How long can the "Water Cube" survive? Zheng Fang, the chief designer for the "Water Cube," gave the following answer -- 100 years. Can any architectural structure survive one hundred years, subject to bad weather and other outside forces? Tests have proven that the strength of the membrane structure of the National Aquatic Center can meet these stability requirements, even in bad weather conditions. such as hailstones.

The membrane structure of the "Water Cube" uses a special material called ETFE. This material was first used in the aviation industry and honored as the "bubbles." With the construction of the National Aquatics Center, ETFE membrane has been used for the first time in China.

In the past 20-30 years, ETFE was used in 600 to 800 architectural structures in Europe. The transmission of light and strength of the ETFE membrane in the past 20 years have not deteriorated at all. The "Water Cube" is designed to last 100 years; the performance of ETFE membrane in the past 30 years boosts the designers' confidence.

According to Zheng Fang, a moat was constructed around the "Water Cube" and the interior membrane structure also maintains a certain distance from the public area. Such a design makes sure that the spectators cannot touch the "bubbles," which greatly reduces the possibility to harming the structure.

Studies of avian behaviour have shown that birds do not alight on semitransparent surfaces. The only place atop the "Water Cube" that birds might land on is the rain water collection system. The designers set up metal wires on the collection system particularly to let the birds rest and make sure they do not step on the "bubbles."