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855773520-LEED-v5-ID-C-Reference-Guide-Launch-Edition-1 - Page 223

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In aggregate, fan systems supplying less than 15% of the project’s total outdoor air can be excluded.

AND/OR

PATH 2. LOW THERMAL CONDUCTANCE (1 POINT)

For initial build-out, comply prescriptively with the thermal bridging requirements of ASHRAE 90.1-2022, Section 5.5.5. Projects in climate zones 0–3 shall not be excepted.

For projects locating in an existing building, demonstrate one of the following:

  • Total envelope UA (the sum of U-factor times assembly area) no more than 125% of the total building envelope UA meeting the ASHRAE 90.1-2022 prescriptive building envelope criteria for new construction.

  • Minimum 30% improvement in total envelope UA for the alteration versus historical total envelope UA (no more than three years prior to project registration), AND total envelope UA is no more than 200% of the conductance of a total building envelope UA meeting the ASHRAE 90.1-2022 prescriptive envelope criteria for new construction.

AND/OR

PATH 3. INFILTRATION (1 POINT)

Either at the building level, or for the compartmentalized tenant space, demonstrate one of the following through air leakage testing conducted within five years of project occupancy:

  • Measured air leakage of the building envelope less than or equal to Table 1, below. OR

  • For projects locating in existing buildings, a reduction in air leakage of at least 30%, to a measured air leakage less than 1.0 cfm/sq. ft. (5 L/s*sq. m.) at 75 Pascals (0.3 in H2O)

documented through air leakage testing before and after alterations are implemented.

Table 1. Caps on air leakage rates

Pressure test conditions across
the building envelope		Maximum air leakage*Col3
Pressure test conditions across
the building envelope

Initial build-out
Renovation of previously
occupied space
At pressure difference of 50 Pascals
(0.2 in H2O)
0.17 cfm/sq. ft.
(0.85 L/s*sq. m.)*****

0.26 cfm/sq. ft.
(1.3 L/s*sq. m.)*****

At pressure difference of 75 Pascals
(0.3 in H2O)
0.24 cfm/sq. ft.
(1.20 L/s*sq. m.)*****
0.35 cfm/sq. ft.
(1.75 L/s*sq. m.)*****

*Air leakage per square foot or square meter of building envelope area (including exterior walls, roofs, and base floor/slab).

PATH 3 NOTE: Complete air leakage testing using ASTM E779, ANSI/RESNET/ICC 380, ASTM E3158, ASTM E1827, or equivalent.

AND/OR

U.S. Green Building Council LEED v5 Reference Guide for Interior Design and Construction, April 2025 Launch Edition 212

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