Article 14 paragraph 3 states that manufacturers can choose to apply one of the procedures which apply to a higher category if available. The words ‘if available’ make it clear that if an item of pressure equipment was classified as category IV, then a module from a higher category is not available. Even for those tables in Annex II where categories III and/or IV are not listed, such procedures can be chosen.
The procedures available are the modules or module combinations described under Article 14 paragraph 2.
If a module (or a module combination) from a higher category is chosen, all the requirements of that module must be met, including the marking of the identification number of the Notified body.
However, the use of a module (or a module combination) from a higher category does not change the actual classification of the equipment. The requirements of Annex I are those resulting from the actual classification unless the module itself gives specific requirements.
See also PED Guideline B-18.
Note:
When particular modules are explicitly referenced in the text of the directive, they cannot be substituted, as for example in Table 4 of Annex II.