# Directive 2014/68/EU of the European Parliament and of the Council of 15 May 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of pressure equipment (recast) (Text with EEA relevance), Division 3: The pressure accessories defined in point 5 of Article 2, and referred to in Article 4(1)(d), are classified on the basis of:

Extent: E+W+S+N.I.

their maximum allowable pressure PS,
their volume V or their nominal size DN, as appropriate,
the group of fluids for which they are intended.
The appropriate table for vessels or piping is to be used to determine the conformity assessment category.
Where both the volume and the nominal size are considered appropriate in the second indent of the first subparagraph, the pressure accessory shall be classified in the highest category.

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Source: https://www.legislation.gov.uk/eudr/2014/68/annex/II/division/3 (the official version)
Page: https://openlegislation.uk/eu-directive-2014-68/annex-II/division-3
Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives.