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Architects insist on laminated glass for Tokyo International Forum

For safety reasons, more than 80% of the glass used in the new Tokyo International Forum is laminated glass.

The new Tokyo International Forum, which opened in January 1997, is a $1.65 billion project owned by the Tokyo Metropolitan Government. The Forum provides Japan's largest comprehensive culture and information facility, promoting international communication and contributing to world politics, industry, economics and culture.

The widespread use of laminated glass throughout the Forum's four hall buildings and its unique Glass Hall gives the building a rich variety of unique spaces that make it an ideal site for conferences or trade exhibitions, music, dance, drama and cinema performances or even fashion shows.

Architects insist on laminated glass

The Tokyo International Forum was designed by Rafael Vinoly Architects of New York, winner of international design competition held by the Union Internationale des Architectes (UIA) – this is the first time that a Japanese project was awarded via a UIA-sponsored competition.

The Glass Hall's façade uses approximately 20,000m2 of 17.5mm laminated, heat-strengthened glass supplied by Guardian Industries Corp. (8mm HS/1.52mm PVB/8mm HS with a glass panel size of 2.3m x 2.7m) and Asahi Glass of Japan.

Charles Blomberg, project architect with Rafael Vinoly, explained: "More than 80% of the glass used in this project is laminated glass. We decided to use laminated glass for safety reasons. In the Glass Hall, the Japanese at first opposed the use of laminated glass because of its relatively high cost compared to stick-on films, but we insisted because all the research we've seen points to the fact that laminated glass is just so much safer."

Mr. Blomberg continued: "Since the Forum is located in Tokyo, earthquake protection was a very big factor in the design. You have to design the frames so that they can move with the earthquake and the laminated glass within the frames will not break. We specified laminated glass for the all-glass canopy for the same reason."

A miracle of laminated glass

The all-glass cantilever canopy

Laminated glass features strongly throughout the project. The whole concourse area is of laminated glass including a 600 meter long, 9 meter-wide glass floor at the periphery of the Forum's plaza, joining onto a laminated glass wall at the building's basement. Another significant use of laminated glass is in the 10.5 meter long, all-glass cantilever canopy made of glass beams bolted together at the south end of the building, over the entrance to the Yurakucho subway station.

The theater of Hall A, one of the few conference halls in the world capable of seating more than 5,000 people, uses laminated glass for acoustic, as well as safety, reasons. The acousticians needed enough mass in the glazing to ensure that the walls would not vibrate when music was played. The Glass Hall which serves as the Forum's main lobby, is comprised of an atrium that starts one floor below ground and soars to a height of 60 meters. The Glass Hall building will have conference rooms on the 4^th to 6^th floors and a first basement that functions as both the main lobby and the lobby for the second basement exhibition hall, as well as a gallery for a variety of events and exhibitions.

Karl Straky, Director of Commercial Glass at Guardian commented: "Although the original specifications for the Glass Hall were for 19mm, fully-tempered glass with a PET film on the outside, extensive tests showed that films would not be capable of holding the glass in the case of breakage, so we advised that laminated glass should be used – which also amounted to a cost saving."

Museum glass with a colored white laminate was used for aesthetic reasons on the building's ceilings and on the glowing, luminous floor between the ground and the basement levels.

For added safety, laminated glass was used on many fixtures such as handrails and for glass objects such as information and ticket booths within the building. Laminated glass is also used for most of the building's skylights because the architects believed it was the safest option, although Japanese building codes often specify wired glass for these.

Thanks to the widespread and imaginative use of laminated glass, the Tokyo International Forum is a stunning architectural project which is a fitting symbol of the government and culture of Tokyo.