Deals with the fusion welding of aluminium structures and equipment by inert-gas arc welding processes. The code requirements are based on prequalified procedures, and provide for three levels of weld quality. Tables of aluminium alloys suitable for welding, details of welded connections, methods of qualification of procedures and personnel, recommendations for good workmanship, and guidance on the recommended procedures to achieve specified levels of quality assurance, are included. Tables of prequalified procedures are also included and an appendix gives guidance on the selection of and the extent of non-destructive testing to be applied.