19 Non-metallic building and construction materials; windows, not of metal, for buildings, building structures, balustrades, awnings and facades; windows for buildings; glass for the windows of buildings; glass for windows; glass in sheet form for use in windows; glass panels for windows; non-metallic window frames; non-metallic glazing elements for windows; multi-layered insulating glass units for glazing buildings; vacuum insulated multi-layered insulating glass units for glazing buildings; non-metallic balustrades; non-metallic awnings for buildings made of glass; facades of non-metallic materials; non-metallic window facades; curtain walling of non-metallic materials; curtain walling installations of non-metallic materials; non-metallic frames and structures for buildings; roofing, not of metal, incorporating photovoltaic cells; infrared reflective glass for use in buildings