In the construction process, the insulation materials of the external envelope should be determined according to the requirements of the design drawings. All kinds of insulation materials should have factory certificate or test report of relevant indicators. When there is no factory certificate or test report, it should be sampled and tested, and its relevant indexes should meet the requirements.
With the deep development of China's building energy-saving work, many varieties of thermal insulation materials are emerging, and some thermal insulation materials are gradually eliminated from the market due to their energy-saving and thermal insulation performance. Choosing suitable thermal insulation materials can not only achieve the purpose of energy saving and heat preservation, but also prolong the life of the building, and vice versa affect or even shorten the life of the building.
According to the different use parts of insulation materials in the envelope structure, it is divided into internal wall insulation materials and external wall insulation materials; according to the different states of energy-saving insulation materials, it is divided into board (solid) insulation materials and slurry insulation materials.
Plate thermal insulation material
Board thermal insulation material, the use of the area and the scope is relatively wide, can be used in the external wall insulation project, also can be used in the external wall internal insulation project. The insulation main body of board insulation material can be different materials such as foamed polystyrene board, extruded polystyrene board, rock wool board, glass wool board and so on.
The board insulation material can be divided into single insulation material and system insulation material, and the following issues should be noted in the application process:
A:Single thermal insulation material.
It is the main body of insulation project application, and it needs the cooperation of other materials in the process of use. Such as: foamed polystyrene board, extruded polystyrene board, rock wool board, glass wool board, etc. The following test contents should be tested before use:
1, Thermal conductivity: this technical index is the key indicator of the insulation effect of the project, in general, the laboratory test is tested when the plate is dried to constant weight, and the application of the material is used in the air containing certain humidity conditions, therefore, the use of a certain coefficient to multiply; or, directly adjust the material to the use of environmental conditions test.
2、Apparent density (Kg/m3): The apparent density of the material affects its thermal conductivity to a certain extent, and the material with unqualified apparent density will directly lead to the decrease of its physical properties, such as strength, dimensional stability, etc.
3、Compression strength (MPa): refers to the compression stress of the specimen under 10% deformation. It is related to the durability and impact resistance of the surface layer system.
4、Size change rate (mm): The material with large size change rate will lead to the cracking of the surface layer of the system.
5、Water vapor transmission coefficient: This performance determines the performance of water vapor transmission, and to a certain extent determines the condensation of the wall surface or not.
6, oxygen index: need flame retardant type, otherwise fire can not meet the standard.
B:System insulation material
System insulation material refers to a single insulation material and other auxiliary materials composite and become a system, called the system insulation material. The existing system insulation materials are as follows:
1. Exterior wall insulation system: foamed polystyrene board (or extruded polystyrene board) + alkali-resistant glass fiber mesh + polymer mortar containing adhesive, such as special Witt exterior wall insulation system, Beijing in the construction of the exterior wall insulation system, Preswitt insulation system, etc.; exterior insulation system to be tested for the following items:
a: heat transfer coefficient: system insulation materials and the main structure after the composite insulation effect by
Construction quality and environmental temperature and humidity of the impact and change, so to field site test, grasp its actual effect. According to the Ministry of Construction "civil building energy-saving thermal design code" JGJ 26-95 and around the "rules" requirements for indicators, shall not be lower than its limit value;
b: water resistance, freeze-thaw resistance, weather resistance, impact resistance, wind pressure resistance: as external insulation, its surface directly in contact with the outside environment must resist rain, freeze-thaw, impact and strong wind and other adverse factors, so before use should test the above features. The tensile strength of the alkali-resistant glass fiber mesh cloth supporting the exterior insulation system should be greater than 200N/cm, and the remaining tensile strength after alkali resistance should be not less than 150N/cm; the 7-day tensile bond strength of the adhesive should be greater than 1 Mpa, water resistance, freeze-thaw resistance after tensile bond strength should be greater than 0.9Mpa.
2. The internal insulation system: there are foamed polystyrene board (or extruded polystyrene board) + paper-faced gypsum board; GRC insulation board (hair gun type polystyrene board and cement mortar composite); rock wool sandwich insulation board; enhanced cement polystyrene insulation board, etc.
Internal insulation needs to be tested: heat transfer coefficient, water vapor permeability coefficient, water absorption rate, shrinkage rate, oxygen index, for the same reasons as above.
