City of Thornton Amendment to 2015 IECC Code Adoption

The City of Thornton has amended the 2015 IECC to require all duct systems to be tested and meet a maximum leakage amount on all new residential construction. This requirement applies regardless of the location of the duct system.

Ducted HVAC Systems - Location is No Longer a Factor

The City of Thornton has amended the 2015 IECC to require all duct systems to be tested and meet a maximum leakage amount on all new residential construction. This requirement applies regardless of the location of the duct system.

This amendment requires the duct leakage test to be passed as part of the rough mechanical inspection. Therefore, the test needs to be performed prior to the installation of insulation. For many of EnergyLogic's performance path clients, this will require an additional site visit. Please contact us to discuss how this change will affect our scope of work.

Adopted Amendments

• Subsections N1103.3.3(R403.3.3) and N1103.3.4(R403.3.4) are hereby repealed in their entirety and replaced with the following: N1103.3.3 (R403.3.3) Duct testing (Mandatory). 66

• Ducts shall be pressure tested to determine air leakage by a rough-in test. The 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.

• 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.