What is Ductwork Leakage Equipment?
Ductwork Leakage Equipment, such as the Minneapolis Duct Blaster (pictured), is a calibrated set of air flow measurement equipment designed to test and document the airtightness of forced air duct systems in both houses and light commercial buildings. The equipment is a fan connected directly to the duct system in a house, typically at a central return, or at the air handler cabinet. With the remaining registers and grilles temporarily taped off, duct airtightness is measured by either pressurizing or depressurizing the duct system and precisely measuring the fan flow and duct pressure.
Duct airtightness measurements are used to diagnose and demonstrate leakage problems, estimate efficiency losses from duct leakage, and certify compliance with duct leakage standards.
Ductwork Leakage Testing – Technical Information
R403.3.3 Duct testing (Mandatory): Ducts shall be pressure tested to determine air leakage by one of the following methods:1.Rough-in test: Total leakage shall be measured with a pressure differential of 0.1 inch w.g. (25 Pa) across the system, including the manufacturer’s air handler enclosure if installed at the time of the test.
All registers shall be taped or otherwise sealed during the test.2.Postconstruction test: Total leakage shall be measured with a pressure differential of 0.1 inch w.g. (25 Pa) across the entire system, including the manufacturer’s air handler enclosure. Registers shall be taped or otherwise sealed during the test.
Exception: A duct air leakage test shall not be required where the ducts and air handlers are located entirely within the building thermal envelope.
A written report of the results of the test shall be signed by the party conducting the test and provided to the code official.
R403.3.4 Duct leakage (Prescriptive):The total leakage of the ducts, where measured in accordance with Section R403.3.3, shall be as follows:1.Rough-in test: The total leakage shall be less than or equal to 4 cubic feet per minute (113.3 L/min) per 100 square feet (9.29 m2) of conditioned floor area where the air handler is installed at the time of the test. Where the air handler is not installed at the time of the test, the total leakage shall be less than or equal to 3 cubic feet per minute (85 L/min) per 100 square feet (9.29 m2) of conditioned floor area.2.Postconstruction test: Total leakage shall be less than or equal to 4 cubic feet per minute (113.3 L/min) per 100 square feet (9.29 sq. meters) of conditioned floor area.
