard, and flame retardants are expensive, many businesses in order to pursue profits, they add less flame retardants, and some even do not. Individual construction units purchased inferior thermal insulation materials deliberately to make the second best, save costs, coupled with inadequate fire control supervision, it is easy to blur through. Second, the fire prevention countermeasures of exterior wall thermal insulation materials are to improve the public's awareness of exterior thermal insulation materials and to achieve scientific prevention. From a realistic point of view, it is impossible for people to totally deny the use of external thermal insulation materials in buildings because some of them are flammable. In fact, the key lies in how to use them safely and regularly. If we standardize the use of exterior wall insulation materials, increase the supervision of exterior wall insulation materials, complete fire extinguishing measures and improve safety awareness, most of the fires caused by exterior wall insulation materials can be prevented. At present, a large number of new domestic buildings use organic external insulation materials, such as moulded polystyrene board, extruded polystyrene board and foamed polyurethane. Their thermal insulation performance is better than most inorganic materials, and they are the mainstream building thermal insulation materials.
However, in terms of material properties, they have low ignition point and are flammable. If they are wrapped in a large number of buildings with a certain flammability of thermal insulation materials, it will inevitably leave a fire hazard to the building. Therefore, the relevant departments must strengthen the fire control management of such buildings, and improve the public's scientific understanding of these materials, so as to achieve scientific prevention. Second, strict construction site management to eliminate potential safety hazards. According to a domestic statistical report, about 25% of the fires involving building thermal insulation materials occur during the storage of thermal insulation materials, 65% occur in the laying process of thermal insulation materials, and less than 10% occur in the use of buildings. Therefore, the construction process of building wall insulation is a high-risk period of fire. Supervisory departments should strengthen the standardized management of the production enterprises, construction enterprises and the market of building thermal insulation materials, carry out the certification of wall thermal insulation system, introduce permits, insurance and other systems, in order to improve the safety of building wall thermal insulation. When carrying out fire control supervision and inspection, fire departments should convey fire prevention awareness to construction site managers, and also require the construction site to ensure that each working face has fire water supply, in order to carry out self-rescue in case of fire. Only by strict construction site management can the hidden dangers of fire safety be eliminated to the limit. Third, we will update and improve all kinds of fire fighting and rescue equipment and enhance our ability to tackle key problems. At present, the speed of "long height" of fire fighting equipment in China is far behind the speed of "long height" of buildings.
According to statistics, in recent years, more than 100 super high-rise buildings have been built in China, and a number of them are under construction. Combining with the characteristics of high-rise building exterior wall thermal insulation material fire, such as great destructive power, great difficulty in fighting and fire spreading ways, fire departments can consciously add eddy spray fire trucks, high spray fire trucks and ladder fire trucks according to the government's fire fighting plan and the actual situation of regional economic development, and use high-end equipment to enhance the emergency rescue and combat capability of fire forces. And extinguishing exterior wall insulation material fire quickly to prevent mass casualties and casualties. In short, the extensive use of building exterior wall thermal insulation materials makes the building fire prevention problem not only consider the building interior fire prevention, but also consider the building exterior fire prevention. Only by earnestly drawing lessons from domestic fire accidents, recognizing the root causes of external wall insulation material fire, and taking effective measures, can urban fire safety be based and people's life and property safety be guaranteed.
