General arrangement drawing

Where schematics define what connects, general arrangements (GAs) define what fits. The GA lays out an area to scale: equipment located and dimensioned, structures, platforms and access, major routing corridors — the spatial agreement that every discipline designs within and against. Civil takes foundations from it, piping routes to it, construction plans lifts and access around it, and operations inherits its judgements about maintainability every day thereafter.

GAs are where spatial conflict is negotiated before steel makes it permanent: laydown for the exchanger bundle pull, crane access, escape routes, the pump that must be reachable by more than a contortionist. In model-based workflows the GA is extracted from the 3D model as a view — which is efficient, and which quietly relocates authority: when model and GA disagree, projects must have decided in advance which one governs, because a mixed 2D/3D workflow maintained by separate hands will manufacture such disagreements on schedule.