If these component parts are incorporated to an item of pressure equipment, the relevant requirements of the directive will apply.
However, these component parts do not meet the definition of pressure equipment in Article 2 (1), therefore they shall not bear the CE mark.
It is the responsibility of the pressure equipment manufacturer to ensure that the component parts enable the pressure equipment to meet the essential safety requirements of the directive.
See also PED Guideline A-08
Note:
Another example of a component part is a split tee.