Which device is commonly used to perform a duct leakage test under static pressure?

Which device is commonly used to perform a duct leakage test under static pressure?

• A. Blower Door
• B. Thermometer
• C. Hygrometer
• D. Smoke pencil

Answer: (A)

When you need to measure how much air leaks from ducts under a known pressure, you must create and maintain a defined static pressure and observe the resulting airflow. A blower door does exactly that: it uses a calibrated fan installed in an exterior door to pressurize or depressurize the building to a set pressure, so leaks—including through the duct system—cause a measurable flow. This setup provides a controlled, repeatable condition to quantify leakage. Thermometers or hygrometers measure temperature or humidity, not air leakage under pressure. A smoke pencil can help visualize leaks but doesn’t quantify leakage under a controlled static pressure. So the device best suited for performing a duct leakage test under static pressure is the blower door.

When you need to measure how much air leaks from ducts under a known pressure, you must create and maintain a defined static pressure and observe the resulting airflow. A blower door does exactly that: it uses a calibrated fan installed in an exterior door to pressurize or depressurize the building to a set pressure, so leaks—including through the duct system—cause a measurable flow. This setup provides a controlled, repeatable condition to quantify leakage.

Thermometers or hygrometers measure temperature or humidity, not air leakage under pressure. A smoke pencil can help visualize leaks but doesn’t quantify leakage under a controlled static pressure. So the device best suited for performing a duct leakage test under static pressure is the blower door.