CSN EN 12975 This document is applicable to all types of fluid heating solar collectors. This document specifies performance requirements for fluid heating solar collectors with respect to durability, reliability, safety and thermal performance. This document deals with the solar collector and not with assemblies. This document is not applicable to those devices in which a thermal storage unit is an integral part to such an extent that the collection process cannot be separated from the storage process for making the collector thermal performance measurements. Original English text of CSN EN Standard. The price of the Standard included all amendments and correcturs.