This part six of EN 764 is a Technical Report and as such is a generic document that identifies requirements for operating instructions which accompany the pressure equipment when it is placed on the marked. It only provides general statements and thus does not claim to give presumption of conformity to the essential safety requirements of the Pressure Equipment Directive 97/23/EC (PED). Operating instructions contain the necessary safety information covering installation including assembling, putting into service and maintenance. For specific items of pressure equipment or assemblies, more detailed requirements on the content of operating instructions can be found in specific standard series such as EN 13445 “Unfired pressure vessels”, EN 13480 “Industrial piping”, EN 12952 “Water-tube boilers and auxil-iary installations”, or EN 12953 “Shell boilers”.