The bolting parts (screw, nut, stud, etc) are joining components.
When these components contribute to the pressure resistance, their materials shall fulfil the relevant requirements of Annex I, section 4.
Regarding section 4.3 of Annex I, a bolt is not considered to be a main pressure bearing part unless its failure would result in a sudden discharge of pressure energy.
When bolts are used as
- main pressure bearing parts a certificate of specific product control is required (unless the item of pressure equipment itself is in Category I)
- pressure bearing parts a test report is sufficient,
- non pressure bearing part a certificate of compliance is sufficient
(refer to PED Guideline G-05).