This European Standard provides guidance and, where appropriate, defines procedures for variations of certain parameters and factors associated with the design of curtain walling according to EN  13830 which have been tested in accordance with EN  1364‑3 and classified according to EN  13501‑2 (curtain walling type B according to 3.2), components of curtain walling type A or type B according to 3.1 and 3.2, e.g. spandrel panels, which have been tested in accordance with EN  1364‑4, and classified according to EN  13501‑2.