855773667-LEED-v5-O-M-Reference-Guide-Launch-Edition-1 - Page 218

Extracted Content

Equation 2. Minimum outdoor air rate in SI units Minimum outdoor air rate in L/s = 0.15 L/s*sq. m.x dwelling unit �loor area (in sq. m.)

Equation 2. Minimum outdoor air rate in SI units

• 7.5 cfm/person x (number of bedrooms + 1) Compliance with minimum outdoor rates is required for each residential unit for this prerequisite.

In each full bathroom, have either an exhaust fan that vents directly to the outdoors or an operable window.

On each floor of the residential unit, have a carbon monoxide (CO) monitor hardwired with battery backup. CO monitors are required in all types of units, regardless of the type of equipment installed in the unit.

REQUIREMENTS EXPLAINED

This prerequisite requires that projects understand how indoor air quality (IAQ) is being managed in the building and assess ventilation rates and filtration levels against current recommended minimums. The verification process instills confidence that the building is committed to creating a healthier indoor environment while addressing energy efficiency, IAQ, and resiliency concurrently.

Over the lifespan of a building indoor air quality can become compromised. Deferred HVAC system maintenance, such as skipping filter replacements, reduces the effectiveness of the ventilation system’s ability to provide outdoor air with few contaminants. Without regular cleaning, screens and louvers can experience buildup of dirt and biological material that pollutes the outdoor air intake into the building. Natural ventilation strategies that depend on operable windows may be degraded as windows age or if restrictors (i.e., fall safety mechanisms) are added. Regular maintenance and confirmation of adequate outdoor air delivery is paramount to achieving adequate ventilation and a healthy indoor environment in existing buildings.

Ventilation System Operation and Preventative Maintenance

This prerequisite requires a commitment to preventative maintenance for the ventilation-related systems in the building using Table 8-1 in ASHRAE 62.1 [93] as a guide for determining minimum maintenance activities and frequency.

93 “ASHRAE 62.1-2022: Ventilation and Acceptable Indoor Air Quality”, ASHRAE, (2022), accessed March 31, 2025, https://www.ashrae.org/technical-resources/bookstore/standards-62-1-62-2.

U.S. Green Building Council LEED v5 Reference Guide for Operations and Maintenance, April 2025 Launch Edition 208