This part of this European Standard defines the terms, definitions, quantities, symbols and units that are used throughout the EN 13445. It also contains instructions on how to use the standard (Annex A) as well as an index which covers the whole standard (Annex B).This information is aimed to aid the user of the EN 13445.This European Standard applies to unfired pressure vessels with a maximum allowable pressure greater than 0,5 bar gauge but may be used for vessels operating at lower pressures, including vacuum. NOTE The selection, application and installation of safety related accessories intended to protect pressure vessels during operation are covered in EN 764-7.This European Standard is not applicable to pressure vessels of the following types: vessels of riveted construction; vessels of lamellar cast iron or any other materials not included in parts 2, 6, or 8 of the standard; multilayered, autofrettaged or pre-stressed vessels;This European standard may be applied to the following vessels, provided that account is taken of additional and/or alternative requirements resulting from the hazard analysis and from rules or instructions specific for: transportable vessels; items specifically designed for nuclear use; pressure vessels with a risk of overheating Other European standards apply to industrial piping (EN 13480) and to water tube and shell boilers (EN 12952 and 12953).