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Chapter 8 — ALTERATIONS—LEVEL 2

Section 807 — MECHANICAL

2025 California Existing Building Code (Title 24, Part 10) · 2025 edition · updated 2026-07-29 · California

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

807.1 Reconfigured or converted spaces.

Reconfigured spaces intended for occupancy and spaces converted to habitable or occupiable space in any work area shall be provided with natural or mechanical ventilation in accordance with the California Mechanical Code .

Exception: Existing mechanical ventilation systems shall comply with the requirements of Section 807.2.

807.2 Altered existing systems.

In mechanically ventilated spaces, existing mechanical ventilation systems that are altered, reconfigured or extended shall provide not less than 5 cubic feet per minute (cfm) (0.0024 m [3] /s) per person of outdoor air and not less than 15 cfm (0.0071 m [3] /s) of ventilation air per person, or not less than the amount of ventilation air determined by the Indoor Air Quality Procedure of ASHRAE 62.1.

807.3 Local exhaust.

Newly introduced devices, equipment or operations that produce airborne particulate matter, odors, fumes, vapor, combustion products, gaseous contaminants, pathogenic and allergenic organisms, and microbial contaminants in such quantities as to affect adversely or impair health or cause discomfort to occupants shall be provided with local exhaust.

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▸ Contents — 2025 California Existing Building Code (Title 24, Part 10)
2025 California Existing Building Code (Title 24, Part 10)
  1. Chapter 1 — ADMINISTRATION
  2. Chapter 2 — DEFINITIONS
  3. Chapter 3 — PROVISIONS FOR ALL COMPLIANCE METHODS
  4. Chapter 3A — PROVISIONS FOR ALL COMPLIANCE METHODS
  5. Chapter 4 — REPAIRS
  6. Chapter 4A — REPAIRS
  7. Chapter 5 — PRESCRIPTIVE COMPLIANCE METHOD
  8. Chapter 5A — PRESCRIPTIVE COMPLIANCE METHOD
  9. Chapter 6 — CLASSIFICATION OF WORK
  10. Chapter 7 — ALTERATIONS—LEVEL 1
  11. ▸ Chapter 8 — ALTERATIONS—LEVEL 2
    Overview
    1. Section 801 — GENERAL
    2. Section 802 — BUILDING ELEMENTS AND MATERIALS
    3. Section 803 — FIRE PROTECTION
    4. Section 804 — MEANS OF EGRESS
    5. Section 805 — STRUCTURAL
    6. Section 806 — ELECTRICAL
    7. Section 807 — MECHANICAL
    8. Section 808 — RESERVED
    9. Section 809 — ENERGY CONSERVATION
  12. Chapter 9 — ALTERATIONS—LEVEL 3
  13. Chapter 10 — CHANGE OF OCCUPANCY
  14. Chapter 11 — ADDITIONS
  15. Chapter 12 — HISTORIC BUILDINGS
  16. Chapter 13 — PERFORMANCE COMPLIANCE METHODS
  17. Chapter 14 — RELOCATED OR MOVED BUILDINGS
  18. Chapter 15 — CONSTRUCTION SAFEGUARDS
  19. Chapter 16 — REFERENCED STANDARDS
  20. Appendix A — GUIDELINES FOR THE SEISMIC RETROFIT OF EXISTING B…
  21. Appendix B — SUPPLEMENTARY ACCESSIBILITY REQUIREMENTS FOR EXIS…
  22. Appendix C — GUIDELINES FOR THE WIND RETROFIT OF EXISTING BUIL…
  23. Appendix D — BOARD OF APPEALS
  24. Appendix E — TEMPORARY EMERGENCY USES
  25. Appendix A — GUIDELINES ON FIRE RATINGS OF ARCHAIC MATERIALS A…

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