How do I perform a duct pressure test (leak test) with an orifice tube?

Plain-English answer

1. Blank off and seal every open branch and diffuser outlet terminal inside the target testing loop segment using heavy plastic wrap and duct tape. 2. Connect the flexible intake hose of the Duct Leakage Tester machine directly into a starter port on the test run. 3. Turn on the machine blower to pressurize the inside of the duct run up to its designated operating static pressure rating (e.g., +2" WG). 4. Read the pressure differential tracking across the calibrated internal orifice tube flow plate to calculate the exact cubic feet per minute (CFM) of leakage air escaping from the run, and check that it drops below the maximum allowable code limit.

Field checklist

• Stop and verify the approved detail, manufacturer instructions, foreman direction, and project specs before touching it.
• Blank off and seal every open branch and diffuser outlet terminal inside the target testing loop segment using heavy plastic wrap and duct tape.
• Connect the flexible intake hose of the Duct Leakage Tester machine directly into a starter port on the test run.
• Turn on the machine blower to pressurize the inside of the duct run up to its designated operating static pressure rating (e.g., +2" WG).
• Read the pressure differential tracking across the calibrated internal orifice tube flow plate to calculate the exact cubic feet per minute (CFM) of leakage air escaping from the run,...

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