CBC · California Building Code

How must penetrations through fire‑resistance‑rated assemblies be protected?

Penetrations (holes for pipes, conduits, boxes, etc.) in fire‑rated walls or floors must either be installed exactly as the assembly was tested or be sealed with a listed firestop system tested to ASTM E814/UL1479 (including a 0.01 in. water test) so the wall’s fire rating—and, for smoke barriers, leakage limits—are preserved; limited exceptions (e.g., small steel pipes in concrete) exist but have strict size and material conditions.

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Last reviewed: July 5, 2026

What the code requires — 2-4 sentences

Penetrations (through and membrane) of fire‑resistance‑rated walls and horizontal assemblies must be protected so the assembly’s fire‑resistance (and, where applicable, smoke‑leakage resistance) is maintained. Protection must be either (a) by systems installed as tested in the approved fire‑resistance‑rated assembly or (b) by an approved through‑penetration (penetration firestop) system tested to ASTM E814 / UL 1479 with the required F (and where required T or L) ratings and tested under a minimum positive pressure differential of 0.01 inch water. These requirements are stated in § 714.1, § 714.2 and § 714.4 of the CBC.

Requirements in detail

General rule and test basis

  • Two permitted methods to protect a penetration:
    1. Install the penetrating item using the exact materials and configuration tested as part of the approved fire‑resistance‑rated assembly (i.e., “installed as tested”). (§ 714.4.1.1).
    2. Use an approved through‑penetration firestop system (a listed penetration firestop) that has been tested in accordance with ASTM E814 / UL 1479 and installed per its listing and the manufacturer’s instructions. The firestop must meet the applicable F‑rating (and T‑rating or L‑rating where required) and the test includes a minimum positive pressure differential of 0.01 in. water. (§ 714.2; § 714.4.1.2).

Through penetrations of fire‑resistance‑rated walls (§ 714.4)

  • Required performance: Through‑penetration firestop system must provide an F rating not less than the required fire‑resistance rating of the wall being penetrated. The system must be tested to ASTM E814 / UL 1479 with the minimum 0.01 in. water positive pressure. (§ 714.4.1.2).
  • Alternative: Penetrations may be protected by systems installed as tested in the approved fire‑resistance‑rated assembly (see § 714.4.1.1).
  • Dissimilar materials rule: Noncombustible penetrating items must not be connected to combustible items beyond the point of firestopping unless the fire‑resistance integrity is demonstrated to be maintained. (§ 714.4.3).

Key numeric limits and decision dimensions (quick lookup table)

Decision dimension Value / limit When it applies Code Reference
Minimum test pressure for listed systems 0.01 in. water (≈2.49 Pa) All through‑penetration tests per ASTM E814 / UL 1479 required by CBC § 714.4.1.2
Required F‑rating for penetration system Not less than required fire‑resistance rating of wall Through penetrations of fire‑resistance‑rated walls § 714.4.1.2
Steel/ferrous/copper pipe exception — max penetrating diameter 6 in. nominal Allows special filling options in concrete/masonry walls (see area limit) § 714.4.1 Exception
Steel/ferrous/copper pipe exception — maximum opening area 144 in² Concrete/grout/mortar fill permitted where installed full thickness (concrete or masonry walls) § 714.4.1 Exception
Membrane electrical box — single box area (common exception) 16 in² Membrane penetrations of up to 2‑hour walls by steel electrical boxes (with aggregate limits) § 714.4.2 exceptions (and related residential provisions)
Aggregate area limit (membrane box exceptions) 100 in² per 100 ft² of wall/ceiling area Limits total area of small membrane penetrations permitted without listed system § 714.4.2 / § 714.5.2 exceptions
Annular space tolerance for some listed boxes 1/8 in. (≈3.2 mm) For listed box exceptions unless listing allows larger gap § 714.4.2 exceptions
Smoke‑barrier leakage (L rating) ≤ 5.0 cfm/ft² per penetration OR ≤ 50 cfm per 100 ft² total For penetrations in smoke barriers — measured at 0.30 in. water in both ambient and elevated temp tests § 714.5.4

(See referenced sections for full context and additional exceptions.)

Sleeves and installation

  • Sleeves must be securely fastened to the assembly and installed per sleeve manufacturer’s instructions; any space between the penetrating item and sleeve or between sleeve and assembly must be protected in accordance with Section 714. Insulation or coverings may not be extended through the assembly unless specifically tested. (§ 714.3).
  • All listed penetration firestop systems must be installed per the manufacturer’s installation instructions and the listing criteria — the listing/installation controls the allowed materials, annular space, backing, thickness, etc. (§ 714.2).

Exceptions & special cases

  • Steel/ferrous/copper pipes, tubes or conduits in concrete/masonry walls: where item ≤ 6‑in. nominal diameter and opening area ≤ 144 in², the annular space may be filled with concrete, grout or mortar installed full thickness of the wall (or thickness required to maintain the wall’s rating) instead of an engineered listed firestop. Alternatively, the filler material may be any material that prevents passage of flame/hot gases under ASTM E119 / UL 263 time‑temperature exposure at a minimum positive pressure of 0.01 in. water for the rating period. (See § 714.4.1 Exception).
  • Membrane penetrations: limited small electrical boxes, listed boxes, listed putty pads and other listed membrane protection methods are allowed without a through‑penetration firestop system where the code exceptions apply (including aggregate area limits and annular space limits). Review the specific exception text for sizes, aggregate limits and separation requirements. (§ 714.4.2).
  • Smoke barriers: penetrations in smoke barriers must meet UL 1479 air‑leakage (L) criteria measured at 0.30 in. water and must meet the leakage limits specified in § 714.5.4 (5.0 cfm/ft² per penetration or 50 cfm per 100 ft² aggregate).
  • Dissimilar materials: noncombustible penetrating items cannot be allowed to continue into combustible items beyond the firestop unless it is demonstrated that fire‑resistance integrity is preserved. (§ 714.4.3).

Common mistakes

  • Using an unlisted “field” assembly rather than a listed penetration firestop system or an assembly that was actually tested as an assembly — the CBC requires listed systems or “installed as tested” assemblies (not ad hoc recipes). (§ 714.2; § 714.4.1.1).
  • Ignoring the 0.01 in. water pressure requirement used in the penetration firestop test and required by the code — many listings include this test criteria and the code requires installation per that listing. (§ 714.4.1.2).
  • Misapplying the steel‑pipe exceptions (e.g., using grout in nonconcrete walls or exceeding the 144 in² rule or 6‑in. diameter limit). Read the exception’s conditions carefully. (§ 714.4.1 Exception).
  • Failing to meet L‑rating leakage limits for smoke barrier penetrations — smoke control requirements are separate and stricter than basic firestop F‑ratings. (§ 714.5.4).
  • Not following the listed product’s installation instructions (backing, annular space, thickness of seal, etc.) — installation per listing is mandatory. (§ 714.2).

Worked example — concrete scenario

Scenario: A 2‑hour concrete fire barrier (masonry/concrete wall) is penetrated by a single 4‑inch nominal steel pipe. The annular gap between pipe and wall is 1/2 inch (approximately 0.5 in).

How to comply:

  1. Check exception for steel pipes in concrete walls: the pipe nominal diameter (4 in.) is ≤ 6 in. and area of opening = area of 4 in. pipe ≈ 12.6 in², which is < 144 in²; the wall is concrete. Under § 714.4.1 Exception, the annular space may be filled with concrete, grout or mortar installed the full thickness of the wall (or thickness required to maintain rating) to preserve the rating. If the filler is installed full thickness, that complies.
  2. Alternative: If you do not (or cannot) install concrete/grout full thickness, you must use a listed through‑penetration firestop system tested to ASTM E814 / UL 1479 with an F rating ≥ 2 hours and installed per its listing (including using the correct backer and sealant depth for a 1/2‑in annulus). The listed system will have been tested at the 0.01 in. water pressure called out by the code. (§ 714.4.1.2; § 714.2).

Conclusion: For this concrete 2‑hour wall and 4‑in steel pipe, using full‑depth grout/concrete fill in the annulus meets the exception; otherwise, install a listed 2‑hour rated penetration firestop per the listing.

Related provisions (quick references)

  • Installation of listed penetration systems — § 714.2.
  • Sleeves, fastening and protection of sleeve annulus — § 714.3.
  • Horizontalassemblies / floor penetrations and membrane penetrations — § 714.5 (and its exceptions).
  • Smoke‑barrier penetration leakage criteria (L‑rating) — § 714.5.4.
  • Shaft penetrations (penalties and special handling) — § 713.8 (penetrations in shafts must comply with § 714).

Code references

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

  • CBC § 509.1. High relevance — show source text

    Waste chutes shall not terminate in an incinerator room. Waste and linen rooms that are not provided with chutes need only comply with Table 509.1.

    713.13.5 Incinerator room. Incinerator rooms shall comply with Table 509.1.

    713.13.6 Automatic sprinkler system. An approved automatic sprinkler system shall be installed in accordance with Section 903.2.11.2.

    713.14 Elevator, dumbwaiter and other hoistways. A hoistway for elevators, dumbwaiters and other vertical devices shall comply with Section 712. Where the hoistway is required to be enclosed, it shall be constructed as a shaft enclosure in accordance with Section 713 and Chapter 30.

    SECTION 714—PENETRATIONS

    714.1 Scope. The provisions of this section shall govern the materials and methods of construction used to protect through penetrations and membrane penetrations of horizontal assemblies and fire-resistance-rated wall assemblies.

    714.1.1 Ducts and air transfer openings. Penetrations of fire-resistance-rated walls by ducts that are not protected with dampers shall comply with Sections 714.3 through 714.4.3. Penetrations of horizontal assemblies not protected with a shaft as permitted by Section 717.6, and not required to be protected with fire dampers by other sections of this code, shall comply with Sections 714.5 through 714.6.2. Ducts and air transfer openings that are protected with dampers shall comply with Section 717.

    714.2 Installation. A listed penetration firestop system shall be installed in accordance with the manufacturer’s installation instructions and the listing criteria.

    714.3 Sleeves. Where sleeves are used, they shall be securely fastened to the assembly penetrated and installed in accordance with the sleeve manufacturer’s installation instructions. Where listed systems are used, the sleeve shall be installed in accordance with the listing criteria for the system. The space between the item contained in the sleeve and the sleeve itself and any space between the sleeve and the assembly penetrated shall be protected in accordance with this section. Insulation and coverings on or in the penetrating item shall not penetrate the assembly unless the specific material used has been tested as part of the assembly in accordance with this section.

    714.4 Fire-resistance-rated walls. Penetrations into or through fire walls, fire barriers, smoke barrier walls and fire partitions shall comply with Sections 714.4.1 through 714.4.3. Penetrations in smoke barrier walls shall also comply with Section 714.5.4.

    714.4.1 Through penetrations. Through penetrations of fire-resistance-rated walls shall comply with Section 714.4.1.1 or 714.4.1.2.

    Exception: Where the penetrating items are steel, ferrous or copper pipes, tubes or conduits, the annular space between the penetrating item and the fire-resistance-rated wall is permitted to be protected by either of the following measures:

    1. In concrete or masonry walls where the penetrating item is a maximum 6-inch (152 mm) nominal diameter and the area of the opening through the wall does not exceed 144 square inches (0.0929 m [2] ), concrete, grout or mortar is permitted where installed the full thickness of the wall or the thickness required to maintain the fire-resistance rating.
  • CBC § 714.3 High relevance — show source text

    714.3 Sleeves. Where sleeves are used, they shall be securely fastened to the assembly penetrated and installed in accordance with the sleeve manufacturer’s installation instructions. Where listed systems are used, the sleeve shall be installed in accordance with the listing criteria for the system. The space between the item contained in the sleeve and the sleeve itself and any space between the sleeve and the assembly penetrated shall be protected in accordance with this section. Insulation and coverings on or in the penetrating item shall not penetrate the assembly unless the specific material used has been tested as part of the assembly in accordance with this section.

    714.4 Fire-resistance-rated walls. Penetrations into or through fire walls, fire barriers, smoke barrier walls and fire partitions shall comply with Sections 714.4.1 through 714.4.3. Penetrations in smoke barrier walls shall also comply with Section 714.5.4.

    714.4.1 Through penetrations. Through penetrations of fire-resistance-rated walls shall comply with Section 714.4.1.1 or 714.4.1.2.

    Exception: Where the penetrating items are steel, ferrous or copper pipes, tubes or conduits, the annular space between the penetrating item and the fire-resistance-rated wall is permitted to be protected by either of the following measures:

    1. In concrete or masonry walls where the penetrating item is a maximum 6-inch (152 mm) nominal diameter and the area of the opening through the wall does not exceed 144 square inches (0.0929 m [2] ), concrete, grout or mortar is permitted where installed the full thickness of the wall or the thickness required to maintain the fire-resistance rating.
    2. The material used to fill the annular space shall prevent the passage of flame and hot gases sufficient to ignite cotton waste when subjected to ASTM E119 or UL 263 time-temperature fire conditions under a minimum positive pressure

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    differential of 0.01 inch of water (2.49 Pa) at the location of the penetration for the time period equivalent to the fireresistance rating of the construction penetrated.

    714.4.1.1 Fire-resistance-rated assemblies. Through penetrations shall be protected using systems installed as tested in the approved fire-resistance-rated assembly.

    714.4.1.2 Through-penetration firestop system. Through penetrations shall be protected by an approved penetration firestop system installed as tested in accordance with ASTM E814 or UL 1479, with a minimum positive pressure differential of 0.01 inch of water (2.49 Pa) and shall have an F rating of not less than the required fire-resistance rating of the wall penetrated.

    714.4.2 Membrane penetrations. Membrane penetrations shall comply with Section 714.4.1. Where walls or partitions are required to have a fire-resistance rating, recessed fixtures shall be installed such that the required fire resistance will not be reduced.

    Exceptions: 1.

  • CBC § 4.1.1 High relevance — show source text

    R302.4.1.1 Fire-resistance-rated assembly. Penetrations shall be installed as tested in the approved fire-resistance-rated assembly.

    R302.4.1.2 Penetration firestop system. Penetrations shall be protected by an approved penetration firestop system installed as tested in accordance with ASTM E814 or UL 1479, with a positive pressure differential of not less than 0.01 inch of water (3 Pa) and shall have an F rating of not less than the required fire-resistance rating of the wall or floor-ceiling assembly penetrated.

    R302.4.2 Membrane penetrations. Membrane penetrations shall comply with Section R302.4.1. Where walls are required to have a fire-resistance rating, recessed fixtures shall be installed so that the required fire-resistance rating will not be reduced.

    Exceptions:

    1. Membrane penetrations of not more than 2-hour fire-resistance-rated walls and partitions by steel electrical boxes that do not exceed 16 square inches (0.0103 m [2] ) in area provided that the aggregate area of the openings through the membrane does not exceed 100 square inches (0.0645 m [2] ) in any 100 square feet (9.29 m [2] ) of wall area. The annular space between the wall membrane and the box shall not exceed [1] / 8 inch (3.1 mm). Such boxes on opposite sides of the wall shall be separated by one of the following: 1.1. By a horizontal distance of not less than 24 inches (610 mm) where the wall or partition is constructed with individual noncommunicating stud cavities. 1.2. By a horizontal distance of not less than the depth of the wall cavity where the wall cavity is filled with cellulose loose-fill, rockwool or slag mineral wool insulation. 1.3. By solid fireblocking in accordance with Section R302.11. 1.4. By protecting both boxes with listed putty pads. 1.5. By other listed materials and methods.
    2. Membrane penetrations by listed electrical boxes of any materials provided that the boxes have been tested for use in fire-resistance-rated assemblies and are installed in accordance with the instructions included in the listing. The annular space between the wall membrane and the box shall not exceed [1] / 8 inch (3.1 mm) unless listed otherwise. Such boxes on opposite sides of the wall shall be separated by one of the following: 2.1. By the horizontal distance specified in the listing of the electrical boxes. 2.2. By solid fireblocking in accordance with Section R302.11. 2.3. By protecting both boxes with listed putty pads. 2.4. By other listed materials and methods.
    3. The annular space created by the penetration of a fire sprinkler or water-filled fire sprinkler piping, provided that the annular space is covered by a metal escutcheon plate.
    4. Ceiling membrane penetrations by listed luminaires or by luminaires protected with listed materials that have been tested for use in fire-resistance-rated assemblies and are installed in accordance with the instructions included in the listing.

    R302.5 Dwelling unit garage opening and penetration protection. Openings and penetrations through the walls or ceilings separating the dwelling unit from the garage shall be in accordance with Sections R302.5.1 through R302.5.3.

  • CBC § 714.5.1 High relevance — show source text

    714.5.1 Through penetrations. Through penetrations of horizontal assemblies shall comply with Section 714.5.1.1 or 714.5.1.2.

    Exceptions:

    1. Penetrations by steel, ferrous or copper conduits, pipes, tubes or vents or concrete or masonry items through a single fire-resistance-rated floor assembly where the annular space is protected with materials that prevent the passage of flame and hot gases sufficient to ignite cotton waste when subjected to ASTM E119 or UL 263 time-temperature fire conditions under a minimum positive pressure differential of 0.01 inch of water (2.49 Pa) at the location of the penetration for the time period equivalent to the fire-resistance rating of the construction penetrated. Penetrating items

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    with a maximum 6-inch (152 mm) nominal diameter shall not be limited to the penetration of a single fire-resistancerated floor assembly, provided that the aggregate area of the openings through the assembly does not exceed 144 square inches (92 900 mm [2] ) in any 100 square feet (9.3 m [2] ) of floor area. 2. Penetrations in a single concrete floor by steel, ferrous or copper conduits, pipes, tubes or vents with a maximum 6inch (152 mm) nominal diameter, provided that the concrete, grout or mortar is installed the full thickness of the floor or the thickness required to maintain the fire-resistance rating. The penetrating items shall not be limited to the penetration of a single concrete floor, provided that the area of the opening through each floor does not exceed 144 square inches (92 900 mm [2] ).

    1. Penetrations by listed electrical boxes of any material, provided that such boxes have been tested for use in fire-resistance-rated assemblies and installed in accordance with the instructions included in the listing.
    2. Penetrations of concrete floors or ramps within parking garages or structures constructed in accordance with Sections 406.5 and 406.6 where the areas above and below the penetrations are parking areas.

    714.5.1.1 Fire-resistance-rated assemblies. Through penetrations shall be protected using systems installed as tested in the approved fire-resistance-rated assembly.

    714.5.1.2 Through-penetration firestop system. Through penetrations shall be protected by an approved through-penetration firestop system installed and tested in accordance with ASTM E814 or UL 1479, with a minimum positive pressure differential of 0.01 inch of water (2.49 Pa). The system shall have an F rating/T rating of not less than 1 hour but not less than the required rating of the floor penetrated.

    Exceptions:

    1. Floor penetrations contained and located within the cavity of a wall above the floor or below the floor do not require a T rating.
    2. Floor penetrations by floor drains, tub drains or shower drains contained and located within the concealed space of a horizontal assembly do not require a T rating.
    3. Floor penetrations of maximum 4-inch (102 mm) nominal diameter metal conduit or tubing penetrating directly into metal-enclosed electrical power switchgear do not require a T rating.
    4. Penetrations in a single concrete floor by steel, ferrous or copper conduits, pipes, tubes or vents with a maximum 6-inch (152 mm) nominal diameter do not require a T rating.
  • CBC § 406.5 High relevance — show source text
    1. Penetrations by listed electrical boxes of any material, provided that such boxes have been tested for use in fire-resistance-rated assemblies and installed in accordance with the instructions included in the listing.
    2. Penetrations of concrete floors or ramps within parking garages or structures constructed in accordance with Sections 406.5 and 406.6 where the areas above and below the penetrations are parking areas.

    714.5.1.1 Fire-resistance-rated assemblies. Through penetrations shall be protected using systems installed as tested in the approved fire-resistance-rated assembly.

    714.5.1.2 Through-penetration firestop system. Through penetrations shall be protected by an approved through-penetration firestop system installed and tested in accordance with ASTM E814 or UL 1479, with a minimum positive pressure differential of 0.01 inch of water (2.49 Pa). The system shall have an F rating/T rating of not less than 1 hour but not less than the required rating of the floor penetrated.

    Exceptions:

    1. Floor penetrations contained and located within the cavity of a wall above the floor or below the floor do not require a T rating.
    2. Floor penetrations by floor drains, tub drains or shower drains contained and located within the concealed space of a horizontal assembly do not require a T rating.
    3. Floor penetrations of maximum 4-inch (102 mm) nominal diameter metal conduit or tubing penetrating directly into metal-enclosed electrical power switchgear do not require a T rating.
    4. Penetrations in a single concrete floor by steel, ferrous or copper conduits, pipes, tubes or vents with a maximum 6-inch (152 mm) nominal diameter do not require a T rating. These penetrating items shall not be limited to the penetration of a single concrete floor, provided that the area of the opening through each floor does not exceed 144 square inches (92,900 mm [2] ).

    714.5.2 Membrane penetrations. Penetrations of membranes that are part of a horizontal assembly shall comply with Section 714.5.1.1 or 714.5.1.2. Where floor/ceiling assemblies are required to have a fire-resistance rating, recessed fixtures shall be installed such that the required fire resistance will not be reduced.

    Exceptions:

    1. Membrane penetrations by steel, ferrous or copper conduits, pipes, tubes or vents, or concrete or masonry items where the annular space is protected either in accordance with Section 714.5.1 or to prevent the free passage of flame and the products of combustion. The aggregate area of the openings through the membrane shall not exceed 100 square inches (64 500 mm [2] ) in any 100 square feet (9.3 m [2] ) of ceiling area in assemblies tested without penetrations.
    2. Ceiling membrane penetrations of maximum 2-hour horizontal assemblies by steel electrical boxes that do not exceed 16 square inches (10 323 mm [2] ) in area, provided that the aggregate area of such penetrations does not exceed 100 square inches (44 500 mm [2] ) in any 100 square feet (9.29 m [2] ) of ceiling area, and the annular space between the ceiling membrane and the box does not exceed [1] / 8 inch (3.2 mm).
    3. Membrane penetrations by electrical boxes of any size or type, that have been listed as part of an opening protective material system for use in horizontal assemblies and are installed in accordance with the instructions included in the listing.
  • CBC § 0.01 High relevance — show source text
    1. Membrane penetrations by boxes other than electrical boxes, provided that such penetrating items and the annular space between the wall membrane and the box, are protected by an approved membrane penetration firestop system installed as tested in accordance with ASTM E814 or UL 1479, with a minimum positive pressure differential of 0.01 inch of water (2.49 Pa), and shall have an F and T rating of not less than the required fire-resistance rating of the wall penetrated and be installed in accordance with their listing.
    2. The annular space created by the penetration of an automatic sprinkler, provided that it is covered by a metal escutcheon plate.
    3. Membrane penetrations of maximum 2-hour fire-resistance-rated walls and partitions by steel electrical boxes that exceed 16 square inches (0.0 103 m [2] ) in area, or steel electrical boxes of any size having an aggregate area through the membrane exceeding 100 square inches (0.0645 m [2] ) in any 100 square feet (9.29 m [2] ) of wall area, provided that such penetrating items are protected by listed putty pads or other listed materials and methods, and installed in accordance with the listing.

    714.4.3 Dissimilar materials. Noncombustible penetrating items shall not connect to combustible items beyond the point of firestopping unless it can be demonstrated that the fire-resistance integrity of the wall is maintained.

    714.5 Horizontal assemblies. Penetrations of a fire-resistance-rated floor, floor/ceiling assembly or the ceiling membrane of a roof/ceiling assembly not required to be enclosed in a shaft by Section 712.1 shall be protected in accordance with Sections 714.5.1 through 714.5.4.

    714.5.1 Through penetrations. Through penetrations of horizontal assemblies shall comply with Section 714.5.1.1 or 714.5.1.2.

    Exceptions:

    1. Penetrations by steel, ferrous or copper conduits, pipes, tubes or vents or concrete or masonry items through a single fire-resistance-rated floor assembly where the annular space is protected with materials that prevent the passage of flame and hot gases sufficient to ignite cotton waste when subjected to ASTM E119 or UL 263 time-temperature fire conditions under a minimum positive pressure differential of 0.01 inch of water (2.49 Pa) at the location of the penetration for the time period equivalent to the fire-resistance rating of the construction penetrated. Penetrating items

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    with a maximum 6-inch (152 mm) nominal diameter shall not be limited to the penetration of a single fire-resistancerated floor assembly, provided that the aggregate area of the openings through the assembly does not exceed 144 square inches (92 900 mm [2] ) in any 100 square feet (9.3 m [2] ) of floor area. 2. Penetrations in a single concrete floor by steel, ferrous or copper conduits, pipes, tubes or vents with a maximum 6inch (152 mm) nominal diameter, provided that the concrete, grout or mortar is installed the full thickness of the floor or the thickness required to maintain the fire-resistance rating.

  • CBC § 3.2 High relevance — show source text

    The annular space between the wall membrane and the box shall not exceed [1] / 8 inch (3.2 mm). Such boxes on opposite sides of the wall or partition shall be separated by one of the following: 1.1. By a horizontal distance of not less than 24 inches (610 mm) where the wall or partition is constructed with individual noncommunicating stud cavities. 1.2. By a horizontal distance of not less than the depth of the wall cavity where the wall cavity is filled with cellulose loose-fill, rockwool or slag mineral wool insulation. 1.3. By solid fireblocking in accordance with Section 718.2.1. 1.4. By protecting both outlet boxes with listed putty pads. 1.5. By other listed materials and methods. 2. Membrane penetrations by listed electrical boxes of any material, provided that such boxes have been tested for use in fire-resistance-rated assemblies and are installed in accordance with the instructions included in the listing. The annular space between the wall membrane and the box shall not exceed [1] / 8 inch (3.2 mm) unless listed otherwise. Such boxes on opposite sides of the wall or partition shall be separated by one of the following: 2.1. By the horizontal distance specified in the listing of the electrical boxes. 2.2. By solid fireblocking in accordance with Section 718.2.1. 2.3. By protecting both boxes with listed putty pads. 2.4. By other listed materials and methods. 3. Membrane penetrations by electrical boxes of any size or type, that have been listed as part of a wall opening protective material system for use in fire-resistance-rated assemblies and are installed in accordance with the instructions included in the listing. 4. Membrane penetrations by boxes other than electrical boxes, provided that such penetrating items and the annular space between the wall membrane and the box, are protected by an approved membrane penetration firestop system installed as tested in accordance with ASTM E814 or UL 1479, with a minimum positive pressure differential of 0.01 inch of water (2.49 Pa), and shall have an F and T rating of not less than the required fire-resistance rating of the wall penetrated and be installed in accordance with their listing. 5. The annular space created by the penetration of an automatic sprinkler, provided that it is covered by a metal escutcheon plate. 6. Membrane penetrations of maximum 2-hour fire-resistance-rated walls and partitions by steel electrical boxes that exceed 16 square inches (0.0 103 m [2] ) in area, or steel electrical boxes of any size having an aggregate area through the membrane exceeding 100 square inches (0.0645 m [2] ) in any 100 square feet (9.29 m [2] ) of wall area, provided that such penetrating items are protected by listed putty pads or other listed materials and methods, and installed in accordance with the listing.

    714.4.3 Dissimilar materials. Noncombustible penetrating items shall not connect to combustible items beyond the point of firestopping unless it can be demonstrated that the fire-resistance integrity of the wall is maintained.

    714.5 Horizontal assemblies. Penetrations of a fire-resistance-rated floor, floor/ceiling assembly or the ceiling membrane of a roof/ceiling assembly not required to be enclosed in a shaft by Section 712.1 shall be protected in accordance with Sections 714.5.1 through 714.5.4.

  • CBC § 3.2 High relevance — show source text

    1. Membrane penetrations by listed electrical boxes of any material, provided that such boxes have been tested for use in fire-resistance-rated assemblies and are installed in accordance with the instructions included in the listing. The annular space between the ceiling membrane and the box shall not exceed [1] / 8 inch (3.2 mm) unless listed otherwise.

    2. The annular space created by the penetration of a fire sprinkler, provided that it is covered by a metal escutcheon plate.

    3. Noncombustible items that are cast into concrete building elements and that do not penetrate both top and bottom surfaces of the element.

    4. The ceiling membrane of a maximum 2-hour fire-resistance-rated horizontal assembly is permitted to be interrupted with the double wood top plate of a wall assembly that is sheathed with Type X gypsum wallboard, provided that all penetrating items through the double top plates are protected in accordance with Section 714.5.1.1 or 714.5.1.2 and the ceiling membrane is tight to the top plates.

    5. Ceiling membrane penetrations by listed luminaires (light fixtures) or by luminaires protected with listed materials, which have been tested for use in fire-resistance-rated assemblies and are installed in accordance with the instructions included in the listing.

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    FIRE AND SMOKE PROTECTION FEATURES

    714.5.3 Dissimilar materials. Noncombustible penetrating items shall not connect to combustible materials beyond the point of firestopping unless it can be demonstrated that the fire-resistance integrity of the horizontal assembly is maintained.

    714.5.4 Penetrations in smoke barriers. Penetrations in smoke barriers shall be protected by an approved through-penetration firestop system installed and tested in accordance with the requirements of UL 1479 for air leakage. The L rating of the system measured at 0.30 inch of water (74.7 Pa) in both the ambient temperature and elevated temperature tests shall not exceed either of the following:

    1. 5.0 cfm per square foot (0.025 m [3] / s × m [2] ) of penetration opening for each through-penetration firestop system.
    2. A total cumulative leakage of 50 cfm (0.024 m [3] /s) for any 100 square feet (9.3 m [2] ) of wall area, or floor area.

    714.6 Nonfire-resistance-rated assemblies. Penetrations of nonfire-resistance-rated floor or floor/ceiling assemblies or the ceiling membrane of a nonfire-resistance-rated roof/ceiling assembly shall meet the requirements of Section 713 or shall comply with Section 714.6.1 or 714.6.2.

    714.6.1 Noncombustible penetrating items. Noncombustible penetrating items that connect not more than five stories are permitted, provided that the annular space is filled to resist the free passage of flame and the products of combustion with an approved noncombustible material or with a fill, void or cavity material that is tested and classified for use in through-penetration firestop systems.

    714.6.2 Penetrating items. Penetrating items that connect not more than two stories are permitted, provided that the annular space is filled with an approved material to resist the free passage of flame and the products of combustion.

    SECTION 715—JOINTS AND VOIDS

  • CBC § 713.6 High relevance — show source text

    713.6 Exterior walls. Where exterior walls serve as a part of a required shaft enclosure, such walls shall comply with the requirements of Section 705 for exterior walls and the fire-resistance-rated enclosure requirements shall not apply.

    Exception: Exterior walls required to be fire-resistance rated in accordance with Section 1021.2 for exterior egress balconies, Section 1023.7 for interior exit stairways and ramps and Section 1027.6 for exterior exit stairways and ramps.

    713.7 Openings. Openings in a shaft enclosure shall be protected in accordance with Section 716 as required for fire barriers. Doors shall be self- or automatic-closing by smoke detection in accordance with Section 716.2.6.6.

    713.7.1 Prohibited openings. Openings other than those necessary for the purpose of the shaft shall not be permitted in shaft enclosures.

    713.8 Penetrations. Penetrations in a shaft enclosure shall be protected in accordance with Section 714 as required for fire barriers or horizontal assemblies or both. Structural elements, such as beams or joists, where protected in accordance with Section 714 shall be permitted to penetrate a shaft enclosure.

    713.8.1 Prohibited penetrations. Penetrations other than those necessary for the purpose of the shaft shall not be permitted in shaft enclosures.

    Exception: Membrane penetrations shall be permitted on the outside of shaft enclosures. Such penetrations shall be protected in accordance with Section 714.4.2.

    713.9 Joints. Joints in a shaft enclosure shall comply with Section 715.

    713.10 Duct and air transfer openings. Penetrations of a shaft enclosure by ducts and air transfer openings shall comply with Section 717.

    713.11 Enclosure at the bottom. Shafts that do not extend to the bottom of the building or structure shall comply with one of the following:

    1. Be enclosed at the lowest level with construction of the same fire-resistance rating as the lowest floor through which the shaft passes, but not less than the rating required for the shaft enclosure.

    2. Terminate in a room having a use related to the purpose of the shaft. The room shall be separated from the remainder of the building by fire barriers constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both. The fire-resistance rating and opening protectives shall be not less than the protection required for the shaft enclosure.

    3. Be protected by approved fire dampers installed in accordance with their listing at the lowest floor level within the shaft enclosure.

    Exceptions:

    1. The fire-resistance-rated room separation is not required, provided that the only openings in or penetrations of the shaft enclosure to the interior of the building occur at the bottom. The bottom of the shaft shall be closed off around the penetrating items with materials permitted by Section 718.3.1 for draftstops, or the room shall be provided with an approved automatic sprinkler system.
    2. A shaft enclosure containing a waste or linen chute shall not be used for any other purpose and shall discharge in a room protected in accordance with Section 713.13.4.
    3. The fire-resistance-rated room separation and the protection at the bottom of the shaft are not required provided that there are no combustibles in the shaft and there are no openings or other penetrations through the shaft enclosure to the interior of the building.
  • CBC § 713.13.2 High relevance — show source text

    713.13.2 Materials. A shaft enclosure containing a waste, recycling, or linen chute shall be constructed of materials as permitted by the building type of construction.

    713.13.3 Chute access rooms. Access openings for waste, recycling or linen chutes shall be located in rooms or compartments enclosed by not less than 1-hour fire barriers constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both. Openings into the access rooms shall be protected by opening protectives having a fire protection rating of not less than [3] / 4 hour. Doors shall be self- or automatic-closing upon the detection of smoke in accordance with Section 716.2.6.6. The room or compartment shall be configured to allow the access door to the room or compartment to close and latch with the access panel to the chute in any position.

    713.13.4 Chute discharge room. Waste, recycling or linen chutes shall discharge into an enclosed room separated by fire barriers with a fire-resistance rating not less than the required fire rating of the shaft enclosure and constructed in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both. Openings into the discharge room from the remainder of the building shall be protected by opening protectives having a fire protection rating based on the fire rating of the shaft enclosure in accordance with Tables 716.1(2) and 716.1(3). Doors shall be self- or automatic-closing upon the detection of smoke in accordance with Section 716.2.6.6. Waste chutes shall not terminate in an incinerator room. Waste and linen rooms that are not provided with chutes need only comply with Table 509.1.

    713.13.5 Incinerator room. Incinerator rooms shall comply with Table 509.1.

    713.13.6 Automatic sprinkler system. An approved automatic sprinkler system shall be installed in accordance with Section 903.2.11.2.

    713.14 Elevator, dumbwaiter and other hoistways. A hoistway for elevators, dumbwaiters and other vertical devices shall comply with Section 712. Where the hoistway is required to be enclosed, it shall be constructed as a shaft enclosure in accordance with Section 713 and Chapter 30.

    SECTION 714—PENETRATIONS

    714.1 Scope. The provisions of this section shall govern the materials and methods of construction used to protect through penetrations and membrane penetrations of horizontal assemblies and fire-resistance-rated wall assemblies.

    714.1.1 Ducts and air transfer openings. Penetrations of fire-resistance-rated walls by ducts that are not protected with dampers shall comply with Sections 714.3 through 714.4.3. Penetrations of horizontal assemblies not protected with a shaft as permitted by Section 717.6, and not required to be protected with fire dampers by other sections of this code, shall comply with Sections 714.5 through 714.6.2. Ducts and air transfer openings that are protected with dampers shall comply with Section 717.

    714.2 Installation. A listed penetration firestop system shall be installed in accordance with the manufacturer’s installation instructions and the listing criteria.

  • CBC § 3.6.3 High relevance — show source text

    R302.3.6.3 Other penetrations. Penetrations through the walls, ceiling and floor-level separation required in Section R302.3.6 shall be protected as required by Section R302.11, Item 4.

    R302.4 Dwelling unit rated penetrations. Penetrations of wall or floor-ceiling assemblies required to be fire-resistance rated in accordance with Section R302.2 or R302.3 shall be protected in accordance with this section.

    R302.4.1 Through penetrations. Through penetrations of fire-resistance-rated wall or floor assemblies shall comply with Section R302.4.1.1 or R302.4.1.2.

    Exceptions:

    1. Where the penetrating items are steel, ferrous or copper pipes, tubes or conduits, the annular space shall be protected as follows: 1.1. In concrete or masonry wall or floor assemblies, concrete, grout or mortar shall be permitted where installed to the full thickness of the wall or floor assembly or the thickness required to maintain the fire-resistance rating, provided that both of the following are complied with: 1.1.1. The nominal diameter of the penetrating item is not more than 6 inches (152 mm). 1.1.2. The area of the opening through the wall does not exceed 144 square inches (92 900 mm [2] ).

    3-26 2025 CALIFORNIA RESIDENTIAL CODE

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

    BUILDING PLANNING

    1.2. The material used to fill the annular space shall prevent the passage of flame and hot gases sufficient to ignite cotton waste where subjected to ASTM E119 or UL 263 time temperature fire conditions under a positive pressure differential of not less than 0.01 inch of water (3 Pa) at the location of the penetration for the time period equivalent to the fire-resistance rating of the construction penetrated. 2. The annular space created by the penetration of water-filled fire sprinkler piping, provided that the annular space is filled using a material complying with Item 1.2 of Exception 1.

    R302.4.1.1 Fire-resistance-rated assembly. Penetrations shall be installed as tested in the approved fire-resistance-rated assembly.

    R302.4.1.2 Penetration firestop system. Penetrations shall be protected by an approved penetration firestop system installed as tested in accordance with ASTM E814 or UL 1479, with a positive pressure differential of not less than 0.01 inch of water (3 Pa) and shall have an F rating of not less than the required fire-resistance rating of the wall or floor-ceiling assembly penetrated.

    R302.4.2 Membrane penetrations. Membrane penetrations shall comply with Section R302.4.1. Where walls are required to have a fire-resistance rating, recessed fixtures shall be installed so that the required fire-resistance rating will not be reduced.

    Exceptions:

    1. Membrane penetrations of not more than 2-hour fire-resistance-rated walls and partitions by steel electrical boxes that do not exceed 16 square inches (0.0103 m [2] ) in area provided that the aggregate area of the openings through the membrane does not exceed 100 square inches (0.0645 m [2] ) in any 100 square feet (9.29 m [2] ) of wall area. The annular space between the wall membrane and the box shall not exceed [1] / 8 inch (3.1 mm).
  • CBC § 712.1.16 High relevance — show source text

    712.1.16 Openings otherwise permitted. Vertical openings shall be permitted where allowed by other sections of this code.

    SECTION 713—SHAFT ENCLOSURES

    713.1 General. The provisions of this section shall apply to shafts required to protect openings and penetrations through floor/ceiling and roof/ceiling assemblies. Interior exit stairways and ramps shall be enclosed in accordance with Section 1023.

    713.2 Construction. Shaft enclosures shall be constructed as fire barriers in accordance with Section 707 or horizontal assemblies in accordance with Section 711, or both.

    713.3 Materials. Shaft enclosures shall be of materials permitted by the building type of construction.

    2025 CALIFORNIA BUILDING CODE 7-21

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

    FIRE AND SMOKE PROTECTION FEATURES

    713.4 Fire-resistance rating. Shaft enclosures shall have a fire-resistance rating of not less than 2 hours where connecting four stories or more, and not less than 1 hour where connecting less than four stories. The number of stories connected by the shaft enclosure shall include any basements but not any mezzanines. Shaft enclosures shall have a fire-resistance rating not less than the floor assembly penetrated, but need not exceed 2 hours. Shaft enclosures shall meet the requirements of Section 703.2.1.1.

    Exception: Shafts having a reduced fire-resistance rating in high-rise buildings in accordance with Section 403.2.1.2.

    713.5 Continuity. Shaft enclosures shall be constructed as fire barriers in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both, and shall have continuity in accordance with Section 707.5 for fire barriers or Section 711.2.2 for horizontal assemblies, as applicable.

    713.6 Exterior walls. Where exterior walls serve as a part of a required shaft enclosure, such walls shall comply with the requirements of Section 705 for exterior walls and the fire-resistance-rated enclosure requirements shall not apply.

    Exception: Exterior walls required to be fire-resistance rated in accordance with Section 1021.2 for exterior egress balconies, Section 1023.7 for interior exit stairways and ramps and Section 1027.6 for exterior exit stairways and ramps.

    713.7 Openings. Openings in a shaft enclosure shall be protected in accordance with Section 716 as required for fire barriers. Doors shall be self- or automatic-closing by smoke detection in accordance with Section 716.2.6.6.

    713.7.1 Prohibited openings. Openings other than those necessary for the purpose of the shaft shall not be permitted in shaft enclosures.

    713.8 Penetrations. Penetrations in a shaft enclosure shall be protected in accordance with Section 714 as required for fire barriers or horizontal assemblies or both. Structural elements, such as beams or joists, where protected in accordance with Section 714 shall be permitted to penetrate a shaft enclosure.

    713.8.1 Prohibited penetrations. Penetrations other than those necessary for the purpose of the shaft shall not be permitted in shaft enclosures.

    Exception: Membrane penetrations shall be permitted on the outside of shaft enclosures. Such penetrations shall be protected in accordance with Section 714.4.2.

    713.9 Joints. Joints in a shaft enclosure shall comply with Section 715.

Frequently asked questions

Do I always need a listed firestop product for every penetration?

Not always. You can either install the penetrating item as tested in the approved fire‑resistance‑rated assembly or use an approved/listed through‑penetration firestop tested to ASTM E814 / UL 1479. Specific exceptions (for example limited steel pipe in concrete walls, small electrical boxes under aggregate limits, etc.) permit alternative treatments; check the applicable exception text. § 714.4.1.1–.2 and attendant exceptions.

What does the code mean by the 0.01 in. water pressure requirement?

That is the minimum positive pressure differential applied during the ASTM E814 / UL 1479 time‑temperature test required by the code for through‑penetration firestop systems. Listed systems will identify the test criteria and installations must follow their listing. § 714.4.1.2; § 714.2.

Can I just grout small gaps around pipes in any wall?

No. The grout/full‑depth concrete fill exception applies only in concrete or masonry walls and only for steel/ferrous/copper items ≤ 6‑in nominal diameter and openings ≤ 144 in². Otherwise use a listed firestop or an assembly tested with the penetration. § 714.4.1 Exception.

Are smoke barriers treated differently than ordinary fire‑resistance walls?

Yes. Penetrations in smoke barriers must meet UL 1479 air leakage criteria (L‑rating) tested at 0.30 in. water and must meet the leakage limits specified in § 714.5.4 (per‑penetration and aggregate limits). § 714.5.4.

If a penetration is protected by a listed product, can the installer deviate from the listed annular gap or backing depth?

No. A listed penetration firestop must be installed in accordance with the manufacturer’s installation instructions and the listing criteria — deviations can void the tested performance and are not compliant. § 714.2.

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