Lecture AIR INFLATED building systems

Imagine a material that weighs less than glass. It is 100% recyclable, has a very high insulation value and can stretch four times its own length before it rips. It exists and is called ETFE (ethylene-tetrafluoroethylene).

After the oil crisis of 1973-74 was also the architecture world interested in this material: raw materials were not infinite and Fuller's adage — doing more with less — became a reality for many projects. 

The Eden Project in Cornwall, UK 

Most people know EFTE of this tropical garden. Architect Nicolas Grimshaw and his team faced the challenge to build a transparent skin with maximum light output and minimal construction. A glass enclosure on this scale would have brought with it a heavy construction; that was so not an option. After they had made several design studies they came from on a GEODESIC structure that derived from the work of Buckminster Fuller.

Watercube OS Beijing, China

The roof of this EFTE ‘Water Cube' has a gigantic span in two directions of 177 meters. The of water bubbles inspired design is divided into modules of 20 to 40 metres to keep the structure clear. The walls are 3.6 meters thick and the roof 7.2 meters thick. Cause is the dual climate facade that on both sides of the support structure is covered with a layer of etfe cushions.  The EFTE cushions do have a sound-absorbing effect, which comes in handy as well for a swimming pool. The sizes of all the structural elements were made of simple circular tubes. Those were automatically selected by the engineering software, and then welded to the spherical nodes at each end to form the bubble structure frame. The proposed ETFE pillows provides for a continuous and insulting skin for the walls and roof. The double skin ensures that the building through out all seasons with minimal heat and cold losses can operate. In summer ventilation between the two layers provides ensure that the building not too very warms up, and when in winter the interlayer is closed, it keeps the heat fixed.

Another way to tightened the foil is on pneumatic way. This is the most common way because very large spans are possible (15 metres). The principle is to weld two layers EFTE to a construction. If this construction by means of  a valve inflates, the pillows strains themselves so that they can be charged. Additional advantage of the pillows is that they can adopt any form, allowing the underlying support structure each shape can have and can work independently of the structure of the cushions.

By the airlayer in the ETFE cushions is the insulation in the cushions also very good. Inflating the cushions also ensures a uniformly distribution over the surface, making the bumps in all directions will be far reduced.  

At three double ply cushions is in the middle an additional membrane ETFE added. The extra layer also makes a better insulation and can be used for to reduce daylight acess.