Fire hazard and prevention and control measures for building exterior insulation materials

: Fire Management Research on Fire Hazard and Prevention and Control Measures for Building Exterior Insulation Materials Bo Jianwei (Fire Department of the Ministry of Public Security, Beijing 100054) analyzes the fire hazard of building exterior insulation materials, and introduces relevant fire protection requirements for building exterior insulation materials and systems in some foreign countries. Further suggestions on countermeasures against fire prevention and control of building exterior insulation materials were put forward.

On November 15, 2010, the apartment at No. 728, Jiaozhou Road, Jing'an District, Shanghai was damaged by the construction workers during the energy-saving renovation. The fire was caused by the burning of polyurethane insulation materials and debris, causing 58 deaths and 71 injuries. On February 3, 2011, Shenyang Wanshi International Building in Shenyang City fired due to illegal fireworks igniting the exterior wall decoration and insulation materials of the building. "Mi Wang Chuanfa. Fire Performance Management Performance Evaluation. Western China Science and Technology, 2005,), female , Langfang, Hebei, Professor of Fire Command Department, Chinese People's Armed Police Force Academy, master's degree, mainly engaged in fire management teaching and research, Langfang City, Hebei Province, 065000. Disaster, over fire area of ​​more than 10,000 m2, resulting in direct property losses of 93.84 million yuan In recent years, the fire of building exterior insulation materials has shown a high momentum. According to statistics, from 2007 to 2010, there were 1,359 such fires in the country (excluding the "115" fire in Shanghai), causing 75 deaths and 87 injuries. The direct property loss is 180 million yuan. The use of flammable and flammable external thermal insulation materials has become a new fire hazard. Strengthening the research on the fire hazard of building exterior insulation materials and taking effective fire prevention and control measures as soon as possible is a very urgent task.

1 Types of building thermal insulation materials and engineering applications Since 2005, China has vigorously promoted building energy conservation policies. One of the main measures is to add insulation to the exterior walls of buildings. According to the statistics of the Ministry of Housing and Urban-Rural Development, as of the end of 2009, the country has built a total of 4.08 billion m2 of energy-saving building area, and completed the transformation area of ​​15 provinces and cities in the north. With the comprehensive promotion of building energy-saving work, the annual energy-saving building area of ​​cities and towns in China is about 1 billion. M2, in which the construction area of ​​the external wall insulation material is 6.7 billion m2. In addition, there are more than 3 billion m2 of existing buildings in the northern area that need to be energy-saving. Building thermal insulation materials are broadly divided into organic materials and inorganic materials. According to the burning properties of materials, they can be divided into non-combustible (Class A), flame retardant (B1), flammable (B2) and flammable (B3). ) Levels.

1.1 Non-combustible materials are mainly inorganic materials such as rock wool and glass wool. They have good fireproof performance and high temperature resistance, but they are easily exposed to moisture and cause thermal insulation performance to be reduced. Domestically, they are mainly used in industrial fields. Rock wool is used in small quantities in building energy-saving projects, and glass wool is almost useless. Other non-combustible materials are currently in the process of research and development and small-scale demonstration in China.

1.2 Flame-retardant materials are mainly rubber powder polystyrene granule insulation slurry, which has good fireproof performance, simple construction process, but poor thermal insulation performance, and is not suitable for building energy-saving projects in northern areas. There is a certain amount of application in the southern region.

1.3 Combustible materials mainly include organic materials such as molded polystyrene foam board (EPS), extruded polystyrene foam board (XPS) and polyurethane rigid foam (PU). It is characterized by good insulation performance, light weight and simple construction. The process is mature, and it is the main external wall insulation material used in building energy-saving projects in the north. According to the statistics of the Beijing Building Energy Conservation Professional Committee in 2008, the insulation materials in the Beijing market accounted for 72% of EPS, XPS accounted for 25%, and polyurethane and inorganic materials accounted for 3%. 1.4 Flammable materials and similar types of combustible materials, after exposure to open flames More flammable, this type of material is not allowed to be used for insulation projects of various buildings in accordance with relevant national standards. However, due to weak market supervision and vicious competition, many companies' B1 and B2 insulation materials have not met the standard requirements. The market is flooded with B3 flammable insulation materials.

2 Fire hazard of building exterior insulation materials From the current application of building energy-saving projects, organic materials such as polystyrene foam and polyurethane foam are widely used in building exterior insulation materials.

Most of these materials are flammable and combustible materials and have a large fire risk.

2.1 Very easy to be ignited In the process of construction and use, various uncontrollable factors such as inadvertent construction, fireworks, external fire sources, etc. are easily ignited to form a fire. In the fire of Shenyang Wanxin Building, fireworks ignited the plastic turf of the platform outside the building, which in turn ignited the exposed polystyrene insulation board behind the curtain wall panel; in the fire of Shanghai Jiaozhou Road apartment building, the electric welding spark ignited from the external wall insulation The foam debris under the material is cut and the outer wall insulation material is ignited.

2.2 It is easy to cause fire during construction. The construction site uses frequent fire and electricity. It is often used to heat and paste waterproof materials with open flames, or to use electric welding, gas welding, welding curtain wall brackets, scaffolding, etc., which is slightly inadvertent and easy to ignite flammable and flammable external insulation. The materials lead to large-area fires, especially in the façades of existing buildings where people live, work and operate, using flammable and flammable insulation materials for energy-saving renovation, which is more likely to cause a group of fires and deaths. The fire at Shanghai Jiaozhou Road apartment building is Typical Case. According to statistics, 65% of the fires in building exterior insulation materials occur in the process of laying insulation materials, and the construction process is a high-risk period of fire.

2.3 It is easy to form large-area three-dimensional fire. Most insulation materials have fast burning speed, large combustion heat release, and high toxicity of combustion products. They are used for continuous distribution of building exterior wall insulation, and the combustion is affected by wind and other climates. It is easy to form a three-dimensional fire that connects inside and outside the building and has a large area. The outer wall insulation material of Shenyang Huangshi Wanxin Building was ignited within 1 min, that is, from a small fire to a full-fired fire. The fire spread from 11 to 37 in 15 minutes; Shanghai Jiaozhou Road apartment building from 9 layers of polyurethane The foam crumb is ignited to the fire side to form a three-dimensional combustion and spread in all directions for only 4 minutes, forming a three-dimensional combustion and the ignition time of the indoor combustible material is about 15mn. 2.4 The overall fireproof performance of the external thermal insulation wall is poor. The specification lacks regulations on the thermal insulation properties of building exterior insulation materials and systems, and lacks strict fire protection construction measures for insulation layers. Due to the insufficient fireproof performance of the protective layer and exterior wall decoration material of the external thermal insulation material, it is easily attacked by an external fire source, and the internal thermal insulation material is ignited and burned. In the construction of the building using the external thermal insulation material, the protective layer outside the thermal insulation material is easily detached due to factors such as negative wind pressure, cold and hot temperature difference, and weak bonding between organic and inorganic materials, resulting in the exposure of the thermal insulation material. Inflammation of fire sources can easily lead to building fires.

2.5 External thermal insulation materials are not protected by fire protection facilities. The current fire protection technical standards are mainly for the fire inside the building, and the countermeasures for the ignition of the building exterior insulation materials are not considered. Under the existing fire-fighting technical conditions, fires occur in the flammable and flammable external thermal insulation materials on the external walls of buildings. Fire-fighting facilities such as fire separation, smoke control and automatic fire-extinguishing systems inside the building can not play a role in controlling fires.

6 External thermal insulation materials Fire-fighting rescue and evacuation of personnel is difficult. This type of fire spreads extremely fast, and it is almost impossible to distinguish different stages of fire development. When the fire brigade arrives, the fire often develops into a large-scale three-dimensional combustion, and the best fire-fighting opportunity has been lost. . At the same time, the combustion of flammable and combustible insulation materials produces a large amount of toxic fumes, accompanied by a large number of falling objects and high-temperature dripping objects. It is very difficult for the fire brigade to save fires and carry out rescues from inside and outside.

In addition, the outer window walkway and the outer wall evacuation stairway in the building become the passage of fireworks into the building in the fire of building exterior insulation materials, which not only causes the fire to spread deep inside the building, but also makes the vertical safety evacuation of the building and The rescue channel is full of danger and cannot even be used. The smoke-proof stairwell of the Shanghai Jiaozhou Road apartment building is due to the influx of smoke from the natural smoke exhaust window in a short period of time, which hinders the evacuation of personnel.

2.7 External thermal insulation materials pose a serious threat to the surrounding buildings. A large number of high-temperature melts and flammable objects fall and burn and fly away when there is a fire in the exterior wall insulation materials. This poses a serious threat to neighboring buildings. The "115" fire in Shanghai has a flying distance of 1km and ignited the combustibles on the roof of a high-rise building more than 200 meters away. The Shenyang wall insulation material was ignited by the flying fire and heat radiation of Block B.

3 Developed countries' fire protection requirements for building thermal insulation materials and systems 1 EU 004 has the surface layer external thermal insulation composite system European technical standard certification, the test method for external thermal insulation fire resistance should be in accordance with CEN standard PREN13501-1 building products Or the classification of the combustion performance of the component. Part 1 uses the fire reaction test data classification to test the combustion performance level (A1 to E). The determination of the fire rating and the associated tests need to be carried out twice: once for the entire system, once for the insulation material only, and the possibility of the flame spreading in the insulation material needs to be considered during the test. System suppliers should recommend a fire isolation method to prevent the spread of fire. As part of the system, its fire performance can be determined by reference to the product performance list or the results of the large size test. At the same time, fire protection requirements for external insulation will be based on laws, regulations and regulations applicable to the ultimate use of buildings.

3.2 The application of the German plastering exterior insulation system (WDVS system) in Germany is regulated by national building codes. All components of the WDVS system must be system tested, matched to each other, and must be supplied by only one manufacturer. Fire protection is an important part of ensuring the quality and safety of the WDVS system.

For the installed WDVS system, the requirements for insulation materials are: EPS expanded polystyrene board must meet the requirements of flame retardant; rockwool material must meet the requirements of non-combustible; members of WDVS system professional association can not provide WDVS with building material grade B2 system. Different levels of WDVS systems set the corresponding application range requirements.

: Minimum thickness of 300mm or less, no additional fire protection measures, non-combustible insulation materials (rock wool or mineral foam), mineral paint (lime/cement) or silicone coating (water glass).

Measures: 100300mm shall be fireproofed. Polyurethane or phenolic resin below 300mm shall not require fire prevention measures. When it is insulated with soft wood fiber, it may be 100mm thick, using diffuse or silicone paint.

Combustible WDVS (D or E): Fire-resistant WDVS thickness greater than 100mm does not require additional fire protection measures.

3.3 British and British technical standards stipulate: due to the use of flammable materials and a large number of holes in the building envelope system may pose risks to high-rise buildings, the outer coating system shall not use fire propagation media that may cause harm to health or safety. . For buildings of 18m or higher, insulation materials and filler materials (excluding gaskets, sealants and similar materials) used in the construction of external walls shall be flame retardant.

3.4 The relevant technical standards stipulate that the burning performance is lower than that of the standard thermal insulation material (the phenolic foam with the burning performance of B1 grade), and it is not allowed to be used in public buildings.

3.5 Canada and Canada related technical standards: when the base coating is non-combustible material, the non-foam plastic insulation system can be used for non-combustible construction without any restrictions; the foam insulation system when the test proves that the base coating is non-combustible, and the root-S101 test, the base layer The thin layer of paint is refractory for 15 minutes and the system can be used for non-combustible construction.

When the base coat is flammable, the non-foam insulation system passes the ULC-S13 4 fire test test requirements and can be used for non-combustible construction; the foam insulation system can be used in areas where flammable construction is permitted.

4 Measures to strengthen fire prevention and control of external thermal insulation materials Building energy conservation policy is an important strategic task carried out by China. Strengthening fire prevention and control of building thermal insulation materials must be placed in the overall situation of national economic and social development to plan and consider relevant countermeasures. . At present, in view of the fire safety problems exposed in the engineering application of building exterior insulation materials, it is necessary to adopt the principle of “conforming the symptoms and treating the disease and comprehensively managing”, adopting the revision of the standard and specifications, strengthening the source and control, strengthening the supervision, and developing alternative products. Governing

Measures to carry out comprehensive remediation.

4.1 Immediately proceed to amend the relevant technical standards. First, the Ministry of Public Security, the Ministry of Housing and Urban-Rural Development, the civil building external thermal insulation system and the external wall decoration fire emergency regulations will be revised as soon as possible, and the technical requirements for building energy conservation and fire safety will be put forward, and the external wall of the building will be resolutely put an end to Flammable external thermal insulation materials shall strictly limit the application range and location of combustible external thermal insulation materials; the burning performance of curtain wall building thermal insulation materials shall be Class A; for non-curtain wall buildings, residential buildings with heights greater than or equal to 50 m, their thermal insulation materials The burning performance shall be Class A; for residential buildings with a height less than 50m, the burning performance of the insulating materials shall not be lower than Class B1; for other civil buildings with a height of 24m or more, the burning performance of the insulating materials shall be Class A; the height shall be less than 24m. For other civil buildings, the insulation performance of the insulation materials shall be Class A or Class B1; when using Class B1 insulation materials, each layer shall be horizontally partitioned by the non-combustible body not lower than the fire resistance limit of the floor, and the base wall shall be The outer and outer protective layers are connected; the external thermal insulation system should be made of non-combustible material as a protective layer, and the thermal insulation material is completely covered. The thickness of the protective layer of the layer shall not be less than 50mm, and the other layers shall not be less than 30mm. At the same time, the provisional regulations shall be revised in the form of national standards to enhance the binding force required by the technical standards.

Second, in the merger and revision of the national standard GB 5016-2006 building design fire protection code, GB50045-95 high-rise civil building design fire protection specifications, the fire protection technical requirements of the building external thermal insulation system are clearly defined.

The third is to increase the fire safety technology and management measures during the construction process of the building external thermal insulation system when formulating the national standard GB 50720-2011 construction site fire safety technical specifications.

4.2 Strengthening fire safety control of building exterior insulation materials The public security fire department shall strictly implement the notice of the Ministry of Public Security Fire Department on further clarifying the relevant requirements for fire protection supervision and management of civil building exterior insulation materials, and incorporate the building exterior insulation materials into the fire protection design, review and acceptance of construction projects. And the scope of the investigation and inspection, urge the design and construction units to strictly implement the fire protection technical standards, improve the fire protection capacity of the building exterior wall insulation system, preferentially use non-combustible and non-combustible materials, adopt fire barriers on the outer wall surface, and use non-combustible materials on the outer surface of the insulation layer. Measures such as protective layers strengthen the fire protection structure of the project.

3 Strengthen the daily fire supervision and inspection of the buildings that have been put into use. For buildings with external thermal insulation materials that have been completed and accepted for use or have completed energy-saving renovation, the public security fire department should strengthen the regular fire supervision and inspection, and urge the building owners to strengthen fire protection according to law. Security management. Where the outer wall is not tightly sealed, the protective layer is detached and cracked, and the thermal insulation material is exposed, it must be sealed and covered with non-combustible materials. For curtain wall-type buildings that use non-conforming external decorative materials, effective measures must be taken to rectify In the eye-catching position of the external wall of the building, a sign has been set up for the insulation and fire protection of the external wall to remind the public to pay attention to fire safety; it is forbidden to carry out hot and high-temperature operations on the external wall of the building, and it is forbidden to install billboards, light boxes and other electrical equipment on the outer wall; It is forbidden to stack flammable materials in the surrounding area of ​​the building and set off fireworks and firecrackers.

4.4 Strict construction site fire supervision and management If the construction of the building external thermal insulation system is underway, the construction unit shall be urged to strictly implement the fire safety management measures. When the thermal insulation material enters the construction site, the construction unit shall check the quality of the thermal insulation material, use qualified products, and choose to stack it away from the specified location of the fire source; the construction work of the thermal insulation project shall be carried out in sections, especially the construction of hot work and external wall insulation materials. Before the operation is separated, the combustible materials at the job site should be cleaned before the hot work such as electric welding gas cutting, equipped with fire extinguishing equipment, and the on-site fire guardian should be set up for monitoring. For energy-saving renovation of buildings that have already been put into use, public buildings shall not be subjected to construction work of external thermal insulation materials during business and use. In principle, the residential buildings shall be moved out of the residential buildings before construction. If it is difficult to move out, construction shall be carried out. The former relevant units shall organize the removal of debris in the corridor, conduct targeted fire prevention publicity education and evacuation drills for the resident personnel, and the construction unit shall be guarded by the construction personnel during the construction period, and shall be disposed of immediately after the fire occurs.

4.5 Organize building energy-saving fire safety technology to encourage and guide relevant research institutes and production enterprises to carry out technical research, and actively promote the research and development and production of new insulation materials with good thermal insulation performance and fire performance, and provide sufficient market as soon as possible. Insulation material replacement for fire performance. At the same time, we will increase the research on key technologies for fire protection of building exterior insulation systems and other forms of research and development of building energy-saving insulation technology, and provide fire safety technical support for energy conservation and emission reduction policy implementation and building energy conservation work.

4.6 Strengthening the fire-fighting and rescue preparation for fires of building exterior insulation materials The fire-fighting forces should carefully analyze and summarize the lessons learned from the fire-resistance of building exterior insulation materials in recent years, and formulate fire-fighting plans one by one for buildings with flammable and flammable external thermal insulation materials in the jurisdiction. Field drills ensure rapid and effective disposal in the event of a fire accident, minimizing casualties and property damage caused by fire.

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