Ductwork
CSI Division 23, HVAC
The sheet metal or fiberglass-duct-board network that carries conditioned air from a building's HVAC equipment to each room, sized and routed based on airflow calculations, not just whatever path happens to fit above the ceiling.
Why it matters
Ductwork that's undersized, poorly sealed, or routed with too many sharp turns can quietly undermine an otherwise well-designed HVAC system: airflow that never reaches the rooms it was calculated for shows up as uneven temperatures and higher energy use that's hard to diagnose once the ceiling is closed.
On a real project
A sheet metal crew fabricates and hangs ductwork through a building's ceiling plenum following the mechanical drawings' exact routing and sizing, sealing every joint with mastic or tape rated for the ductwork's pressure class before the system is tested.
Who this matters most to
An HVAC Technician installs and seals ductwork to the mechanical drawings, a task where duct leakage directly undercuts the system's designed performance. A Superintendent coordinates ductwork's large physical footprint above the ceiling against competing space needs from electrical, plumbing, and fire sprinkler rough-in happening in the same plenum.
Where this goes wrong
A ductwork installer leaves several joints unsealed to save time, assuming the system's overall airflow will still average out. Once the ceiling closes and the system is balanced, rooms at the far end of the run receive noticeably less airflow than designed, and the leakage isn't found until an energy audit or comfort complaint traces it back to the unsealed joints.