This standard deals with damage caused by scale formation and water-side corrosion. It gives recommendations for their avoidance in hot water heating systems according to DIN EN 12828 within a building, where the specified flow temperature does not exceed 100 °C. It also applies to hot water heating systems which are operated temporarily or permanently in direct hydraulic connection with cold or cooling water circuits, unless other regulations or regulations for cold and cooling water circuits specify stricter requirements. The standard takes into account the previously separate topics of "scale formation" and "water-side corrosion" in a combined standard. Current technical findings and the subject area of existing installations were taken into account in the revision and consolidation.