Earlier editions: 2022 2019

403.3 Single-Zone Systems — 2025 California Mechanical Code

California Mechanical Code (Title 24, Part 4) · 2025 edition · updated 2026-09-25 · California

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Italicized text is a California amendment to the model code, as printed in the official publication.

Cite as: 2025 California Mechanical Code (Title 24, Part 4) § 403.3 · Effective January 1, 2026 · Official source: Building Standards Commission

For ventilation systems where one or more air handlers supply a mixture of outdoor air and recirculated air to only one ventilation zone, the outdoor air intake flow ( Vot ) shall be determined in accordance with Equation 403.3. [ASHRAE 62.1:6.2.2]

Vot = Voz (Equation 403.3)

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California Mechanical Code (Title 24, Part 4)

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