Characteristic Analysis of ETFE Films

The Chinese name of ETFE is ethylene-tetrafluoroethylene copolymer. The thickness of the ETFE film is usually less than 0.20 mm and is a transparent film material. This membrane material was used in venues such as the National Stadium in Beijing 2008 and the National Swimming Center.

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ETFE membranes are often used as air cushions in membrane structures. The earliest ETFE project has a history of more than 20 years, and the most famous one is the Eden of England.

The ETFE film is a superior substitute material for transparent building structures and has proven itself as a reliable and economical roofing material for many years in many projects. The film is made of artificial high-strength fluoropolymer (ETFE). Its unique anti-adhesion surface makes it highly resistant to dirt and easy to clean. Normally, rain can remove major dirt.

ETFE membranes have a service life of at least 25-35 years and are ideal for use in permanent multilayered mobile roof structures. The membrane material is mostly used for two or three-story inflatable support structures with a span of 4 meters. It can also increase the membrane span depending on the geometric and climatic conditions of a particular project. The length of the film is based on the ease of installation and is generally 15-30 meters. Small-span single-layer structures can also be used in smaller sizes.

The ETFE membrane meets the B1 and DIN4102 fire rating standards and does not drip when burned. And the quality of the film is very light, only 0.15-0.35 kg per square meter. This feature gives it considerable advantages even when the film is thawed due to smoke or fire.

Depending on the location and surface printing conditions, the ETFE film can have a light transmittance of up to 95%. The material does not block the transmission of light such as ultraviolet light to ensure natural light inside the building. With surface printing, the material's translucency can be further reduced to 50%. According to the geometric conditions and the number of layers of the membrane, the K value can be as high as 2.0 W/m2K. The energy dissipation index can reach 0.77 with a three-layer printing film as an example.

Due to its excellent quality, ETFE membranes require little daily maintenance. It is possible to carry out a simple inspection of the roof due to mechanical damage (it is appropriate once a year) and repair it on-site as required. Also check the ventilation system and replace the filter.

ETFE membranes are completely recyclable materials that can be reused to produce new membrane materials, or to separate impurities to produce other ETFE products. ETFE is completely different from PVC and PTFE. Just like everybody knows about cars, Euro 1 and Euro 2 are easier, while Euro 2 and Euro 3 are completely different.

According to preliminary analysis, the use of PTFE in the Bird's Nest has the following reasons:

1. Its membrane area is at least one-half larger than that of the Water Cube. The application of such a large area is not available in the world. It is very difficult for the membrane structure to be connected with the steel structure.

2. Its large-area open roof has increased the difficulty of design and construction, which is probably unique in the world.

3, to avoid risks, two Olympic venues, since the use of water cube ETFE, Bird's Nest to PTFE is also reasonable;

4, ETFE does have advantages, but it does have drawbacks, and Bird's Nest needs the advantages of PTFE, in other words, PTFE is more suitable for the bird's nest, including from the perspective of the structure;

5. The advent of ETFE film has provided an innovative solution for modern architecture. The roof and walls made of this membrane material are of light weight, only 1% of the glass of the same size; good toughness, high tensile strength, not easily torn, ductility greater than 400%; weather resistance and chemical resistance Strong, melting temperature up to 200 Â°C, and will not spontaneous combustion.

As ETFE membranes for building materials for large-scale competition venues, the greater advantage lies in the fact that they can be processed into any size and shape to meet the needs of large spans and save intermediate support structures. As a kind of material used after inflation, it can adjust the degree of shading and light transmission by controlling the amount of inflation, effectively use natural light, save energy, and play a role in thermal insulation.

Not only that, this film also has a self-cleaning function, so that dust does not easily adhere to its surface, the cleaning cycle is about 5 years. Another great advantage of this material is that it can be prefabricated into thin film bubbles on site to facilitate construction and maintenance. In addition, the reasonable cost is another advantage of its competitiveness. The cost of the overlay and structure is only half that of glass, and the service life is as long as 25 years.

ETFE membrane materials have been used in the world for more than 20 years. However, the research and engineering applications of domestic ETFE membranes are still blank.

At present, the domestic understanding of ETFE, a new thin-film material, is limited to the relevant information provided by foreign manufacturers and the intuitive feeling from typical projects abroad.

The basic performance of ETFE film, the ETFE inflatable pillow internal pressure, wind, snow and other distributed loads (including non-uniform distribution of snow load) and the load of personnel under the inspection of the load performance, thermal conductivity of the inflatable pillow, water tightness, gas The tightness, the connection between the inflatable pillow and the edge member, the design of the edge member and the ETFE construction standard control. Through the system's theoretical analysis, experimental research and applied research, we have established complete application technology for ETFE film materials with independent intellectual property rights to promote the application and development of ETFE films in China.