Duct Leakage Testing per SMACNA CL-6

HVAC / Sheet Metal

Journeyman+75 XP

Order the steps for performing a duct leakage test to SMACNA Seal Class A / Leakage Class 6 requirements.

Drag to reorder, or use the arrow buttons.

1Pressurize the duct system to 1.5 times the design static pressure

2If leakage exceeds CL-6, locate and repair leaks with mastic sealant or approved methods

3Connect calibrated duct leakage test fan and digital manometer to a main trunk opening

4Measure leakage rate in CFM through the test fan at the elevated test pressure

5Re-seal all openings and retest the repaired section to confirm compliance

6Seal all duct openings — registers, grilles, and open ends — with approved caps or plastic and tape

7Document test pressure, measured leakage, allowable leakage, and pass/fail on the leakage test report

8Compare measured leakage to the CL=6 allowable limit per SMACNA Duct Leakage Test Manual