CBC · California Building Code

Limitations for ducts, piping and electrical components in Types I/II

The CBC permits nonmetallic ducts, combustible piping and wiring with combustible insulation in Type I/II buildings only if they are installed to the detailed requirements of the California Mechanical, Plumbing or Electrical Codes; the CBC sections § 603.1.1–.3 are permissive gateways, but the specialty codes provide the material, listing and installation limits.

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Last reviewed: July 5, 2026

What the code requires — 2-4 sentences

The CBC allows certain combustible components inside buildings of Type I and II construction—but only when they are installed in strict conformance with the other California codes that govern those systems. Specifically, nonmetallic ducts are permitted where installed per the California Mechanical Code (see § 603.1.1), combustible piping and plumbing fixtures are permitted where installed per the California Mechanical and California Plumbing Codes (see § 603.1.2), and electrical wiring methods having combustible insulation, tubing, raceways and related components are permitted where installed per this code and the California Electrical Code (see § 603.1.3).

Requirements in detail

Overview / how to read § 603.1.x

  • The three subsections are permissive, not prescriptive: CBC § 603.1.1–603.1.3 allow the listed combustible materials only when those materials and installations comply with the applicable specialty code (Mechanical, Plumbing, Electrical). The CBC does not reproduce the specialty‑code technical limits; it defers to them.

Decision‑relevant quick table

Component What the CBC allows (plain English) Where you must check for technical limits Code reference
Ducts Nonmetallic ducts may be used in Type I/II when installed in compliance with the California Mechanical Code California Mechanical Code for allowable materials, listing, plenum requirements, flame/spread, installation details § 603.1.1
Piping & plumbing fixtures Combustible piping materials and plumbing fixtures may be used when installed per the California Mechanical Code and California Plumbing Code California Mechanical Code and California Plumbing Code for materials, burial/penetration protection, insulation, corrosion protection § 603.1.2
Electrical components Wiring methods with combustible insulation, tubing, raceways and related components may be used when installed per the California Electrical Code and this code California Electrical Code for wiring methods, hazardous‑location requirements, raceway types, separation and enclosures § 603.1.3

(The CBC text is short and delegates the detailed performance and listing requirements to the referenced specialty codes; see the citations above.)

Ducts — specific implementation points

  • The CBC authorizes nonmetallic ducts only by reference to the California Mechanical Code; therefore, acceptability depends on the CMC listing, flame‑spread, smoke development criteria, and any plenum rules in the CMC. § 603.1.1 functions as a gateway — it does not itself specify allowable materials or installation details.
  • Where ducts penetrate fire‑resistance‑rated assemblies or are part of smoke control/shaft systems, the CBC’s fire‑separation and damper rules apply (see Sections governing penetrations and dampers). For example, dampers, penetration protection and related installation rules are called out in the fire‑protection chapters and the Mechanical Code.

Piping & plumbing — specific implementation points

  • CBC § 603.1.2 permits combustible piping only where the California Mechanical and California Plumbing Codes’ limitations are met (materials, burial, protection against corrosion/mechanical damage, expansion provision, and sealing of penetrations). The CPC contains specific installation and penetration protection language (for example, CPC § 312.7 addresses protection of piping penetrations of fire‑resistance assemblies).
  • For piping in concealed spaces or passing through rated assemblies, ensure the required penetration protection/caulking/packaging is provided as required by the CBC penetration sections and the CPC.

Electrical — specific implementation points

  • CBC § 603.1.3 permits the use of electrical wiring methods that include combustible insulation or combustible raceways only when installed according to this code and the California Electrical Code (CEC). The CEC contains the technical criteria for allowable cable types, conduit, raceways, junction box enclosures, hazardous location requirements, and fire‑resistance of penetrations.
  • Where electrical equipment is located in or adjacent to flammable or dust‑laden atmospheres, the Fire Code and CEC impose special hazardous‑location (Class/Division) requirements and listing criteria. See California Fire Code provisions on flammable‑vapor/dust areas for context and grounding to CEC requirements. file

Intersections with other CBC provisions and site conditions

  • Concealed spaces in Type I/II have their own limits: combustible materials in concealed spaces are limited (and the CBC prescribes sprinklering or noncombustible insulation or gypsum sheathings as mitigation measures). If nonmetallic ducts or combustible piping are to be placed in concealed spaces or plenums, verify compliance with § 602.4.4.3 and related provisions.
  • Controls and wiring: the CBC’s fire/damper provisions prohibit installation of mechanical, electrical and plumbing controls inside air duct systems except for wiring directly associated with the air distribution system and installed per the Mechanical Code and as short as practicable. Controls shall not be installed through dampers except as permitted by manufacturer/listing. (§ 717.2.4 and related).

Exceptions & special cases

  • The CBC itself provides no detailed “list” of allowed combustible duct or cable materials — it defers to the specialty code(s). That means: if the Mechanical/Plumbing/Electrical Code allows a combustible product and the product is listed for that application, the CBC will permit it in Type I/II (subject to any other CBC requirements such as fire‑resistance, concealment rules or sprinklering).
  • Concealed spaces: where concealed spaces are not sprinklered, the CBC may require noncombustible insulation, full sheathing, or automatic sprinklers (see § 602.4.4.3). If you intend to place combustible piping/ducts in those spaces, the space‑level protections must be satisfied.
  • Duct penetrations of rated assemblies: ducts that penetrate rated assemblies may require fire dampers, smoke dampers or listed penetration protection per the applicable sections (see Part 7 fire‑protection features); manufacturer listing prevails for installation exceptions.
  • Hazardous atmospheres: the Fire Code and CEC may impose stricter wiring/equipment requirements where vapors, residues, dust or spray booths are involved; ordinary permissiveness under § 603.1.3 does not override hazardous‑location rules. file

If you need the precise material criteria (e.g., allowed flame‑spread / smoke‑developed numbers for a duct lining, listing test standards, or exact conduit types allowed), those are in the California Mechanical, Plumbing and Electrical Codes rather than in § 603.1.1–.3; the retrieved CBC excerpts do not include the specialty‑code text for those detailed limits, so you must consult the referenced codes for the technical thresholds.

Common mistakes

  • Treating § 603.1.1–.3 as a standalone approval and skipping the specialty codes — the CBC only permits these materials subject to the other codes’ limits.
  • Installing controls, junctions or equipment inside ducts or through dampers contrary to § 717.2.4 (wiring/controls in ducts are generally prohibited except in narrow, directly associated, code‑compliant situations).
  • Forgetting concealed‑space protections: allowing combustible materials into an unsprinklered concealed space without meeting the CBC’s mitigation options in § 602.4.4.3.
  • Failing to treat hazardous areas correctly: using ordinary wiring or ducts in areas subject to flammable vapors or dust without complying with the Fire Code/CEC hazardous‑location requirements. file
  • Assuming flexible or nonmetallic components are permitted in plenums or smoke control systems without confirming the specialty code listing and performance. The CBC defers this determination to the specialty code(s).

Worked example — concrete scenario

Scenario: You are the design professional for a Type IIA, 4‑story office building. The HVAC design calls for a return/transfer air path using flexible, listed nonmetallic ductwork routed through an interstitial concealed ceiling plenum above the tenant space. You also plan to run low‑voltage control wiring and one short raceway with combustible jacketed cable adjacent to the ducts.

Step 1 — CBC permissibility check:

  • CBC § 603.1.1 allows nonmetallic ducts in Type I/II when installed per the California Mechanical Code, so the proposal is not barred by the CBC itself.

Step 2 — Plenum & concealed‑space requirements:

  • Because the ducts run in a concealed plenum, check § 602.4.4.3: combustible materials in concealed spaces are controlled; if the space is not sprinklered you must satisfy the CBC options (sprinkle the space, use noncombustible insulation, or fully sheath combustible surfaces) before installing combustible duct.

Step 3 — Mechanical Code listing and plenum suitability:

  • Consult the California Mechanical Code for whether that flexible nonmetallic duct is listed for plenum use or for return‑air plenums—if it is not listed for plenum use, the CMC will not permit it even though § 603.1.1 allows nonmetallic ducts in principle. (The CBC excerpt defers the detailed limit to the CMC; that detail is not in the retrieved CBC text.)

Step 4 — Controls and wiring:

  • Do not place mechanical/electrical/plumbing controls inside the duct (CBC § 717.2.4 prohibits controls in air duct systems except in restricted situations). If you need control wiring adjacent to or penetrating ductwork, keep wiring runs short and follow the CMC/CEC criteria; do not run junctions or control devices inside the duct.

Step 5 — Penetrations & firestopping:

  • Any duct or piping penetration of rated floor/ceiling or shaft assemblies will require the penetration protection specified in the CBC (penetration/penalty sections and referenced testing/listing). Consult Section 714 and the Mechanical/Plumbing codes for the specific firestop systems to use; the CBC points you to those penetration requirements. file

Conclusion for the scenario: You can proceed only after (a) verifying the proposed nonmetallic duct is listed/allowed for a plenum in the California Mechanical Code, (b) satisfying the concealed‑space treatment required by § 602.4.4.3 (sprinklering or noncombustible treatment), (c) avoiding controls inside ducts per § 717.2.4, and (d) providing listed penetration/firestop systems at rated assemblies. filefile

Related provisions (CBC and related code sections)

  • § 603.1.1 — Ducts (delegates to the California Mechanical Code).
  • § 603.1.2 — Piping and plumbing fixtures (delegates to California Mechanical and Plumbing Codes). file
  • § 603.1.3 — Electrical (delegates to the California Electrical Code).
  • § 602.4.4.3 — Concealed spaces protections and options (sprinkler/insulation/sheathing).
  • § 717.2.4 — Mechanical, electrical and plumbing controls not permitted in air duct systems (and related damper wiring rules).
  • Sections 714 / 717 and the fire‑protection chapters — for penetration protection, dampers, and dampers’ installation/listing requirements.
  • California Plumbing Code § 312.7 (and related CPC sections) — protection of piping penetrations and piping installation requirements.
  • California Fire Code sections on flammable vapors and dust‑producing operations — for electrical equipment and wiring in hazardous or dust‑laden atmospheres. file

Code references

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

  • CBC § 603.1.1 High relevance — show source text

    603.1.1 Ducts. The use of nonmetallic ducts shall be permitted where installed in accordance with the limitations of the California Mechanical Code .

    603.1.2 Piping and plumbing fixtures. The use of combustible piping materials and plumbing fixtures shall be permitted where installed in accordance with the limitations of the California Mechanical Code and the California Plumbing Code .

    603.1.3 Electrical. The use of electrical wiring methods with combustible insulation, tubing, raceways and related components shall be permitted where installed in accordance with the limitations of this code and the California Electrical Code.

    6-8 2025 CALIFORNIA BUILDING CODE

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

    CALIFORNIA BUILDING CODE – MATRIX ADOPTION TABLE

    CHAPTER 7 – FIRE AND SMOKE PROTECTION FEATURES

    (Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)

    Adopting agency BSC BSC-
    CG    		 SFM HCD Col6 Col7 DSA Col9 Col10 OSHPD Col12 Col13 Col14 Col15 Col16 Col17 BSCC DPH AGR DWR CEC CA SL SLC
    Adopting agency BSC BSC-
    CG    		 SFM 1 2 1/AC AC SS SS/CC 1 1R 2 3 4 5 6 6 6 6 6 6 6 6 6
    Adopt entire chapter X X X X X X X X X X
    Adopt entire chapter as
    amended (amended sections
    listed below)    		 X X X
    Adopt only those sections
    that are listed below
    Chapter / Section
    704.5.1 X
    705.2.3.2 X
    705.5 X
    Table 705.5 X
    705.13 X
    Table 706.4 X
    Table 707.3.10 X
    707.4 X
    708.1 X
    708.3 X
    709.3 X
    709.5 X
    709.5.1 X
    710.
  • CBC § 602.4.4.4 High relevance — show source text
    1. Heavy timber as permitted by Note c to Table 601 and Sections 602.4.4.4 and 705.2.3.1.
    2. Aggregates, component materials and admixtures as permitted by Section 703.2.1.2.
    3. Sprayed fire-resistive materials and intumescent fire-resistive materials, determined on the basis of fire resistance tests in accordance with Section 703.2 and installed in accordance with Sections 1705.15 and 1705.16, respectively.

    2025 CALIFORNIA BUILDING CODE 6-7

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

    �

    TYPES OF CONSTRUCTION

    1. Materials used to protect penetrations in fire-resistance-rated assemblies in accordance with Section 714.
    2. Materials used to protect joints in fire-resistance-rated assemblies in accordance with Section 715.
    3. Materials allowed in the concealed spaces of buildings of Types I and II construction in accordance with Section 718.5.
    4. Materials exposed within plenums complying with the California Mechanical Code .
    5. Wall construction of freezers and coolers of less than 1,000 square feet (92.9 m [2] ), in size, lined on both sides with noncombustible materials and the building is protected throughout with an automatic sprinkler system in accordance with Section 903.3.1.1.
    6. Wood nailers for parapet flashing and roof cants.
    7. Vapor retarders as required by Section 1404.3.

    603.1.1 Ducts. The use of nonmetallic ducts shall be permitted where installed in accordance with the limitations of the California Mechanical Code .

    603.1.2 Piping and plumbing fixtures. The use of combustible piping materials and plumbing fixtures shall be permitted where installed in accordance with the limitations of the California Mechanical Code and the California Plumbing Code .

    603.1.3 Electrical. The use of electrical wiring methods with combustible insulation, tubing, raceways and related components shall be permitted where installed in accordance with the limitations of this code and the California Electrical Code.

    6-8 2025 CALIFORNIA BUILDING CODE

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

    CALIFORNIA BUILDING CODE – MATRIX ADOPTION TABLE

    CHAPTER 7 – FIRE AND SMOKE PROTECTION FEATURES

    (Matrix Adoption Tables are nonregulatory, intended only as an aid to the code user. See Chapter 1 for state agency authority and building applications.)

  • CBC § 5-8 Medium relevance — show source text

    505 Mezzanines and Equipment Platforms. . . . . . . . . . . . 5-8

    506 Building Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9

    507 Unlimited Area Buildings. . . . . . . . . . . . . . . . . . . . . . . 5-13

    508 Mixed Use and Occupancy. . . . . . . . . . . . . . . . . . . . . . 5-15

    509 Incidental Uses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-18

    510 Special Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19

    CHAPTER 6 TYPES OF CONSTRUCTION . . . . . . . . . . . . . . . 6-1

    601 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

    602 Construction Classification. . . . . . . . . . . . . . . . . . . . . . 6-3

    603 Combustible Material in Types I and II Construction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7

    CHAPTER 7 FIRE AND SMOKE PROTECTION FEATURES. . 7-1

    701 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3

    702 Multiple-Use Fire Assemblies . . . . . . . . . . . . . . . . . . . . 7-3

    703 Fire-Resistance Ratings and Fire Tests . . . . . . . . . . . . 7-3

    704 Fire-Resistance Rating of Structural Members . . . . . 7-4

    705 Exterior Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-6

    706 Fire Walls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-12

    707 Fire Barriers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-14

    708 Fire Partitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-16

    709 Smoke Barriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-17

    710 Smoke Partitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-18

    711 Floor and Roof Assemblies. . . . . . . . . . . . . . . . . . . . . . 7-19

  • CBC § 4-66 Medium relevance — show source text

    451 Reserved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-66

    452 School Facilities for Kindergarten Through 12th Grade and Group E Child Care. . . . . . . . . . . . . . . . . . . . . . . . .4-66

    453 Group L [SFM] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-67

    454 Reserved. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-70

    455 Large Family Day-Care Homes [SFM] . . . . . . . . . . . . . .4-70

    CHAPTER 5 GENERAL BUILDING HEIGHTS AND AREAS . . 5-1

    501 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

    502 Building Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3

    503 General Building Height and Area Limitations . . . . . 5-3

    504 Building Height and Number of Stories . . . . . . . . . . . 5-4

    505 Mezzanines and Equipment Platforms. . . . . . . . . . . . 5-8

    506 Building Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-9

    507 Unlimited Area Buildings. . . . . . . . . . . . . . . . . . . . . . . 5-13

    508 Mixed Use and Occupancy. . . . . . . . . . . . . . . . . . . . . . 5-15

    509 Incidental Uses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-18

    510 Special Provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-19

    CHAPTER 6 TYPES OF CONSTRUCTION . . . . . . . . . . . . . . . 6-1

    601 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3

    602 Construction Classification. . . . . . . . . . . . . . . . . . . . . . 6-3

    603 Combustible Material in Types I and II Construction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7

    CHAPTER 7 FIRE AND SMOKE PROTECTION FEATURES. . 7-1

  • CBC § 312.0 Medium relevance — show source text

    Note: Accessory dwelling units are not required to have inde- pendent service utility (drainage) connections provided they meet the specific requirements in Government Code Section 65852.2.

    312.0 Protection of Piping, Tubing, Materials, and Structures.

    312.1 General. Piping passing under or through walls shall be protected from breakage. Piping passing through or under cinders or other corrosive materials shall be protected from external corrosion in an approved manner. Approved provisions shall be made for expansion of hot water piping. Voids around piping passing through concrete floors on the ground shall be sealed.

    312.2 Installation. Piping in connection with a plumbing system shall be so installed that piping or connections will not be subject to undue strains or stresses, and provisions shall be made for expansion, contraction, and structural settlement. No plumbing piping shall be directly embedded in concrete or masonry. No structural member shall be seriously weakened or impaired by cutting, notching, or otherwise, as defined in the California Building Code or California Residential Code . 312.3 Building Sewer and Drainage Piping. No building sewer or other drainage piping or part thereof, constructed of materials other than those approved for use under or within a building, shall be installed under or within 2 feet (610 mm) of a building or structure, or less than 1 foot (305 mm) below the surface of the ground. 312.4 Corrosion, Erosion, and Mechanical Damage. Piping subject to corrosion, erosion, or mechanical damage shall be protected in an approved manner. 312.5 Protectively Coated Pipe. Protectively coated pipe or tubing shall be inspected and tested, and a visible void, damage, or imperfection to the pipe coating shall be repaired in an approved manner. 312.6 Freezing Protection. No water, soil, or waste pipe shall be installed or permitted outside of a building, in attics or crawl spaces, or in an exterior wall unless, where necessary, adequate provision is made to protect such pipe from freezing. 312.7 Fire-Resistant Construction. Piping penetrations of fire-resistance-rated walls, partitions, floors, floor/ceiling assemblies, roof/ceiling assemblies, or shaft enclosures shall be protected in accordance with the requirements of the Cal- ifornia Building Code or California Residential Code . 312.8 Waterproofing of Openings. Joints at the roof around pipes, ducts, or other appurtenances shall be made watertight by the use of lead, copper, galvanized iron, or other approved flashings or flashing material. Exterior wall openings shall be made watertight. Counterflashing shall not restrict the required internal cross-sectional area of the vent. 312.9 Steel Nail Plates. Plastic piping or tubing, and copper or copper alloy piping or tubing penetrating framing members to within 1 inch (25.4 mm) of the exposed framing shall be protected by steel nail plates not less than No. 18 gauge (0.0478 inches) (1.2 mm) in thickness. The steel nail plate shall extend along the framing member not less than 1 [1] ⁄ 2 inches (38 mm) beyond the outside diameter of the pipe or tubing. Fuel gas piping shall be protected in accordance with Section 1210.4.3.

  • CBC § 2.3 Medium relevance — show source text

    2.3, 106.2.6, 108.5, 110.2, 113.2, 115.5, 202, 301.1, 301.3, 302.2, 302.2.1, 302.4, 304, 307.1, 308.1, 309.1, 501.1, 501.1.1, 502.1, 502.3, 502.4, 503, 504.1, 601.1, 602, 603, 604, 1101.3, 1103.1, 1103.2, 1301.1, 1301.1.1, 1302.1, 1302.1.4, 1302.1.6, 1303.1, 1304.1.1, 1304.1.3, 1307.1.1, 1401.2, 1501.3, 1504.1, 1505.2, A105.2, A304.1.1, A402.1, A403.2 Level 1 Chapter 7, 104.3.2, 602, 603.2, 604.2, 801.2 Level 2 Chapter 8, 106.2.3, 505.2, 603 Level 3 Chapter 9, 106.2.3, 604, 1011.4 Alternative Materials, Design and Methods of Construction 104.2.3 Ambulatory Care Facility 202, 302.2.1, 406.1.2, 408.3, 501.3, 503.15, 503.17, 804.4,

    902.3

    Appeals 104.8, 112, 116.6 Approved 202 Approved Agency A304.2.6, 104.2.3.6.1, 202 Archaic Materials and Assemblies

    Resource A

    Architect (see Registered Design Professional) Area (see Building) Automatic Sprinkler System 110.2, 501.2, 504.5, 802.2.1, 802.6, 803.1.1, 803.2, 804.5.1.1, Table 804.5.1.1(1), 804.5.1.2.1, 804.5.1.2.2, 804.7.1, 804.8, 904.1, 1011.2.1, 1011.6.1, 1011.6.1.1, 1011.7.3, 1011.8.3, 1305.1.1, Table 1305.2.9, 1305.2.10.1, 1305.2.17, 1305.2.17.1, Table 1305.2.17, 1305.2.19, Table 1305.2.19, 1507

  • CBC § 5.1.4 Medium relevance — show source text

    Activity programming space 1225.5.1.4 General construction 1225.5.1.1

    Nursing service space 1225.5.1.2 Pharmaceutical service

    space 1225.5.1.3 Skylights and Sloped Glazing 2405, 3106.3 Light, required 1204.2 Loads 2404

    Plastic 2610 Protection from adjacent construction 3307.1 Vertical opening protective 712.1.15 Slab On Ground, Concrete 1907, 2304.12.1.4 Slate Shingles 1504.4.4, 1507.7, 1513 Sleeping Lofts 202 Sleeping Units 202

    Accessibility Chapters 11A and 11B Cooking appliances 420.11, 420.11.2 Group I 308 Group R 310 Scoping 101.2 Separation 420.2, 420.3 Smoke Alarms 202

    Bathrooms 907.2.11.4 Cooking appliances 907.2.11.3 Live/work unit 508.5.7, 907.2.11.2 Multiple-station 907.2.11 Residential aircraft hangars 412.4.3, 412.4.4, 907.2.22 Residential occupancies 420.6, 907.2.11 Single-station 907.2.11 Smoke Barriers 202

    Construction 407.5, 709.4, 909.5 Doors 709.5, 716.2.2.1, 909.5.3 Fire-resistance rating 703, 709.3 Glazing, rated 716.3.4 Inspection 110.3.8 Joints 709.7, 715 Marking 703.4, 703.5 Materials 709.2

    Opening protection 709.5, 714.4, 714.5.4, 716, 717.5.5, 909.5.3 Penetrations 709.6, 714 Smoke control 909.5

    Special provisions Ambulatory care facilities 422.2, 422.3, 709.5.1 Group I-1 420.6, 709.5.1 Group I-2 407.5 Group I-3 408.6, 408.7 Underground 405.4.2, 405.4.3 Smoke Compartment 407, 408, 422 Refuge area (see Refuge Area) Smoke Control 909 Amusement areas, special 411.1 Atrium buildings 404.5 Covered and open mall building 402.7.2

  • CBC § 1616.2.2.1 Medium relevance — show source text

    Demolition 3303 Design Flood 1612 Design Strength Column splice 1616.2.2.1 Conformance to standards 1706.1

    New materials 1706.2 Designated Seismic System 1704.3.2, 1704.4, 1704.5 Seismic certification 1705.14.3

    Special inspection 1705.13.4 Detached Single-family Dwelling 202 Detectable Warning 202 Diaphragms 202 Analysis 1604.4 Ceilings 2508.6

    Penetrations 714

    Permit application 105.1 Relocation 107.2.8

    Retention 107.5

    Review 107.3

    Roof assemblies 1503

    Roof live load 1603.1.2

    Roof rain load data 1603.1.9

    Roof snow load 1603.1.3

    Seismic 1603.1.5, 1705.14.2, 1705.14.3 Site plan 107.2.6 Special loads 1603.1.8 Temporary structures 3103.2 Wind data 1603.1.4 Construction Types 202, Chapter 6 Aircraft-related occupancies 412.2.1, Table 412.3.6, 412.5.2 Classification 602 Combustible material in Type I and Type II construction 603, 805 Covered and open mall buildings 402.4.1 Fire district D102.2.3

    Fire resistance Table 601, Table 705.5 High-rise 403.2 Type I Table 601, 602.2, 603 Type II Table 601, 602.2, 603 Type III Table 601, 602.3 Type IV Table 601, 602.4 Type V Table 601, 602.5 Underground buildings 405.2 Continuity Head-Of-Wall System 202 Continuous Insulation (ci) 202 Contractor’s Responsibilities 901.5, 1704.4 Control Area 414.2, 707.3.8 Construction 414.2.1

    Fire-resistance rating 414.2.4 Maximum allowed quantities 414.2.2 Number 414.2.3 Conventional Light-frame Construction 2302.1, 2308 Additional seismic requirements 2308 Braced wall lines 2308.10 Design of elements 2308.8 Floor joists 2308.8.2 Foundation plates or sills 2308.7 Girders 2308.8.1 Roof and ceiling framing 2308.11 Wall framing 2308.9 Conveying System S3004 Cornices

    Definition 202 Draftstopping 718.2.6 Live load Table 1607.1

    Masonry 2104.1.2 Projection 705.2, 705.2.3.1 Public right-of-way encroachments 3202.3.2, 3202.3.3 Correctional Treatment Centers

    [OSHPD 4] 1227 Application 1227.2 Ceiling heights 1227.8 Corridors 1227.5

  • CBC § 1.1 Medium relevance — show source text

    A229/A229M—17: Standard Specification for Steel Wire, Quenched and Tempered for Mechanical Springs

    1211.1.1

    A240/A240M—20a: Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications

    Table 1507.4.3

    A252/A252M—19: Specification for Welded and Seamless Steel Pipe Piles

    1810.3.2.3

    A283/A283M—2018: Specification for Low and Intermediate Tensile Strength Carbon Steel Plates

    1810.3.2.3

    A416/A416M—18: Standard Specification for Low-Relaxation, Seven-Wire Steel Strand, for Prestressed Concrete

    1810.3.2.2

    A463/A463M—15(2020)e1: Standard Specification for Steel Sheet, Aluminum-Coated, by the Hot-Dip Process

    Table 1507.4.3

    A572/A572M—21e1: Specification for High-Strength Low-Alloy Columbium-Vanadium Structural Steel

    1810.3.2.3

    A588/A588M—19: Specification for High-Strength Low-Alloy Structural Steel, up to 50 ksi (345 MPa)- Minimum Yield Point with Atmospheric Corrosion Resistance

    1810.3.2.3

    A615/A615M—20: Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement

    1704.5, 1810.3.10.2

    A615/A615M— 22 : Standard Specification for Deformed and Plain Carbon-Steel Bars for Concrete Reinforcement

    1704.5, 1810.3.10.2

    A641/A641M—19: Specification for Zinc-coated (Galvanized) Carbon Steel Wire

    2304.10.6

    A653/A653M—20: Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip

    Process

    Table 1507.4.3, 2304.10.6.1

    35-10 2025 CALIFORNIA BUILDING CODE

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

    REFERENCED STANDARDS

    A690/A690M—13a(2018): Standard Specification for High-Strength Low-Alloy Nickel, Copper, Phosphorus Steel H-Piles and Sheet Piling with Atmospheric Corrosion Resistance for Use in Marine Environments

    1810.3.2.3

    A706/A706M—2016: Standard Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement 1704.5, Table 1705.3, 2107.3, 2108.3

    A706/A706M— 22a : Standard Specification for Deformed and Plain Low-Alloy Steel Bars for Concrete Reinforcement 1704A.4, Table 1705A.3, 2107A.3, 2108A.3

    A722/A722M—2018: Specification for High-Strength Steel Bars for Prestressed Concrete

    1810.3.10.2, 1811.4, 1811A.4, 1812.4.2, 1812A.4.2

  • CBC § 109.3 Medium relevance — show source text

    1211

    Valuation or Value (see Fees, Permit) 109.3 Vapor Diffusion Port 202 Vapor Retarders 1202.3, 1404.3, 1404.3.2 Vegetative Artificial decorative 419, 419.1 Vegetative roofs 1505.10, 1507.15 Vehicle Barrier 1607.11 Vehicle Barrier Systems 406.4.2, 1607.11 Vehicle Show Rooms 304 Vehicular Fueling 406.7 Vehicular Gates 3110 Vehicular Repair 406.8

    Veneer Cement plaster 1404.16, 1411 Fastening 1404.5 Fiber-cement siding 1404.17, 1411 Glazing 1404.13, 1411 Masonry, adhered 1404.11, 2101.2.1, 2103.2.4 Masonry, anchored 1404.7, 1411, 2101.2.1

    Metal 1404.12

    Plastic 1411, 2605 Slab-type 1404.9, 1411

    Testing Automatic fire-extinguishing systems 904.4

    Automatic water mist systems 904.11.3 Building official required 104.2.3.6 Carbon dioxide systems 904.8 Clean agent system 904.10 Dry chemical systems 904.6 Emergency and standby power 2702.4 Fire alarm systems 907.7, 907.8 Fire pumps 913.5 Fire-resistant materials 703.2

    Foam systems 904.7 Glazing 2406, 2408.2.1 Halon systems 904.9 Personnel and material hoists 3004.4

    Roof tile 1504.3.1

    Seismic 1704.2

    Smoke control 909.3, 909.5.2, 909.10.2, 909.12.1, 909.13.3, 909.18, 909.20.7.3, 909.21.7, 1705.19 Soils1 803

    Sound transmission 1208 Sprinkler protection 903.5 Structural (see Special Inspections and Tests) Wet chemical systems 904.5 Testing Agency (definition) 202 Theaters [see Assembly Occupancy (Group A), Projection Rooms and Stages and Platforms] Thermal Barrier, Foam Plastic Insulation 2603.4, 2603.5.2 Thermal-insulating Materials (See Insulation) 712 Tile 202 Ceramic (see Ceramic Tile) Fire resistance, clay or shale 721.1 Tires, Bulk Storage of 311.2 Toddler 202 Toilets and Toilet Rooms Chapters 11A and 11B, 3305 Accessible 1127A, 1134A, 11B-213,

    1607.9.2

  • CBC § 8.2.1.2 Medium relevance — show source text

    RESOURCE A-120 2025 CALIFORNIA EXISTING BUILDING CODE

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

    Accessibility 1.8.2.1.2, 1.9.1, 104.2.4, 306, 801.1, 901.2, 1101.2, 1508, Appendix B Additions Chapter 11, 101.2, 101.3, 101.4, 104.3, 104.3.1, 104.2.4.1, 106.2.3, 109.3.3, 113.2, 115.5, 202, 301.1, 301.3, 302.2, 302.2.1, 303.2, 304.1, 304.2, 307.1, 308.1, 309, 501.1, 502, 601.1, 606, 1301.1, 1301.1.1, 1302.1, 1302.1.3, 1303.1, 1304.1.1, 1304.1.3, 1501.3, 1505.2 Administration Chapter 1 Alterations Chapter 7, Chapter 8, Chapter 9, 101.2, 101.3, 101.4, 101.6, 104.3, 104.3.1, 104.3.2, 104.2.4.1, 105.1.1, 105.1.2, 105.2.2, 105.2.3, 106.2.3, 106.2.6, 108.5, 110.2, 113.2, 115.5, 202, 301.1, 301.3, 302.2, 302.2.1, 302.4, 304, 307.1, 308.1, 309.1, 501.1, 501.1.1, 502.1, 502.3, 502.4, 503, 504.1, 601.1, 602, 603, 604, 1101.3, 1103.1, 1103.2, 1301.1, 1301.1.1, 1302.1, 1302.1.4, 1302.1.6, 1303.1, 1304.1.1, 1304.1.3, 1307.1.1, 1401.2, 1501.3, 1504.1, 1505.2, A105.2, A304.1.1, A402.1, A403.2 Level 1 Chapter 7, 104.3.2, 602, 603.2, 604.2, 801.2 Level 2 Chapter 8, 106.2.3, 505.2, 603 Level 3 Chapter 9, 106.2.3, 604, 1011.4 Alternative Materials, Design and Methods of Construction 104.2.3 Ambulatory Care Facility 202, 302.2.1, 406.1.2, 408.3, 501.3, 503.15, 503.17,

  • California Building Code Medium relevance — show source text

    |TYPICAL
    DISTRIBUTION TRENCH
    Joint Trench − Franchise Area or P.U.E.
    18 INCHES
    MINIMUM
    STREET
    SIDE
    MIN.
    24"
    (NON PG&E)
    (PREFERRED)
    **
    Minimum
    T C SL 5"
    54"
    6"
    G 5"
    See Note 5
    7"
    3" MIN
    P SL S 7"
    FIG. 1
    Placement of the Distribution Trench within a P.U.E. is the preferred method. Trenching in the
    Franchise Area should only be used when a P.U.E. is unobtainable or otherwise infeasible.
     Increase cover to 30" in the street area (see Note 3).
    ** Separation must be 12" unless a reduction (6") is mutually agreed upon by affected utilities.|TYPICAL
    SERVICE TRENCH
    18 INCHES
    MINIMUM
    *
    18"
    MINIMUM
    T C (SEE NOTE 7) 3"
    39"
    12"
    6"
    S Min. G 4"
    BEDDING MATERIAL 2"
    FIG. 2
    (View facing Distribution Trench)
    MINIMUM SEPARATION AND
    CLEARANCE REQUIREMENTS
    DUCT DB
    G T T C S P
    G (GAS) SEE NOTES 4, 7 & 13  12" 12" 12" 6" 12"
    
    T (TELEPHONE) DUCT 12"  1" 1" 12" 12"
    T (TELEPHONE) DIRECT 12" 1"  1" 12" 12"
    BURY
    C (CATV) 12" 1" 1"  12" 12"
    S (ELECTRIC SECONDARY) 6" 12" 12" 12"  3"
    P (ELECTRIC PRIMARY) 12" 12" 12" 12" 3" 
    SEE
    SL (STREETLIGHT) 6" 12" 12" 12" 1" 3"
    NOTE 5
    SEPARATION AND CLEARANCE DEFINITIONS
    Cover:
    The term cover" means the radial distance between the sur-
    face of an underground cable, conduit, pipe, or other substruc-
    ture and the surface elevation (grade).
    Backfill:
    The term backfill" refers to the materials used to refill a cut or
    other excavation, or the act of such refilling after any needed
    shading is performed.
    Shading:
    The term shading" refers to the materials used to provide a
    measure of separation between facilities installed at different
    levels within an excavation or cut.
    Lift:
    The term lift" is a layer of fill as spread or as compacted or a
    measurement of material depth that is the rated effective soil
    depth a compactor can achieve.
    Bedding:
    The term bedding" refers to the materials installed beneath
    facilities at the bottom of a cut or other excavation and in-
    tended to provide support and/or protection for those facilities.

Frequently asked questions

Can I use PVC ducts freely in Type I construction because § 603.1.1 allows nonmetallic ducts?

No. § 603.1.1 only permits nonmetallic ducts when they are installed in accordance with the California Mechanical Code. The CMC (not § 603.1.1 itself) establishes whether a given nonmetallic product (PVC, flexible fabric, etc.) is listed and acceptable for the intended use (including plenums).

Are combustible piping materials banned in Type I/II?

No — § 603.1.2 allows combustible piping and plumbing fixtures in Type I/II, but only where installed per the California Mechanical Code and California Plumbing Code; those specialty codes set required protections, penetration treatments, and limits. file

Can control wiring be routed through ducts or through fire dampers?

Generally no. CBC § 717.2.4 prohibits installing mechanical, electrical and plumbing controls in air duct systems, and wiring should not be run through fire dampers unless the damper manufacturer and listing permit it.

If a concealed space is sprinklered, may I place combustible piping/ducts there?

Yes — one of the CBC options to allow combustible materials in concealed spaces is full sprinkler protection of the concealed space. But you must still meet the specialty codes’ installation/listing requirements for those components. See § 602.4.4.3 and § 603.1.x. file

Where do I find the technical (numerical) limits for materials allowed by § 603.1.1–.3?

The technical limits (flame spread values, listing standards, allowable cable/duct types, plenum rules, penetration systems, etc.) are in the California Mechanical Code, California Plumbing Code and California Electrical Code. The CBC text for §§ 603.1.1–.3 defers to those codes; the retrieved CBC excerpts do not include the full specialty‑code text.

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