How are fan airflow pressures typically measured?

The measurement of fan airflow pressures in inches of water column (WC) is a standard practice in the HVAC industry. This unit of measurement is specifically designed to quantify the pressure exerted by a column of water at a certain height, making it very suitable for assessing the minute pressures created by fans and airflow in ducts.

When evaluating how efficiently air moves through a system, understanding the pressure drop caused by components such as filters, grilles, and ducts is essential. Inches of water column allows technicians to measure these small variations in pressure accurately, ensuring that systems are operating effectively and efficiently.

In contrast, other units mentioned are not appropriate for measuring airflow pressures. Pounds per square inch (psi) quantify pressure in a different context, primarily suited for applications involving gases in high-pressure systems. Cubic feet per minute (CFM) is a measurement of airflow volume, not pressure, and degrees Fahrenheit (°F) measures temperature, which is unrelated to airflow pressure assessments. Therefore, measuring fan airflow pressures in inches of water column allows for precise evaluation of system performance.