Inspect duct fabrication and installation, fittings, joints, seams, reinforcement, supports, hangers, bracing, flexible connections, access doors, dampers, fire and smoke damper interfaces, terminal-unit connections, equipment connections, identification, access clearances, cleanliness, insulation readiness, and related trade interfaces. Demonstrated knowledge of duct systems, fittings, joints, seams, reinforcement, supports, hangers, dampers, equipment connections, sealing, leakage testing, and system readiness.