Experts discuss safety of polyurethane materials

Polyurethane materials, which were not very familiar to the public, have recently attracted the attention of people from all walks of life. This was due to a major fire incident in a high-rise residential building in Shanghai on November 15, 2010, which caused dozens of deaths. The exterior wall insulation material of this building is the use of polyurethane hard foam material. Some people questioned whether the polyurethane material itself has security problems. Should it be forbidden to use? On December 30, 2010, at the symposium on the fire safety of polyurethane building energy-saving materials held in Beijing, experts from industry associations, institutes and research institutes, and CEOs of key polyurethane companies at home and abroad discussed the properties, usage methods, and construction of polyurethane materials. The topics of management, safety supervision and other issues were warmly discussed.

Li Yongwu, president of the China Petroleum and Chemical Industry Federation, emphasized that the polyurethane industry has been developing in China for more than 40 years and has become one of the rapidly growing industries in the chemical industry. Polyurethane is widely used in the national economy and various fields of daily life for its excellent performance. From rockets to aircraft, from building construction to refrigerator freezer, the preferred thermal insulation materials are polyurethane; in the textile and electronic devices industries, polyurethane Soft foam materials are also widely used. Li Jianbo, deputy secretary-general of the China Polyurethane Industry Association, told reporters: “Polyurethane materials are an indispensable basic material for national economic and social development, and their thermal insulation efficacy, safety, and advantages for human health have not yet been compared with other materials.” In the 18th meeting of the 11th National Standing Committee held on December 21st, 2010, the vice chairman of the National People's Congress emphasized the need to vigorously strengthen the building energy conservation efforts, strive to improve the efficiency of building energy use, and further improve supporting facilities. Regulations, policies, and standards, intensify law enforcement; deepen reforms and establish long-term energy-saving mechanisms. It shows that the country attaches great importance to building energy conservation.

So, what caused the "11·15" catastrophic fire? The reporter learned from relevant parties that the current conclusion of the accident has not yet been announced by the State Administration of Work Safety. The preliminary investigation results of the Shanghai Municipal Fire Protection Department indicated that the exterior wall of the building was made of polyurethane. However, Shanghai Fire Department disclosed that the fire occurred in the upper and lower positions of the 10th floor of this house. From the fire image, the polyurethane hard foam material under the 9th floor was basically intact, and there was no sign of burning. It should be said that as long as a layer of concrete mortar is applied outside the polyurethane insulation material, it can ensure that the polyurethane material is not ignited by the fire. This is a standard construction method. As the conclusion of the accident is yet to be announced, the person in charge of the China Polyurethane Industry Association stated that it is not yet convenient to comment on the Shanghai fire. However, whether the building's external wall thermal insulation materials are safe and standard construction is an important part, and whether the polyurethane material itself conforms to the relevant national technical standards is also very important.

Zhou Zhengyi, secretary general of the China Flame Retardant Society, told reporters that according to the national classification of the burning properties of building materials, polyurethane materials are classified into B1 (flame-retardant), B2 (flammable), B3 (flammable), and B2 and above. Can be used for exterior wall insulation, that is, not all polyurethane materials are flammable. At present, China's construction and other industries that need to use insulation materials according to different regulatory requirements, polyurethane industry can produce B1 grade, B2 grade polyurethane material. However, in order to achieve profit, some construction companies often use low-priced B3 grade polyurethane materials for building external wall insulation. In addition, if a building mortar is not applied outside the polyurethane material in a standardized manner, it may cause fire accident if fire is encountered. occur. On September 20, 2008, a major fire broke out in a club in Shenzhen, which caused a tragedy of 44 deaths. The use of flammable B3 polyurethane materials was investigated. It can be said that the cause of fire accidents should be carefully analyzed, and it cannot be said that polyurethane is not safe without analysis.

Experts from the Institute of Building Fire Prevention at the Chinese Academy of Building Research stated that polyurethane materials are used for the insulation of external walls of buildings and that they cannot be replaced with other materials. Although inorganic materials such as rock wool, mineral wool, etc. can also be used for building external wall insulation, due to limited mineral resources, non-renewable, require protective mining, and rock wool, etc. will cause occupational disease in the respiratory system to the construction workers, so inorganic materials are still Unable to compare with polyurethane material. That being the case, then, whether in the field of polyurethane manufacturing or the use or consumption of buildings, electronic devices, etc., it is necessary to strengthen management and standardize operations to ensure safety.

Regarding the public's doubts about the safety of insulation materials, Li Jianbo said that only standard operations can ensure safety, and the safety of qualified polyurethane materials can be assured. Li Yongwu emphasized in particular that it is necessary to strengthen the safety management of the construction site and effectively implement the construction in accordance with the standard. He suggested that we should speed up the development of safety management standards for construction sites. This is an effective measure to curb the frequent occurrence of fires on construction sites; strengthen the supervision of building insulation materials, and the relevant national departments formulate building insulation materials permit system and guarantees, insurance and other management Measures. At the same time, it is necessary to strengthen self-discipline in the industry, establish healthy and orderly markets, and perform good social responsibilities.