Focus on the Development of External Thermal Insulation Fire Protection Technology in the World

The level of research and emphasis on domestic fire protection technology for external wall external insulation systems has been generally concerned by the lack of early development to the current industry. However, most of the technical standards and product descriptions refer to the combustion performance index of thermal insulation materials. Requirements, such as the oxygen index and the determination of Class B2 through flammability tests, have not made specific requirements for the fire protection performance of the insulation system. Although the “High-rise Civil Building Design Fire Prevention Code” and “Architectural Design Fire Protection Code” that are being revised have attempted to add the principle of fire protection for exterior wall insulation systems, there is no fire protection design for external wall insulation systems in the current standards. Requirements: There is a lack of regulations on the fire protection performance of different external wall insulation systems and the applicable building height.

Looking at some of the external insulation systems popularized and applied in the market, there are generally the following fire hazards: First, the organic insulation board thin plastering system has strict restrictions on the scope of its use due to fire performance requirements in some countries, but there are no domestic standards. Make provisions for this. This kind of non-fire-prevention structure system is still used in high-rise buildings with a height of more than 170 meters, and there is a fire risk that should be highly valued by relevant departments. Second, there are many projects for applying high-quality organic insulation boards and thin plastering grids for domestic high-rise buildings. The danger of this process is that after the tiles are bonded, the thickness of the protective layer is increased. Once a fire occurs, the fire performance of the front-end brick system is excellent. In the coating facing system, if the fire continues, not only toxic gases and flames produced by the combustion of organic insulation panels pose great danger to the evacuees, but also the thermal melting and deformation of the organic insulation panels and the overheating of the grid cloth will cause the tiles to fall. There are potential dangers for escape workers and rescue workers.

Third, the current public buildings, the practice of sticking or packing organic insulation materials and no fire isolation measures are common. Generally, in the practice of external insulation of the exterior wall, the organic insulation material is exposed on the inner side of the curtain wall. The large cavity existing between the organic insulation plate and the curtain wall and the small cavity existing between the insulation plate and the wall are all likely to form a chimney effect to accelerate the fire. The rate of spread has made the consequences of the fire even worse. In contrast, in countries with earlier applications of exterior insulation systems in Europe and America, the fire safety requirements for exterior insulation systems have always been the preferred conditions for the application of this technology. External insulation systems and insulation materials for exterior walls have fire test methods and grading evaluation standards. The use of different fire protection grades of exterior wall insulation systems in buildings is limited. According to foreign experts, the most important aspect of exterior wall insulation systems is the quality and safety of the system. Therefore, it is necessary to consider the fire safety of building insulation, especially in high-rise buildings in large cities.

Worldwide, the scope of application for building insulation systems of different fire protection grades is stipulated because of differences in government policies and regulations. Such as Germany will be divided into three levels of insulation fire protection issues: First, in the laws and regulations clearly stipulate that the construction of more than 22 meters is strictly prohibited the use of combustible insulation material, polystyrene wall external insulation system can only be used in buildings not exceeding 22 meters Most buildings above 22 meters use rock wool exterior insulation systems. The second is to stipulate in the European Standard ETAG 004 "European Technical Standards Verification of Exterior Insulation Compound System with Plastering Layer" that external wall external thermal insulation systems and insulation materials shall be in accordance with EN 13501-1 "Classification of combustion performance of building products or components" Part 1 - Classification of fire performance ratings A1-E using fire response test data classification, and stipulate that the possibility of flame propagation in insulation materials should be indicated.

In order to prevent the spread of flames, some countries have proposed the use of “fire barriers (fire barriers)”. The fire protection requirements for external wall insulation systems must be based on laws, regulations, and regulations that apply to the final use of buildings. Germany classifies the fire protection grade into A-B3 grade (non-equivalent GB8624-1997). The standard requires that the fireproof grade of polystyrene material and insulation system should reach Class B1. According to EN 13501-1, polystyrene board materials and insulation The system must meet the B/C level requirements. Third, when the thickness of polystyrene board in the exterior insulation system of polystyrene board is more than 10mm, the fire protection structure shall be constructed under the condition that the first layer is met to meet the building fire safety regulations. The construction method is to add non-combustible high-strength mineral wool fireproof insulation strips to each window sill and upper sill, the thickness of which is the same as that of the polyphenylene plate, and the upward width is ≥200mm; the length direction should be ≥300mm longer than the two sides of the window, and it should be paved with full stickiness. Posts, mainly to prevent the fire in the room when the flame out of the window caused by the external wall insulation system fire.

In the United Kingdom, a building that requires more than 18 meters must use materials that meet British Standard 0 or European Standard B or above, that is, must use non-flammable or non-flammable materials; the Building Code in New York State ("BUILDING CODE OF NEW YORK" It is stipulated in the stipulation that the polystyrene thin-plaster external insulation system with a fire-resistant limit of less than 2 hours is not allowed to be used in residential buildings above 75 feet (22.86 meters). In fact, at present, the global building wall insulation market, external insulation systems made of rock wool and other incombustible materials, has been widely used in various types of buildings, and has become the most widely used exterior wall external wall insulation system in the world. one.

The fire safety of exterior insulation systems is an important and urgent issue related to the safety of people's livelihood. Research from foreign countries on the case of fire caused by thermal insulation material or intensifying the spread of fire and domestic fire accidents can be seen, the current domestic It is an indisputable fact that there are widespread fire safety hazards in exterior insulation systems. Under the background of China's vigorous promotion of building energy conservation, all buildings must meet relevant energy conservation standards. However, about 80% of the insulation materials currently used are organic combustible materials, and the external insulation system of external walls is based on poor fireproof performance. The thin plastering organic insulation system material mainly. From the current status of external thermal insulation systems and the frequency of fires, how to conduct fire safety testing of external insulation systems and improve the fire safety of external insulation systems of various types of buildings is currently A major topic.

Actual national conditions determine that the fire protection performance of exterior insulation systems should be higher than that of foreign countries. China's urban housing is different from Europe and the United States where low-rise and multi-story buildings are dominant. There are more high-rise buildings, high-rise buildings, and even high-rise buildings, especially in the more developed eastern regions. , The urban population and buildings are dense and the distance between the buildings is small.

Fires in high-rise buildings have the following characteristics: First, the fire spread quickly. There are many vertical shafts such as stairwells, elevator shafts, pipeline wells, and air ducts in high-rise buildings. The outer cavity has many cavity structures, forming a towering chimney effect. Once a fire starts, it burns fiercely and spreads rapidly. The second is evacuation difficulties. The high number of people in high-rise buildings accommodates a large vertical distance, coupled with the panic of people in a fire environment and the toxic effects of fire smoke, the safety evacuation is more difficult to solve. The higher the number of floors, the more people there are and the longer the escape time. Third, it is difficult to save. High-rise buildings are as high as tens or even hundreds of meters. It is very difficult to save from the outside when a fire breaks out. Fires that typically occur above the 18th floor are mainly based on firefighting facilities inside the building and self-rescue.

Under such circumstances, how to ensure that building fires are not caused by insulation materials, how to ensure that the fire insulation materials do not contribute to the spread and expansion of the flame, how to avoid the smoke and heat release in the event of a fire will not become an obstacle for people to escape, How to avoid the fire protection when the fire insulation material does not harm the fire and rescue is worth studying. In order to solve the above problems, according to the characteristics of our country's urban architecture, we should deal with the stricter fire protection requirements of exterior insulation systems. No matter whether it is a system product developed by domestic independent innovation or a system product imported from abroad, it must be suitable for the characteristics and national conditions of our country's architecture and meet the fire safety requirements.