855773520-LEED-v5-ID-C-Reference-Guide-Launch-Edition-1 - Page 309

Extracted Content

• In-room air-cleaning systems.

o Use systems tested for effectiveness and safety per ASHRAE Standard 241-2023,

Section 7.4 and Normative Appendix A. If treating for particles and gases, use systems tested for effectiveness per ASHRAE 62.1-2022, Addendum N. If treating for infectious aerosols, use systems tested for effectiveness per ASHRAE Standard 241-2023, Section 7.

Outdoor air measurement Provide outdoor airflow measurement devices for all mechanical ventilation systems in the project scope of work with outdoor air intake flow greater than 1,000 cfm (472 L/s).

Healthcare

• For healthcare spaces, meet the requirements of Sections 6–10 of ASHRAE Standard 170-2021 as applicable.

AND

Entryway System Designs

Install permanent entryway systems to capture dirt and particulates entering the building at primary exterior entrances within the project scope of work. There is no length requirement for entryway systems.

REQUIREMENTS EXPLAINED

This prerequisite requires the project team to research regional and local air quality and provide ventilation systems and design elements that effectively support air quality within the building. Healthcare and residential projects have additional considerations.

Investigate Regional and Local Air Quality

IAQ is significantly influenced by outdoor air quality, which can be highly localized, varying over time, season, and throughout the project site.

To understand outdoor air quality for the project, regional air quality and local air quality must be investigated, considering seasonal variations. ASHRAE 62.1 [112] provides a template for documenting this investigation. In many regions, spring months have higher pollen levels from flowering plants and trees. Summer months in some dry, hot regions have higher levels of PM2.5 due to wildfires and ozone from photochemical smog. Air quality for the project’s location

112 “ASHRAE 62.1”, ASHRAE, accessed March 31, 2025, https://www.ashrae.org/technical-resources/bookstore/standards-62-1-622.

U.S. Green Building Council LEED v5 Reference Guide for Interior Design and Construction, April 2025 Launch Edition 298