CHBC · California Historical Building Code

Which basements and sleeping rooms must have an approved escape or rescue opening?

If you own or modify a qualified historic dwelling, remember: CHBC **§ 8-503** requires basements in dwelling units and every sleeping room below the fourth floor to have at least one approved emergency escape or rescue opening that opens to a public way, provides a minimum **3.3 sq ft** clear area, has a minimum **18 in** width or height, and is operable from inside without special tools.

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Last reviewed: July 6, 2026

What the code requires — plain English

Basements located in dwelling units and every sleeping room below the fourth floor must have at least one approved escape or rescue opening that opens directly to a public street, public way, yard or exit court. That opening must provide a minimum clear area of 3.3 square feet (0.31 m2), have a minimum width or height of 18 inches (457 mm), and be operable from the inside to provide a full clear opening without special tools. See § 8-503 for the requirement.

The single most important rule: Basements in dwelling units and any sleeping room below the fourth floor must have an openable emergency escape opening that meets the size and operability limits in § 8-503.

Requirements in detail

Which spaces are covered (scope)

  • Basements in dwelling units — CHBC says basements in dwelling units are required to have an approved escape or rescue opening. § 8-503.
  • Every sleeping room below the fourth floor — any sleeping room located below the fourth floor must have at least one escape/rescue opening. § 8-503.

Note: CHBC residential provisions cross-reference the escape requirement: windows in sleeping rooms shall be openable (see § 8-503). § 8-303.6 points you to § 8-503 for the escape-opening requirement.

Minimum size and operability (key thresholds)

Decision item Required value Code reference
Minimum clear opening area 3.3 sq ft (0.31 m²) § 8-503
Minimum clear width OR height 18 inches (457 mm) § 8-503
Operability from inside Must be operable from the inside to provide a full, clear opening without the use of special tools § 8-503
Where the opening must lead Directly into a public street, public way, yard or exit court § 8-503
Which floors covered (sleeping rooms) Sleeping rooms below the fourth floor § 8-503

Measurement notes

  • § 8-503 states the minimum clear area and minimum width/height but does not provide an expanded measurement method in its text. If you need clarification on measuring net clear opening or methods for calculating the clear area from a particular window style, the CHBC text for § 8-503 does not specify measurement procedure; the enforcing agency or applicable regular code may be consulted for measurement practice. § 8-503

Exceptions & special cases

  • The CHBC text for § 8-503 as retrieved is concise and does not list exceptions (for example, it does not supply the variety of exceptions you may find in the regular codes). The CHBC requires the stated minima for basements in dwelling units and sleeping rooms below the fourth floor. § 8-503
  • CHBC residential provisions reference the escape rule; for example, § 8-303.6 requires sleeping-room windows to be openable and points to § 8-503 for escape/opening details. Use that cross-reference when applying the rule to residential spaces. § 8-303.6
  • The CHBC is an alternative code intended to preserve historic character while providing life-safety; other CHBC chapters explain the intent to accept alternatives when strict compliance threatens historical significance. Where preservation concerns exist, the enforcing agency may accept reasonably equivalent alternatives — but the baseline escape-opening requirement in § 8-503 is the CHBC provision you must address. See the CHBC residential intent and application language (Chapter 8-3) for context. § 8-303.1–8-303.3

If you need the many exception permutations found in the regular Building, Residential or Fire Code (for example, ceiling-height exemptions, small non-habitable basements, or sprinkler-based exceptions), those are not stated in § 8-503 as retrieved here; consult the enforcing agency or the regular code text for parallel exception language.

Common mistakes

  • Treating the requirement as applying to all basements — CHBC requires it for basements in dwelling units specifically; non-dwelling basements are not covered by § 8-503 as written. § 8-503
  • Confusing rough opening with clear opening — the code mandates a minimum clear area and minimum clear width/height; the rough opening or frame size can be larger, but the clear opening after operation is what must meet the minima. § 8-503
  • Assuming CHBC includes the same exceptions and measurement details found in the regular residential code — § 8-503 is brief and does not reproduce those exception lists. Where the CHBC is silent, do not invent alternate allowances without approval from the enforcing agency. § 8-503
  • Forgetting the requirement that the opening must open directly to a public street, public way, yard or exit court (some installers route openings to spaces that do not meet that requirement). § 8-503

Worked example

Scenario: A homeowner converts a basement room into a sleeping room on the second floor below the fourth floor. They plan to use an existing window that, when fully opened, gives a clear opening of 22 inches high by 30 inches wide.

  • Calculate clear area: 22 in × 30 in = 660 in². Convert to ft²: 660 ÷ 144 = 4.58 ft².
  • CHBC requirement: minimum clear area = 3.3 ft² and minimum width or height = 18 in (457 mm). § 8-503
  • Result: 4.58 ft² > 3.3 ft² and both width (30 in) and height (22 in) exceed 18 in, so the window meets the CHBC minima. It also must open directly to a public street/yard/etc. and be operable from the inside without special tools. § 8-503

Counterexample: A smaller basement window provides a full clear opening of 18 in × 24 in = 432 in² = 3.0 ft². This fails the 3.3 ft² minimum in § 8-503 and therefore is not acceptable without an alternative means or modification. § 8-503

Related CHBC provisions

  • § 8-503 — Escape or Rescue Windows and Doors (controlling requirement).
  • § 8-303.6 — Light and ventilation; windows in sleeping rooms shall be openable (cross-references § 8-503).
  • Chapter 8-3 (Residential Occupancies) — Purpose, scope and intent for residential provisions (context for how § 8-503 applies to qualified historical dwellings). § 8-303.1–8-303.4.
  • § 8-504 — Railings and guardrails (other egress-related historic exceptions/context).

If you need to apply exceptions or measurement methods commonly found in the regular Residential/Building Code (for example, larger minimums, grade-floor exceptions, replacement-window allowances, security-bar release device rules, or sprinkler-based exceptions), those details are not contained in § 8-503 as retrieved; consult the enforcing agency or the regular code sections for those specifics.

Code references

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

  • CHBC § 8-503 High relevance — show source text

    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.

    8-601.2 Intent. The intent of this chapter is to preserve the integrity of qualified historical buildings and properties while providing access to and use by persons with disabilities.

    8-601.3 Scope. The CHBC shall apply to every qualified historical building or property that is required to provide access to persons with disabilities.

    1. Provisions of this chapter do not apply to new construction or reconstruction/replicas of historical buildings.
    2. Where provisions of this chapter apply to alteration of qualified historical buildings or properties, alteration is defined in California Building Code (CBC), Chapter 2.

    8-601.4 General application. The provisions in the CHBC apply to local, state and federal governments (Title II entities); alteration of commercial facilities and places of public accommodation (Title III entities); and barrier removal in commercial facilities and places of public accommodation (Title III entities). Except as noted in this chapter.

    SECTION 8-602 — BASIC PROVISIONS

    8-602.1 Regular code. The regular code for access for people with disabilities (Title 24, Part 2, Vol. 1, Chapter 11B) shall be applied to qualified historical buildings or properties unless strict compliance with the regular code will threaten or destroy the historical significance or character-defining features of the building or property.

    8-602.2 Alternative provisions. If the historical significance or character-defining features are threatened, alternative provisions for access may be applied pursuant to this chapter, provided the following conditions are met:

    1. These provisions shall be applied only on an item-by-item or a case-by-case basis.
    2. Documentation is provided, including meeting minutes or letters, stating the reasons for the application of the alternative provisions. Such documentation shall be retained in the permanent file of the enforcing agency.

    SECTION 8-603 — ALTERNATIVES

  • CHBC § 3-64 High relevance — show source text

    R318.8 Ramps. Where required by this code or provided, ramps shall comply with this section.

    Exception: Ramps not within or serving a building, porch or deck.

    3-64 2025 CALIFORNIA RESIDENTIAL CODE

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    BUILDING PLANNING

    R318.8.1 Maximum slope. Ramps serving the egress door required by Section R318.2 shall have a slope of not more than 1 unit vertical in 12 units horizontal (8.3-percent slope).

    Other ramps shall have a slope of not more than 1 unit vertical in 8 units horizontal (12.5 percent).

    Exception: Where it is technically infeasible to comply because of site constraints, ramps shall have a slope of not more than 1 unit vertical in 8 units horizontal (12.5 percent).

    R318.8.2 Landings required. There shall be a floor or landing at the top and bottom of each ramp, where doors open onto ramps, and where ramps change directions. The width of the landing perpendicular to the ramp slope shall be not less than the width of the ramp. The depth of the landing in the direction of the ramp slope shall be not less than 36 inches (914 mm).

    R318.8.3 Handrails required. Handrails shall be provided on not less than one side of ramps exceeding a slope of 1 unit vertical in 12 units horizontal (8.33-percent slope) and shall comply with Section R320.

    SECTION R319—EMERGENCY ESCAPE AND RESCUE OPENINGS

    R319.1 Emergency escape and rescue opening required. Basements, habitable attics, the room to which a sleeping loft is open, and every sleeping room shall have not less than one operable emergency escape and rescue opening. Where basements contain one or more sleeping rooms, an emergency escape and rescue opening shall be required in each sleeping room. Emergency escape and rescue openings shall open directly into a public way, or to a yard or court that opens to a public way.

    Exceptions [SFM]: 1. Basements with a ceiling height of less than 80 inches (2032 mm) shall not be required to have emergency escape and rescue openings. 2. Emergency escape and rescue openings are not required from basements or sleeping rooms that have an exit door or exit access door that opens directly into a public way or to a yard, court or exterior egress balcony that opens to a public way. 3. Basements without habitable spaces and having not more than 200 square feet (18.6 m [2] ) in floor area shall not be required to have emergency escape and rescue openings. 4. Storm shelters are not required to comply with this section where the shelter is constructed in accordance with ICC 500. 5. Where the dwelling unit or townhouse unit is equipped with an automatic sprinkler system installed in accordance with Section R309, sleeping rooms in basements shall not be required to have emergency escape and rescue openings provided that the basement has one of the following: 5.1. One means of egress complying with Section R318 and one emergency escape and rescue opening. 5.2. Two means of egress complying with Section R318.

  • CHBC § 1030.17.4 High relevance — show source text

    1030.17.4 Guards at the end of aisles. A fascia or railing system complying with the guard requirements of Section 1015 shall be provided for the full width of the aisle where the foot of the aisle is more than 30 inches (762 mm) above the floor or grade below. The fascia or railing shall be not less than 36 inches (914 mm) high and shall provide not less than 42 inches (1067 mm) measured diagonally between the top of the rail and the nosing of the nearest tread.

    SECTION 1031—EMERGENCY ESCAPE AND RESCUE

    1031.1 General. Emergency escape and rescue openings shall comply with the requirements of this section.

    1031.2 Where required. In addition to the means of egress required by this chapter, emergency escape and rescue openings shall be provided in Group R occupancies .

    Basements and sleeping rooms below the fourth story above grade plane shall have not fewer than one emergency escape and rescue opening in accordance with this section. Where basements contain one or more sleeping rooms, an emergency escape and rescue opening shall be required in each sleeping room, but shall not be required in adjoining areas of the basement. Such open

    2025 CALIFORNIA BUILDING CODE 10-59

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    MEANS OF EGRESS

    ings shall open directly into a public way or to a yard or court that opens to a public way, or to an egress balcony that leads to a public way.

    Exceptions: 1. In Groups R-1 and R-2 occupancies constructed of Type I, Type IIA, Type IIIA or Type IV construction equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1. 2. Group R-2.1 occupancies meeting the requirements for delayed egress in accordance with Section 1010.2.13 may have oper- able windows that are breakable in sleeping rooms permanently restricted to a maximum of 4-inch open position. 3 . Basements with a ceiling height of less than 80 inches (2032 mm) shall not be required to have emergency escape and rescue openings. 4 . Emergency escape and rescue openings are not required from basements or sleeping rooms that have an exit door or exit access door that opens directly into a public way or to a yard, court or exterior egress balcony that leads to a public

    way. 5 . Basements without habitable spaces and having not more than 200 square feet (18.6 m [2] ) in floor area shall not be required to have emergency escape and rescue openings. 6 . Storm shelters are not required to comply with this section where the shelter is constructed in accordance with ICC 500. 7 . Within individual dwelling and sleeping units in Groups R-2 and R-3, where the building is equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1, 903.3.1.2 or 903.3.1.3, sleeping rooms in basements shall not be required to have emergency escape and rescue openings provided that the basement has one of the following: 7.1. One means of egress and one emergency escape and rescue opening. 7.2. Two means of egress. 8. In Group R-2.2 occupancies a certified fire escape is acceptable as a secondary means of egress for existing buildings for this section of the code.

  • CHBC § 10-61 High relevance — show source text
    1. Group R-3 and R-4 occupancies.

    Basements and sleeping rooms below the fourth story above grade plane shall have not fewer than one emergency escape and rescue opening in accordance with this section. Where basements contain one or more sleeping rooms, an emergency escape and rescue opening shall be required in each sleeping room, but shall not be required in adjoining areas of the basement. Such open

    2025 CALIFORNIA FIRE CODE 10-61

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    MEANS OF EGRESS

    ings shall open directly into a public way or to a yard or court that opens to a public way, or to an egress balcony that leads to a public way.

    Exceptions: 1. In Groups R-1 and R-2 occupancies constructed of Type I, Type IIA, Type IIIA or Type IV construction equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1. 2. Group R-2.1 occupancies meeting the requirements for delayed egress in accordance with Section 1010.2.13 may have oper- able windows that are breakable in sleeping rooms permanently restricted to a maximum of 4-inch open position. 3. Basements with a ceiling height of less than 80 inches (2032 mm) shall not be required to have emergency escape and rescue openings. 4. Emergency escape and rescue openings are not required from basements or sleeping rooms that have an exit door or exit access door that opens directly into a public way or to a yard, court or exterior egress balcony that leads to a public

    way. 5. Basements without habitable spaces and having not more than 200 square feet (18.6 m [2] ) in floor area shall not be required to have emergency escape and rescue openings. 6. Storm shelters are not required to comply with this section where the shelter is constructed in accordance with ICC 500. 7. Within individual dwelling and sleeping units in Groups R-2 and R-3, where the building is equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1, 903.3.1.2 or 903.3.1.3, sleeping rooms in basements shall not be required to have emergency escape and rescue openings provided that the basement has one of the following: 7.1. One means of egress and one emergency escape and rescue opening. 7.2. Two means of egress. 8. In Group R-2.2 occupancies a certified fire escape is acceptable as a secondary means of egress of existing buildings for this section of the code.

    [BE] 1031.2.1 Operational constraints and opening control devices. Emergency escape and rescue openings and any exit doors shall be maintained free of any obstructions other than those allowed by this section and shall be operational from inside the room without the use of keys or tools. Window-opening control devices complying with ASTM F2090 shall be permitted for use on windows serving as a required emergency escape and rescue opening. The release mechanism shall be maintained operable at all times.

    Such bars, grills, grates or any similar devices shall be equipped with an approved exterior release device for use by the fire department only when required by the authority having jurisdiction.

  • CHBC § 4.2.2 High relevance — show source text

    R319.4.2.2 Steps. Steps shall have an inside width of not less than 12 inches (305 mm), a minimum tread depth of 5 inches (127 mm) and a maximum riser height of 18 inches (457 mm) for the full height of the area well.

    R319.4.3 Drainage. Area wells shall be designed for proper drainage by connecting to the building’s foundation drainage system required by Section R405.1.

    Exception: A drainage system for area wells is not required where the foundation is on well-drained soil or sand-gravel mixture soils in accordance with the United Soil Classification System, Group I Soils, as detailed in Table R401.4.1(2).

    R319.4.4 Bars, grilles, covers and screens. Where bars, grilles, covers, screens or similar devices are placed over emergency escape and rescue openings, bulkhead enclosures or area wells that serve such openings, the minimum net clear opening size shall comply with Sections R319.2 through R319.2.2 and R319.4.1. Such devices shall be releasable or removable from the inside without the use of a key or tool or force greater than that required for the normal operation of the escape and rescue opening. The release mechanism shall be maintained operable at all times.

    Such bars, grills, grates or any similar devices shall be equipped with an approved exterior release device for use by the fire department only when required by the authority having jurisdiction.

    Where security bars (burglar bars) are installed on emergency egress and rescue windows or doors, on or after July 1, 2000, such devices shall comply with California Building Standards Code, Part 12, Chapter 12-3 and other applicable provisions of this code.

    R319.5 Replacement windows for emergency escape and rescue openings. Replacement for emergency escape and rescue openings installed in buildings meeting the scope of this code shall be exempt from Sections R319.2 and R319.4.4, provided that the replacement window meets the following conditions:

    1. The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window shall be permitted to be of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.
    2. The replacement window is not part of a change of occupancy.

    R319.5.1 Window opening control device and fall protection device height. Window opening control devices or fall protection devices shall be located at a height in accordance with Section R319.1.1 or at as low a height as the device can be installed within the existing clear opening.

    R319.6 Dwelling additions. Where dwelling unit additions contain sleeping rooms, an emergency escape and rescue opening shall be provided in each new sleeping room. Where dwelling unit additions have basements, an emergency escape and rescue opening shall be provided in the new basement.

    Exceptions:

    1. An emergency escape and rescue opening is not required in a new basement that contains a sleeping room with an emergency escape and rescue opening.
    2. An emergency escape and rescue opening is not required in a new basement where there is an emergency escape and rescue opening in an existing basement that is accessed from the new basement.
    3. An operable window complying with Section R319.7.1 shall be acceptable as an emergency escape and rescue opening.
  • CHBC § 18.6 High relevance — show source text

    way. 5. Basements without habitable spaces and having not more than 200 square feet (18.6 m [2] ) in floor area shall not be required to have emergency escape and rescue openings. 6. Storm shelters are not required to comply with this section where the shelter is constructed in accordance with ICC 500. 7. Within individual dwelling and sleeping units in Groups R-2 and R-3, where the building is equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1, 903.3.1.2 or 903.3.1.3, sleeping rooms in basements shall not be required to have emergency escape and rescue openings provided that the basement has one of the following: 7.1. One means of egress and one emergency escape and rescue opening. 7.2. Two means of egress. 8. In Group R-2.2 occupancies a certified fire escape is acceptable as a secondary means of egress of existing buildings for this section of the code.

    [BE] 1031.2.1 Operational constraints and opening control devices. Emergency escape and rescue openings and any exit doors shall be maintained free of any obstructions other than those allowed by this section and shall be operational from inside the room without the use of keys or tools. Window-opening control devices complying with ASTM F2090 shall be permitted for use on windows serving as a required emergency escape and rescue opening. The release mechanism shall be maintained operable at all times.

    Such bars, grills, grates or any similar devices shall be equipped with an approved exterior release device for use by the fire department only when required by the authority having jurisdiction.

    Where security bars (burglar bars) are installed on emergency egress and rescue windows or doors, on or after July 1, 2000, such devices shall comply with California Building Standards Code, Part 12, Chapter 12-3 and other applicable provisions of Part 2.

    Exception: Group R-1 occupancies provided with a monitored fire sprinkler system in accordance with Section 903.2.8 and designed in accordance with NFPA 13 may have openable windows permanently restricted to a maximum 4-inch (102 mm) open position.

    [California Code of Regulations, Title 19, Division 1, §4.2] Labeling.

    Burglar bars shall not be sold in California at wholesale or retail unless warning information as specified in California Code of Regula- tions, Title 19, Division 1, Section 4.3 is provided either on the packaging or provided inside the packaging along with the burglar bars.

    [California Code of Regulations, Title 19, Division 1, §4.3(a) through (c)] Warning Information.

    (a) Warning information located on or in burglar bar packaging shall contain the following information: (1) Warning that the burglar bars are intended to deter or delay intruders, they are not intended to prevent entry. (2) A reprint of the following requirements from California Building Code, Part 2, Chapter 10: “Bars, grilles, grates or similar devices may be installed on emergency escape or rescue windows, doors or window wells or any required exit door, provided: 1. The devices are equipped with approved release mechanisms which are openable from the inside without the use of a key or special knowledge or effort; and 2. The building is equipped with smoke alarms installed in accordance with California Building Code, Part 2, Section 907.

  • CHBC § 18.6 High relevance — show source text

    Basements with a ceiling height of less than 80 inches (2032 mm) shall not be required to have emergency escape and rescue openings. 4 . Emergency escape and rescue openings are not required from basements or sleeping rooms that have an exit door or exit access door that opens directly into a public way or to a yard, court or exterior egress balcony that leads to a public

    way. 5 . Basements without habitable spaces and having not more than 200 square feet (18.6 m [2] ) in floor area shall not be required to have emergency escape and rescue openings. 6 . Storm shelters are not required to comply with this section where the shelter is constructed in accordance with ICC 500. 7 . Within individual dwelling and sleeping units in Groups R-2 and R-3, where the building is equipped throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1, 903.3.1.2 or 903.3.1.3, sleeping rooms in basements shall not be required to have emergency escape and rescue openings provided that the basement has one of the following: 7.1. One means of egress and one emergency escape and rescue opening. 7.2. Two means of egress. 8. In Group R-2.2 occupancies a certified fire escape is acceptable as a secondary means of egress for existing buildings for this section of the code.

    1031.2.1 Operational constraints and opening control devices. Emergency escape and rescue openings and any exit doors shall be maintained free of any obstructions other than those allowed by this section and shall be operational from inside the room without the use of keys or tools. Window-opening control devices complying with ASTM F2090 shall be permitted for use on windows serving as a required emergency escape and rescue opening. The release mechanism shall be maintained operable at all times.

    Such bars, grills, grates or any similar devices shall be equipped with an approved exterior release device for use by the fire department only when required by the authority having jurisdiction.

    Where security bars (burglar bars) are installed on emergency egress and rescue windows or doors, on or after July 1, 2000, such devices shall comply with California Building Standards Code, Part 12, Chapter 12-3 and other applicable provisions of Part 2.

    Exception: Group R-1 occupancies provided with a monitored fire sprinkler system in accordance with Section 903.2.8 and designed in accordance with NFPA 13 may have openable windows permanently restricted to a maximum 4-inch (102 mm) open position.

    1031.2.2 Maintenance. Fire escape stairways and balconies shall be kept clear and unobstructed at all times and shall be main- tained in good working order.

    1031.2.3 Examination. Fire escape stairways and balconies shall be examined for structural adequacy and safety by a registered design professional or other person acceptable to the fire code official every 5 years. The examination shall determine whether the fire escape stairways and balconies can support the dead load plus a live load of not less than 100 pounds per square foot (4.78 kN/m). An inspection report shall be submitted to the fire code official after such examination.

    1031.3 Emergency escape and rescue openings. Emergency escape and rescue openings shall comply with Sections 1031.3.1 through 1031.3.3.

  • CHBC § 18.6 High relevance — show source text

    R319.1 Emergency escape and rescue opening required. Basements, habitable attics, the room to which a sleeping loft is open, and every sleeping room shall have not less than one operable emergency escape and rescue opening. Where basements contain one or more sleeping rooms, an emergency escape and rescue opening shall be required in each sleeping room. Emergency escape and rescue openings shall open directly into a public way, or to a yard or court that opens to a public way.

    Exceptions [SFM]: 1. Basements with a ceiling height of less than 80 inches (2032 mm) shall not be required to have emergency escape and rescue openings. 2. Emergency escape and rescue openings are not required from basements or sleeping rooms that have an exit door or exit access door that opens directly into a public way or to a yard, court or exterior egress balcony that opens to a public way. 3. Basements without habitable spaces and having not more than 200 square feet (18.6 m [2] ) in floor area shall not be required to have emergency escape and rescue openings. 4. Storm shelters are not required to comply with this section where the shelter is constructed in accordance with ICC 500. 5. Where the dwelling unit or townhouse unit is equipped with an automatic sprinkler system installed in accordance with Section R309, sleeping rooms in basements shall not be required to have emergency escape and rescue openings provided that the basement has one of the following: 5.1. One means of egress complying with Section R318 and one emergency escape and rescue opening. 5.2. Two means of egress complying with Section R318.

    R319.1.1 Operational constraints and opening control devices. Emergency escape and rescue openings shall be maintained free of any obstructions other than those allowed by this section and shall be operational from the inside of the room without the use of keys, tools or special knowledge. Window opening control devices and fall prevention devices complying with ASTM F2090 shall be permitted for use on windows serving as a required emergency escape and rescue opening and shall be not more than 70 inches (178 cm) above the finished floor. The release mechanism shall be maintained operable at all times.

    Such bars, grills, grates or any similar devices shall be equipped with an approved exterior release device for use by the fire department only when required by the authority having jurisdiction.

    Where security bars (burglar bars) are installed on emergency egress and rescue windows or doors, on or after July 1, 2000, such devices shall comply with California Building Standards Code, Part 12, Chapter 12-3 and other applicable provisions of this code.

    R319.2 Emergency escape and rescue openings. Emergency escape and rescue openings shall have minimum dimensions in accordance with Sections R319.2.1 through R319.2.4.

    R319.2.1 Minimum size. Emergency escape and rescue openings shall have a net clear opening of not less than 5.7 square feet (0.530 m [2] ).

    Exception: The minimum net clear opening for grade-floor emergency escape and rescue openings shall be 5 square feet (0.465 m [2] ).

    R319.2.2 Minimum dimensions. The minimum net clear opening height dimension shall be 24 inches (610 mm). The minimum net clear opening width dimension shall be 20 inches (508 mm). The net clear opening dimensions shall be the result of normal operation of the opening.

  • CHBC § 1030.17.1 High relevance — show source text

    1030.17.1 Perimeter guards. Perimeter guards shall be provided where the footboards or walking surface of seating facilities are more than 30 inches (762 mm) above the floor or grade below. Where the seatboards are adjacent to the perimeter, guard height shall be 42 inches (1067 mm) high minimum, measured from the seatboard. Where the seats are self-rising, guard height shall be 42 inches (1067 mm) high minimum, measured from the floor surface. Where there is an aisle between the seating and the perimeter, the guard height shall be measured in accordance with Section 1015.3.

    Exceptions:

    1. Guards that impact sightlines shall be permitted to comply with Section 1030.17.3.
    2. Bleachers, grandstands and folding and telescopic seating shall not be required to have perimeter guards where the seating is located adjacent to a wall and the space between the wall and the seating is less than 4 inches (102 mm).

    1030.17.2 Cross aisles. Cross aisles located more than 30 inches (762 mm) above the floor or grade below shall have guards in accordance with Section 1015.

    Where an elevation change of 30 inches (762 mm) or less occurs between a cross aisle and the adjacent floor or grade below, guards not less than 26 inches (660 mm) above the aisle floor shall be provided.

    Exception: Where the backs of seats on the front of the cross aisle project 24 inches (610 mm) or more above the adjacent floor of the aisle, a guard need not be provided.

    1030.17.3 Sightline-constrained guard heights. Unless subject to the requirements of Section 1030.17.4, a fascia or railing system in accordance with the guard requirements of Section 1015 and having a minimum height of 26 inches (660 mm) shall be provided where the floor or footboard elevation is more than 30 inches (762 mm) above the floor or grade below and the fascia or railing would otherwise interfere with the sightlines of immediately adjacent seating.

    1030.17.4 Guards at the end of aisles. A fascia or railing system complying with the guard requirements of Section 1015 shall be provided for the full width of the aisle where the foot of the aisle is more than 30 inches (762 mm) above the floor or grade below. The fascia or railing shall be not less than 36 inches (914 mm) high and shall provide not less than 42 inches (1067 mm) measured diagonally between the top of the rail and the nosing of the nearest tread.

    SECTION 1031—EMERGENCY ESCAPE AND RESCUE

    1031.1 General. Emergency escape and rescue openings shall comply with the requirements of this section.

    1031.2 Where required. In addition to the means of egress required by this chapter, emergency escape and rescue openings shall be provided in Group R occupancies .

    Basements and sleeping rooms below the fourth story above grade plane shall have not fewer than one emergency escape and rescue opening in accordance with this section. Where basements contain one or more sleeping rooms, an emergency escape and rescue opening shall be required in each sleeping room, but shall not be required in adjoining areas of the basement. Such open

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  • CHBC § 1030.17.3 High relevance — show source text

    Where an elevation change of 30 inches (762 mm) or less occurs between a cross aisle and the adjacent floor or grade below, guards not less than 26 inches (660 mm) above the aisle floor shall be provided.

    Exception: Where the backs of seats on the front of the cross aisle project 24 inches (610 mm) or more above the adjacent floor of the aisle, a guard need not be provided.

    [BE] 1030.17.3 Sightline-constrained guard heights. Unless subject to the requirements of Section 1030.17.4, a fascia or railing system in accordance with the guard requirements of Section 1015 and having a minimum height of 26 inches (660 mm) shall be provided where the floor or footboard elevation is more than 30 inches (762 mm) above the floor or grade below and the fascia or railing would otherwise interfere with the sightlines of immediately adjacent seating.

    [BE] 1030.17.4 Guards at the end of aisles. A fascia or railing system complying with the guard requirements of Section 1015 shall be provided for the full width of the aisle where the foot of the aisle is more than 30 inches (762 mm) above the floor or grade below. The fascia or railing shall be not less than 36 inches (914 mm) high and shall provide not less than 42 inches (1067 mm) measured diagonally between the top of the rail and the nosing of the nearest tread.

    SECTION 1031—EMERGENCY ESCAPE AND RESCUE

    [BE] 1031.1 General. Emergency escape and rescue openings shall comply with the requirements of this section.

    [BE] 1031.2 Where required. In addition to the means of egress required by this chapter, emergency escape and rescue openings shall be provided in Group R occupancies:

    1. Group R-2 occupancies located in stories with only one exit or access to only one exit as permitted by Tables 1006.3.4(1) and 1006.3.4(2).

    2. Group R-3 and R-4 occupancies.

    Basements and sleeping rooms below the fourth story above grade plane shall have not fewer than one emergency escape and rescue opening in accordance with this section. Where basements contain one or more sleeping rooms, an emergency escape and rescue opening shall be required in each sleeping room, but shall not be required in adjoining areas of the basement. Such open

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    ings shall open directly into a public way or to a yard or court that opens to a public way, or to an egress balcony that leads to a public way.

    Exceptions: 1. In Groups R-1 and R-2 occupancies constructed of Type I, Type IIA, Type IIIA or Type IV construction equipped throughout with an approved automatic sprinkler system in accordance with Section 903.3.1.1. 2. Group R-2.1 occupancies meeting the requirements for delayed egress in accordance with Section 1010.2.13 may have oper- able windows that are breakable in sleeping rooms permanently restricted to a maximum of 4-inch open position. 3. Basements with a ceiling height of less than 80 inches (2032 mm) shall not be required to have emergency escape and rescue openings.

  • CHBC § 4.4 High relevance — show source text

    R319.5 Replacement windows for emergency escape and rescue openings. Replacement for emergency escape and rescue openings installed in buildings meeting the scope of this code shall be exempt from Sections R319.2 and R319.4.4, provided that the replacement window meets the following conditions:

    1. The replacement window is the manufacturer’s largest standard size window that will fit within the existing frame or existing rough opening. The replacement window shall be permitted to be of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.
    2. The replacement window is not part of a change of occupancy.

    R319.5.1 Window opening control device and fall protection device height. Window opening control devices or fall protection devices shall be located at a height in accordance with Section R319.1.1 or at as low a height as the device can be installed within the existing clear opening.

    R319.6 Dwelling additions. Where dwelling unit additions contain sleeping rooms, an emergency escape and rescue opening shall be provided in each new sleeping room. Where dwelling unit additions have basements, an emergency escape and rescue opening shall be provided in the new basement.

    Exceptions:

    1. An emergency escape and rescue opening is not required in a new basement that contains a sleeping room with an emergency escape and rescue opening.
    2. An emergency escape and rescue opening is not required in a new basement where there is an emergency escape and rescue opening in an existing basement that is accessed from the new basement.
    3. An operable window complying with Section R319.7.1 shall be acceptable as an emergency escape and rescue opening.

    R319.7 Alterations or repairs of existing basements. New sleeping rooms created in an existing basement shall be provided with emergency escape and rescue openings in accordance with Section R319.1. Other than new sleeping rooms, where existing basements undergo alterations or repairs, an emergency escape and rescue opening is not required.

    Exception: An operable window complying with Section R319.7.1 shall be acceptable as an emergency escape and rescue opening.

    R319.7.1 Existing emergency escape and rescue openings. Where a change of occupancy would require an emergency escape and rescue opening in accordance with Section R319.1, operable windows serving as the emergency escape and rescue opening shall comply with the following:

    1. An existing operable window shall provide a minimum net clear opening of 4 square feet (0.38 m [2] ) with a minimum net clear opening height of 22 inches (559 mm) and a minimum net clear opening width of 20 inches (508 mm).

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    1. A replacement window where such window complies with both of the following: 2.1. The replacement window meets the size requirements in Item 1. 2.2. The replacement window is the manufacturer’s largest standard-size window that will fit within the existing frame or existing rough opening. The replacement window shall be permitted to be of the same operating style as the existing window or a style that provides for an equal or greater window opening area than the existing window.

    SECTION R320—HANDRAILS

    R320.1 General. Handrails shall comply with Section R320.

  • 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.

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    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.

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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.

Frequently asked questions

Do all basements have to have an escape opening?

No. The CHBC text in § 8-503 requires escape/opening for basements in dwelling units specifically. The section as retrieved does not list general exemptions for non-dwelling basements. § 8-503

Are sleeping rooms on the fourth floor required to have an escape opening?

No. § 8-503 applies to every sleeping room below the fourth floor; sleeping rooms at the fourth floor and above are not covered by that specific sentence in § 8-503. § 8-503

Is a 3.3 ft² clear opening the same as the Residential Code requirement?

No. The CHBC § 8-503 sets the CHBC minimum at 3.3 sq ft (0.31 m²) with 18 in minimum width or height. Other codes (regular Residential Code) use different numerical minima — the CHBC value is the controlling CHBC text for qualified historic buildings. § 8-503

Can I install security bars over required escape windows?

§ 8-503 specifies size and operability but does not address security bars or release mechanisms. The CHBC text for § 8-503 as retrieved is silent on bars; consult the enforcing agency or the regular code provisions if you plan to add bars or grills. § 8-503

What if preserving historic fabric prevents meeting these dimensions?

The CHBC is expressly intended to permit alternative provisions when strict code compliance would threaten historic significance (see the CHBC residential intent and scope). However, § 8-503 remains the escape-opening requirement; any alternative must be documented and accepted by the enforcing agency per CHBC procedures. See Chapter 8-3 for the CHBC approach to alternatives. § 8-303.1–8-303.3

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