CPC · California Plumbing Code

Location, venting, and clearances

This hub summarizes where the CPC sets appliance/vent locations, termination and clearance rules and points to the venting and sizing sections and clearance tables you must follow.

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Last reviewed: July 6, 2026

Overview

This area of the California Plumbing Code (CPC) covers where plumbing and fuel‑burning appliances may be located, how their vents and vent connectors must be routed and terminated, and the minimum clearances required to combustible materials, openings, and building features to protect life, health and property. See the venting chapter (§509.0) for appliance venting rules and the appliance location and clearance provisions in Chapter 5 (examples: §507.26) for combustible clearances . The CPC also groups vent termination and roof/through‑the‑wall rules (for example §509.8.1 and Table 509.8.1) and specific venting topics (roof terminations, vent rise, common vertical stacks) in the 900 series (§905–§911) for fixture venting and special venting arrangements .

Why it matters: proper location and clearances prevent fire hazards and allow vents to draft safely (protecting occupants from carbon monoxide), while correct termination and sizing keep appliances operating as listed. The CPC uses tables and figures for required clearances (e.g., Table 509.8.1 and Table 509.7.3.4(1)/(2) for clearance reductions), and sizing rules appear in the vent‑sizing sections (for example §510.0) that interface with the location and termination provisions .

In this section

Code references

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

CPC § 12.8.5 High relevance — show source text

(3) The vent cap or a roof assembly shall have a venting capacity not less than that of the pipe to which it is attached. [NFPA 54:12.8.5]

509.7.5 Support of Single-Wall Metal Pipe. All portions of single-wall metal pipe shall be supported for the design and weight of the material employed. [NFPA 54:12.8.6]

509.7.6 Marking. Single-wall metal pipe shall comply with the marking provisions of Section 509.6.5. [NFPA 54:12.8.7]

509.8 Through-the-Wall Vent Termination. Throughthe-wall vent termination shall be in accordance with Section 509.8.1 through Section 509.8.3.

509.8.1 Clearance for Through-the-Wall Vent Ter- mination. The clearance for through-the-wall direct and non-direct vent terminals shall be in accordance with Table 509.8.1 and Figure 509.8.1.

Exception: The clearances in Table 509.8.1 shall not apply to the combustion air intake of a direct vent appliance. [NFPA 54:12.9.1]

» FIGURE 509.8.1 EXIT TERMINALS OF MECHANICAL DRAFT AND DIRECT-VENT VENTING SYSTEMS

[NFPA 54: FIGURE 12.9.1]

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TABLE 509.8.1

THROUGH-THE-WALL DIRECT-VENT TERMINATION CLEARANCES

[NFPA 54: TABLE 12.9.1]

FIGURE CLEARANCE	CLEARANCE LOCATION	MINIMUM CLEARANCES FOR DIRECT VENT TERMINALS	MINIMUM CLEARANCES FOR NON-DIRECT VENT TERMINALS
A	Clearance above finished grade level, veranda, porch, deck, or balcony	12 inches	12 inches
B	Clearance to window or door that is openable	6 inches for appliances ≤ 10 000 Btu/hr	4 feet below or to side of opening or 1 foot above opening
B	Clearance to window or door that is openable	9 inches for appliances > 10 000 Btu/hr≤ 50 000 Btu/hr	9 inches for appliances > 10 000 Btu/hr≤ 50 000 Btu/hr
B	Clearance to window or door that is openable	12 inches for appliances > 50 000 Btu/hr≤ 150 000 Btu/hr	12 inches for appliances > 50 000 Btu/hr≤ 150 000 Btu/hr
B	Clearance to window or door that is openable	Appliances > 150 000 Btu/hr, in accordance with the appliance manufacturer’s instructions and not less than the clearances specified for non-direct vent terminals in row B	Appliances > 150 000 Btu/hr, in accordance with the appliance manufacturer’s instructions and not less than the clearances specified for non-direct vent terminals in row B
C	Clearance to non-openable window	None unless otherwise specified by the appliance

CPC § 509.7.3.3 High relevance — show source text

509.7.3.3 Incinerator. Single-wall metal pipe used for venting an incinerator shall be exposed and readily examinable for its full length and shall have required clearances maintained.

509.7.3.4 Clearances. Minimum clearances from single-wall metal pipe to combustible material shall be in accordance with Table 509.7.3.4(1). Reduced clearances from single-wall metal pipe to combustible material shall be as specified for vent connectors in Table 509.7.3.4(2). [NFPA 54:12.8.4.4]

509.7.3.5 Combustible Exterior Wall. Singlewall metal pipe shall not pass through a combustible exterior wall unless guarded at the point of passage by a ventilated metal thimble not smaller than the following:

(1) For listed appliances with draft hoods and appliances listed for use with Type B gas vents, the thimble shall be a minimum of 4 inches (100 mm) larger in diameter than the metal pipe. Where there is a run of not less than 6 feet (1829 mm) of metal pipe in the opening between the draft hood outlet and the thimble, the thimble shall be a minimum of 2 inches (50 mm) larger in diameter than the metal pipe.

(2) For unlisted appliances having draft hoods, the thimble shall be a minimum of 6 inches (150 mm) larger in diameter than the metal pipe.

TABLE 509.7.3.4(1) CLEARANCES FOR CONNECTORS {NFPA 54: TABLE 12.8.4.4}*	Col2	Col3	Col4	Col5
MINIMUM DISTANCE FROM COMBUSTIBLE MATERIAL (inches)	MINIMUM DISTANCE FROM COMBUSTIBLE MATERIAL (inches)	MINIMUM DISTANCE FROM COMBUSTIBLE MATERIAL (inches)	MINIMUM DISTANCE FROM COMBUSTIBLE MATERIAL (inches)	MINIMUM DISTANCE FROM COMBUSTIBLE MATERIAL (inches)
APPLIANCE	LISTED TYPE B GAS VENT MATERIAL	LISTED TYPE L VENT MATERIAL	SINGLE-WALL METAL PIPE	FACTORY-BUILT CHIMNEY SECTIONS
Listed appliances with draft hoods and appli- ances listed for use with Type B gas vents	As listed	As listed	6	As listed
Residential boilers and furnaces with listed gas conversion burner and with draft hood	6	6	9	As listed
Residential appliances listed for use with Type L vents	Not permitted	As listed	9	As listed
Unlisted residential appliances with draft hood	Not permitted	6	9	As listed
Residential and low-heat appliances other than those above	Not permitted	9	18	As listed
Medium-heat appliances	Not permitted	Not permitted	36	As listed

For SI units: 1 inch = 25.4 mm

These clearances shall apply unless the installation instructions of a listed appliance or connector specify different clearances, in which case the listed clearances shall apply.

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CPC § 509.1 High relevance — show source text
509.1 Listing . . . . . . . . . . . . . . . . . . . . . . .91

509.2 Connection to Venting Systems . . .91

509.3 Minimum Safe Performance . . . . . .91

509.4 Type of Venting System to be Used . . . . . . . . . . . . . . . . . . . . .92

Table 509.4 Type of Venting System to be Used . . . . . . . . . . . . . . . . . . .92

509.5 Masonry, Metal, and Factory-Built Chimneys . . . . . . . . .93

509.6 Gas Vents . . . . . . . . . . . . . . . . . . . .94

Table 509.6.1 Roof Slope Heights . . . . . . . . . . . .95

509.7 Single-Wall Metal Pipe . . . . . . . . . .97

Table 509.7.3.4(1) Clearances for Connectors . . . . . . .97

Table 509.7.3.4(2) Reduction of Clearances with Specified Forms of Protection . . . .99

509.8 Through-the-Wall Vent Termination . . . . . . . . . . . . . . . . . .100

509.9 Condensation Drain . . . . . . . . . . .100

509.10 Vent Connectors for

Category I Appliances . . . . . . . . .100

Table 509.8.1 Through-the-Wall Direct-Vent Termination Clearances . . . . . . . .101

Table 509.10.1.3 Minimum Thickness for

Galvanized Steel Vent

Connectors for Low-Heat

Appliances . . . . . . . . . . . . . . . . . .102

Table 509.10.1.4 Minimum Thickness for Steel

Vent Connectors for

Medium-Heat Appliances . . . . . . .102

509.11 Vent Connectors for

Category II, Category III, and Category IV Appliances . . . . . . . .104

509.12 Appliances Requiring Draft Hoods . . . . . . . . . . . . . . . . . . . . . .104

509.13 Manually Operated Dampers . . . .104

509.14 Automatically Operated Vent Dampers . . . . . . . . . . . . . . . .104

509.15 Obstructions . . . . . . . . . . . . . . . . .104

510.0 Sizing of Category I Venting Systems . . . . . . . . . . . . . . . . . . . .104

510.1 Additional Requirements to Single Appliance Vent . . . . . . . . .104

510.2 Additional Requirements to Multiple-Appliance Vent . . . . . . . . .106

Table 510.2.1 Vent Connector Maximum

Length . . . . . . . . . . . . . . . . . . . . . .106

Table 510.1.2(1) Type B Double-Wall Gas Vent . . .110

Table 510.1.2(2) Type B Double-Wall Gas Vent . . .113

Table 510.1.2(3) Masonry Chimney . . . . . . . . . . . . .115
CPC § 34.3 High relevance — show source text
General Order (G.O.) 128 . . . . . . . . . . . . . . . . . . . . . . . . TIL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G.O. 128

California Administrative Code:

Title 8 − Industrial Relations, Chapter 4, Sub-Chapter 5, Electrical Safety Orders

Title 24 − State Building Standards, Part 3 − California Code of Regulations, California Electric Code

1. Clearances

Clearances are divided into the following sections:
- Building clearances.
- Clearances to foreign substructure.
- Horizontal work space clearances.
- Hazardous locations.
Underground equipment, pads and enclosures shall be located so that they meet or exceed the required clearances in each of the clearances sections and in each of their subsections.

Rev. #22: 03−25−22 051122 Page 1 of 28

UG-1: General Greenbook Clearances and Location Requirements for Enclosures, Pads, and Underground Equipment

2. Building Clearances

A. Clearances from building surfaces (see Figure 1): Oil filled pad-mount equipment shall have the following clearances (based on G.O. 128, Rule 34.3 [D] ):

a) 3-foot minimum from combustible building surfaces to the edge of the pad.

b) 2-foot minimum from non-combustible building surfaces to the edge of the pad. Non-combustible materials include brick, clay, concrete, steel, stone, and stucco.

B. Doorway clearance (see Figure 1): Pad-mounted equipment shall not be placed where it impedes the flow of traffic through a doorway. In general, 4 feet of doorway clearance is sufficient (based on the Uniform Building Code).

Figure 1 Building and Doorway Clearances (see Notes 2.A and 2.B)

051122 Page 2 of 28 Rev. #22: 03−25−22

UG-1: General Greenbook

Clearances and Location Requirements for Enclosures, Pads, and Underground Equipment

2. Building Clearances (continued)

C. Vertical clearance from overhangs (see Figure 2): To provide space for hoisting equipment so that equipment can be replaced, the following vertical clearances from the top of the pad for pad-mounted equipment or top of the enclosure for subsurface equipment are required (based on G.O. 128, Rules 17.3 and 34.2 ).
CPC § 507.5 High relevance — show source text
507.5 Drainage Pan. Where a water heater is located in an attic, in or on an attic ceiling assembly, floor-ceiling assembly, floor-subfloor assembly or where damage results from a leaking water heater, a watertight pan of corrosion-resistant materials shall be installed beneath the water heater in accordance with the following: (1) The drainage pan shall be provided with not less than [3] ⁄ 4 of an inch (20 mm) diameter drain to an approved location. The terminating end of the drainpipe shall be readily visible. (2) The drainage pan shall be not less than 1 [1] ⁄ 2 inches (38 mm) in depth. (3) Where a drainage pan pipe is installed, the material of the piping shall be rated for the temperature rating of the water heater and shall be approved for use with the liquid being discharged. (4) Discharge from a relief valve into a drainage pan shall be prohibited. 507.6 Added or Converted Equipment or Appliances. When additional or replacement appliances or equipment is installed or an appliance is converted to gas from another fuel, the location in which the appliances or equipment is to be operated shall be checked to verify the following: (1) Air for combustion and ventilation is provided where required, in accordance with the provisions of Section 506.0. Where existing facilities are not adequate, they shall be upgraded to meet Section 506.0 specifications. (2) The installation components and appliances meet the clearances to combustible material provisions of Section 507.26. It shall be determined that the installation and operation of the additional or replacement appliances do not render the remaining appliances unsafe for continued operation. (3) The venting system is constructed and sized in accordance with the provisions of Section 509.0. Where the existing venting system is not adequate, it shall be upgraded to comply with Section 509.0. [NFPA 54:9.1.2] 507.7 Type of Gas(es). The appliance shall be connected to the fuel gas for which it was designed. No attempt shall be made to convert the appliance from the gas specified on the rating plate for use with a different gas without consulting the installation instructions, the serving gas supplier, or the appliance manufacturer for complete instructions. Listed appliances shall

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not be converted unless permitted by and in accordance with the manufacturer’s installation instructions. [NFPA 54:9.1.3] 507.8 Safety Shutoff Devices for Unlisted LP-Gas Appliance Used Indoors. Unlisted appliances for use with undiluted LP-Gases and installed indoors, except attended laboratory equipment, shall be equipped with safety shutoff devices of the complete shutoff type. [NFPA 54:9.1.4] 507.9 Use of Air or Oxygen Under Pressure. Where air or oxygen under pressure is used in connection with the gas supply, effective means such as a backpressure regulator and relief valve shall be provided to prevent air or oxygen from passing back into the gas piping. Where oxygen is used, installation shall be in accordance with NFPA 51. [NFPA 54:9.1.5]
CPC § 507.20 High relevance — show source text
507.20 Gas Appliance Pressure Regulators . . . . . . . . . . . . . . . . . . .89

507.21 Bleed Lines for Diaphragm-Type Valves . . . . . . . . . . . . . . . . . . . . . . .89

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TABLE OF CONTENTS

507.22 Combination of Appliances and Equipment . . . . . . . . . . . . . . . .90

507.23 Installation Instructions . . . . . . . . . .90

507.24 Protection of Outdoor

Appliances . . . . . . . . . . . . . . . . . . .90

507.25 Accessibility for Service . . . . . . . . .90

507.26 Clearance to Combustible

Materials . . . . . . . . . . . . . . . . . . . . .90

508.0 Appliances on Roofs, in Attics or Under-Floor Spaces . . . . . . . . . .90

508.1 General . . . . . . . . . . . . . . . . . . . . . .90

508.2 Installation of Appliances on Roofs . . . . . . . . . . . . . . . . . . . . .90

508.3 Appliances on Roofs . . . . . . . . . . .90

508.4 Appliances in Attics and Under-Floor Spaces . . . . . . . . . . . .91

509.0 Venting of Appliances . . . . . . . . . . .91

509.1 Listing . . . . . . . . . . . . . . . . . . . . . . .91

509.2 Connection to Venting Systems . . .91

509.3 Minimum Safe Performance . . . . . .91

509.4 Type of Venting System to be Used . . . . . . . . . . . . . . . . . . . . .92

Table 509.4 Type of Venting System to be Used . . . . . . . . . . . . . . . . . . .92

509.5 Masonry, Metal, and Factory-Built Chimneys . . . . . . . . .93

509.6 Gas Vents . . . . . . . . . . . . . . . . . . . .94

Table 509.6.1 Roof Slope Heights . . . . . . . . . . . .95

509.7 Single-Wall Metal Pipe . . . . . . . . . .97

Table 509.7.3.4(1) Clearances for Connectors . . . . . . .97

Table 509.7.3.4(2) Reduction of Clearances with Specified Forms of Protection . . . .99

509.8 Through-the-Wall Vent Termination . . . . . . . . . . . . . . . . . .100

509.9 Condensation Drain . . . . . . . . . . .100

509.10 Vent Connectors for

Category I Appliances . . . . . . . . .100

Table 509.8.1 Through-the-Wall Direct-Vent Termination Clearances . . . . . . . .101

Table 509.10.1.3 Minimum Thickness for
CPC § 12.13.6 High relevance — show source text
planes and shall be located so that the relief opening is not obstructed by any part of the appliance or adjacent construction. The appliance and its draft hood shall be located so that the relief opening is accessible for checking vent operation. [NFPA 54:12.13.6]

509.12.6 Clearance. A draft hood shall be located so that its relief opening is not less than 6 inches (152 mm) from any surface except that of the appliance it serves and the venting system to which the draft hood is connected. Where a greater or lesser clearance is indicated on the appliance label, the clearance shall not be less than that specified on the label. Such clearances shall not be reduced. [NFPA 54:12.13.7] 509.13 Manually Operated Dampers. A manually operated damper shall not be placed in any appliance vent connector. Fixed baffles and balancing baffles shall not be classified as manually operated dampers. Balancing baffles shall be mechanically locked in the desired position before placing the appliance in service. Balancing baffles shall be listed in accordance with UL 378. [NFPA 54:12.14.1 – 12.14.3] 509.14 Automatically Operated Vent Dampers. An automatically operated vent damper shall be listed. [NFPA 54:12.15]

509.14.1 Listing. Automatically operated vent dampers for oil fired appliances shall comply with UL 17. The automatic damper control shall comply with UL 378.

509.15 Obstructions. Devices that retard the flow of vent gases shall not be installed in a vent connector, chimney, or vent. The following shall not be considered as obstructions:

(1) Draft regulators and safety controls specifically listed for installation in venting systems and installed in accordance with the manufacturer’s installation instructions.

(2) Approved draft regulators and safety controls designed and installed in accordance with engineering methods.

(3) Listed heat reclaimers and automatically operated vent dampers installed in accordance with the manufacturers’ installation instructions.

(4) Vent dampers serving listed appliances installed in accordance with Section 510.1 or Section 510.2 or engineering methods.

(5) Approved economizers, heat reclaimers, and recuperators installed in venting systems of appliances not required to be equipped with draft hoods, provided the appliance manufacturer’s instructions cover the installation of such a device in the venting system and performance in accordance with Section 509.3 and Section 509.3.1 is obtained. [NFPA 54:12.16]

510.0 Sizing of Category I Venting Systems. 510.1 Additional Requirements to Single Appliance Vent. Venting Table 510.1.2(1) through Table 510.1.2(6) shall not be used where obstructions are installed in the venting system. The installation of vents serving listed appliances with vent dampers shall be in accordance with the appliance manufacturer’s instructions or in accordance with the following:

»

B gas vents that pass through walls or partitions constructed of combustible material shall be installed

with not less than the listed clearance to combustible

material.

(2) Vent connectors shall be permitted to pass through ceilings, floors, or walls in accordance with Section 509.7.3.1 and Section 509.7.3.5.
CPC § 509.7.3.4 High relevance — show source text
[See Figure 509.7.3.4(2) and Figure 509.7.3.4(3)] 5 At least 1 inch (25.4 mm) shall be between clearance reduction systems and combustible walls and ceilings for reduction systems using a ventilated air space. 6 Where a wall protector is installed on a single flat wall away from corners, it shall have a minimum 1 inch (25.4 mm) air gap. To provide adequate air circulation, the bottom and top edges, or only the side and top edges, or all edges shall be left open. 7 Mineral wool batts (blanket or board) shall have a minimum density of 8 pounds per cubic foot (lb/ft 3 ) (128 kg/m 3 ) and a minimum melting point of 1500°F (816°C). 8 Insulation material used as part of a clearance reduction system shall have a thermal conductivity of 1.0 British thermal unit inch per hour square foot degree Fahrenheit [Btu•in/(h•ft [2] - °F)] [0.1 W/(m•K)] or less. 9 At least 1 inch (25.4 mm) shall be between the appliance and the protector. The clearance between the appliance and the combustible surface shall not be

reduced below that allowed in this table. 10 All clearances and thicknesses are minimum; larger clearances and thicknesses are acceptable. 11 Listed single-wall connectors shall be installed in accordance with the terms of their listing and the manufacturer’s installation instructions.

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«

«

509.8.2 Annular Spaces. Where vents, including those for direct-vent appliances or combustion air intake pipes, penetrate outside walls of buildings, the annular spaces around such penetrations shall be permanently sealed using approved materials to prevent entry of combustion products into the building. [NFPA 54:12.9.2] 509.8.3 Vent Terminals. Vent systems for Category IV appliances that terminate through an outside wall of a building and discharge flue gases perpendicular to the adjacent wall shall be located not less than 10 feet (3048 mm) horizontally from an operable opening in an adjacent building.

Exception: This shall not apply to vent terminals that are 2 feet (610 mm) or more above or 25 feet (7620 mm) or more below operable openings. [NFPA 54:12.9.3]

509.9 Condensation Drain. Provision shall be made to collect and dispose of condensate from venting systems serving Category II and Category IV appliances and noncategorized condensing appliances. [NFPA 54:12.10.1]

509.9.1 Installation. Drains for condensate shall be installed in accordance with the appliance and vent manufacturers’ installation instructions. [NFPA 54:12.10.2] 509.10 Vent Connectors for Category I Appliances. A vent connector shall be used to connect an appliance to a gas vent, chimney, or single-wall metal pipe, except where the gas vent, chimney, or single-wall metal pipe is directly connected to the appliance. [NFPA 54:12.11.1]
CPC § 604.1 High relevance — show source text
CHLORINATED POLYVINYL

CHLORIDE/ALUMINUM/CHLORINATED

POLYVINYL CHLORIDE

(CPVC-AL-CPVC) PIPE OR TUBING

Approved standards, water supply . . . . . . . .Table 604.1

Joining and connections . . . . . . . . . . . . . . . .(see Joints

and connections)

CIRCUIT VENTING . . . . . . . . . . . . . . . . . . . . . . . . . . . .911.0

CLARIFIERS . . . . . . . . . . . . . . . . . . . . . . . . . .205.0, 1009.0

CLEANOUT PLUGS OR CAPS . . . . . . . . . . .707.1 – 707.3,

707.13, 1107.2

CLEANOUTS

Access . . . . . . . . . . . . . . . . . . . . . .707.8, 719.5, 801.3.2

Building sewer . . . . . . . . . . . . . . . . . . . . . . 310.12, 719.0 Change of direction . . . . . . . . . . . . . . . . . .707.4, 719.1,

801.3.2, 803.3, 1002.3

Clearances . . . . . . . . . . . . . . . . . . . . . . . . .707.8, 707.9

Condensate drain . . . . . . . . . . . . . . . . . . . . . . . .814.3.1

Cover plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .707.8

Direction of flow . . . . . . . . . . . . . . . . . . . . . .707.5, 719.4

Horizontal drains . . . . . . . . . . . . . . . . . . . . .707.4, 719.1

Manholes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .719.6

Plugs . . . . . . . . . . . . . . . . . . . . . . . .707.1, 707.2, 707.12

Prohibited use of . . . . . . . . . . . . . . . . . . . . . . . . . .316.1

Size . . . . . . . . . . . . . . . . . . . . . . . . . .707.1, Table 707.1

Soil or drainpipes . . . . . . . . . . . . . . . . . . . . . . . . . .317.1

Where required . . . . . . . . . . . . . . . .707.4, 719.1, 909.1,

910.6, 1002.3, 1008.1,

1017.1, 1101.13.1, E 301.4

CLEARANCE

CPC § 12.9.1 High relevance — show source text

[NFPA 54: TABLE 12.9.1]

FIGURE CLEARANCE	CLEARANCE LOCATION	MINIMUM CLEARANCES FOR DIRECT VENT TERMINALS	MINIMUM CLEARANCES FOR NON-DIRECT VENT TERMINALS
A	Clearance above finished grade level, veranda, porch, deck, or balcony	12 inches	12 inches
B	Clearance to window or door that is openable	6 inches for appliances ≤ 10 000 Btu/hr	4 feet below or to side of opening or 1 foot above opening
B	Clearance to window or door that is openable	9 inches for appliances > 10 000 Btu/hr≤ 50 000 Btu/hr	9 inches for appliances > 10 000 Btu/hr≤ 50 000 Btu/hr
B	Clearance to window or door that is openable	12 inches for appliances > 50 000 Btu/hr≤ 150 000 Btu/hr	12 inches for appliances > 50 000 Btu/hr≤ 150 000 Btu/hr
B	Clearance to window or door that is openable	Appliances > 150 000 Btu/hr, in accordance with the appliance manufacturer’s instructions and not less than the clearances specified for non-direct vent terminals in row B	Appliances > 150 000 Btu/hr, in accordance with the appliance manufacturer’s instructions and not less than the clearances specified for non-direct vent terminals in row B
C	Clearance to non-openable window	None unless otherwise specified by the appliance manufacturer	None unless otherwise specified by the appliance manufacturer
D	Vertical clearance to ventilated soffit located above the terminal within a horizontal distance of 2 feet (610 mm) from the center line of the terminal	None unless otherwise specified by the appliance manufacturer	None unless otherwise specified by the appliance manufacturer
E	Clearance to unventilated soffit	None unless otherwise specified by the appliance manufacture	None unless otherwise specified by the appliance manufacture
F	Clearance to outside corner of building	None unless otherwise specified by the appliance manufacture	None unless otherwise specified by the appliance manufacture
G	Clearance to inside corner of building	None unless otherwise specified by the appliance manufacture	None unless otherwise specified by the appliance manufacture
H	Clearance to non-mechanical air supply inlet to building and the combustion air inlet to any other appliance	Same clearance as specified for row B	Same clearance as specified for row B
I	Clearance to a mechanical air supply inlet	10 feet horizontally from inlet or 3 feet above inlet	10 feet horizontally from inlet or 3 feet above inlet
J	Clearance above paved sidewalk or paved driveway located on public property or other areas where condensate or vapor can cause a nuisance or hazard	7 feet and not located above public walkways or other areas where condensate or vapor can cause a nuisance or hazard	7 feet and not located above public walkways or other areas where condensate or vapor can cause a nuisance or hazard
K	Clearance to underside of veranda, porch, deck, or balcony	12 inches where the area beneath the veranda, porch, deck, or balcony is open on not less than two sides.

CPC § 923.0 High relevance — show source text
923.0 Illuminating Appliances. . . . . . . . . 211

923.1 Clearances for Listed Appliances. . 211

923.2 Clearances for Unlisted

Appliances . . . . . . . . . . . . . . . . . . 211

Table 923.2.1 Clearances for Unlisted Outdoor

Open-Flame Illuminating Appliances . . . . . . . . . . . . . . . . . . 211

923.3 Mounting on Buildings . . . . . . . . . 211

923.4 Mounting on Posts . . . . . . . . . . . . 211

923.5 Appliance Pressure Regulators . . . 211

924.0 Incinerators and Crematories . . . . 211

924.1 Field Constructed Commercial Industrial Incinerators . . . . . . . . . . 211

924.2 Factory-Built Commercial Crematories . . . . . . . . . . . . . . . . . 211

924.3 Residential Incinerators . . . . . . . . 211

925.0 Infrared Heaters . . . . . . . . . . . . . . 211

925.1 Application . . . . . . . . . . . . . . . . . . 211

925.2 Support . . . . . . . . . . . . . . . . . . . . . 211

925.3 Clearance . . . . . . . . . . . . . . . . . . . 211

925.4 Combustion and Ventilation Air . . . 212

925.5 Installation in Commercial

Garages and Aircraft Hangars . . . 212

925.6 Electric Radiant Heaters. . . . . . . . 212

926.0 Pool Heaters. . . . . . . . . . . . . . . . . 212

926.1 Application . . . . . . . . . . . . . . . . . . 212

926.2 Location . . . . . . . . . . . . . . . . . . . . 212

926.3 Clearance . . . . . . . . . . . . . . . . . . . 212

926.4 Temperature or PressureLimiting Devices . . . . . . . . . . . . . . 212

926.5 Bypass Valves . . . . . . . . . . . . . . . 212

926.6 Venting . . . . . . . . . . . . . . . . . . . . . 212

927.0 Refrigerators. . . . . . . . . . . . . . . . . 212

927.1 Application . . . . . . . . . . . . . . . . . . 212

927.2 Clearance . . . . . . . . . . . . . . . . . . . 212

927.3 Venting or Ventilating Kits Approved for Use with a Refrigerator. . . . . . . . . . . . . . . . . . 212

928.0 Gas-Fired Toilets . . . . . . . . . . . . . 212

928.1 Clearance . . . . . . . . . . . . . . . . . . . 212

928.2 Installation on Combustible
CPC § 509.8.2 High relevance — show source text
WATER HEATERS

«

«

509.8.2 Annular Spaces. Where vents, including those for direct-vent appliances or combustion air intake pipes, penetrate outside walls of buildings, the annular spaces around such penetrations shall be permanently sealed using approved materials to prevent entry of combustion products into the building. [NFPA 54:12.9.2] 509.8.3 Vent Terminals. Vent systems for Category IV appliances that terminate through an outside wall of a building and discharge flue gases perpendicular to the adjacent wall shall be located not less than 10 feet (3048 mm) horizontally from an operable opening in an adjacent building.

Exception: This shall not apply to vent terminals that are 2 feet (610 mm) or more above or 25 feet (7620 mm) or more below operable openings. [NFPA 54:12.9.3]

509.9 Condensation Drain. Provision shall be made to collect and dispose of condensate from venting systems serving Category II and Category IV appliances and noncategorized condensing appliances. [NFPA 54:12.10.1]

509.9.1 Installation. Drains for condensate shall be installed in accordance with the appliance and vent manufacturers’ installation instructions. [NFPA 54:12.10.2] 509.10 Vent Connectors for Category I Appliances. A vent connector shall be used to connect an appliance to a gas vent, chimney, or single-wall metal pipe, except where the gas vent, chimney, or single-wall metal pipe is directly connected to the appliance. [NFPA 54:12.11.1]

(2) Where a single-wall metal pipe is used and has a shape other than round, it shall have an equivalent effective area equal to the effective area of the round pipe for which it is substituted and the minimum internal dimension of the pipe shall be 2 inches (50 mm).

(3) The vent cap or a roof assembly shall have a venting capacity not less than that of the pipe to which it is attached. [NFPA 54:12.8.5]

509.7.5 Support of Single-Wall Metal Pipe. All portions of single-wall metal pipe shall be supported for the design and weight of the material employed. [NFPA 54:12.8.6]

509.7.6 Marking. Single-wall metal pipe shall comply with the marking provisions of Section 509.6.5. [NFPA 54:12.8.7]

509.8 Through-the-Wall Vent Termination. Throughthe-wall vent termination shall be in accordance with Section 509.8.1 through Section 509.8.3.

509.8.1 Clearance for Through-the-Wall Vent Ter- mination. The clearance for through-the-wall direct and non-direct vent terminals shall be in accordance with Table 509.8.1 and Figure 509.8.1.

Exception: The clearances in Table 509.8.1 shall not apply to the combustion air intake of a direct vent appliance. [NFPA 54:12.9.1]

» FIGURE 509.8.1 EXIT TERMINALS OF MECHANICAL DRAFT AND DIRECT-VENT VENTING SYSTEMS

[NFPA 54: FIGURE 12.9.1]

100 2025 CALIFORNIA PLUMBING CODE

Frequently asked questions

Where are through‑the‑wall vent termination clearances specified?

Through‑the‑wall and direct‑vent termination clearances are set out in §509.8.1 and Table 509.8.1 (shown with Figure 509.8.1). That table lists minimum distances to grade, openings, soffits, air inlets, sidewalks, etc., and includes special horizontal distance limits for Category IV terminals .

How close can a vent connector or single‑wall pipe be to combustible material?

Minimum clearances are given in Table 509.7.3.4(1); where protection is provided, reduced clearances are allowed per Table 509.7.3.4(2) and the associated figures showing air gaps and protectors. Installers must follow the listed appliance/connector instructions where those specify different clearances .

Which CPC sections govern vent sizing and special venting (wet, circuit, island)?

Venting sizing and related rules are in §510.0 (sizing of Category I systems) and the venting series §905–§911 covers roof termination, vent pipe rise, common vertical vents, wet venting, circuit vents and combination waste/vent systems .

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Related in the CPC

General requirements & permits

Safety devices, relief valves & temperature controls

Combustion air, appliance installation, oil/indirect-fired heaters

Water Heaters

California Plumbing Code