PU technology China's building thermal insulation materials go from Huang Maosong Jia Runping School of Materials Science and Engineering, Shanghai Institute of Applied Technology Shanghai In March this year, the Ministry of Public Security Fire Department issued a plan. In the second chapter of the first chapter of the "No. 46" document in September 2009, the combustion performance of civil building exterior insulation materials should be Grade A, and should not be lower than Grade B2. As a result, the construction materials industry in China has caused great shocks. According to this document, organic insulation materials will not be allowed to be used in the field of civil construction, and only inorganic insulation materials can be applied. Inorganic thermal insulation materials still have many problems in the application of high-rise buildings in China, and the architectural design department is also difficult to promote and use, and its current supply is far from meeting the huge demand for building exterior insulation in China. At the same time, the pace of building energy conservation in China is accelerating in all parts of the country. According to the national energy-saving standards, the construction of buildings in China cannot meet the requirements of energy-saving technical indicators and cannot be used. According to the new regulations, the fire safety performance of organic insulation materials does not meet the requirements of Class A, and it cannot be used. Therefore, the construction of external thermal insulation of many buildings under construction in China has been in a state of heavy shutdown. People are anxiously waiting for this "shock" time to end when China's building insulation materials go to the new standards when to introduce the industry.

1. Development and application of foreign building thermal insulation materials 1.1 The EU attaches great importance to building energy conservation The EU national statistics show that 50% energy is used for building HVAC and air conditioning, and improving building energy-saving insulation effect is the most effective way to reduce CO2 emissions; The improvement of the insulation effect of the wall and roof is equivalent to the reduction of 3.3 million barrels of oil per day. According to 2010, the energy cost of the year is 8 billion euros, and from 2015, it can save 14.5 billion euros per year.

The 25 countries of the European Union will carry out energy-saving renovation of existing buildings, which will create employment opportunities for 530,000 people.

In Europe, the government has adopted a series of incentives for building energy efficiency, such as energy-saving renovation of typical existing buildings, and the government gives preferential policies for interest-free or low-interest loans. In Europe and the United States, the building energy conservation is graded, and according to the size of energy conservation, professional institutions will issue grade certificates when the building is completed. Real estate developers must present energy-saving certificates when the house is sold. This measure guarantees the enthusiasm of house builders for energy-saving design.

In the European Union, more and more buildings require energy efficient insulation products.

It is considered that PU insulation material has a low heat transfer coefficient and a long working life, and is a highly efficient heat preservation product.

1.2 In Europe and the United States PU insulation materials are getting more and more attention in Europe and the United States, building insulation materials are mainly based on organic insulation materials, of which PU insulation materials are getting more and more attention, and the application in the construction field is more and more extensive.

There are three main forms of PU insulation materials used in Europe and America: spraying, PU sheet and metal sandwich panels, of which spraying and sheet are mainly used for civil and commercial building exterior walls, wall insulation, internal insulation, roof and so on. Metal sandwich panels are mainly used in civil buildings, commercial buildings, factories, and warehouses.

In the UK and Germany, PU metal sandwich panels are used in both exterior and roof of office and commercial buildings. In Europe, PU sandwich panels have been used for 35 years.

In the European Iberian Peninsula (including all of Spain, Portugal and France), the PU rigid foam insulation system is the most widely used form of insulation, enabling buildings to meet energy efficiency standards and provide comfort. In Spain, more than 35 million square meters of buildings use PU insulation materials every year. PU rigid foams come in two forms, namely internal insulation and external insulation. In Europe, PU hard foam insulation materials have been used for more than 30 years, whether it is spray coating or sheet metal construction. In Europe, Germany, Poland and Russia, PU has been widely used in exterior insulation systems.

According to the relevant experts of the American PU Industry Association, a survey of 160 sets of 1600 suites in the United States that have been sprayed with PU roof insulation and waterproofing system shows that the construction time of the PU roof insulation and waterproofing system is adopted under the six climatic conditions in the United States. The longest period has been 26 years. So far, 97.6% of the projects have not leaked, 93% of the projects have not deteriorated by more than 10%, and 55% have not been repaired.

In Europe and the United States, why should we use PU rigid foam as the external wall insulation material? Under the premise of achieving the same energy-saving effect, the PU rigid foam insulation layer is the thinnest and shows good fireproof performance; it is also considered that the inorganic thermal insulation material cannot be used in the external wall insulation system. Meet this performance requirement.

In Europe, rockwool sandwich panels are rarely used in residential buildings due to their high thermal conductivity and unstable performance in humid environments, and have been discontinued in cold storage and medical rooms. It is only used in buildings that do not emphasize insulation and emphasize fire rating. For the polystyrene sandwich panel, since it starts to melt at a lower temperature, the combustion produces droplets, and there is a serious fire hazard. Insurance companies have banned the construction of buildings that use polystyrene insulation.

1.3 Overview of fire safety of foreign thermal insulation materials In each member country of Europe, there are different fire protection standards, different fire protection grades, and no uniform fire protection standards; however, the fire safety performance test standards have been unified.

Some performances are requested by insurance companies to test related performance indicators. The main performance indicators include vertical combustion, horizontal combustion, smoke density, dripping, and heat release. The test methods are: small flame (size) burning test, corner burning test and radiation (fire, wind, radiation coexistence) burning test.

In the European Union, it is necessary to measure the fire safety performance of pure insulation materials, as well as the fire safety performance of insulation systems. EU experts believe that for thermal insulation materials, the surface properties of the insulation materials are more important.

German external wall insulation system test standard: small-scale test standard EN13501-1; system test standard DIN4102-20. According to different building heights, different fire protection levels are required: height um meters (low level: below 3 layers): need to reach 4102 E level, It is equivalent to the B2 level of China's GB8624-1997.

Both PU and PIR (polyisocyanurate) insulation materials are available, eliminating the need for fire barriers.

7 meters height > 22 meters (high level: more than 8 layers): A grade insulation material is used.

Discussion is being made on the possibility of using PIR insulation, which is less than 22 meters in most buildings in Germany.

In Europe and the United States, most of the external wall insulation materials are non-toxic, and this is required for special occasions.

Japan PU Industry Co., Ltd. (U) Business Planning Department, Shouya Kiyoshi, reported their research results at the PU Fire International Forum held in Beijing in 2009. U The test for the toxicity of PU foam products was carried out according to the gas toxicity test method. The test results show that the PU foam produced by the PU foam has a longer influence on the stop time of the rats than the standard H. Compared with widely used wood and other building materials, it is confirmed that PU foam does not hinder the evacuation action.

According to the European German DIN53436 standard, the toxicological data of PU hard foam decomposition products and decomposition products such as pine, wool, leather and felt were determined. The results showed that the toxicity of the two was equivalent.

2. Development and Application of Domestic Building Insulation Materials The domestic situation of foreign thermal insulation materials mainly has the following five characteristics: (1) Polystyrene board (EPS and XPS) is the mainstream product. For a long time, China's building materials market insulation materials have been gathering. The main benzene board is about 80%. There are dozens of polystyrene board production plants in China with an annual production capacity of several million tons. Especially in recent years, some large foreign companies have taken the opportunity to introduce polystyrene board insulation materials into China in order to seize the huge building materials market in China. At present, in the field of thermal insulation in foreign countries, a strong economic entity dominated by polystyrene board enterprises has been formed, which has a non-negligible influence on China's building materials market. Polystyrene board has the advantage of low cost and is easily accepted by domestic real estate developers. It has broad potential market prospects for China's vast rural and small and medium-sized urban construction market, as well as disaster-resistant and safe shelters.

PU rigid foam external thermal insulation material has a rapid growth momentum. PU thermal insulation material has the characteristics of small thermal conductivity and excellent comprehensive performance, and is one of the ideal materials for building thermal insulation. Under the strong support of the implementation of national building energy-saving policies and the rapid development of China's PU industry, in recent years, China's PU insulation materials have shown a significant rapid growth and development momentum. China's PU insulation materials have played an increasingly important role in China's building energy conservation.

With the continuous implementation of China's building energy conservation policy and fire safety performance specifications, the prospect of China's PU insulation materials will be brighter and brighter.

China's building insulation materials market has great potential According to the building energy conservation plan of the Ministry of Housing and Construction, China has 2 billion m2 new buildings and 40 billion m2 existing buildings every year. The relevant leaders of the Ministry of Housing and Urban-Rural Development pointed out that in the next few years, China's existing buildings need to carry out energy-saving renovation. According to the standard of 200 yuan per square meter, the future market capacity of building energy-saving materials is as high as 2.6 trillion yuan. China's huge building insulation market not only brings huge business opportunities to building insulation materials, but also saves energy for China and drives the development of related industries to create very favorable conditions.

China's high-rise and super high-rise buildings are developing rapidly. At present, there are 162,000 high-rise buildings in China, more than 1,500 super high-rise buildings with a building height of more than 100 meters, and more than 100,000 high-rise buildings will be built in the next few years. China's high-rise and super-tall buildings have surpassed the total construction of the world, which brings opportunities and challenges to foreign thermal insulation materials. Especially the fire safety of external insulation materials for high-rise and super-tall buildings has become a problem that must be solved in China. This is also a world problem.

The current development trend of high-rise and super high-rise buildings in China is that the number is increasing, and the fire safety is becoming more and more difficult. The difficulty is much greater than that of foreign buildings. Especially in the economically developed eastern region, the urban population and buildings are dense and the spacing between buildings is small. Under such national conditions, how to ensure that the building fire is not caused by the external wall insulation material and how to ensure the fire occurs, the insulation material does not contribute to the rapid spread and expansion of the flame, so that the smoke and radiant heat will not become in the event of a fire. Obstacles to people's survival For these problems, the departments of research, manufacturing, design, application and management of foreign thermal insulation materials must attach great importance to them.

China's external thermal insulation materials construction market management is chaotic and poor supervision.

In the building materials market, China's thermal insulation materials have neither the energy-saving mark certificate nor the fire safety performance mark certificate, so that the insulation materials that fail to meet the requirements of energy-saving indicators and fail to meet the requirements of flame-retardant performance indicators have long been flooding the domestic construction market. . Some unscrupulous builders have put some non-flame-retardant and heat-insulating materials into the domestic construction market in order to replenish them in a timely manner, thus posing a huge fire safety hazard to China's high-rise buildings and super high-rise buildings.

At the 3.15 quality year party this year, we reported on the use of non-flame retardant materials in high-rise buildings in Wuhan and Nanchang. These unconscion builders even ignored the national fire safety regulations after the promulgation of the "No. 46" document of the Ministry of Public Security Fire Department. In some local high-rise buildings, non-flame retardant insulation materials were still openly used. This puzzling situation caused great repercussions in the domestic and industry after the live broadcast of the TV.

In this regard, what important lessons should be learned from continuing to improve the flame retardant standards of thermal insulation materials? Or strengthen management and strengthen supervision over the domestic construction market. 3. What lessons should be learned from three typical major fire accidents in recent years in China since 2009? Three typical major fire accidents On February 9, 2009, a major fire accident occurred at the CCTV Cultural Center (CCTV), causing huge economic losses and serious adverse social impacts to the country. The direct cause of the fire was that the firecracker ignited the titanium zinc plate of the building curtain wall, and then ignited the polystyrene board (XPS), which instantly formed a large area of ​​combustion, and the firefighters could not save the huge flame. The fire was the fastest burning example of buildings since the founding of the People's Republic of China.

On February 3, 2011, a fire accident occurred at Shenyang Wanxin Hotel. In the event of a fire, the flame spreads extremely quickly and is quickly burned from 10 to 37 layers in 15 minutes. When the burning continues to produce a lot of dripping, firefighters simply can't get close to the fire.

The external thermal insulation materials of CCTV and Shenyang Wanxin Wanxin Hotel Building are polystyrene board. This kind of thermal insulation material shows extremely fast flame spread speed in the case of real fire. This is because the polystyrene board has the following four defects in the burning state: 1 low burning point (80~100C), easy to be ignited; 2 in the fire burning state, it is easy to produce droplets.

The droplets are dripped into the unburned part, which is easy to produce a secondary flame, which rapidly expands the fire spread speed; 3 volume shrinks rapidly, forming voids, causing deflagration; 4 in the event of fire, due to the rapid fall of the droplets, fire It is difficult for personnel to save the fire in time.

CCTV uses titanium-zinc alloy as wall panel, titanium burning point 418C, zinc burning point 500C. At present, aluminum-plastic board is widely used as insulation material in China. The ignition point of aluminum is 540C, and the temperature generated by fireworks and electric sparks exceeds 1000C. Such light alloy panels are extremely ignitable. It is especially important that the aluminum has a high calorific value when burned, and the amount of heat released is 6 to 7 times that of carbon and more than 3 times that of hydrogen. That is, once such a light metal is burned, it will be released from the organic insulating material composed of C and H elements. Double the heat. Deflagration is easily formed in a fire state, which greatly accelerates the speed of flame propagation when a fire occurs. This is also one of the important reasons for the rapid formation of large-scale combustion in the event of a CCTV fire.

On November 15, 2010, a large fire accident occurred in Jiaozhou Apartment, Jiaozhou Road, Shanghai, causing heavy casualties. This is the most painful fire and death accident in Shanghai since the founding of the People's Republic of China. Its negative impact has spread to the whole country and even the world.

The 11.15 mega-fire that occurred in the Jiaozhou Road Teacher's Apartment in Shanghai has nothing to do with the external thermal insulation materials. At present, there is no open authority relationship. As for the gas-induced deaths and the direct use of PU materials and polystyrene board insulation materials, there is no authoritative conclusion. However, a lesson must be learned from this mega-fire. The insulation materials used in high-rise and super-tall buildings must be highly valued for their smoke density and toxic gas composition.

Three of the most important major fire accidents should be learned from the high-rise and super-tall buildings, polystyrene board (EPS and XPS) and other thermoplastic insulation materials must be cautious or prohibited.

For high-rise and super-tall buildings, aluminum-plastic panels and light metal sheets, the flame propagation speed of such insulation materials is extremely fast and must be used with caution.

For insulation materials used in high-rise and super-tall buildings, the smoke density and toxic gas composition of the combustion products must be given high priority.

4. My foreign thermal insulation materials adhere to the development path of both building energy conservation and fire safety. Building energy conservation is the basic national policy that China has long adhered to. 1 Building energy conservation is an important way to reduce energy consumption. Under the influence of the global financial crisis, China Whether the national economy can maintain a sustained and steady development speed, the energy issue has become a prominent contradiction. China is currently the world's largest construction market. China has a construction area of ​​40 billion square meters, and the annual new construction volume is 2 billion square meters. At present, more than 95% of new buildings in China are still high-energy buildings, and building energy consumption has reached the whole society. 27% of energy consumption. If energy-saving measures are not taken, 50% of national energy will be consumed in buildings by 2020. According to statistics from relevant departments, the insulation performance of building envelopes in China is generally low. The thermal conductivity coefficient of external walls and windows is 3-4 times that of the same developed countries, and the energy consumption per unit of building area is 4-5 times higher. The total heat per unit area of ​​China is 2 to 5 times higher than that of developed countries with close climatic conditions, which indicates that the potential of building energy conservation in China is very large. According to the overall goal of building energy conservation in the Ministry of Construction: in the next few years, new urban buildings in the country will achieve energy savings of 50%, 25% for existing buildings, and 15% for medium-sized cities, 10% for small cities, and 10% for small cities. And new buildings in coastal economically developed areas will achieve energy savings of 65%. China's Ministry of Construction and other ministries are formulating a three-year implementation plan for building energy conservation, stipulating that from July 1, 2010, Beijing, Tianjin, Dalian, Qingdao, Shanghai, Shenzhen, etc. will be enforced. All buildings in the six major cities must achieve a 65% energy saving standard. At the same time, the Ministry of Construction requires real estate developers to carry out five-year insurance for external wall insulation, which will force developers to use qualified insulation materials. This shows that building energy conservation has become a key factor affecting China's energy sustainable development strategy decision-making, and it is the country's long-term unshakable national policy.

Some experts pointed out: If the new building is fully enforced, the building energy-saving design standards will be implemented, and the existing buildings will be implemented step by step.

Then by 2020, China's energy-saving energy consumption can be reduced by 335 million tons of standard coal, and the peak load of air-conditioning can be reduced by about 80 million kilowatts/hour. It is close to 4.5 full-load power of the Three Gorges Power Station, which can reduce the investment in power construction by about 1 trillion. yuan.

2 Building energy conservation is an important measure to achieve low carbon emission reduction Building energy conservation is also an important measure to achieve low carbon green economy in China. China has promised to do a good job in energy conservation and emission reduction in the future development of the national economy. At the UN Climate Conference in Copenhagen in 2009, China promised to the world that China's carbon dioxide emissions per unit of GDP will be 40% to 50% lower than in 2005 by 2020. According to the data, building energy conservation will be warmed up by 2030. Gas emissions reached 5.6 billion tons.

Whether the building energy-saving indicators can be completed is not only related to the country's overall energy use and consumption, but also affects whether the low-carbon emission reduction targets promised by China to the international community can be completed on schedule.

Building insulation materials fire safety must ensure the safety performance of insulation materials is a necessary prerequisite for building energy conservation, but also an important condition to ensure the safety of people's lives and property. The safety performance of materials will not meet the requirements, and building energy conservation will be lost. Therefore, it is currently mobilizing the whole society to work together to ensure the safety performance of thermal insulation materials, so that China's thermal insulation materials will make new contributions to the continuous innovation of building energy conservation and emission reduction in China.

Insulation material building energy-saving and fire safety performance must be the correct orientation of both insulation materials: adhere to the development path of both building energy efficiency and fire safety.

At present, there is a notable public opinion tendency in the construction industry and the building materials market: only concerned whether the fire safety performance indicators of building exterior insulation materials have been reached, but whether energy conservation indicators can be achieved. Obviously, this tendency will have a serious negative effect on major decisions on national building energy conservation and low carbon emission reduction.

Adhere to the technical approach of combining organic materials with inorganic materials. Organic materials are the mainstay of the development of thermal insulation materials. Throughout the development of the world's external thermal insulation materials, it is not difficult to see that the thermal insulation of organic materials is always in the first place. At present, domestic and foreign thermal insulation materials are mainly composed of organic thermal insulation materials, accounting for about 80%. Organic materials are the mainstream of future insulation materials development, which is an indisputable fact.

Actively developing composite thermal insulation materials combining organic and inorganic materials In general, organic thermal insulation materials have good thermal insulation properties, but fire safety performance is insufficient; inorganic thermal insulation materials have good fireproof performance, but insufficient thermal insulation properties. Combining the two materials into composite materials can exert their respective advantages and overcome their respective shortcomings. This is undoubtedly an important way for the development of thermal insulation materials technology in the future. The product forms include organic/inorganic composite sheets, organic insulation materials containing high-solid inorganic materials, and the like.

Adhere to the technical route combining thermal insulation materials and fireproof construction. The roads worn by domestic and foreign building thermal insulation systems have fully demonstrated that it is necessary to take the technical route combining thermal insulation materials and fireproof construction, especially for high-rise and super high-rises with high fire performance requirements. Buildings are even more so. For high-rise and super-tall buildings, the fire safety performance must meet the requirements of the specified indicators. It is difficult to achieve by simply relying on thermal insulation materials. It must rely on the corresponding fire-proof structures, such as fire-proof barriers and fire-proof beams. Only in this way can the fire safety performance of the external insulation system be effectively achieved. It must be emphasized here that even with the fireproof construction measures, it is impossible to allow the use of insulation materials with poor fire safety performance as a protective umbrella and enter the building materials market. The external thermal insulation system must adhere to the principle of thermal insulation materials and fire protection construction. Because in the insulation system, the insulation material accounts for 80% of its volume. If the fire safety performance of the insulation material is not up to standard, even if the fireproof structure is better, such a fire protection system cannot be adopted.

5. Actively promote the development of PU rigid foam insulation materials. China's PU foam application fields are widely used. At present, China is the world's largest polyurethane production and consumption country. In 2010, the output of PU products has exceeded 6 million tons, and the annual output value has reached several hundred billion yuan, involving nearly 100 million people. The PU industry has a very close relationship with national defense construction and national economic construction. Polyurethane foams (including soft foams and rigid foams) are the largest varieties of polyurethane products, accounting for more than 50% of the total product. PU rigid foam is mainly used in electrical appliances (refrigerators, freezers, electric water heaters, solar water heaters), buildings (building wall insulation, roof waterproof insulation, building pipe insulation, house decoration, sandwich panels, cold storage, etc.), industrial (industrial pipeline level) Transportation pipe insulation, thermal pipe network insulation, equipment insulation, etc.), transportation (refrigerated trucks, refrigerated/freezer containers, and transport vessels), imitation wood decoration (furniture, flower pots, gardening decoration), aerospace (cold liquid fuel insulation, Space rocket thermal insulation and other fields. PU soft foam is mainly used in transportation (automobiles, trains, airplanes, motorcycle seats, handrails, steering wheels, ceilings and compartment insulation materials), furniture industry (sofa, seats, mattresses) and other industries (packaging, clothing) , shoes and hats, etc.). Polyurethane foam products have penetrated into every aspect of people's daily lives. The application level of polyurethane foam is to some extent an important indicator reflecting the development of a country's national economy and the affluence of people's living standards.

PU rigid foam is an ideal material for energy saving and emission reduction. It is believed that PU hard foam material is the most ideal building energy-saving thermal insulation material at home and abroad. Its thermal insulation effect is 1.75 times of polystyrene board (EPS and XPS) and twice of rock wool. 29 times of masonry, 85 times of wood, and 89 times of concrete. PU insulation materials are also an important means to improve energy and reduce carbon dioxide emissions. Studies have shown that every kilogram of PU material used in a building is equivalent to a reduction of 75.5 kilograms of CO2 emissions over its average life span.

Halogen-free, low-smoke, low-toxic PU insulation materials are the future development direction. According to China's national conditions, in order to meet the practical requirements of fire safety performance of many high-rise and super-tall buildings in large cities in China, PU insulation materials must be halogen-free, low-smoke and low-toxic. The direction of development. Although the flame retardant effect of halogen-containing (bromine, chlorine atom) flame retardant materials is good, there are disadvantages of large smoke and high toxicity of combustion products, so it is restricted in many occasions. EU countries have stipulated that the use of polymer materials containing halogen flame retardants is prohibited.

Although the US and Europe building insulation materials currently do not regard the toxic gas and smoke density as hard assessment indicators, according to China's national conditions, it is reasonable to include these two indicators in the assessment indicators as the basis for assessing the combustion rating standards.

Polyurethane inorganic composite material is an ideal thermal insulation material. PU building exterior insulation material has the highest fire safety performance grade of Bi flame retardant grade. Document No. 46 of the National Fire Department of the Ministry of Public Security stipulates that Class A non-combustible materials are required for high fire safety requirements. According to this requirement, only inorganic materials can meet the A-level fire protection requirements, but the thermal conductivity of inorganic materials is much larger than that of organic insulation materials such as PU, that is, the insulation performance is very poor, and it is difficult to meet the national energy-saving index requirements. Therefore, the development of B1 (or B2) grade PU / inorganic A grade insulation materials is the future development direction.

Jiangsu Lvyuan New Materials Co., Ltd., Guangzhou Langteng Polyurethane Co., Ltd., Bayer Co., and Huntsman Co., Ltd. have successfully developed such composite insulation materials, and are currently in the stage of industrialization and application research.

(1) About the problem of PU hard foam combustion products smoke and toxicity At present, there is a misunderstanding of PU hard foam in China. It is believed that a large amount of smoke and toxic gas must be generated after PU hard foam combustion. Therefore, it is proposed that such a material cannot be used as an inner thermal insulation and an outer thermal insulation material, and this insight has a certain one-sidedness.

The smoke generated by the combustion of a material depends mainly on the material structure, the halogen content and the combustion state. Generally, in the early stage of a fire, a flammable material generates a large amount of smoke particles due to incomplete combustion. This is not an inherent feature of PU material combustion. By formula adjustment, low-smoke PU materials can be produced.

PU foam combustion product toxicity problem: Japan PU Industry Association and Germany DIN-53436 standard test results show that the toxicity of its combustion products is comparable to the toxicity of combustion products of materials such as wood, wool, leather and felt and the toxicity of HCN gas. The toxicity of PU foam combustion products can be adjusted by formula to meet the fire rating standards.

The main cause of casualties in the event of fire is generally the inflammable material in the early stage of the fire due to incomplete combustion, not only produces a large amount of smoke, but also generates a large amount of carbon monoxide (CO) toxic gas, which is the main cause of human suffocation. The smoke and gas toxicity of PU rigid foam insulation can be adjusted to achieve the required fire rating.

The performance evaluation criteria for inorganic thermal insulation materials are: thermal insulation, fire safety and performance durability. Inorganic thermal insulation materials such as rock wool, glass wool and expanded perlite have the greatest advantage of excellent fire safety performance and are Class A non-combustible materials. However, the inorganic thermal insulation material has the fatal shortcoming of poor thermal insulation performance, and it is difficult to achieve the 65 °% energy-saving index inorganic material. Inorganic insulation materials also have shortcomings such as poor overall mechanical durability and harm to human health. In addition, inorganic thermal insulation materials generally have higher calorific value than organic materials, which will accelerate the flame propagation speed in the event of fire, and have fewer application cases in domestic high-rise buildings and super high-rise buildings.

Execution of standards before the introduction of new standards Before the promulgation of the new standards for fire safety performance of external thermal insulation materials, the document No. 46 is still the only basis, that is, according to the second chapter of the first section of the "46" document, the combustion performance of civil building thermal insulation materials should be Class A, and should not be lower than Class B2. This article is a mandatory document jointly issued by the Ministry of Public Security and the Ministry of Housing and Urban-Rural Development. The document clearly stipulates the strengthening of the fire protection management of the building external thermal insulation system, effectively preventing fire accidents in the construction of external thermal insulation, and protecting the lives and property of the people. The document puts forward clear requirements for the combustion performance of the external thermal insulation material and the fireproof construction measures of the external thermal insulation system. The document also embodies the principles of building energy efficiency and building fire prevention, and adopts different insulation materials and different fire prevention measures for different fire hazard building requirements. It is also regulated from different aspects of wall, roof and metal sandwich composite panels. The document was jointly enacted and promulgated by the two ministries and is authoritative, reasonable and time-sensitive.

Regarding the B2 and B1 standards of the insulation materials related test items, two test items of the combustion drip test and the electric spark ignition test are added. The reason is that burning dripping is the culprit of forming a secondary flame and accelerating the speed of flame propagation. EDM is the most prone fire in the construction of thermal insulation materials.

The B2 grade oxygen index standard was increased from 26 to 28. The reason is that the oxygen index is a measure of how easily a material is ignited in the air. Increasing the oxygen index level, that is, improving the ability of insulation materials to counter the initial occurrence of fire.

Whether B2 hard foam PU can be used as external thermal insulation material B2 hard foam PU can be used as external thermal insulation material. The reason is that the Institute of Fire Protection of China Academy of Building Sciences has done a lot of tests, including large-scale combustion performance test, and the conclusion is :The hard foam PU with burning performance not lower than ugly grade 2, belonging to thermosetting insulation material, does not melt in case of fire, forms dense carbonized layer on the surface, has no burning dripping, has better fire resistance performance; and adopts combustion performance not lower than The b2 grade hard foam polyurethane is the outer wall insulation system of the insulation layer. As long as the thickness of the protective layer (the surface layer) is not less than 3~5 mm, the overall structure of the system does not have flame propagation property, and has good fireproof performance. The fireproof isolation belt may not be provided; the burning structure is not lower than the blister 2 hard foam polyurethane surface coated with a certain thickness of thermal insulation mortar or thermal insulation slurry, which can effectively prevent the polystyrene board from thin plastering. The flame propagation of the external thermal insulation system can be used as a fire barrier for the EPS thin plaster external insulation system.

Successful European experience in building energy efficiency in Germany, the United States and France, after the relevant inspection and testing of completed buildings, will be issued according to the energy-saving grade, the corresponding energy-saving certificate. It is recommended that the state formulate standards for building energy-saving grades for various types of buildings, clarify energy-saving indicators, and issue energy-saving qualification certificates for building insulation materials and insulation systems. When real estate developers sell houses, they need to present an energy-saving certificate, and units that contribute to building energy conservation should be given subsidies and rewards.

Before the promulgation of the new standards for fire safety performance of external thermal insulation materials, it is recommended that the document No. 46 be the only basis. According to Article 2 of the first chapter of the “No. 46” document, the combustion performance of civil building external thermal insulation materials should be Grade A, and should not be Below the B2 level.

In the BDBi standard, it is recommended to increase the test criteria for combustion dripping and electric spark test.

It is recommended that the B2 grade oxygen index be increased from 26 to 28 to expand the application of B2 insulation materials in building energy conservation.

Because B2 grade rigid foam PU has good anti-flame ignition ability and fireproof performance, it can be used as insulation material for external thermal insulation system.

It is recommended that the gas smoke density and toxicity test be included in the assessment criteria for external thermal insulation performance.

It is recommended that the state formulate standards for building energy-saving grades for various types of buildings, clarify energy-saving indicators, and issue energy-saving qualification certificates for building insulation materials and insulation systems. When real estate developers sell houses, they need to present an energy-saving certificate, and units that contribute to building energy conservation should be given subsidies and rewards.

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