855773644-LEED-v5-BD-C-Reference-Guide-Launch-Edition - Page 303
Extracted Content
ASTM testing criteria ASTM defines air leakage testing criteria. ASTM E779 uses the fan-pressurization method for testing. [93] ASTM E3158 provides a standard method for testing large or multizone buildings. ASTM E1827 determines air tightness using an orifice blower door. Residential spaces in mixed-use buildings may also apply ANSI/RESNET/ICC 380 .
Residential buildings In residential buildings, compartmentalize each unit, incorporating measures to limit air leakage between units). Determine credit compliance by conducting blower door testing of units per ANSI/RESNET/ICC 380 . Sample rates may apply depending on the number of units within the building.
Maximum leakage rates for each unit cannot exceed 150% of the Table 1 thresholds for the enclosure area.
Furthermore, weighted average building leakage rates must be less than the Table 1 thresholds. Calculate the weighted average using the measured results for the individual dwelling units.
Failed testing If a unit fails testing, corrective action is recommended to reduce air leakage in the space. Determine compliance with the credit by the weighted average of leakage rates reported for the project. If a single unit fails in a project with a large number of dwelling units, the project may still show compliance with this option.
Option 2. Ventilation Heat Recovery
Energy recovery ventilators (ERV) or heat recovery ventilators (HRV) reduce peak heating and cooling loads associated with ventilation by pre-treating the incoming outside air with heated or cooled air recovered from the exhaust stream.
For each system that supplies outdoor air to the building, include an ERV or HRV with at least a 70% enthalpy recovery ratio or 75% sensible heat recovery ratio.
Controls for ERVs and HRVs ERVs must have controls to disable energy exchange or bypass air during economizer operation. The requirement does not apply to systems with design outdoor airflow rates of less
93 “Standard Test Method for Determining Air Leakage Rate by Fan Pressurization,” ASTM, January 23, 2019, https://www.astm.org/e0779-19.html.
U.S. Green Building Council LEED v5 Reference Guide for Building Design and Construction, April 2025 Launch Edition 293