Duct System Air-Tightness Test

Purpose:
To verify air-tightness of HVAC duct systems

Equipment:
A water manometer or equivalent device

Procedure:
A supply duct system is tested for the air-tightness by applying static pressure to the duct system. All registers should be sealed and the furnace air circulator should be at high speed. The static pressure in the duct system should be at least 80 percent of the pressure measured in the furnace casing. Pressures are measured with a water manometer or an equivalent device.