Why volume, resistance and sound must be considered together.
Airflow: define the requirement
Air volume Q (m³/h) and pressure loss Δp (Pa) describe related aspects of a system. Selecting ducts or fans without evaluating both can compromise the intended performance.
Pressure loss along the route
Elbows, transitions, internal surfaces, joint tightness and equipment location all affect the final result. The shortest route is not necessarily best when noise and service access are considered.
Duct geometry and distribution
Duct dimensions, unnecessary resistance and accessible connections are considered together to create a predictable air distribution path.
Balance energy and comfort
Air volume, pressure loss and acoustic criteria must be evaluated together for the space and equipment involved.
Check what can be measured
Final review may include visual inspection, accessible connections and the testing specified for the project. Compliance with a standard should only be claimed after appropriate verification.
ASHRAE Handbook — Duct Design ↗ · SMACNA — Technical Standards ↗
Final materials, dimensions, airflow and methodology depend on site conditions and applicable requirements.