Green Hall 2 -open to nature and the sun. Because we can do more by working together with it. Green Hall 2 is designed so that each workplace is illuminated with high quality natural light. The facade of the building is comprised of 3800 square metres of particularly clear Guardian ExtraClear™ glass whose light transmission index is as high as 90 percent. The even distribution of light during the day is ensured by an automatic facade blind control system which moves together with the sun.