Double skin façades: Almost a self-explanatory name for façade systems consisting of two layers, usually glass, wherein air flows through the intermediate cavity. This space (which can vary from 20 cm to a few meters) acts as insulation against extreme temperatures, winds, and sound, improving the building's thermal efficiency for both high and low temperatures. Perhaps one of the most famous examples of double-skin facades is Foster+Partners' 30 St Mary Ax Building, "The Gherkin."
The airflow through the intermediate cavity can occur naturally or be mechanically driven, and the two glass layers may include sun protection devices.
