nnectedtothebaseisrepresentedasPartTo.Thelevelsofblockassemblytoassemblesteelplatesandsectionsintothefinalblockareclassifiedintosubassembly(SA)level,unitblockassembly(UBA)level,andfinalblockassembly(FBA)level.Subassemblylevelsmaybedividedintosmallsubassembly(SSA)levelsandintermediatesubassembly(ISA)levelsaccordingtothesizeandweightofthesubassemblyasshowninFig..Fordeterminingweldingpostures,theblockassemblylevelsareclassifiedintotwogroups.Thefirstgroupisthesmallsubassemblylevel;thesecondgroupconsistsoftheintermediatesubassembly,theunitblockassembly,andthefinalblockassemblylevels.Thereasonforthisgroupingisthatthereisnoturnoverprocessinthesmallsubassemblylevel,buttheassemblylevelsbelongingtothesecondgroupmayhaveturnoverprocesses.TurnoverprocessescausethechangeofweldingposturesthataredeonnectionType=)(LegLength≥.mm)(WeldingPosture=O,H,V)THEN(WeldingMethod=FCAW-