Photography: Nacasa & Partners Inc.

The No. 5 Building is situated in the center of NTT Central Training Center, surrounded by rich nature. The PcaPC structure skeleton is directly used as the facade while also acting as a solar shading lattice. With the adjustable partitioning, the long-span column-less classrooms can be divided into large or small sized rooms according to the use of the space. Energy conservation is achieved by utilizing the utility conduit (underground infrastructure tunnel) in the facility, which is kept in a stable temperature environment throughout the year, as a cooling/heating tube. The stairwell in the center functions as a solar chimney by virtue of the see-through sunlight panels installed on the top light. Various environmental measures are taken, including the preservation or recycling of the trees and the use of recycled building materials made of NTT's waste materials (e.g., tiles made out of the glass used for telephone booths, concrete block flooring materials made out of concrete telegraph poles).