User's Voice

Chiken: Titanium is a relatively new material compared to copper with about 6,000 years of history, steel with 4,000 years, and aluminum with 200 years. Only about 70 years have passed since the industrial production of titanium began. While titanium ore was found before that, it was so difficult to extract the material, as being suggested by its naming after Titans, who were imprisoned in the underworld in Greek mythology. Use of titanium in architecture began merely about 45 years ago.
　As a metal, titanium has three distinctive features of being lightweight, rust-resistant, and highly-durable, and is mainly used for products for aerospace, special industrial plants, and certain equipment such as heat exchangers.
　“Being lightweight” helps ensure safety and (important for some countries) quake-resistance, and helps reduce burden in processing and construction. “Being rust-resistance” means to contribute to reduction in the life cycle cost (LCC), as compared to metals it replaces there is no need for maintenance and no limitation in where it is to be used. Finally, “being strong” enables, for example, a titanium sheet to be thinner than an aluminum sheet for the same application. Titanium imparts virtually no impact to the environment. As titanium is also a biocompatible material, it has been adopted in medical applications for artificial bones and artificial joints.
　Moreover, as a great design-related feature, titanium shows interference colors. Titanium does not rust due to the protective, colorless, and transparent oxide layer that forms on its surface but various colors are produced due to light interference phenomena when the light passes through the film. In case of exterior cladding made of titanium, the wall colors change with differences of incident light in the morning, at noon, and in the evening, and depending on where you stand and look at the material. Such interesting effects can be created with titanium.

Shimizu: Use of titanium in modern architecture is particularly gaining popularity overseas. It was triggered by architect Frank O. Gehry who extensively used titanium in the Guggenheim Museum Bilbao (1997) in Spain. Gehry likes interference colors and adopted titanium made by NIPPON STEEL Corporation in the Hotel Marqué de Riscal (2004) in Spain. Then, French architect Paul Andrew saw the titanium used in the Bilbao and asked NSSMC to supply titanium products for National Centre for the Performing Arts (2007) in China.
The first titanium project I was personally involved in Japan was the spherical observation platform of Fuji TV’s headquarters building (1996) in Odaiba, Tokyo, designed by Kenzo Tange. The roll dull finish (ND20) product was adopted there. Architect Kiyonori Kikutake also uses various titanium products in his works. We supplied pickled-surface white titanium for roofing of the Shimane Art Museum (1998) and glossy blue titanium for roofing of the Kyushu National Museum (2004). Our titanium product was adopted for the first time in exterior cladding of a large-scale structure at the National Showa Memorial Museum (1998) in Tokyo. The titanium sheet was 1.5mm in thickness and 7m in length with no surface strain. I believe this is a representative case of using titanium in architecture.

Miyazawa: Without having used titanium material in architecture, I initially thought of titanium as an expensive material compared to aluminum, for example. I therefore thought that this was the first obstacle to overcome.
　In addition, various competing aluminum louvers were already available in the market. Being an extruded material, aluminum louvers are manufactured with a uniform cross-sectional surface. This means that the horizontal surface can be designed but the lateral surface cannot. I thought this can be one of factors to be considered in designing titanium louvers.
　In our office, with regard to architecture that emphasizes materials, louvers are one of the main parts deserving consideration. Similar to koshi grating in old days, in Japan louvers are used not only for design reasons but also as functional components of structures. In that sense, I think we can say that louvers are not a temporary fad.
　According to architect Kuma, the light which “particulates” through louvers can be incorporated in architecture. The louver thus plays a role of a filter. Rather than being simply a frame with panels, the louver can be one of methods to intentionally control the “particulated” light so as to obtain a desired effect on the surface where it falls.
　When I talked with Kuma for the project, he showed interest in soft reflection of the roll dull finish. As one of the issues is how thin the panel can be, I have asked Sanwa Tajima to actually make louver mock-ups at their plant.

Miyazawa: I think titanium is the superb in replacing kawara tiles and creating onigawara tile for temples and other buildings as the material has distinctive features well. Given the present status in material improvement, I am thinking of what can be possible in case of louvers. I would say that molding, or imparting a visual impression by pattern pressing, can be doable as one of the methods.

Ueda: Indeed, we are also working on issues such as costs and ensuring of strength. We also intend to look at how to locate and attach a louver to the wall and how to cope with issues raised by the wall materials, among other issues.