ETFE: A Material of the Future

Engineers are always on the lookout for new technologies and materials that decrease the price of projects and allow greater freedom in the design of projects. Before the advent of mass-produced iron and steel, buildings were limited to the constraints of stone and lumber. Very tall buildings were not feasible. The taller a stone building was built, the thicker the bottom levels of the building would have to be to bear the weight of the structure. An example of this is the Philadelphia City Hall, which when built in 1901, was designed to be the tallest structure in the world. As the structure of the building was built of brick and stone, the first floor walls were up to 22 feet thick at parts. Before Philadelphia’s City Hall was completed however, the Eiffel Tower surpassed it as the tallest structure at almost twice the height. This illustrates how new materials and techniques can affect the buildings we build.

Over 40 years ago, a material called ETFE was developed by DuPont. Although this material has been around for a while, it is just starting to see prominent use in architectural applications. Some notable buildings that make use of this polymer are The Water Cube used in the 2008 Beijing Olympics, the Allianz Arena football stadium in Germany, and the Minnesota Vikings Stadium in Minneapolis which is currently under construction.

The material is a polymer that is extruded into thin, transparent sheets that are used as cladding, roofing and façade systems. The material is very unique in that it is strong, very light, and highly resistant to corrosive forces. The material does not degrade under UV light or other radioactive forces, and does not corrode or react with pollution or air. Additionally, ETFE has many of the same properties as PTFE or Teflon that you may have seen on non-stick pots and pans. Just like Teflon, ETFE has a very low coefficient of friction and water and snow slide off of it very easily. There is little need to clean the material as the dust, dirt, and other contaminants simply get carried off with rain water.  Because of these properties, ETFE is highly resistant to discoloration or deterioration. As mentioned earlier, ETFE is often used in roofing and cladding applications. In the Minnesota Vikings stadium for example, just over half the roof will be made of the material, giving it a unique, clear ceiling.

Another benefit of the material is its light weight. ETFE can weigh 1-3 percent of traditional cladding systems. This combined with its strength allows dramatic cost savings as the surrounding structure does not have to support as great of a load. There are also many applications for which traditional systems would not work. ETFE has the additional benefit of being able to stretch to three times its length before failing. The material is also highly recyclable, and following its useful life, can be completely recycled for re-use. This means the environmental impact of the material is much lower than comparable claddings.

In conclusion, ETFE will continue to see new use and more widespread application as new uses and implementations are found for it. There are many exciting new possibilities for the widespread use of ETFE and it will continue to be adopted. As the material is still relatively new the limitations and full possibilities are not even close to being fully explored.