Which airflow instrument is considered the industry standard and does not require calibration, converting velocity pressure to velocity?

• A. Pitot Tube
• B. Heated Wire Anemometer
• C. Hot-wire Anemometer
• D. Vane Anemometer

Answer: (A)

Measuring how fast air is moving by turning pressure differences into velocity is most straightforward with a Pitot tube. It has a forward-facing port that measures stagnation (total) pressure and, usually in the same or a separate port, measures static pressure; the difference between these pressures gives dynamic (velocity) pressure. That dynamic pressure is directly related to velocity through the basic Bernoulli relationship, v = sqrt(2 ΔP / ρ). Because this relies on a simple pressure difference and a well-known equation, it provides a direct way to convert pressure to velocity without needing complex electronics or a separate calibration step for the device itself. The Pitot tube is also rugged, has no moving parts, and can be used in ducts or open air, which is why it’s the standard in many industrial hygiene and ventilation tests. In contrast, devices that rely on heating elements or rotating parts require calibration to translate their signals into velocity and are more sensitive to temperature, contamination, and installation conditions, making them less universally standard.