CHBC · California Historical Building Code

What are the CHBC sill-height, clear opening and access requirements for egress openings leading to fire escapes?

If your exit opens onto a fire escape in a qualified historical building, the CHBC requires that the opening provide at least a 29‑inch clear width when open and have a sill no higher than 30 inches above the floor (see § 8-502.5). For basement or sleeping-room escape windows under § 8-503 the CHBC sets a minimum clear area of 3.3 sq ft and at least one dimension of 18 inches, operable from the inside without special tools. Always confirm both provisions with your enforcing agency — especially when an opening both serves as an escape window and provides direct access to a fire escape.

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Last reviewed: July 6, 2026

What the code requires — 2–4 sentences

Per § 8-502.5 of the CHBC, an existing approved fire escape may be used as a required means of egress only if access is provided by an opening with a minimum width of 29 inches and a sill no higher than 30 inches above the adjacent floor, landing or approved step. For emergency escape or rescue windows and doors serving basements and sleeping rooms below the fourth floor, § 8-503 requires a minimum clear area of 3.3 ft² and a minimum width or height dimension of 18 inches, operable from the inside without special tools. Use the fire-escape-specific rule in § 8-502.5 when an opening leads directly to a fire escape; otherwise apply § 8-503 for general escape/rescue openings.

The single most important rule: if the opening provides access to a fire escape it must meet the CHBC fire-escape access rules — minimum 29 in. clear width and sill ≤ 30 in. (§ 8-502.5) — even when other window escape rules (§ 8-503) are also relevant.

Requirements in detail

1) Access to existing fire escapes — what the CHBC says

  • Access must be by an opening having a minimum width of 29 inches (737 mm) when open. § 8-502.5.
  • The sill of that opening must be no more than 30 inches (762 mm) above the adjacent floor, landing or approved step. § 8-502.5.
  • The fire escape itself must extend to the ground and be easily negotiated, adequately signed and in good working order to be acceptable as a required means of egress. § 8-502.5.

2) Escape or rescue windows and doors (basements and sleeping rooms below 4th floor)

  • Minimum clear area: 3.3 square feet (0.31 m²). § 8-503.
  • Minimum width or height dimension: 18 inches (457 mm) (one of the dimensions must meet or exceed this). § 8-503.
  • Must be operable from the inside and provide a full, clear opening without the use of special tools. § 8-503.

Quick-reference decision table (dimensions / values)

Decision question Required dimension / value Code Reference
Minimum opening width for access to an existing fire escape (when open) 29 inches (737 mm) § 8-502.5
Maximum sill height for opening giving access to a fire escape 30 inches (762 mm) § 8-502.5
Minimum clear area for escape/rescue window or door (basement or sleeping room < 4th fl) 3.3 ft² (0.31 m²) § 8-503
Minimum single dimension (width OR height) for escape/rescue opening 18 inches (457 mm) § 8-503
Operability requirement for escape/rescue openings Openable from the inside without special tools § 8-503
Condition for existing fire escape to count as required egress Extends to ground; easily negotiated; adequately signed; in good working order § 8-502.5

Exceptions & special cases

  • The CHBC specifically references existing previously approved fire escapes; those may be accepted as a required means of egress provided they meet the access, condition and extension-to-ground criteria in § 8-502.5.
  • § 8-503 applies to basements in dwelling units and every sleeping room below the fourth floor; it sets the escape/opening size and operability but does not supplant the fire-escape access rules of § 8-502.5 when the opening leads to a fire escape.
  • Where the CHBC and other California codes differ (e.g., larger CBC emergency window sizes for new construction), the CHBC provisions above govern qualified historical buildings unless the enforcing agency requires otherwise; the enforcing agency also has authority to grant reasonable exceptions under CHBC means-of-egress provisions. § 8-502.1 (granting reasonable exceptions) provides that flexibility.

Common mistakes

  • Confusing the CHBC window minimums (3.3 ft² and 18 in.) in § 8-503 with CBC/new-construction emergency window sizing (larger values such as 5.7 ft²). For historical buildings under the CHBC, use § 8-503 unless the enforcing agency says otherwise.
  • Assuming the 44 in. sill limit from the CBC (for many new-construction escape windows) applies to fire-escape access — for openings leading to fire escapes the CHBC cap is 30 in. per § 8-502.5.
  • Treating the 29 in. requirement (§ 8-502.5) as an “area” requirement instead of a minimum width when open — the text specifies width for fire-escape access.

Worked example

Scenario: A second-floor sleeping room in a qualified historical building has a window opening onto an existing, previously approved fire escape. The window, when fully open, yields a clear opening of 30 inches wide × 20 inches high.

Step-by-step check:

  1. Fire-escape access width: the opening width when open is 30 in., which is ≥ the 29 in. minimum required by § 8-502.5 — compliant.
  2. Sill height: measure from the finished floor to the window sill. If the sill is ≤ 30 in., it meets § 8-502.5; if the sill is higher (for example 44 in.), it does NOT meet the fire-escape access rule and would need modification or approval from the enforcing agency.
  3. Escape window size: the open clear area is 30 × 20 = 600 in² ≈ 4.17 ft², which exceeds the 3.3 ft² minimum of § 8-503, and at least one dimension (both here) ≥ 18 in., so § 8-503 is satisfied.

Conclusion: Provided the sill is ≤ 30 in., the example window complies with both § 8-502.5 (fire-escape access width & sill) and § 8-503 (escape window size & operability).

Related provisions (CHBC)

  • § 8-502.6 — Requirements for new fire escapes and fire escape ladders (dimensions, loads and sill limits similar to § 8-502.5).
  • § 8-502.1 — Enforcing agency may grant reasonable exceptions to egress regulations.
  • § 8-504 — Railings and guardrail provisions for historical buildings (height/spacing).
  • § 8-501 — Purpose, intent and scope of CHBC means-of-egress provisions.

Code references

Grounded in the retrieved California Historical Building Code — click a citation to read the verbatim passage:

  • CHBC § 8-5 High relevance — show source text

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

    8-5 MEANS OF EGRESS

    SECTION 8-501 — PURPOSE, INTENT AND SCOPE

    8-501.1 Purpose. The purpose of this chapter is to establish minimum means of egress regulations for qualified historical buildings or properties. The CHBC requires enforcing agencies to accept reasonably equivalent alternatives to the means of egress requirements in the regular code.

    8-501.2 Intent. The intent of these regulations is to provide an adequate means of egress.

    8-501.3 Scope. Every qualified historical building or portion thereof shall be provided with exits as required by the CHBC when required by the provisions of Section 8-102.

    SECTION 8-502 — GENERAL

    8-502.1 General. The enforcing agency shall grant reasonable exceptions to the specific provisions of applicable egress regulations where such exceptions will not adversely affect life safety.

    8-502.2. Existing door openings and corridor widths of less than dimensions required by regular code shall be permitted where there is sufficient width and height for the occupants to pass through the opening or traverse the exit.

    8-502.3 Stairs. Existing stairs having risers and treads or width at variance with the regular code are allowed if determined by the enforcing agency to not constitute a distinct hazard. Handrails with nonconforming grip size or extensions are allowed if determined by the enforcing agency to not constitute a distinct hazard.

    8-502.4 Main entry doors. The front or main entry doors need not be rehung to swing in the direction of exit travel, provided other means or conditions of exiting, as necessary to serve the total occupant load, are provided.

    8-502.5 Existing fire escapes. Existing previously approved fire escapes and fire escape ladders shall be acceptable as one of the required means of egress, provided they extend to the ground and are easily negotiated, adequately signed and in good working order. Access shall be by an opening having a minimum width of 29 inches (737 mm) when open with a sill no more than 30 inches (762 mm) above the adjacent floor, landing or approved step.

    8-502.6 New fire escapes and fire escape ladders. New fire escapes and fire escape ladders which comply with this section shall be acceptable as one of the required means of egress. New fire escapes and new fire escape ladders shall comply with the following:

    1. Access from a corridor shall not be through an intervening room.
    2. All openings within 10 feet (3048 mm) shall be protected by three-fourths-hour fire assemblies. When located within a recess or vestibule, adjacent enclosure walls shall be of not less than one-hour fire-resistive construction.
    3. Egress from the building shall be by a clear opening having a minimum dimension of not less than 29 inches (737 mm). Such openings shall be openable from the inside without the use of a key or special knowledge or effort. The sill of an opening giving access shall not be more than 30 inches (737 mm) above the floor, step or landing of the building or balcony.
    4. Fire escape stairways and balconies shall support the dead load plus a live load of not less than 100 pounds per square foot (4.79 kN/m [2] ) and shall be provided with a top and intermediate handrail on each side. The pitch of the stairway shall not exceed 72 degrees with a minimum width of 18 inches (457 mm).
  • CHBC § 8-502.6 High relevance — show source text

    8-502.6 New fire escapes and fire escape ladders. New fire escapes and fire escape ladders which comply with this section shall be acceptable as one of the required means of egress. New fire escapes and new fire escape ladders shall comply with the following:

    1. Access from a corridor shall not be through an intervening room.
    2. All openings within 10 feet (3048 mm) shall be protected by three-fourths-hour fire assemblies. When located within a recess or vestibule, adjacent enclosure walls shall be of not less than one-hour fire-resistive construction.
    3. Egress from the building shall be by a clear opening having a minimum dimension of not less than 29 inches (737 mm). Such openings shall be openable from the inside without the use of a key or special knowledge or effort. The sill of an opening giving access shall not be more than 30 inches (737 mm) above the floor, step or landing of the building or balcony.
    4. Fire escape stairways and balconies shall support the dead load plus a live load of not less than 100 pounds per square foot (4.79 kN/m [2] ) and shall be provided with a top and intermediate handrail on each side. The pitch of the stairway shall not exceed 72 degrees with a minimum width of 18 inches (457 mm). Treads shall not be less than 4 inches (102 mm) in width, and the rise between treads shall not exceed 10 inches (254 mm). All stair and balcony railings shall support a horizontal force of not less than 50 pounds per lineal foot (729.5 N/m [2] ) of railing.
    5. Balconies shall not be less than 44 inches (1118 mm) in width with no floor opening other than the stairway opening greater than [5] / 8 inch (15.9 mm) in width. Stairway openings in such balconies shall not be less than 22 inches by 44 inches (559 by 1118 mm). The balustrade of each balcony shall not be less than 36 inches (914 mm) high with not more than 9 inches (287 mm) between balusters.
    6. Fire escapes shall extend to the roof or provide an approved gooseneck ladder between the top floor landing and the roof when serving buildings four or more stories in height having roofs with less than 4 units vertical in 12 units horizontal (33.3 percent slope). Fire escape ladders shall be designed and connected to the building to withstand a horizontal force of 100 pounds (445 N) placed anywhere on the rung. All ladders shall be at least 15 inches (381 mm) wide, located within 12 inches (305 mm) of the building. Ladder rungs shall be [3] / 4 inch (19.1 mm) in diameter and shall be located 12 inches (305 mm) on center. Openings for roof access ladders through cornices and similar projections shall have minimum dimensions of 30 inches by 33 inches (762 by 838 mm). The length of fire escapes and exit ladder devices shall be limited to that approved by the building official based on products listed by a recognized testing laboratory.
    7. The lowest balcony shall not be more than 18 feet (5486 mm) from the ground. Fire escapes shall extend to the ground or be provided with counterbalanced stairs reaching to the ground.
    8. Fire escapes shall not take the place of stairways required by the codes under which the building was constructed.
  • CHBC § 1113.2 High relevance — show source text

    1113.2 Number of exits. Every apartment and every other sleeping room shall have access to not less than two exits when the occupant load is 10 or more (exits need not be directly from the apartment or sleeping room). A fire escape as specified herein may be used as one required exit.

    Subject to approval of the authority having jurisdiction, a ladder device as specified herein may be used in lieu of a fire escape when the construction feature or the location of the building on the property cause the installation of a fire escape to be impractical.

    1113.3 Stair construction. All stairs shall have a minimum run of 9 inches (229 mm) and a maximum rise of 8 inches (203 mm) and a minimum width exclusive of handrails of 30 inches (762 mm). Every stairway shall have at least one handrail. A landing having a mini- mum horizontal dimension of 30 inches (762 mm) shall be provided at each point of access to the stairway.

    1113.4 Interior stairways. Every interior stairway shall be enclosed with walls of not less than one-hour fire-resistive construction. Where existing partitions form part of a stairwell enclosure, wood lath and plaster in good condition will be acceptable in lieu of one- hour fire-resistive construction. Doors to such enclosures shall be protected by a self-closing door equivalent to a solid wood door with a thickness of not less than 1 [3] / 4 inches (44.5 mm).

    Enclosures shall include all landings between flights and any corridors, passageways or public rooms necessary for continuous exit to the exterior of the buildings. The stairway need not be enclosed in a continuous shaft if cut off at each story by the fire-resistive construc- tion required by this subsection for stairwell enclosures. Enclosures shall not be required if an automatic sprinkler system is provided for all portions of the building except bedrooms, apartments and rooms accessory thereto. Interior stairs and vertical openings need not be enclosed in two-story buildings.

    1113.5 Exterior stairways. Exterior stairways shall be noncombustible or of wood of not less than 2-inch (51 mm) nominal thickness with solid treads and risers.

    1113.6 Fire escapes, exit ladder devices. Fire escapes may be used as one means of egress if the pitch does not exceed 60 degrees, the width is not less than 18 inches (457 mm), the treads are not less than 4 inches (102 mm) wide, and they extend to the ground or are provided with counterbalanced stairs reaching to the ground. Access shall be by an opening having a minimum dimension of 29 inches (737 mm) when open. The sill shall not be more than 30 inches (762 mm) above the floor and landing.

    A ladder device, when used in lieu of a fire escape, shall conform to Section 1113.6.1 and the following:

    Serves an occupant load of nine people or less or a single dwelling unit or hotel room.

    The building does not exceed three stories in height.

    2025 CALIFORNIA FIRE CODE 11-23

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

    CONSTRUCTION REQUIREMENTS FOR EXISTING BUILDINGS

    The access is adjacent to an opening as specified for emergency egress or rescue or from a balcony.

    The device does not pass in front of any building opening below the unit being served.

  • CHBC § 1113.5 High relevance — show source text

    1113.5 Exterior stairways. Exterior stairways shall be noncombustible or of wood of not less than 2-inch (51 mm) nominal thickness with solid treads and risers.

    1113.6 Fire escapes, exit ladder devices. Fire escapes may be used as one means of egress if the pitch does not exceed 60 degrees, the width is not less than 18 inches (457 mm), the treads are not less than 4 inches (102 mm) wide, and they extend to the ground or are provided with counterbalanced stairs reaching to the ground. Access shall be by an opening having a minimum dimension of 29 inches (737 mm) when open. The sill shall not be more than 30 inches (762 mm) above the floor and landing.

    A ladder device, when used in lieu of a fire escape, shall conform to Section 1113.6.1 and the following:

    Serves an occupant load of nine people or less or a single dwelling unit or hotel room.

    The building does not exceed three stories in height.

    2025 CALIFORNIA FIRE CODE 11-23

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

    CONSTRUCTION REQUIREMENTS FOR EXISTING BUILDINGS

    The access is adjacent to an opening as specified for emergency egress or rescue or from a balcony.

    The device does not pass in front of any building opening below the unit being served.

    The availability of activating the ladder device is accessible only to the opening or balcony served.

    The device as installed will not cause a person using it to be within 12 feet (3658 mm) of exposed energized high-voltage conductors.

    1113.6.1 Exit ladder devices.

    1113.6.1.1 Scope. This standard for exit ladder devices is applicable where such devices are permitted by the building official for installation on existing apartment houses and hotels in conformance with the California Building Code.

    1113.6.1.2 Instructions. Installation shall be in accordance with the manufacturer’s instructions. Instructions shall be illustrated and shall include directions and information adequate for attaining proper and safe installation of the product. Where exit ladder devices are intended for mounting on different support surfaces, specific installation instructions shall be provided for each surface.

    1113.6.1.3 General design. All load-bearing surfaces and supporting hardware shall be of noncombustible materials. Exit ladder devices shall have a minimum width of 12 inches (305 mm) when in the position intended for use. The design load shall not be less than 400 pounds (1780 N) for 16-foot (4877 mm) length and 600 pounds (2699 N) for 25-foot (7620 mm) length.

    1113.6.1.4 Performance.

    1113.6.1.4.1 Exit ladder devices shall be capable of withstanding an applied load of four times the design load when installed in the manner intended for use. Test loads shall be applied for a period of one hour.

    1113.6.1.4.2 Exit ladder devices of the retractable type shall, in addition to the static load requirements of Section 413.6.1.4.1 of the California Building Code, be capable of withstanding the following tests: 1. Rung strength 2. Rung-to-side-rail shear strength

    3. Release mechanism

  • CHBC § 903.3.1.1 High relevance — show source text

    Group B, F and S occupancies in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 of the_California Fire Code_ or on the
    roof of such buildings shall have a maximum exit access travel distance of 100 feet.|

    �

    804.5.1.2 Fire escapes required. Where more than one exit is required, an existing fire escape complying with Section 804.5.1.2.1 shall be accepted as providing one of the required means of egress.

    804.5.1.2.1 Fire escape access and details. Fire escapes shall comply with all of the following requirements:

    1. Occupants shall have unobstructed access to the fire escape without having to pass through a room subject to locking.
    2. Access to a fire escape shall be through a door, except that windows shall be permitted to provide access from single dwelling units or sleeping units in Group R-1 and R-2 occupancies or to provide access from spaces having a maximum occupant load of 10 in other occupancy classifications. 2.1. The window shall have a minimum net clear opening of 5.7 square feet (0.53 m [2] ) or 5 square feet (0.46 m [2] ) where located at grade. 2.2. The minimum net clear opening height shall be 24 inches (610 mm) and net clear opening width shall be 20 inches (508 mm). 2.3. The bottom of the clear opening shall not be greater than 44 inches (1118 mm) above the floor. 2.4. The operation of the window shall comply with the operational constraints of the California Building Code .

    8-6 2025 CALIFORNIA EXISTING BUILDING CODE

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

    ALTERATIONS—LEVEL 2

    1. Newly constructed fire escapes shall be permitted only where exterior stairways cannot be utilized because of lot lines.

    2. Openings within 10 feet (3048 mm) of fire escape stairways shall be protected by fire assemblies having minimum [3] / 4 hour fire-resistance ratings. Exception: Opening protection shall not be required in buildings equipped throughout with an approved automatic sprinkler system.

    3. In all buildings of Group E occupancy, up to and including the 12th grade, buildings of Group I occupancy, rooming houses and childcare centers, ladders of any type are prohibited on fire escapes used as a required means of egress.

    804.5.1.2.2 Construction. The fire escape shall be designed to support a live load of 100 pounds per square foot (4788 Pa) and shall be constructed of steel or other approved noncombustible materials. Fire escapes constructed of wood not less than nominal 2 inches (51 mm) thick are permitted on buildings of Type V construction. Walkways and railings located over or supported by combustible roofs in buildings of Types III and IV construction are permitted to be of wood not less than nominal 2 inches (51 mm) thick.

    804.5.1.2.3 Dimensions. Stairways shall be not less than 22 inches (559 mm) wide with risers not more than, and treads not less than, 8 inches (203 mm). Landings at the foot of stairways shall be not less than 40 inches (1016 mm) wide by 36 inches (914 mm) long and located not more than 8 inches (203 mm) below the door.

  • CHBC § 903.3.1.1 High relevance — show source text

    The length of exit access travel distance in a Group S-2 open parking garage shall be not more than 100 feet.
    b. Group B, F and S occupancies in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 of the_California Fire Code_ or on the
    roof of such buildings shall have a maximum exit access travel distance of 100 feet.|For SI: 1 foot = 304.8 mm.
    NP = Not Permitted.
    NA = Not Applicable.
    a. The length of exit access travel distance in a Group S-2 open parking garage shall be not more than 100 feet.
    b. Group B, F and S occupancies in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 of the_California Fire Code_ or on the
    roof of such buildings shall have a maximum exit access travel distance of 100 feet.|For SI: 1 foot = 304.8 mm.
    NP = Not Permitted.
    NA = Not Applicable.
    a. The length of exit access travel distance in a Group S-2 open parking garage shall be not more than 100 feet.
    b. Group B, F and S occupancies in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 of the_California Fire Code_ or on the
    roof of such buildings shall have a maximum exit access travel distance of 100 feet.|For SI: 1 foot = 304.8 mm.
    NP = Not Permitted.
    NA = Not Applicable.
    a. The length of exit access travel distance in a Group S-2 open parking garage shall be not more than 100 feet.
    b. Group B, F and S occupancies in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 of the_California Fire Code_ or on the
    roof of such buildings shall have a maximum exit access travel distance of 100 feet.|

    �

    804.5.1.2 Fire escapes required. Where more than one exit is required, an existing fire escape complying with Section 804.5.1.2.1 shall be accepted as providing one of the required means of egress.

    804.5.1.2.1 Fire escape access and details. Fire escapes shall comply with all of the following requirements:

    1. Occupants shall have unobstructed access to the fire escape without having to pass through a room subject to locking.
    2. Access to a fire escape shall be through a door, except that windows shall be permitted to provide access from single dwelling units or sleeping units in Group R-1 and R-2 occupancies or to provide access from spaces having a maximum occupant load of 10 in other occupancy classifications. 2.1. The window shall have a minimum net clear opening of 5.7 square feet (0.53 m [2] ) or 5 square feet (0.46 m [2] ) where located at grade. 2.2. The minimum net clear opening height shall be 24 inches (610 mm) and net clear opening width shall be 20 inches (508 mm). 2.3. The bottom of the clear opening shall not be greater than 44 inches (1118 mm) above the floor. 2.4. The operation of the window shall comply with the operational constraints of the California Building Code .

    8-6 2025 CALIFORNIA EXISTING BUILDING CODE

  • CHBC § 314.7 High relevance — show source text

    Note: It is the intent of this provisions that existing wood frames may have their use continued.

    314.7 New construction. All new construction shall be composed of materials and assemblies of materials conforming to the fire-resistive provisions of these regulations. In no case shall enclosure walls be required to be of more than one-hour fire-resistive construction.

    Exception: When approved by the enforcing agency, materials specified in Section 314.6 may be used for new construction when necessary to maintain continuity of design and measurement of existing construction.

    314.8 Exits. Every floor from an existing high-rise building shall have access to two separate means of egress, one of which, when approved by the enforcing agency, may be an existing exterior fire escape. New installations of smoke-proof enclosures shall not be required.

    Note: In determining the adequacy of exits and their design, Chapter 10 of the California Building Code may be used as a guide. It is the intent of this section that every existing high-rise building need not mandatorily conform or be made to conform with the requirements for new high-rise buildings. Reasonable judgment in the application of requirements must be exercised by the enforcing agency.

    314.9 Fire escapes. An existing fire escape in good structural condition may be acceptable as one of the required means of egress from each floor. Access to such fire escapes may be by any one of the following: 1. Through a room between the corridor and the fire escape if the door to the room is operable from the corridor side without the use of any key, special knowledge or effort. 2. By a door operable to a fire escape from the interior without the use of any key, special knowledge or effort. 3. By a window operable from the interior. Such window shall have a minimum dimension of 29 inches (737 mm) when open. 4. The sill shall not be more than 30 inches (762 mm) above the floor and landing.

    314.10 Protection of exterior openings. When an existing fire escape is accepted as one of the require means of egress, openings onto the fire escape landing and openings within 5 feet (1524 mm) horizontally of the landings shall be protected in a manner acceptable to the enforcing agency.

    314.11 Locking of stairway doors. When exit doors from corridors to exit stairways are locked to prohibit access from the stairway side, the locking mechanisms shall be retracted to the unlocked position upon failure of electrical power and a telephone or other two-way communication system connected to an approved emergency service that operates continuously shall be provided at not less than every fifth floor in each required stairway. In lieu thereof, master keys which will unlock all such doors from the stairway side shall be provided in such numbers and locations as approved by the enforcing agency.

    314.12 Enclosures. Interior vertical shafts, including but not limited to, elevators, stairway and utility, shall be enclosed with construction as set forth in Section 314.6.

    314.13 Opening protection. Doors in other than elevators, which shall be of a type acceptable to the enforcing agency, shall be approved one-hour, fire-rated, tight-fitting or gasketed doors or equivalent protection, and shall be of the normally closed type, self- closing or a type which will close automatically in accordance with Section 715 of the California Building Code.

  • CHBC § 33.3 High relevance — show source text

    Stairway openings in such balconies shall not be less than 22 inches by 44 inches (559 by 1118 mm). The balustrade of each balcony shall not be less than 36 inches (914 mm) high with not more than 9 inches (287 mm) between balusters. 6. Fire escapes shall extend to the roof or provide an approved gooseneck ladder between the top floor landing and the roof when serving buildings four or more stories in height having roofs with less than 4 units vertical in 12 units horizontal (33.3 percent slope). Fire escape ladders shall be designed and connected to the building to withstand a horizontal force of 100 pounds (445 N) placed anywhere on the rung. All ladders shall be at least 15 inches (381 mm) wide, located within 12 inches (305 mm) of the building. Ladder rungs shall be [3] / 4 inch (19.1 mm) in diameter and shall be located 12 inches (305 mm) on center. Openings for roof access ladders through cornices and similar projections shall have minimum dimensions of 30 inches by 33 inches (762 by 838 mm). The length of fire escapes and exit ladder devices shall be limited to that approved by the building official based on products listed by a recognized testing laboratory. 7. The lowest balcony shall not be more than 18 feet (5486 mm) from the ground. Fire escapes shall extend to the ground or be provided with counterbalanced stairs reaching to the ground. 8. Fire escapes shall not take the place of stairways required by the codes under which the building was constructed. 9. Fire escapes shall be kept clear and unobstructed at all times and maintained in good working order.

    2025 CALIFORNIA HISTORICAL BUILDING CODE 9

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    MEANS OF EGRESS

    SECTION 8-503 — ESCAPE OR RESCUE WINDOWS AND DOORS

    Basements in dwelling units and every sleeping room below the fourth floor shall have at least one openable window or door approved for emergency escape which shall open directly into a public street, public way, yard or exit court. Escape or rescue windows or doors shall have a minimum clear area of 3.3 square feet (0.31 m [2] ) and a minimum width or height dimension of 18 inches (457 mm) and be operable from the inside to provide a full, clear opening without the use of special tools.

    SECTION 8-504 — RAILINGS AND GUARDRAILS

    The height of railings and guard railings and the spacing of balusters may continue in their historical height and spacing unless a distinct hazard has been identified or created by a change in use or occupancy.

    10 2025 CALIFORNIA HISTORICAL BUILDING CODE

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    8-6 ACCESSIBILITY

    SECTION 8-601 — PURPOSE, INTENT AND SCOPE

    8-601.1 Purpose. The purpose of the CHBC is to provide alternative regulations to facilitate access and use by persons with disabilities to and throughout facilities designated as qualified historical buildings or properties. These regulations require enforcing agencies to accept alternatives to regular code when dealing with qualified historical buildings or properties.

  • CHBC § 0.93 High relevance — show source text

    In Group I-2 or an ambulatory care facility, doors serving as means of egress doors where used for the movement of beds and stretcher patients shall provide a minimum clear opening width of 44 inches (1118 mm). Where this section requires a minimum clear opening width of 44 inches (1118 mm) and a door opening includes two door leaves without a mullion, one leaf shall provide a minimum clear opening width of 44 inches (1118 mm). The minimum clear opening height of doors shall be not less than 80 inches (2032 mm).

    Exceptions:

    1. In Group R-2 and R-3 dwelling and sleeping units that are not required to be an Accessible unit, Type A unit or Type B unit, the minimum width shall not apply to door openings that are not part of the required means of egress.
    2. Group I-3 door openings to resident sleeping units that are not required to be an Accessible unit shall have a minimum clear opening width of 28 inches (711 mm).
    3. Door openings to storage closets less than 10 square feet (0.93 m [2] ) in area shall not be limited by the minimum clear opening width.
    4. Door openings within a dwelling unit or sleeping unit shall have a minimum clear opening height of 78 inches (1981 mm).
    5. In dwelling and sleeping units that are not required to be Accessible, Type A or Type B units, exterior door openings, other than the required exit door, shall have a minimum clear opening height of 76 inches (1930 mm).
    6. In Groups R-2, R-3 and R-4, in dwelling and sleeping units that are not required to be Accessible, Type A or Type B units, the minimum clear opening widths shall not apply to interior egress doors.
    7. Door openings required to be accessible within Type B units intended for user passage shall have a minimum clear opening width of 31.75 inches (806 mm).
    8. Doors serving sauna compartments, toilet compartments or dressing, fitting or changing rooms compartments that are not required to be accessible shall have a minimum clear opening width of 20 inches (508 mm).
    9. Doors serving shower compartments shall comply with Section 421.4.2 of the California Plumbing Code .

    [BE] 1010.1.1.1 Projections into clear opening. There shall not be projections into the required clear opening width lower than 34 inches (864 mm) above the floor or ground. Projections into the clear opening width between 34 inches (864 mm) and 80 inches (2032 mm) above the floor or ground shall not exceed 4 inches (102 mm).

    Exceptions: 1. Door closers, overhead doorstops, frame stops, power door operators, and electromagnetic door locks shall project into the door opening height not lower than 78 inches (1980 mm) above the floor. 2. In a Group I-2 occupancy, there shall be no projections into the clear width of doors used for the movement of beds and stretcher patients in the means of egress.

    [BE] 1010.1.2 Egress door types. Egress doors shall be of the side-hinged swinging door, pivoted door or balanced door types.

    Exceptions:

    1. Private garages, office areas, factory and storage areas with an occupant load of 10 or less.
    2. Group I-3 occupancies used as a place of detention.
    3. Critical or intensive care patient rooms within suites of health care facilities.
    4. Doors within or serving a single dwelling unit in Groups R-2 and R-3.
  • CHBC § 1114.9 High relevance — show source text

    Note: In determining the adequacy of exits and their design, Chapter 10 of the California Building Code may be used as a guide. It is the intent of this section that every existing high-rise building need not mandatorily conform or be made to conform with the requirements for new high-rise buildings. Reasonable judgment in the application of requirements must be exercised by the enforcing agency.

    1114.9 Fire escapes. An existing fire escape in good structural condition may be acceptable as one of the required means of egress from each floor. Access to such fire escapes may be by any one of the following:

    Through a room between the corridor and the fire escape if the door to the room is operable from the corridor side without the use of any key, special knowledge or effort.

    By a door operable to a fire escape from the interior without the use of any key, special knowledge or effort.

    By a window operable from the interior. Such window shall have a minimum dimension of 29 inches (737 mm) when open.

    The sill shall not be more than 30 inches (762 mm) above the floor and landing.

    11-26 2025 CALIFORNIA FIRE CODE

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

    CONSTRUCTION REQUIREMENTS FOR EXISTING BUILDINGS

    1114.10 Protection of exterior openings. When an existing fire escape is accepted as one of the require means of egress, openings onto the fire escape landing and openings within 5 feet (1524 mm) horizontally of the landings shall be protected in a manner acceptable to the enforcing agency.

    1114.11 Locking of stairway doors. When exit doors from corridors to exit stairways are locked to prohibit access from the stairway side, the locking mechanisms shall be retracted to the unlocked position upon failure of electrical power and a telephone or other two- way communication system connected to an approved emergency service that operates continuously shall be provided at not less than every fifth floor in each required stairway. In lieu thereof, master keys which will unlock all such doors from the stairway side shall be provided in such numbers and locations as approved by the enforcing agency.

    1114.12 Enclosures. Interior vertical shafts, including but not limited to, elevators, stairway and utility, shall be enclosed with construc- tion as set forth in Section 1114.6.

    1114.13 Opening protection. Doors in other than elevators, which shall be of a type acceptable to the enforcing agency, shall be approved one-hour, fire-rated, tight-fitting or gasketed doors or equivalent protection, and shall be of the normally closed type, self- closing or a type which will close automatically in accordance with Section 715 of the California Building Code.

    Exception: In lieu of stairway enclosures, smoke barriers may be provided in such a manner that fire and smoke will not spread to other floors or otherwise impair exit facilities. In these instances, smoke barriers shall not be less than one-hour fire resistive with openings protected by not less than approved one-third-hour, fire-rated, tight-fitting or gasketed doors. Such doors shall be of the self-closing type or of a type which will close automatically in the manner specified in Section 715 of the California Building Code.

    Doors crossing corridors shall be provided with wired-glass vision panels set in approved steel frames. Doors for elevators shall not be of the open-grille type.

  • CHBC § 1104.5.1 High relevance — show source text
    1. Group F having more than 100 occupants.

    Exception: Buildings used only during daylight hours and that are provided with windows for natural light in accordance with the California Building Code .

    1. Group I.

    2. Group M. Exception: Buildings less than 3,000 square feet (279 m [2] ) in gross sales area on one story only, excluding mezzanines.

    3. Groups R-1 and R-2.

    Exception: Where each dwelling unit or sleeping unit has direct access to the outside of the building at grade.

    1104.5.1 Emergency power duration and installation. Emergency power for means of egress illumination shall be provided in accordance with Section 1203. In other than Group I-2, emergency power shall be provided for not less than 60 minutes for systems requiring emergency power.

    1104.6 Guards. Guards complying with this section shall be provided at the open sides of means of egress that are more than 30 inches (762 mm) above the floor or grade below.

    1104.6.1 Height of guards. Guards shall form a protective barrier not less than 42 inches (1067 mm) high.

    Exceptions:

    1. Existing guards on the open side of exit access and exit stairways and ramps shall be not less than 30 inches (760 mm) high.
    2. Existing guards within dwelling units shall be not less than 36 inches (910 mm) high.
    3. Existing guards in assembly seating areas.

    1104.6.2 Opening limitations. Open guards shall have balusters or ornamental patterns such that a 6-inch-diameter (152 mm) sphere cannot pass through any opening up to a height of 34 inches (864 mm).

    Exceptions:

    1. At elevated walking surfaces for access to, and use of, electrical, mechanical or plumbing systems or equipment, guards shall have balusters or be of solid materials such that a sphere with a diameter of 21 inches (533 mm) cannot pass through any opening.

    2. In occupancies in Group I-3, F, H or S, the clear distance between intermediate rails measured at right angles to the rails shall not exceed 21 inches (533 mm).

    3. Approved existing open guards.

    1104.7 Size of doors. The required capacity of each door opening shall be sufficient for the occupant load thereof and shall provide a minimum clear opening width of 28 inches (711 mm). Where this section requires a minimum clear opening width of 28 inches (711 mm) and a door opening includes two door leaves without a mullion, one leaf shall provide a clear opening width of 28 inches (711 mm). The minimum clear opening height of doorways shall be 80 inches (2032 mm).

    Exceptions:

    1. The minimum and maximum width shall not apply to door openings that are not part of the required means of egress in occupancies in Group R-2 and R-3 units that are not required to be an Accessible unit, Type A unit or Type B unit.
    2. Door openings to storage closets less than 10 square feet (0.93 m [2] ) in area shall not be limited by the minimum clear opening width.
    3. The width of door leaves in revolving doors that comply with Section 1010.3.1 shall not be limited.
    4. The maximum width of door leaves in power-operated doors that comply with Section 1010.3.2 shall not be limited.
    5. Door openings within a dwelling unit shall have a minimum clear opening height of 78 inches (1981 mm).
  • CHBC § 504.3 High relevance — show source text

    [BE] 504.3 Construction. The fire escape shall be designed to support a live load of 100 pounds per square foot (4788 Pa) and shall be constructed of steel or other approved noncombustible materials. Fire escapes constructed of wood not less than nominal 2 inches (51 mm) thick are permitted on buildings of Type V construction. Walkways and railings located over or supported by combustible roofs in buildings of Type III and IV construction are permitted to be of wood not less than nominal 2 inches (51 mm) thick.

    [BE] 504.4 Dimensions. Stairways shall be not less than 22 inches (559 mm) wide with risers not more than, and treads not less than, 8 inches (203 mm) and landings at the foot of stairways not less than 40 inches (1016 mm) wide by 36 inches (914 mm) long, located not more than 8 inches (203 mm) below the door.

    [BE] 504.5 Opening protectives. Doors and windows within 10 feet (3048 mm) of fire escape stairways shall be protected with [3] / 4 hour opening protectives.

    Exception: Opening protection shall not be required in buildings equipped throughout with an approved automatic sprinkler system.

    SECTION 505—WINDOWS AND EMERGENCY ESCAPE OPENINGS

    505.1 Replacement windows. The installation or replacement of windows shall be as required for new installations.

    505.2 Window fall prevention on replacement windows. In Group R-1, R-2 or R-3 buildings containing dwelling or sleeping units, and one- and two-family dwellings and townhouses regulated by the California Residential Code, window opening control devices or other window fall prevention devices complying with ASTM F2090 shall be installed where an existing window is replaced and where all of the following apply to the replacement window:

    1. The window is operable.
    2. One of the following applies: 2.1. The window replacement includes replacement of the sash and frame. 2.2. The window replacement includes the sash only where the existing frame remains.
    3. One of the following applies: 3.1. In Group R-2 or R-3 buildings containing dwelling or sleeping units, the bottom of the clear opening of the window opening is at a height less than 36 inches (915 mm) above the finished floor. 3.2. In one- and two-family dwellings and townhouses regulated by the California Residential Code, the bottom of the clear opening of the window opening is at a height less than 24 inches (610 mm) above the finished floor.
    4. The window will permit openings that will allow passage of a 4-inch-diameter (102 mm) sphere when the window is in its largest opened position.
    5. The vertical distance from the bottom of the clear opening of the window opening to the finished grade or other surface below, on the exterior of the building, is greater than 72 inches (1829 mm).

    Exception: Operable windows where the bottom of the clear opening of the window opening is located more than 75 feet (22 860 mm) above the finished grade or other surface below, on the exterior of the room, space or building, and that are provided with window fall prevention devices that comply with ASTM F2006.

Frequently asked questions

If a sleeping-room window meets § 8-503 but its sill is 40 inches high, is it still OK to use the fire escape?

No. If the opening provides access to the fire escape, § 8-502.5 requires the sill be no more than 30 inches above the floor; a 40-inch sill would not meet that fire-escape access requirement.

Which wins if § 8-502.5 and § 8-503 seem to conflict (for example different width/area limits)?

When an opening specifically provides access to a fire escape, follow the fire-escape access rule in § 8-502.5 (minimum 29 in. width; sill ≤ 30 in.). § 8-503 governs general escape openings; use both where applicable and consult the enforcing agency for enforcement or alternatives.

Does § 8-503 require windows to be openable without tools?

Yes — § 8-503 requires escape/rescue windows and doors be operable from the inside to provide a full, clear opening without the use of special tools.

Are older, “previously approved” fire escapes allowed to remain even if some dimensions differ from new-code values?

Yes — the CHBC allows existing previously approved fire escapes to be acceptable as a required means of egress provided they meet the conditions in § 8-502.5 (extend to the ground, be easily negotiated, adequately signed and in good working order). The enforcing agency can grant reasonable exceptions per § 8-502.1.

If I replace a window that opens to a fire escape, what should I check to stay compliant?

Confirm that the fully open window gives at least 29 in. clear width for fire-escape access (if serving the fire escape), that the sill will be ≤ 30 in., and that the clear opening area and dimensions meet § 8-503 when applicable; ensure operability from the inside without special tools.

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