855773644-LEED-v5-BD-C-Reference-Guide-Launch-Edition - Page 304

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than 80% and design outdoor air volume of less than 10,000 cfm. For details, refer to ASHRAE 90.1-2022 Section 6.5.6.1.2.2, Provision for Air Economizer or Bypass Operation.

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

Exclude the following systems from the requirements in addition to this 15% exclusion: Kitchen exhaust demand ventilation systems meeting the provisions of ASHRAE 90.1 6.5.7.2.3 (b).

Laboratory exhaust systems meeting the provisions of ASHRAE 90.1 Section 6.5.7.3 (a) or (b). Kitchen or laboratory systems must meet these criteria to be eligible for this exclusion, even if the project’s total kitchen or laboratory exhaust volumes are less than those referenced in Section 6.5.7.

Option 3. Thermal Bridging

Projects must document prescriptive compliance with each thermal bridging requirement in ASHRAE 90.1-2022 Section 5.5.5a, designing and constructing a continuous thermal barrier that minimizes heat conductance associated with thermal bridges. A thermal bridge is an element that penetrates the building insulation, such as a wall and roof intersection, a wall and window intersection, an exterior cladding support, or a beam penetrating the exterior wall assembly.

Do not use the envelope trade-off method to show compliance with this option.

Climate zones 0–3 Projects in warmer climate zones (0–3) cannot apply any exceptions and must comply entirely with Section 5.5.5. Providing thermal breaks, continuous insulation, and using reflective exterior coatings on exterior surfaces can reduce solar heat gain and prevent moisture intrusion.

Option 4. Peak Thermal Load Reductions

Option 4 rewards overall peak thermal load reduction quantitatively assessed for the project using one of three methods:

U.S. Green Building Council LEED v5 Reference Guide for Building Design and Construction, April 2025 Launch Edition 294