Design and selection of thermal insulation roof steel structure insulation roofing system scheme Wei Yongmei 12 (1. Department of Automation, Shanghai Jiaotong University, Shanghai 200240; 2. BlueScope Building System Butler (Shanghai) Co., Ltd., Shanghai 201613), this article Through the analysis of the thermal performance of these two types of insulation materials, combined with its typical application in Butler's steel structure building system, including two systems of single-layer insulation cotton and double-layer insulation cotton suitable for different climate zones, it is steel. Provide reference for the design and selection of structural building insulation roofing systems. Steel structure has many advantages, such as recycling, recycling, light weight, energy saving, less environmental pollution during component processing and installation. Compared with traditional concrete structure and masonry structure, it has many advantages. Because of its incomparable advantages, steel structure construction is the development direction of the international construction industry and has a broad market space. At present, steel structure buildings are gradually coming from industrial plants and logistics warehouses: 2011-06-16 grid building system Butler (Shanghai) Co., Ltd. Contact address: 201613 Shanghai Songjiang District Rongle East Road storage development to large supermarkets, convention centers and other large public buildings, and continue to form industrialization, systematization, diversification. 1Proposed problem Steel structure construction is considered from the perspective of energy saving. On the one hand, the building is preferably north-south oriented, and the body shape design is emphasized, and the outer surface roughness is reduced. On the other hand, starting from the improvement of the thermal performance of the outer wall and the roof, it is necessary to control the outer wall. And the thermal inertia of the roof, reducing room temperature fluctuations. At present, steel structure buildings are often combined with high-quality insulation materials to achieve the effect of building insulation. Then, in the operation process of the actual project, how to choose the appropriate thermal insulation material can make the building achieve both the thermal insulation effect and the thermal performance parameters of the building. Roof insulation, thermal resistance of the external protection structure, etc. To improve the thermal performance of a building, it is necessary to analyze the impact of these parameters on the building. The thermal performance of buildings is mainly reflected in the two aspects of insulation and insulation. Insulation, in the case of indoors, refers to the ability of building materials and structures to prevent heat transfer from indoors to outdoors during the winter, thereby maintaining the proper temperature in the room; heat insulation, taking the exterior walls and roofs of buildings as examples, refers to the construction Materials and structures isolate the effects of solar radiant heat and outdoor high temperatures during the summer, allowing the chamber to maintain the proper temperature. Generally, the heat retention performance is evaluated by the heat transfer coefficient value or the heat transfer resistance value; the heat insulation performance is evaluated by the highest temperature value of the inner surface of the envelope structure under outdoor outdoor temperature calculation conditions (ie, hot weather). The material heat transfer coefficient K refers to the heat per unit area in the direction of the temperature gradient per unit time, unit: WKm2K). The heat transfer resistance R is the reciprocal of the heat transfer coefficient K, and the unit is m2'K/W. The smaller the heat transfer coefficient K value of the envelope structure, or the larger the heat transfer resistance R value, the better the heat preservation performance. The thermal conductivity X, which is a physical indicator characterizing the thermal conductivity of a material, is numerically equal to the heat flux density divided by the negative temperature gradient in units of W/(mK). Reducing building energy consumption, reducing the heat consumption of the envelope structure and improving its thermal performance are the key to building energy efficiency. According to GB50189 public building energy-saving design standards, the limits of heat transfer coefficient of the envelope structure are sorted out, see Table 1. Table 1 Heat transfer coefficient limits of different climate zone enclosure structures Heat transfer coefficient K/IWKm2 shape of climate zone enclosure structure Coefficient name 0.3 0.3 Steel structure commonly used insulation materials, glass wool, rock wool, polystyrene extruded foam board. These materials have great differences in thermal insulation performance, fire resistance, stability, compressive strength, waterproof performance, sound insulation performance, and harmful substance content. When selecting insulation materials for building envelopes, in addition to the insulation materials themselves, factors such as the use and location of the buildings and the shape, size and orientation of the buildings should be considered. 3.1 Glass wool for building insulation and glass wool for thermal insulation has become a commonly used thermal insulation material for metal structure construction. It divides the unit volume of air into numerous small air chambers by vertically and transversely intersecting glass fibers, thereby obstructing the convection of air for thermal insulation. In addition to superior insulation performance, insulating glass wool also has the characteristics of heat insulation, sound insulation, moisture resistance, light weight, high elasticity, pressure resistance, convenient installation and low cost. Insulation glass wool selected for construction, the performance of the product should meet the requirements of glass wool products for building insulation (GB/T17795), and its combustion performance is not lower than Grade A2 of building materials and products combustion performance classification (GB8624); its 24T: average The thermal conductivity at temperature is shown in Table 2. The heat transfer coefficient corresponding to different thicknesses is shown in Table 3. Table 2 Insulation Glass wool 24 The greater the bulk density of the insulation material, the smaller the heat transfer coefficient of the material. The increase in the bulk density of the insulating glass wool can increase the thermal resistance value, but it is not obvious, and the cost increases rapidly. Insulation glass wool has a lower limit temperature. When the temperature reaches 538 ft, the insulating glass wool will soften, so the insulating glass wool is not suitable for buildings with fireproof limit requirements. It is clearly stated in the explanation that the roof load-bearing members of the secondary fire-rated building can adopt metal components without protective layer. The provisions explain the legal basis for the widespread use of insulating glass wool. 3.2 Construction of rock wool, slag cotton Some buildings have special requirements, such as fire limit, it is recommended to use thermal insulation rock wool as insulation material in metal structure construction. The material has the characteristics of heat insulation, sound insulation, light weight, high elasticity, pressure resistance, convenient installation, low cost, anti-aging and good weather resistance. For such requirements, the brand rock wool should be selected. The product performance should meet the relevant regulations of rock wool and slag wool insulation products (GB/T19686) for construction, and the combustion performance should reach Grade A in the burning performance of building materials and products (8624). The thermal conductivity of the rock wool insulation material at 24 °C is shown in Table 4. The heat transfer coefficient of the rock wool felt with different thickness is shown in Table 5. The heat transfer coefficient of the rock wool board with different thickness at 24 o'clock is shown in Table 6. Table 4 Cotton thermal insulation material 24 Project rock wool felt rock wool board bulk density / (kg / m) 50608010040506080100120 material thermal conductivity coefficient 04 A: rock insulation glass wool Relatively speaking, rock wool insulation material is heavier than glass insulation cotton material, and the price is high, so The roofing system using rockwool insulation material is more expensive. 4 Typical steel structure insulation roofing system and its application Perforated inner f plate-6 Typical single-layer insulation cotton roofing system 4.1 Typical steel structure insulation roofing system 1) Typical single-layer insulation cotton roofing system Table 7 Typical single-layer insulation Cotton roofing system and its thermal resistance coefficient name material description number theoretical value actual value roofing panel 0.61.0mm thick Hengli board or aluminum slate wool insulation cotton rock wool glass insulation cotton vapor barrier non-woven fabric inner liner sound-absorbing plate foam perforation The total thermal resistance of the inner lining plate/total heat transfer coefficient is applicable to the single-layer rock wool in the hot summer and warm winter area. The single-layer rock wool is hot in the summer and warm in the winter, the hot summer and cold winter regions, and the cold-skinned single-layer glass wool summer hot winter warm Area, hot summer and cold winter area, single-layer glass wool, hot summer and warm winter area, hot summer and cold winter area, cold area single-layer thermal insulation cotton roofing system can meet the needs of the building, meet the relevant national regulations, and is more economical. Most owners prefer. 2) Typical double-layer insulation cotton roofing system When the internal environment of the building is high temperature, high humidity and easy to dew condensation, such as textile workshops and buildings in cold areas, single-layer insulation cotton roofing can not meet the insulation requirements, then it is necessary to thicken the insulation materials. thickness of. However, when the limits of the mounting accessories are exceeded, such as the length, strength, etc. of the connector nails, the insulation cotton must be laid down in layers. It is a typical double-layer thermal insulation cotton roofing system in Butler's steel structure building system. Table 9 is the corresponding thermal resistance coefficient of the roofing system, and Table 10 is the corresponding heat transfer coefficient of the thermal insulation material. Similarly, use the heat transfer coefficient in Table 10 and the public building energy-saving design standard (GB (with insulation mat) typical double-layer insulation cotton roofing system table 9 typical double-layer insulation cotton roofing system and its thermal resistance coefficient No. Theoretical value Actual value of the roof panel 0.61.0mm thick Hengli plate or aluminum slate wool insulation cotton rock wool glass insulation cotton insulation cotton 50mm thick 12kg/m3 glass insulation cotton insulation layer non-woven sound-absorbing board foam perforated liner metal total Thermal resistance / total heat transfer coefficient Application range Rock wool is suitable for steel structures with fire protection requirements. If there are sound insulation requirements, 5+6 is required. 2012.3 Chinese building waterproofing. The roof has the heat transfer coefficient corresponding to the different double insulation schemes and the heat transfer coefficient of the insulation material in the applicable area. K/Applicable area rock wool + 50mm thick 12kg/m3 glass insulation cotton summer hot winter warm area, summer hot winter cold area rock Cotton +50mm thick 12kg/m3 glass insulation cotton summer hot winter warm area, hot summer and cold winter area, cold area, cold area BE, cold area A area insulation cotton +50mm glass insulation cotton summer hot winter warm area, summer hot winter cold Comparison of heat transfer limits in areas, cold area insulation cotton +50mm glass insulation cotton summer hot winter warm area, summer hot winter cold area, cold area, severe cold area B area, severe cold area A area 50189), can be easily determined The scope and area to which the insulation scheme applies. The double-layer thermal insulation cotton roofing system increases the thickness of the thermal insulation material on the basis of the single-layer thermal insulation cotton system. The installation can be carried out by means of staggered seams to avoid the cold bridge generated when the thermal insulation cotton is spliced ​​horizontally, and the thermal insulation is improved. effect. High-temperature and high-humidity buildings, such as textile workshops, use double-layer insulation cotton roofing system with anti-seepage membrane to avoid condensation on cold bridges, and can also add inner liners. From the inside of the building, it is beautiful and beautiful, and the building is improved. Aesthetics are some of the most frequently chosen options for building. 4.2 Application Case The production workshop of a company in Wuhan, Hubei Province, built in 2005, is 443m long, 241m wide and 13.5m high. The production plant adopts steel structure system with a construction area of ​​about 980,000m2. The outer wall of the workshop is equipped with ventilation windows. The lighting in the central part of the workshop is mainly achieved by setting the lighting panels on the roof. Part of the ventilation system is installed in the plant, and the roof is equipped with a ventilator to adapt to the hot summer climate in Wuhan. Wuhan is located near 30° north latitude. It is affected by subtropical high in summer, rainy, and it is located in the plain, and the Yangtze River and Hanjiang River meet. The water vapor is strong and it is not easy to disperse. It is commonly known as “sauna day†but it is colder and less rainy in winter. The cold air drives straight in and cools down quickly. The dominant wind direction in summer is southeast wind, and the dominant wind direction in winter is northeast wind. The area is typical of hot summer and cold winter areas. The factory is a metal product processing building, no flammable materials, fire protection requirements are two, can not use rock wool insulation. Moreover, the interior of the workshop is not a high temperature and high humidity environment, and there is no need to use a double insulation cotton roofing system. After calculation, the figure coefficient of the building is 0.31. The comparison of the insulation scheme of the house surface is shown in Table 11. Table 11 The heat insulation coefficient K/ roof of the roof insulation system of a steel structure factory in Wuhan area Heat consumption Q/WA scheme: 75mm thick kg/m3 glass insulation cotton B scheme: 50mm thick kg/m3 glass insulation cotton inside and outside temperature difference AT is 10T:; A is the material surface area, here is the roof area of ​​the plant. Under the premise that the material prices of the two roofing systems are identical, it can be seen from Table 11 that the hourly roof heat consumption of the B scheme is nearly 30% higher than that of the A scheme. Therefore, the former is selected. 5 Conclusion In summary, metal structure construction combined with high-quality insulation materials, it is easy to achieve thermal insulation, to meet the national requirements for building energy. The development and progress of architectural culture comes from the continuous improvement of architectural concept. The expression of architectural concept is inseparable from the support of architectural technology. The relationship between the two complements each other. The construction technology also has the characteristics of innovation, logic and fun. An in-depth understanding of building technology, building construction and materials will help to rationally select materials and power the development of green building (enclosure and roofing) concepts. (Finish) Led Outdoor Wall Lamp,Outdoor Led Wall Lamp,Solar Wall Lights,Garden Wall Lights Jiangmen hengshenghui Lighting Co., Ltd , https://www.jmsunbright.com