Unlike the steel within the building the steel outside the thermal envelope is galvanised (silver) to protect it from the elements, and predrilled for trimming out in timber and fixing a facia.
The steel frame gives an initial impression of the canopy to the ground floor south elevation to limit solar gain and thus minimise overheating, critical to passive comfortable indoor conditions (and without the need for mechanical cooling).
The (Scheock) thermal breaks separate the internal and external steels, reducing heat loss and even more critically avoiding the risk of condensation forming on the internal structure.