This part of ISO 15609 specifies requirements for the content of welding procedure specifications for resistance spot, seam, butt and projection welding processes. It is necessary to establish the acceptability of applying the principles of this part of ISO 15609 to other resistance and related welding processes before any qualification is undertaken. NOTE Details of ISO 15609 (all parts — for titles, see Foreword) are given in ISO 15607:2003, Annex A. Variables listed in this part of ISO 15609 are those influencing either weld dimensions (quality), weld nugget dimension, weld pattern positioning, mechanical properties or geometry of the welded joint.