New technology of heat preservation lining of membrane struc
In recent years, the membrane structure develops very rapidly. The materials develop from PVC, coated PVC, to PTFE perpetual membrane , and the ETFE heat preservation lining of membrane structure. The construction also developed from garden opuscule, landscape construction, awning of toll station, to stadium and other construction of share space.
New technology of heat preservation lining of membrane structure, is the top technology of large span space structure, especially the membrane structure construction after open-close structure and cable dome structure. It is applied in many international large-span constructions, for example, the Millennium dome of U.K, waiting hall of Denver airport of America, Munich exhibition center of Germany, waiting hall of xxx airport of Spanish. In 2008 Olympics , the Bird’s Nest and the Water Cube also applied this membrane structure construction.
What is the heat preservation lining material?
The heat preservation lining material is a combination of coated PVC material, heat-resistance material, heat preservation material and moist-resistance material. It is new construction material of saving-energy and environment protection and also can keep warm and light transmission.
Specification: Coating layer can be PTFE coating, Fluoride coating and PVC coating. We can adopts various thicknesses of lining according to standard of the heat conduction coefficient in different area (See Table 1) and health standard of construction of different function. For example, the swimming pool, gymnasium, and house, have different requirement for surface temperatures. If the temperature of swimming pool lows, it will cause the trouble of condensation and adaptation of human body.
The thickness of heat insulation layer usually is 10cm, 7.5cm or 5cm (for one layer). According to the thermal resistivity, and we can make it two layers or three layers.
Development and application of membrane structure technology gets rid of the limit of tradition materials such as steel, wood, concrete, and it also breaks the traditional concept of construction, creating new imaginary space for architect. It is very different from the traditional construction, and brings more affection for construction industries and will be the main trend for development of construction space.
The features of energy conservation and environment protection make lower secondary pollution. The membrane structure only needs to be stretched and fixed, so the installation is very fast. It also reduce the pollution in construction site. It guarantees the effect of landscape and shows the region culture.
1、Energy conservation: It is because of the features of heat resistance and light transmittance of the lining.
2、Environment protection: It avoids to using massive traditional materials such as steels, bricks and stones, and reduces the secondary pollution. The membrane structure only needs to be stretched and fixed, so the installation is very fast. It also reduce the pollution in construction site.
3、Ecological benefit: After ultraviolet rays filtered by membrane and lining, the lighting into room becomes diffusion light which is good for the growth of vegetation.
◆Main technical features：
The coating material of lining and TEDLAR membrane guarantee its tension strength, tearing strength, durability and fire retardance. Because the lining is fixed inside, there is little affect of wind, rain, snow and ultraviolet rays, at same time, the lining almost be free of pretension (except some special design). So, comparing with the outside membrane, the requirement of lining is much lower.
See table 3
Please note that, different volume-weight will cause different coefficient of heat conductivity and different thermal resistivity.
Thermal resistivity = Thickness/ coefficient of heat conductivity
The surface of outer membrane can refract more than 70% sunlight, so it has good heat insulation. Light transmittance of outer membrane is up to 20-25%. Inner lining membrane is mostly transparent; Light transmittance of insulation layer is about 40-50%. After through the three layers, the light transmittance must be affected, but the total light transmission will still be 10% and absolutely meet the requirement of lighting and the growth of vegetation.
The fire proofing performance of inner membrane can reach the standard of ASTMZ-136 and had been registered by fire proofing station of California and Los Angeles. At he same time, it can reach the standards of many countries and was widely applied in U.K, France, Italy, Japan, Australia, Germany. The inner lining also has good fire resistance and reach A1 standard of fire proofing. If we adopt PTFE material, the inner membrane and outer membrane can also reach A1 standard of fire proofing.
Generally, noise reducing coefficient determinates sound absorption of the material. Quality of membrane exactly shows the ability of noise reducing. It can muffle the reverberation in certain frequency range of noise, has good effect for noise absorption. Especially, it takes effect in the waiting hall of airport, waiting hall of bus & train station and exhibition center. And it is more effective for the awning in tall station. For the toll station that adopts membrane and colored steel plate, the effect of the former is twice of the latter.
The architect can be a fantast. Construction reflects the culture of certain region. There is a kind of natural fusion between membrane structure and the surrounding environment. Any else construction cannot compete with membrane structure construction in the feature of simple construction, excellent visual sense and curvature change. The perfection of nature and technology is be shown exactly.
Light transmission of lining can reach 10%（PTFE）and completely meet the requirement of indoor lighting. Meanwhile, the light which passed through the membrane material becomes very soft because the membrane material filters off highlight strength, even the ultraviolet rays becomes diffused light. It is comfortable for people. Such light is good for growth of tree and vegetation. With satisfying the people to be close to nature, it also saves energy and make you enjoy the low carbon living.
Membrane material has good heat insulation performance. It reflects 70% heat from sunshine. 17% heat is absorbed, and 13% is conducted.
It is obviously effective for reduce energy consumption in the area where summer is quite hot. However, it is also a big problem to make cool in a long span space and must pay the high maintenance expenses. Heat insulation of membrane material gives a perfect solution.
The energy consumption for the large span space is a big problem. The lining of membrane structure can supply good heat preservation (thermal resistivity). So it can reduce the energy consumption. After using the lining, light transmittance can still reach 10% and satisfy the demand of indoor light in daytime, and it saves the electricity. Because of its feather of energy conservation, now it is widely used for the share space construction and stadium, waiting hall of airport, waiting hall of bus & train station, exhibition center and other public constructions.
9、As the membrane roof is very light，it can reduce the material quantity for Maintenance system of main body and base system, and also the relative functioning cost. At the same time, it is not necessary for the secondary maintenance and fitment, and it saves the relative expenses.
When being arrived in the construction site, membrane structure only needs to be stretched and fixed, so the installation is very fast. (only half time of the traditional steel structure)
the application of membrane structure decreased the steel consumption, reduced secondary pollution, and also lower the consumption of sand, stone, welding in construction site. So it is of good Environmental protection in construction site.
Processing and welding technique for heat preservation lining
Welding: cut and weld the lining membrane according to shape of requirement. When welding, leave the overmeasure for the edge of interlayer. Or we can adhere the insulation layer in site according to the membrane unit and curvature.
Installation processes: Generally, the sequence of installation is first lining material, then outer membrane. According to the condition of steel structure, sometimes we can also take the sequence of outer membrane first and lining later. The lining is fixed by pressing plate or hanging.
installation of lights and packway :
According to the demand of project, lining can be placed above or below the steel structure in order to avoid affecting installation and repair.
Why adopt the heat preservation lining
1、Energy conservation firstly’ had been the continual energy strategy of China.
People pay more attention to the problem of energy source of 2000-2020. Recently, coal-shortage, electric-shortage and oil-shortage had given an alert to human.
As the above stated, the membrane structure and lining can save energy because of the good features of heat preservation, heat insulation, and light transmission.
2、Requirement of environmental protection:
The application of membrane structure and heat preservation lining reduce the quantity of steel material and avoid secondary pollution. With the light transmission, people can enjoy the same sensation both indoor and outdoor.]