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 market. 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 (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 standards such as EN 13445 Unfired pressure vessels, EN 13480 Industrial piping, EN 12952 Water-tube boilers and auxiliary installations, or EN 12953 Shell boilers.