ES8: If applicable, test duct leakage based on floor area served

• Leakage to outside ≤3%. Not required if ducts are located 100% in conditioned space 
• Total leakage ≤6% at final, or rough-in if ducts are located 100% in conditioned space

Purpose

The duct leakage test is a diagnostic tool designed to measure the air tightness of heating and air conditioning duct systems and to identify air leakage locations. Tighter HVAC distribution systems more effectively deliver conditioned air throughout a home and ensure comfort goals are met.

Criteria

Leakage to outside ≤3%. Not required if ducts are located 100% in conditioned space. 

• Duct leakage test result for leakage to outside shall be ≤3% of floor area served. The leakage to outside test is not required if 100% of ductwork, including the mechanical equipment, are located within conditioned space.

Total leakage ≤6% at final, or rough-in if ducts are located 100% in conditioned space 

• Duct leakage test result for total leakage shall be ≤6% for all projects. The total leakage test may be completed during the mid-construction inspection for projects with 100% of ductwork, including the mechanical equipment, located in conditioned space. 
• If any portion of the distribution system, including the mechanical equipment, is located outside of conditioned space then the total leakage test shall be completed during the final inspection.

The calculation for determining percent duct leakage is:

Percent (%) Duct Leakage = (CFM25 ÷ floor area served (ft2) x 100)

Where: Percent Duct Leakage may be applied to Leakage to Outside and Total Leakage CMF25 is the measured duct leakage at 25 pa pressure difference between the ductwork and exterior.

Floor area served is the area of conditioned space served by a single system.

Clarifications 

• The leakage to outside and total leakage duct test apples to all ducted HVAC systems. HVAC systems designed and installed to operate without distribution systems (ductless systems) are exempt from this requirement. 
• Floor area must be calculated using RESNET standards for conditioned floor area.

Confirmation

The EarthCraft Technical Advisor will diagnostically test compliance during mid-construction and/or final inspections, as applicable to project design.