This document defines test and calculation methods for the determination of the reflection and transmission characteristics to be used to determine the thermal and visual comfort performance classes of external blinds, internal blinds and shutters, as specified in EN 14501:2021. This document also specifies the method to determine the darkening performance of external blinds, internal blinds and shutters, as specified in EN 14501:2021. This document applies to the whole range of shutters, awnings and blinds defined in EN 12216, described as solar protection devices in this document. Some of the characteristics (e.g. gtot) are not applicable when products are not parallel to the glazing (e.g. folding-arm awnings). NOTE 1 Informative Annex D presents an approach for the determination of characteristics in case of projectable products. Retro-reflecting products are outside the scope of this document for reflectance measurements. NOTE 2 Retro-reflecting products refer to products for which the reflected radiation comes back to the light source in the same direction. Products using a significant amount of fluorescent are outside the scope of this document. NOTE 3 "Significant amount" refers to materials which are designed to be fluorescent or retroreflective and marketed as such. It does not refer to trace amounts of materials exhibiting fluorescence, e.g. for colour or identification purposes. Small amounts of materials such as titanium dioxide, which are not primarily included to achieve fluorescence, can be present.