WHAT TO DO WITH THE RESULTS

WHAT TO DO WITH THE RESULTS If the test indicates the leakage is greater than acceptable, the ducts should be sealed, repaired, or renovated (replaced). The threshold is set by the October 2005 Title 24 Building Code, which requires duct leakage to be reduced by 15% of the pre-work leakage found. In every case the closer to zero leakage attained, the better your duct system will perform. Sealing Duct sealing involves following established procedures and applying approved materials to seal air leaks. Locations where sealing is typically performed include the supply and return plenums (which are connected to the furnace cabinet), starting collars (where ducts are connected to the plenums), fittings in the duct runs (Ys, where ducts branch off, and elbows), splices within the duct run, and terminations where the ducts connect to the supply registers. The most important leakage areas are in the supply and return plenums, because these areas are closest to the air handler and under the highest pressures when the system is operating.