Industry | Unspeakable "pain": building exterior wall insulation

On the first day of the new year, there was another fire accident, which moved people's hearts.
Fortunately, there were no casualties.
At about 17:00 on January 1, 2020, a fire broke out in Building A4, California Garden Community, Yubei District, Chongqing City.
Emergency, fire, public security and other rescue forces rushed to the scene to evacuate the crowd and extinguish the fire.
The open flame was extinguished at 19:20 without personnel.
casualties.
After the fire broke out, Chongqing's emergency response, fire protection, public security, health and health departments rushed to the scene to command rescue, and cooperated with Yubei District to carry out personnel search and rescue, fire fighting and related work in an orderly manner.
As of 19:20, the open flames were extinguished.
After the firefighters searched and investigated layer by layer, there were no casualties.
Preliminary inspection revealed that the fire caught fire from the balcony of a residential building on the second floor (30 floors) of Building A4 in California Garden District.
The flame burned in a body shape, igniting the outer wall insulation and canopy, and spread to the balcony on the 30th floor and part of it.
Residents' houses.
The specific cause of the fire is under further investigation.
At present, Yubei District is doing its best to deal with the aftermath of the disaster-stricken people, such as comfort and resettlement.
The old saying goes, but the outer wall insulation is to blame.
The old saying goes, but the outer wall insulation is to blame.
I remember that at 21:16 on December 2, 2019, a fire broke out on the exterior wall insulation material of the commercial and residential building at No.
102, Block A, SR Xincheng, Hunnan New District, Shenyang City, Liaoning Province.
After nearly 4 hours of fighting, all the open flames were extinguished.
Fortunately, no casualties were caused.
It is understood that the location of the fire was the outer wall of Building A on the north side of No.
102, SR Xincheng.
The building is a commercial and residential building with 25 floors.
It can be seen from the scenes that the fire started on the 5th floor and spread rapidly along the north side of the building, reaching the top of the building.
The exterior walls and insulation materials of the building fell.
External wall thermal insulation layer The external wall thermal insulation layer , a topic that has to be talked about every once in a while, has been alerting us that the building exterior wall thermal insulation materials need to be changed.
In recent years, as building energy consumption has been increasing year by year and energy-saving standards have been continuously improved, from the perspective of thermal insulation performance, building thermal insulation materials have experienced a leap from inorganic to organic.
As an important building energy-saving technical measure, the building exterior wall insulation system based on the design concepts of thermal insulation, energy saving, and green environmental protection has been widely promoted and applied in engineering practice.
However, at the same time, incidents of falling off of external wall insulation materials and fires are also frequently reported.
According to data, about 70% of fire accidents involving external wall insulation materials occurred during the construction phase, but about 10% also occurred in commercial buildings that have been delivered for use.
In the investigation of numerous building fire accidents, we can find that there are three main reasons for the fire of external wall insulation materials: First, the industry standards are not sound, and the product quality is uneven.
Lack of standard constraints, the implementation of the standards has not been implemented.
The external wall insulation materials produced by individual manufacturers simply do not meet the requirements of building fire protection design, and the fire resistance level and fire resistance limit do not meet the national standards.
After the products are launched on the market, To bury congenital hidden dangers for building fire accidents.
Second, the construction period is long, and hidden dangers on the job site are numerous.
The construction period of some large-scale buildings is too long, the construction procedures overlap each other, the management is inconvenient, and it is easy to neglect the fire hazard investigation on the spot.
At the same time, there are many combustible materials on the job site, which makes it difficult to detect fire hazards.
In addition, some construction projects ignore the burning performance of thermal insulation materials, the heat release rate of thermal insulation systems, and the flame propagation performance of the fire hazards, which have led to more and more serious fire hazards, which has caused many fire accidents.
Third, the cost of qualified materials is high, and the construction unit is shoddy.
Qualified external wall insulation materials will add a certain amount of flame retardant, and its price is expensive, many businesses in order to pursue greater profits, reduce flame retardants, and some even do not add.
Some construction units deliberately purchase low-quality insulation materials, which are shoddy, leading to the existence of fire hazards.
In many building fire accidents, the poor flame retardant performance of external wall insulation materials and the lack of fire barriers are one of the main reasons for the rapid spread of fire.
In addition, for the external wall insulation of high-rise buildings, in addition to the use of protective layers, fire barriers, fire barriers and other external wall insulation and fire protection measures, the most important thing is to use Class A materials with high combustion performance to improve the external wall.
The safety of the wall insulation system itself.
It is understood that my country's current fire protection technical standards require external wall insulation engineering fire safety performance requirements, mainly reflected in the combustion performance of external wall insulation materials and the fire resistance of the overall structure of the insulation system.
Therefore, the combustion performance of the external wall insulation material itself is very important to the fire safety of the external wall insulation system.
According to the "Interim Regulations on Fire Protection for External Thermal Insulation System and Exterior Wall Decoration of Civil Buildings":According to the "Interim Provisions on Fire Protection for External Thermal Insulation System and Exterior Wall Decoration of Civil Buildings": 1.
For buildings with a height greater than or equal to 100m, the combustion performance of the thermal insulation materials should be Class A.
2.
For buildings with a height greater than or equal to 60m and less than 100m, the combustion performance of the insulation materials shall not be lower than Class B2.
When using B2 insulation materials, each layer should be equipped with horizontal fire barriers.
3.
For buildings with a height greater than or equal to 24m and less than 60m, the combustion performance of the insulation materials shall not be lower than Class B2.
When B2 thermal insulation materials are used, horizontal fire barriers should be installed on every two floors.
4.
For buildings with a height of less than 24m, the combustion performance of the insulation materials shall not be lower than B2 level.
Among them, when B2 insulation materials are used, horizontal fire barriers should be installed on every three floors.
Huizheng Information once interviewed the chief engineer of architectural coatings of a paint company.
The chief engineer once said: "This fire on the external insulation of existing buildings once again proves that organic insulation panels can only cause fire accidents in the construction process.
" The point of view is Wrong.
If the building fire protection design code returns to the level of 2009, it will lead to a retrogression in the development of the insulation industry.
With the continuous improvement of energy-saving design standards, if a large area of ​​organic insulation materials is restored, the application of organic insulation materials per square meter will be It is twice as high as 10 years ago.
Once a fire occurs, the amount of heat will be greater.
” He pointed out that in architectural coatings , the flame retardant of organic insulation materials mainly based on PS insulation board is hexabromocyclododecane.
Decomposition loses its effect, and the phenomenon of high-temperature melting and flow of thermoplastic insulation materials leads to rapid flame propagation.
Therefore, high-fire-retardant, low-smoke, low-toxic and high-efficiency insulation materials are the development direction of building insulation materials.
Another analysis pointed out that the main reason for the fire of the insulation material is that the protective surface layer of the insulation material is destroyed.
In fact, there are various express regulations for the protective surface layer from the state to the local level.
Article 6.
7.
8 of GB/T50016-2014 "Code for Fire Protection Design of Buildings" emphasizes: when using B1 and B2 thermal insulation materials, the thickness of the first layer of the protective layer should not be less than 15mm, and the other layers should not be less than 5mm; Article 9 of the “Interim Regulations on Fire Protection of Wall Insulation System” also stipulates that non-combustible or non-combustible materials shall be used for the protective layer of the building’s external thermal insulation system.
.
.
However, although the regulations and regulations have clarified various indicators, in actual use, many buildings seldom achieve this thickness.
Substandard quality such as mesh cloth and plastering glue is very common, which leaves a lot of trouble.
"Hundred holes" security risks.
In addition to the fire in the California Garden Community in Yubei District, Chongqing, there were also 12.
2 fires involving insulation materials on the exterior walls of commercial and residential buildings in Shenyang, the “2.
9” fire at the new CCTV site, the “11.
15” fire in Jing’an District, Shanghai, and the “2.
3” fire in Shenyang Dynasty Wanxin.
Accidents have also fully exposed low-flame-retardant external wall insulation materials, which will cause building fires to spread and expand rapidly, and the usual small and invisible hidden dangers may often be the source of fire accidents.
Nowadays, what lies in front of insulation building materials manufacturers and even the entire industry is not only the flammability of external wall insulation materials, but also the flammability and combustibility.
How to produce products that are more suitable for regional buildings and reduce the probability of disasters is what the entire industry needs to think about.
However, it is imminent to formulate feasible standards, impose strict requirements on the R&D and production of building insulation materials and building fire protection design, and promote the implementation of standards.
Next, let’s talk about the fire rating of external wall thermal insulation materials.
The current thermal insulation materials are divided into four grades: A (non-combustible), B1 (flammable), B2 (flammable), and B3 (flammable).
There are a total of inorganic thermal insulation materials and There are two types of organic thermal insulation materials.
The former is non-combustible, but the thermal insulation effect is poor, and only has a market share of about 20%.
The latter is characterized by good thermal insulation but easy to burn, occupying 80% of the market.
For this reason, it is necessary to add a certain amount of flame retardant to the material to make it meet the standard.
However, the price of flame retardant is expensive.
In order to maximize profits, many businesses add less or even no flame retardant.
Individual construction units deliberately purchase inferior insulation materials, shoddy, cost-saving, and the fire supervision is not in place, it is easy to get confused.
At present, the emergence of integrated panels has greatly reduced the difficulty of construction.
Because of the easy construction and simple and convenient characteristics of integrated panels, they have gradually become the best in exterior wall materials.
However, integrated panels also have certain defects, mainly that they can be used in integrated panels.
A variety of materials, if expanded polystyrene is used as a heat insulation medium in the integrated board, polystyrene is not flame-retardant and will produce harmful gases after burning.
Therefore, the development of integrated boards also needs to take into account factors such as construction, fire protection, and strength, and comprehensively improve the performance of building materials.
At present, some construction units have replaced the external wall thermal insulation materials with rock wool, which has both thermal insulation and flame retardant.
The fire rating is sufficient, but it also has obvious shortcomings.
Rock wool is an inorganic material and needs to be treated with water.
, The strength of rock wool is reduced, the bonding force requirements are increased, and the construction requirements are higher, so it is easy to fall off during the construction process.
In 2019, a large area of ​​external wall falling off occurred in a residential area in Beijing, smashing a small number of private cars.
It is understood that the external wall insulation layer is made of rock wool.
Some building materials companies have thought about how to deal with the gap between the board and the board so as not to be corroded and cause a large area to peel off.
Therefore, there are substrate sealing and caulking agents, and the anchor structure of the wall for fixing.
Australian Run Technical Director Chemical Xukai Bin Hui positive information to the reporters: "From the beginning of 2020, issued regulations in Shanghai, exterior renovation the next three years must be reflective insulation coatings, and in the area south of the Yangtze River, is also promoting the use of reflective insulation Middle coat or top coat replaces external wall insulation.
” For the southern region south of the Yangtze River, due to the long sunshine time, the use of reflective insulation coatings mainly reflects sunlight and reduces air-conditioning energy consumption, thereby achieving the purpose of energy saving and emission reduction.
However, for the insulation materials in the northern region, it is necessary to continuously upgrade the technology, develop new environmentally friendly materials, gradually replace outdated materials, and solve the problem of insulation and fire prevention from the material itself.
The mature method in developed countries is to make the external wall insulation into a composite wall, sandwich the thermal insulation material between the wall, and make it in the middle layer, which not only solves the thermal insulation problem, but also solves the fire prevention problem, which is worthy of our reference.
Written at the end, the fire in the California Garden Community in Yubei District, Chongqing, and the 12.
2 incident of fire on the outer wall insulation material of Shenyang commercial and residential buildings were all because private cars blocked the fire exits and affected the rescue and fire-fighting time.
With the increase of vehicles, the parking lot The construction of the car is also a top priority.
Also, if you have a private car, don’t park it in the fire tunnel, because the disaster is always unknown, but the rescue time is limited.