A technical guide from Carrier Corporation covering methods for measuring airflow in HVAC duct systems.
This Service Application Manual from Carrier Corporation explains various techniques used by HVAC technicians to measure air flow, including pitot tubes, inclined and u‑tube manometers, rotating vane anemometers, hot‑wire devices, and fan‑curve calculations. It emphasizes the importance of accurate measurements for system performance and reliability.
The manual also addresses practical topics such as duct pressure concepts, static and velocity pressure, proper instrument setup, traverse sampling, airflow calculations, and the impact of altitude on air‑distribution system performance.
| Specific gravity of manometer oil | .826 |
|---|---|
| Atmospheric pressure (absolute) | 14.696 psi |
The oil used in inclined manometers should have a specific gravity of .826.
Static pressure is the pressure at rest in the duct, possessing potential energy and the ability to do work.