A protection class is a classification tier in BSI IT-Grundschutz that follows from the assessed protection requirement. It determines how extensive and thorough the security measures for a given asset must be. Higher protection classes require additional technical and organisational measures beyond baseline requirements. You find the corresponding requirements in the BSI Grundschutz Compendium. In an ISO 27001 context, the protection class is conceptually equivalent to the risk class, although the terminology differs. The assignment is documented and updated when changes occur.