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Chapter 3 — BUILDING PLANNING

Section R321 — GUARDS AND WINDOW FALL PROTECTION

2025 California Residential Code (Title 24, Part 2.5) · 2025 edition · updated 2026-07-29 · California

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

R321.1 Guards.

Guards shall be provided in accordance with Sections R321.1.1 through R321.1.4.

R321.1.1 Where required. Guards shall be provided for those portions of open-sided walking surfaces, including floors, stairs, ramps and landings that are located more than 30 inches (762 mm) measured vertically to the floor or grade below at any point within 36 inches (914 mm) horizontally to the edge of the open side. Insect screening shall not be considered as a guard.

R321.1.2 Height. Required guards at open-sided walking surfaces, including stairs, porches, balconies or landings, shall be not less than 42 inches (1067 mm) in height as measured vertically above the adjacent walking surface or the line connecting the nosings.

Exceptions:

  1. Guards on the open sides of stairs shall have a height of not less than 34 inches (864 mm) measured vertically from a line connecting the nosings.

on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.

BUILDING PLANNING

  1. Where the top of the guard serves as a handrail on the open sides of stairs, the top of the guard shall be not less than 34 inches (864 mm) and not more than 38 inches (965 mm) as measured vertically from a line connecting the nosings.

R321.1.3 Opening limitations. Required guards shall not have openings from the walking surface to the required guard height that allow passage of a sphere 4 inches (102 mm) in diameter.

Exceptions:

  1. The triangular openings at the open side of stair, formed by the riser, tread and bottom rail of a guard, shall not allow passage of a sphere 6 inches (153 mm) in diameter.
  2. Guards on the open side of stairs shall not have openings that allow passage of a sphere 4 [3] / 8 inches (111 mm) in diameter.

R321.1.4 Exterior plastic composite guards. Plastic composite exterior guards shall comply with the requirements of Section R507.2.2.

R321.2 Window fall protection.

Window fall protection shall be provided in accordance with Sections R321.2.1 and R321.2.2.

R321.2.1 Window opening height. In dwelling units, where the bottom of the clear opening of an operable window opening is located less than 24 inches (610 mm) above the finished floor and greater than 72 inches (1829 mm) above the finished grade or other surface below on the exterior of the building, the operable window shall comply with one of the following:

  1. Operable window openings will not allow a 4-inch-diameter (102 mm) sphere to pass through where the openings are in their largest opened position.
  2. Operable windows are provided with window opening control devices or fall prevention devices that comply with ASTM F2090.

R321.2.2 Emergency escape and rescue openings. Where an operable window serves as an emergency escape and rescue opening, a window opening control device or fall prevention device, after operation to release the control device or fall prevention device allowing the window to fully open, shall not reduce the net clear opening area of the window unit to less than the area required by Sections R319.2.1 and R319.2.2.

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▸ Contents — 2025 California Residential Code (Title 24, Part 2.5)
2025 California Residential Code (Title 24, Part 2.5)
  1. Chapter 1 — ADMINISTRATION
  2. Chapter 2 — DEFINITIONS
  3. ▸ Chapter 3 — BUILDING PLANNING
    Overview
    1. Section R300 — SITE DRAINAGE
    2. Section R301 — DESIGN CRITERIA
    3. Section R302 — FIRE-RESISTANT CONSTRUCTION
    4. Section R303 — FOAM PLASTIC
    5. Section R304 — PROTECTION OF WOOD AND WOOD-BASED PRODUCTS AGAI…
    6. Section R305 — PROTECTION AGAINST SUBTERRANEAN TERMITES
    7. Section R306 — FLOOD-RESISTANT CONSTRUCTION
    8. Section R307 — STORM SHELTERS
    9. Section R308 — SITE ADDRESS
    10. Section R309 — AUTOMATIC SPRINKLER SYSTEMS
    11. Section R310 — SMOKE ALARMS
    12. Section R311 — CARBON MONOXIDE ALARMS
    13. Section R312 — MINIMUM ROOM AREAS
    14. Section R313 — CEILING HEIGHT
    15. Section R314 — MEZZANINES
    16. Section R315 — SLEEPING LOFTS
    17. Section R316 — HABITABLE ATTICS
    18. Section R317 — GARAGES AND CARPORTS
    19. Section R318 — MEANS OF EGRESS
    20. Section R319 — EMERGENCY ESCAPE AND RESCUE OPENINGS
    21. Section R320 — HANDRAILS
    22. Section R321 — GUARDS AND WINDOW FALL PROTECTION
    23. Section R322 — ACCESSIBILITY
    24. Section R323 — ELEVATORS AND PLATFORM LIFTS
    25. Section R324 — GLAZING
    26. Section R325 — LIGHT, VENTILATION AND HEATING
    27. Section R326 — SANITATION
    28. Section R327 — TOILET, BATH AND SHOWER SPACES
    29. Section R328 — AGING-IN-PLACE DESIGN AND FALL PREVENTION
    30. Section R329 — SOLAR ENERGY SYSTEMS
    31. Section R330 — ENERGY STORAGE SYSTEMS
    32. Section R331 — STATIONARY ENGINE GENERATORS
    33. Section R332 — STATIONARY FUEL CELL POWER SYSTEMS
    34. Section R333 — RESERVED
    35. Section R334 — CONSTRUCTION WASTE REDUCTION, DISPOSAL AND RECY…
    36. Section R335 — SPECIAL PROVISIONS FOR LICENSED 24-HOUR CARE FA…
    37. Section R336 — LARGE FAMILY DAY-CARE HOMES
    38. Section R337 — MATERIALS AND CONSTRUCTION METHODS FOR EXTERIOR…
    39. Section R338 — ELECTRIC VEHICLE
    40. Section 339 — RESERVED
    41. Section R340 — POLLUTANT CONTROL
  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 AA — BOARD OF APPEALS
  13. Appendix AB — PERMIT FEES
  14. Appendix AC — RESERVED
  15. Appendix BA — RESERVED
  16. Appendix BB — TINY HOUSES
  17. Appendix BC — RESERVED
  18. Appendix BD — RESERVED
  19. Appendix BE — RADON CONTROL METHODS
  20. Appendix BF — PATIO COVERS
  21. Appendix BG — SOUND TRANSMISSION
  22. Appendix BH — AUTOMATIC VEHICULAR GATES
  23. Appendix BI — LIGHT STRAW-CLAY CONSTRUCTION
  24. Appendix BJ — STRAWBALE CONSTRUCTION
  25. Appendix BK — COB CONSTRUCTION (MONOLITHIC ADOBE)
  26. Appendix BL — HEMP-LIME (HEMPCRETE) CONSTRUCTION
  27. Appendix BM — 3D-PRINTED BUILDING CONSTRUCTION
  28. Appendix BN — EXTENDED PLATE WALL CONSTRUCTION
  29. Appendix BO — EXISTING BUILDINGS AND STRUCTURES
  30. Appendix CA — RESERVED
  31. Appendix CB — RESERVED
  32. Appendix CC — RESERVED
  33. Appendix CD — RESERVED
  34. Appendix CE — RESERVED
  35. Appendix CF — RESERVED
  36. Appendix CG — NONSEWERED SANITATION SYSTEMS
  37. Appendix CH — PRIVATE SEWAGE DISPOSAL
  38. Appendix CI — SWIMMING POOL SAFETY ACT
  39. Appendix CJ — EMERGENCY HOUSING
  40. Appendix CK — AREAS PROTECTED BY THE FACILITIES OF THE CENTRAL…

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