TheLEED for Homes Rating System (v4)addresses minimum outdoor air ventilation in theIndoor Environmental Quality (EQ) Prerequisite: Ventilation, usingASHRAE Standard 62.2-2010to determine ventilation rates based on conditioned floor area and the number of bedrooms.
According to theLEED Reference Guide for Homes Design and Construction (v4):
EQ Prerequisite: Ventilation
Meet the minimum outdoor air ventilation requirements of ASHRAE Standard 62.2-2010, which calculates ventilation rates based on the conditioned floor area of the home and the number of bedrooms (as a proxy for occupancy). The formula is: Ventilation rate (cfm) = 0.01 × floor area (ft²) + 7.5 × (number of bedrooms + 1).
Source: LEED Reference Guide for Homes Design and Construction, v4, Indoor Environmental Quality Prerequisite: Ventilation, p. 142.
TheLEED v4.1 Residential BD+Crating system confirms:
EQ Prerequisite: Ventilation
Ventilation rates are determined using ASHRAE 62.2-2010, based on conditioned floor area and the number of bedrooms, which accounts for typical occupancy levels.
Source: LEED v4.1 Residential BD+C, Credit Library, accessed via USGBC LEED Online.
The correct answer isnumber of bedrooms(Option B), as ASHRAE 62.2-2010 uses this alongside conditioned floor area to calculate ventilation requirements.
Why not the other options?
[Reference: LEED Reference Guide for Homes Design and Construction, v4, EQ Prerequisite: Ventilation, p. 142., C. Number of bathrooms: Bathrooms influence local exhaust requirements, not whole-house ventilation rates.Reference: LEED Reference Guide for Homes Design and Construction, v4, EQ Credit: Enhanced Ventilation, p. 146., D. Number of full-time occupants: While occupancy affects ventilation needs, ASHRAE 62.2-2010 uses bedrooms as a proxy, not actual occupant counts.Reference: LEED Reference Guide for Homes Design and Construction, v4, EQ Prerequisite: Ventilation, p. 142., TheLEED AP Homes Candidate Handbookemphasizes EQ prerequisites, including ventilation calculations, and references theLEED Reference Guide for Homes Design and Constructionas a key resource. The exam is based onLEED v4, ensuring the relevance of ASHRAE 62.2-2010., References:, LEED Reference Guide for Homes Design and Construction, v4, USGBC, Indoor Environmental Quality Prerequisite: Ventilation, p. 142., LEED v4.1 Residential BD+C, USGBC LEED Credit Library, accessed via LEED Online (https://www.usgbc.org/credits)., LEED AP Homes Candidate Handbook, GBCI, October 2024, p. 12 (references study resources and exam scope based on LEED v4)., USGBC LEED for Homes Rating System (v4), available via USGBC website (https://www.usgbc.org/resources/leed-homes-design-and-construction-v4)., LEED v4.1 for Homes, USGBC, accessed via LEED Online, confirming ventilation calculation criteria., ]
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