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Chapter 3 — BUILDING PLANNING

Section R337.6

California Residential Code (Title 24, Part 2.5) · 2019 edition · updated 2026-09-12 · California

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

VENTS

R337.6.1 General. Where provided, ventilation openings for enclosed attics, enclosed eave soffit spaces, enclosed rafter spaces formed where ceilings are applied directly to the underside of roof rafters, and underfloor ventilation shall be in accordance with Section 1203 of the California Building Code and Sections R337.6.1 through R337.6.3 of this section to resist building ignition from the intrusion of burning embers and flame through the ventilation open- ing.

R337.6.2 Requirements. Ventilation openings for enclosed attics, enclosed eave soffit spaces, enclosed raf- ter spaces formed where ceilings are applied directly to the underside of roof rafters, and underfloor ventilation openings shall be fully covered with metal wire mesh, vents, other materials, or other devices that meet one of the following requirements:

1. Vents shall be listed to ASTM E2886 and comply with all of the following:

1.1. There shall be no flaming ignition of the cot- ton material during the Ember Intrusion Test.

1.2. There shall be no flaming ignition during the Integrity Test portion of the Flame Intrusion Test.

1.3. The maximum temperature of the unexposed side of the vent shall not exceed 662°F (350°C).

2. Vents shall comply with all of the following:

2.1. The dimensions of the openings therein shall be a minimum of 1 /16 inch (1.6 mm) and shall not exceed 1 /8 inch (3.2 mm).

2.2. The materials used shall be noncombustible.

Exception: Vents located under the roof covering, along the ridge of roofs, with

the exposed surface of the vent covered by noncombustible wire mesh, may be of combustible materials.

2.3. The materials used shall be corrosion resis- tant.

R337.6.3 Ventilation openings on the underside of eaves and cornices. Vents shall not be installed on the underside of eaves and cornices.

Exceptions:

1. Vents listed to ASTM E2886 and complying with all of the following:

1.1. There shall be no flaming ignition of the cotton material during the Ember Intru- sion Test.

1.2. There shall be no flaming ignition during the Integrity Test portion of the Flame Intrusion Test.

1.3. The maximum temperature of the unex- posed side of the vent shall not exceed 662°F (350°C).

2. The enforcing agency shall be permitted to accept or approve special eave and cornice vents that resist the intrusion of flame and burning embers.

3. Vents complying with the requirements of Section R337.6.2 shall be permitted to be installed on the underside of eaves and cornices in accordance with either one of the following conditions:

3.1. The attic space being ventilated is fully protected by an automatic sprinkler sys- tem installed in accordance with Section 903.3.1.1 of the California Building Code or,

3.2. The exterior wall covering and exposed underside of the eave are of noncombus- tible material, or ignition-resistant mate- rials, as determined in accordance with SFM Standard 12-7A-5 Ignition-Resis- tant Material the requirements of Section R337.4.3, and the vent is located more than 12 feet (3.66 m) from the ground or walking surface of a deck, porch, patio, or similar surface.

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▸Contents — California Residential Code (Title 24, Part 2.5)
California Residential Code (Title 24, Part 2.5)
  1. Chapter 2 — DEFINITIONS AND ABBREVIATIONS
  2. Chapter 1 — SCOPE AND APPLICATION
  3. ▸Chapter 3 — BUILDING PLANNING
    Overview
    1. Section R300
    2. Section R301
    3. Section R302
    4. Section R303
    5. Section R304
    6. Section R305
    7. Section R306
    8. Section R307
    9. Section R308
    10. Section R309
    11. Section R310
    12. Section R311
    13. Section R312
    14. Section R313
    15. Section R314
    16. Section R315
    17. Section R316
    18. Section R317
    19. Section R318
    20. Section R319
    21. Section R320
    22. Section R321
    23. Section R322
    24. Section R323
    25. Section 324
    26. Section R325
    27. Section R334
    28. Section R335
    29. Section R326
    30. Section R327
    31. Section R336
    32. Section R337
    33. Section R337.1
    34. Section R337.2
    35. Section R337.3
    36. Section R337.4
    37. Section R337.5
    38. Section R337.6
    39. Section R337.7
    40. Section R337.8
    41. Section R337.9
    42. Section R337.10
    43. Section R340
    44. Section R338
  4. Chapter 4 — FOUNDATIONS
  5. Chapter 5 — FLOORS
  6. Chapter 6 — WALL CONSTRUCTION
  7. Chapter 7 — WALL COVERING
  8. Chapter 8 — ROOF-CEILING CONSTRUCTION
  9. Chapter 9 — ROOF ASSEMBLIES
  10. Chapter 10 — CHIMNEYS AND FIREPLACES
  11. Chapter 44 — REFERENCED STANDARDS
  12. Appendix F — RADON CONTROL METHODS
  13. Appendix H — PATIO COVERS
  14. Appendix I — PRIVATE SEWAGE DISPOSAL
  15. Appendix J — EXISTING BUILDINGS AND STRUCTURES
  16. Appendix K — SOUND TRANSMISSION
  17. Appendix L — PERMIT FEES
  18. Appendix O — AUTOMATIC VEHICULAR GATES
  19. Appendix Q — TINY HOUSES
  20. Appendix R — LIGHT STRAW-CLAY CONSTRUCTION
  21. Appendix S — STRAWBALE CONSTRUCTION
  22. Appendix T — SOLAR-READY PROVISIONS—DETACHED ONE- AND
  23. Appendix V — SWIMMING POOL SAFETY ACT
  24. Appendix W — AREAS PROTECTED BY THE FACILITIES
  25. Appendix X — EMERGENCY HOUSING

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