AEC definitions
HVAC stands for heating, ventilation, and air conditioning. It is the mechanical systems that control temperature and bring outdoor air into a building. In construction it is the H of a broader mechanical scope, and part of MEP. The mechanical engineer designs it. The mechanical contractor installs it.
Definition
Heating and cooling equipment, ductwork, piping, controls, and ventilation rates live on the mechanical drawings and in the mechanical specifications. Ventilation is not a courtesy. The mechanical code and the energy code set outdoor-air quantities. Coordination with structure and ceilings is where HVAC fails in the field: a duct and a beam want the same space. Testing and balancing and commissioning prove the installed system matches the design. The equipment schedule is the list of what was designed. The submittal has to match that schedule.
In depth
Air handlers, boilers, chillers, terminal units, exhaust, and the controls that stage them are one system. Replacing a rooftop unit without the controls and the ducts is a partial replacement.
Plumbing and fire protection are separate drawings even when one contractor holds several of them.
Outdoor air is calculated, not guessed. The schedule or the notes should show it. An energy model that assumes one airflow and a mechanical schedule that shows another will fail one of the two reviews.
Exhaust for toilets, kitchens, and garages has its own rates and make-up air. Deleting make-up air to save a duct creates a pressure problem.
Duct depth plus structure plus hangers has to fit under the floor-to-floor height and above the ceiling. That check is MEP coordination. It belongs before the set is issued, and again on coordination drawings during construction.
Diffuser locations on the RCP and the mechanical plan have to match.
Startup shows the unit runs. Testing and balancing measures the air and water the design required.
Commissioning, when specified, verifies sequences. Closeout without the balance report is incomplete if the spec required one.
Examples
The equipment schedule lists a rooftop unit with a stated airflow and efficiency. The submittal matches those numbers. The energy report used the same efficiency.
Coordination drops a corridor ceiling because the duct and the beam do not fit. The change is made on the RCP before issue.
The balancer's report shows a room below design airflow. The contractor corrects it before closeout.
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