This standard BS EN 1333:2006 Flanges and their joints. Pipework components. Definition and selection of PN is classified in these ICS categories:
01.040.23 Fluid systems and components for general use (Vocabularies)
23.040.01 Pipeline components and pipelines in general
This European Standard gives the definition of PN when applied to components of a pipework system, as specified in those standards which use the PN designation system. This standard specifies the PN numbers which are used.