Sch 2 para 21 Permanent joining
(1) Permanent joints and adjacent zones must be free of any surface or internal defects detrimental to the safety of the equipment. (2) The properties of permanent joints must meet the minimum properties specified for the materials to be joined unless other relevant property values are specifically taken into account in the design calculations. (3) For pressure equipment, permanent joining of components which contribute to the pressure resistance of equipment and components which are directly attached to them must be carried out by suitably qualified personnel according to suitable operating procedures and for pressure equipment in categories II, III and IV, operating procedures and personnel must be approved by a competent third party which, at the manufacturer's discretion, may be— (a) an approved body; (b) a recognised third party organisation; or (c) a notified body. (3A) In this Schedule— (a) “ notified body ” means a conformity assessment body which is a notified body for the purposes of the Directive (as provided for in Article 29(5) of the Directive); (b) “ recognised third party organisation ” means a conformity assessment body— (i) within the meaning set out in regulation 52; or (ii) which is a recognised third party organisation for the purposes of the Directive (as provided for in Article 29(5) of the Directive). (4) In order to carry out the approvals referred to above, the third party must perform examinations and tests as set out in the appropriate designated standards or equivalent examinations and tests or must have them performed.