CMC · California Mechanical Code
Household cooking appliances — electric and gas, floor-mounted and built-in
Summary: The California Mechanical Code requires household cooking appliances to be listed and installed per their listings/manufacturer; gas appliances must meet the floor‑mounted and built‑in vertical‑clearance rules (30" default; 24" allowed with specific protections) and all cooking appliances must be installed level.
Last reviewed: July 6, 2026
What the code requires — 2-4 sentences
Household cooking appliances must be listed and installed per their listing and manufacturer instructions — see § 919.1 and § 919.2 for listing and electric-appliance rules. Gas-fired household appliances must comply with the installation and clearance rules found in § 919.4 through § 919.6, as required by § 919.3. In short: use listed equipment, follow the manufacturer, maintain required vertical clearances, and install appliances level.
The single most important rule: Household cooking appliances must be listed (CSA/ANSI Z21.1/CSA 1.1) and installed per their listing/manufacturer; gas appliances must specifically meet the floor-mounted, built-in and level rules in § 919.4–§ 919.6.
Requirements in detail
Scope & listing
- Household cooking appliances (both electric and gas) must be listed in accordance with CSA/ANSI Z21.1/CSA 1.1 — § 919.1.
- Electric household cooking appliances intended for permanent installation must be installed in accordance with the manufacturer’s installation instructions; household electric ranges must comply with UL 858 (see § 919.2).
- Gas-fired household cooking appliances are required to comply with the provisions that govern floor-mounted and built-in installations and level installation: § 919.4 through § 919.6, as stated in § 919.3.
Floor‑mounted units (general)
- Floor-mounted units must be set on their own bases or legs and must not interfere with combustion air, accessibility for operation, or servicing — § 919.4.1.
Vertical clearances (floor‑mounted and built‑in top/surface)
- Default vertical clearance above the cooking top to combustible material or metal cabinets: 30 inches (762 mm) — § 919.4.2 and § 919.5.2.
- Reduced vertical clearance permitted: 24 inches (610 mm) when one of the protective measures is provided (see options below) — § 919.4.2 and § 919.5.2.
Decision‑relevant dimensions and protections (quick reference)
| Item / Decision | Value / Requirement | When it applies | Code Reference |
|---|---|---|---|
| Listing for household appliances | CSA/ANSI Z21.1 / CSA 1.1 | All household cooking appliances | § 919.1 |
| Electric appliance installation | Per manufacturer; ranges comply with UL 858 | Electric, permanently installed | § 919.2 |
| Gas appliance rule pointer | Gas appliances comply with §§ 919.4–919.6 | Gas-fired household appliances | § 919.3 |
| Floor‑mounted set-up | On own base or legs; do not block combustion air or servicing | Floor-mounted units | § 919.4.1 |
| Default vertical clearance | 30 in (762 mm) to combustible material or metal cabinets | Floor‑mounted & built‑in tops | § 919.4.2, § 919.5.2 |
| Reduced vertical clearance | 24 in (610 mm) permitted with specified protection | If protective millboard, hood, or listed upper appliance is used | § 919.4.2, § 919.5.2 |
| Underside protection (millboard + sheet metal) | 1/4 in (6.4 mm) insulating millboard covered with sheet metal ≥ 0.0122 in (0.3099 mm) | Allows 24 in clearance | § 919.4.2(1), § 919.5.2(1) |
| Metal ventilating hood | Sheet metal ≥ 0.0122 in (0.3099 mm); hood width ≥ appliance width; 1/4 in (6.4 mm) clearance between hood and underside | Alternative to millboard to allow 24 in | § 919.4.2(2), § 919.5.2(2) |
| Over‑appliance listed unit (e.g., microwave) | Must be installed per that appliance’s listing/manufacturer | Alternative to other protections | § 919.4.2(3), § 919.5.2(3) |
| Level installation | Cooking top, broiler pan, or oven racks must be level | All cooking appliances | § 919.6 |
(Each table row is drawn from the CMC text cited in the Code Reference column.)
Accessibility, combustion air, servicing
- Installations must not interfere with combustion air or required access for servicing — this requirement appears in the installation rules for floor-mounted and built-in appliances (see § 919.4.1 and § 919.5.1).
Exceptions & special cases
- Where a listed cooking appliance or listed microwave is installed over another listed cooking appliance, the reduced clearances and placement are governed by the terms of that upper appliance’s listing and the manufacturer’s installation instructions — see § 919.4.2(3) and § 919.5.2(3).
- The code allows a 24‑inch clearance in lieu of 30‑inch, but only if one of the specified protections is provided; do not assume 24 inches is always acceptable. See § 919.4.2 and § 919.5.2.
- The CMC requires listed appliances to follow their listings and manufacturer instructions; if an appliance is unlisted, different or additional restrictions may apply — the code disallows unlisted built-in units in or adjacent to combustible material (see § 919.5.1).
If you need requirements that are not found in these controlling sections (for example, specific floor‑protection schemes tied to leg height found elsewhere in the code), that text is not included in the controlling sections you specified — say so and I’ll pull the exact section(s).
Common mistakes
- Assuming reduced clearances (24") are allowed without adding the specified protection (millboard + sheet metal, hood, or listed upper appliance). See § 919.4.2 and § 919.5.2.
- Installing unlisted built‑in appliances adjacent to combustible cabinetry — the code prohibits installation of unlisted built‑in units in or adjacent to combustible material (see § 919.5.1).
- Failing to follow the manufacturer’s installation instructions for electric ranges (UL 858) and other listed equipment — the CMC explicitly defers to listings and manufacturer guidance (see § 919.2 and § 919.5.1).
- Not keeping the appliance level (tilted ovens or racks) — § 919.6 requires cooking tops, broiler pans and oven racks to be level.
Worked example — concrete scenario
Scenario: You are installing a gas cooktop (built‑in top) under upper cabinets.
- Confirm the cooktop is a listed household cooking appliance (CSA/ANSI Z21.1) and read the manufacturer’s installation instructions — § 919.1 and § 919.5.1.
- Measure vertical clearance from the cooking surface to the underside of the cabinet:
- If you can provide 30 in (762 mm), you meet the default requirement — § 919.5.2.
- If the cabinet underside would be 24 in (610 mm) above the cooking top, you may still comply if you install either:
- 1/4 in (6.4 mm) insulating millboard covered with sheet metal ≥ 0.0122 in (0.3099 mm) thick under the cabinet (meets § 919.5.2(1)), or
- A metal ventilating hood made of sheet metal ≥ 0.0122 in thick, centered over and at least as wide as the appliance, and spaced at least 1/4 in (6.4 mm) from the cabinet underside (meets § 919.5.2(2)), or
- Use an approved listed appliance above the cooktop and follow that appliance’s listing and installation instructions (meets § 919.5.2(3)).
- Make sure the cooktop is level when installed so oven racks / broiler pans are level — § 919.6.
Related provisions
- § 919.2 — Electric household cooking appliances (manufacturer instructions; UL 858).
- § 919.5 — Built‑in units: installation, vertical clearances and listing requirements.
- § 917.4 — Installation on noncombustible floors (related floor‑construction guidance referenced by appliance sections).
- § 920.0 / § 920.1 — Cooking appliance listings and commercial range rules (related listing and classification guidance).
Code references
Grounded in the retrieved California Mechanical Code — click a citation to read the verbatim passage:
CMC § 919.0 High relevance — show source text
919.0 Household Cooking Appliances. . . 209
919.1 Application . . . . . . . . . . . . . . . . . . 209
919.2 Electric Household Cooking Appliances . . . . . . . . . . . . . . . . . . 209
919.3 Gas-Fired Household Cooking Appliances . . . . . . . . . . . . . . . . . . 209
919.4 Floor-Mounted Units . . . . . . . . . . . 210
919.5 Built-In Units . . . . . . . . . . . . . . . . . 210
919.6 Level Installation. . . . . . . . . . . . . . 210
920.0 Cooking Appliance Listings . . . . . 210
920.1 Commercial Electric Ranges . . . . 210
920.2 Commercial Wood-Fired
Baking Ovens . . . . . . . . . . . . . . . . 210
920.3 Oil-Burning Ranges . . . . . . . . . . . 210
921.0 Open-Top Broiler Units. . . . . . . . . 210
921.1 Application . . . . . . . . . . . . . . . . . . 210
921.2 Protection Above Domestic Units. . 210
2025 CALIFORNIA MECHANICAL CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
TABLE OF CONTENTS
921.3 Commercial Units . . . . . . . . . . . . . 210
922.0 Outdoor Cooking Appliances . . . . 210
922.1 Application . . . . . . . . . . . . . . . . . . 210
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
CMC § 919.0 High relevance — show source text
919.0 Household Cooking Appliances. 919.1 Application. Household cooking appliances shall be listed in accordance with CSA/ANSI Z21.1/CSA 1.1. [NFPA 54:10.13.1] 919.2 Electric Household Cooking Appliances. Electric household cooking appliances designed for permanent installations shall be installed in accordance with the manufacturer’s installation instructions. Household electric ranges shall comply with UL 858.
919.3 Gas-Fired Household Cooking Appliances. Gas-fired household cooking appliances shall comply with Section 919.4 though Section 919.6.
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installed in accordance with Section 917.4 or be installed in accordance with one of the following:
(1) Where the appliance is set on legs that provide not less than 18 inches (457 mm) open space under the base of the appliance or where it has no burners and no portion of any oven or broiler within 18 inches (457 mm) of the floor, it shall be permitted to be installed on a combustible floor without special floor protection, provided at least one sheet metal baffle is between the burner and the floor.
(2) Where the appliance is set on legs that provide not less than 8 inches (203 mm) open space under the base of the appliance, it shall be permitted to be installed on combustible floors, provided the floor under the appliance is protected with not less than 3 ⁄ 8 of an inch (9.5 mm) insulating millboard covered with sheet metal not less than 0.0195 of an inch (0.4953 mm) thick. The preceding specified floor protection shall extend not less than 6 inches (152 mm) beyond the appliance on all sides.
(3) Where the appliance is set on legs that provide not less than 4 inches (102 mm) under the base of the appliance, it shall be permitted to be installed on combustible floors, provided the floor under the appliance is protected with hollow masonry not less than 4 inches (102 mm) in thickness covered with sheet metal not less than 0.0195 of an inch (0.4953 mm) thick. Such masonry courses shall be laid with ends unsealed and joints matched in such a way as to provide for free circulation of air through the
masonry.
(4) Where the appliance does not have legs at least 4 inches (102 mm) high, it shall be permitted to be installed on combustible floors, provided the floor under the appliance is protected by two courses of 4 inch (102 mm) hollow clay tile, or equivalent, with courses laid at right angles and with ends unsealed and joints matched in such a way as to provide for free circulation of air through such masonry courses, and covered with steel plate not less than [3] ⁄ 16 of an inch (4.8 mm) in thickness. [NFPA 54:10.11.3.2]
917.4 Installation on Noncombustible Floors. Floorinstalled food service appliances that are designed and marked “For use only in noncombustible locations” shall be installed on floors of noncombustible construction with noncombustible flooring and surface finish and with no combustible material against the underside thereof, or on noncombustible slabs or arches having no combustible material against the underside thereof. Such construction shall in all cases extend not less than 12 inches (305 mm) beyond the appliance on all sides.
CMC § 918.0 High relevance — show source text
918.0 Food Service Appliances, Counter Appliances.
918.1 Application. Food service counter appliances shall be listed in accordance with ANSI Z83.11/CSA 1.8. [NFPA 54:10.12.1]
918.2 Vertical Clearance. A vertical distance of not less than 48 inches (1219 mm) shall be provided between the top of all food service hot plates and griddles and combustible material. [NFPA 54:10.12.2]
918.3 Clearance for Listed Appliances. Listed food service counter appliances such as hot plates and griddles, food and dish warmers, and coffee brewers and urns, where installed on combustible surfaces, shall be set on their own bases or legs and shall be installed with a horizontal clearance of not less than 6 inches (152 mm) from combustible material, except that not less than a 2 inches (51 mm) clearance shall be maintained between a draft hood and combustible material. Food service counter appliances listed for installation at lesser clearances shall be installed in accordance with their listing and the manufacturer’s installation instructions.
918.4 Clearance for Unlisted Appliances. Food service counter appliances, where installed on combustible surfaces, shall be installed with a minimum horizontal clearance of 6 inches (152 mm) from combustible material, except that at least a 2 inch (51 mm) clearance shall be maintained between a draft hood and combustible material. Food service counter appliances listed for installation at lesser clearances shall be installed in accordance with the manufacturer’s installation instructions. [NFPA 54:10.12.3]
919.0 Household Cooking Appliances. 919.1 Application. Household cooking appliances shall be listed in accordance with CSA/ANSI Z21.1/CSA 1.1. [NFPA 54:10.13.1] 919.2 Electric Household Cooking Appliances. Electric household cooking appliances designed for permanent installations shall be installed in accordance with the manufacturer’s installation instructions. Household electric ranges shall comply with UL 858.
919.3 Gas-Fired Household Cooking Appliances. Gas-fired household cooking appliances shall comply with Section 919.4 though Section 919.6.
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installed in accordance with Section 917.4 or be installed in accordance with one of the following:
(1) Where the appliance is set on legs that provide not less than 18 inches (457 mm) open space under the base of the appliance or where it has no burners and no portion of any oven or broiler within 18 inches (457 mm) of the floor, it shall be permitted to be installed on a combustible floor without special floor protection, provided at least one sheet metal baffle is between the burner and the floor.
(2) Where the appliance is set on legs that provide not less than 8 inches (203 mm) open space under the base of the appliance, it shall be permitted to be installed on combustible floors, provided the floor under the appliance is protected with not less than 3 ⁄ 8 of an inch (9.5 mm) insulating millboard covered with sheet metal not less than 0.0195 of an inch (0.4953 mm) thick. The preceding specified floor protection shall extend not less than 6 inches (152 mm) beyond the appliance on all sides.
CMC § 6.4 High relevance — show source text
(1) The underside of the combustible material or metal cabinet above the cooking top is protected with not less than [1] ⁄ 4 of an inch (6.4 mm) insulating millboard covered with sheet metal not less than 0.0122 of an inch (0.3099 mm) thick.
(2) A metal ventilating hood of sheet metal not less than 0.0122 of an inch (0.3099 mm) thick is installed above the cooking top with a clearance of not less than [1] ⁄ 4 of an inch (6.4 mm) between the hood and the underside of the combustible material or metal
cabinet, and the hood is not less than the width of the appliance and is centered over the appliance.
(3) A listed cooking appliance or microwave oven installed over a listed cooking appliance shall be in accordance with the terms of the upper appliance’s listing and the manufacturer’s installation instructions. {NFPA 54:10.13.3.1} Microwave ovens shall comply with UL 923.
919.5 Built-In Units. Built-in units shall be installed in accor dance with Section 919.5.1 and Section 919.5.2.
919.5.1 Installation. Listed built-in household cooking appliances shall be installed in accordance with their listing and the manufacturer’s installation instructions. The installation shall not interfere with combustion air, accessibility for operation, and servicing. Unlisted builtin household cooking appliances shall not be installed in or adjacent to combustible material.
919.5.2 Vertical Clearance Above Cooking Top. Built-in top (or surface) cooking appliances shall have a vertical clearance above the cooking top of not less than 30 inches (762 mm) to combustible material or metal cabinets. A clearance of not less than 24 inches (610 mm) is permitted where one of the following is installed:
(1) The underside of the combustible material or metal cabinet above the cooking top is protected with not less than [1] ⁄ 4 of an inch (6.4 mm) insulating millboard covered with sheet metal not less than 0.0122 of an inch (0.3099 mm) thick.
(2) A metal ventilating hood of sheet metal not less than 0.0122 of an inch (0.3099 mm) thick is installed above the cooking top with a clearance of not less
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than [1] ⁄ 4 of an inch (6.4 mm) between the hood and the underside of the combustible material or metal
cabinet, and the hood not less than the width of the appliance and is centered over the appliance.
(3) A listed cooking appliance or microwave oven installed over a listed cooking appliance shall be in accordance with the terms of the upper appliance’s listing and the manufacturer’s installation instructions. Microwave ovens shall comply with UL 923.
919.6 Level Installation. Cooking appliances shall be installed so that the cooking top, broiler pan, or oven racks are level. [NFPA 54-2018:10.14.3]
920.0 Cooking Appliance Listings.
920.1 Commercial Electric Ranges. Commercial electric ranges shall comply with UL 197 and installed in accordance with the manufacturer’s installation instructions.
CMC § 916.7 High relevance — show source text
Garages and Aircraft Hangars . . . 208
916.7 Oil-Fired Unit Heaters. . . . . . . . . . 208
917.0 Food Service Appliance, FloorMounted . . . . . . . . . . . . . . . . . . . . 208
917.1 Application . . . . . . . . . . . . . . . . . . 208
917.2 Clearance for Listed Appliances. . . 208
917.3 Mounting on Combustible Floors . . . . . . . . . . . . . . . . . . . . . . 208
917.4 Installation on Noncombustible
Floors . . . . . . . . . . . . . . . . . . . . . . 209
917.5 Combustible Material
Adjacent to Cooking Top . . . . . . . 209
917.6 Use with Casters . . . . . . . . . . . . . 209
917.7 Level Installation. . . . . . . . . . . . . . 209
917.8 Ventilation. . . . . . . . . . . . . . . . . . . 209
918.0 Food Service Appliances, Counter Appliances . . . . . . . . . . . 209
918.1 Application . . . . . . . . . . . . . . . . . . 209
918.2 Vertical Clearance . . . . . . . . . . . . 209
918.3 Clearance for Listed Appliances. . . 209
918.4 Clearance for Unlisted
Appliances . . . . . . . . . . . . . . . . . . 209
919.0 Household Cooking Appliances. . . 209
919.1 Application . . . . . . . . . . . . . . . . . . 209
919.2 Electric Household Cooking Appliances . . . . . . . . . . . . . . . . . . 209
919.3 Gas-Fired Household Cooking Appliances . . . . . . . . . . . . . . . . . . 209
919.4 Floor-Mounted Units . . . . . . . . . . . 210
919.5 Built-In Units . . . . . . . . . . . . . . . . . 210
919.6 Level Installation. . . . . . . . . . . . . . 210
920.0 Cooking Appliance Listings . . . . . 210
920.1 Commercial Electric Ranges . . . . 210
920.2 Commercial Wood-Fired
Baking Ovens . . . . . . . . . . . . . . . . 210
920.3 Oil-Burning Ranges . . . . . . . . . . . 210
921.0 Open-Top Broiler Units. . . . . . . . . 210
921.1 Application . . . . . . . . . . . . . . . . . . 210
921.2 Protection Above Domestic Units. . 210
2025 CALIFORNIA MECHANICAL CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
TABLE OF CONTENTS
921.3 Commercial Units . . . . . . . . . . . . . 210
922.0 Outdoor Cooking Appliances . . . . 210
CMC § 10.11.4.1 High relevance — show source text
[NFPA 54:10.11.4.1, 10.11.4.2] 917.5 Combustible Material Adjacent to Cooking Top. Food service ranges shall be installed to provide clearance to combustible material of not less than 18 inches (457 mm) horizontally for a distance up to 2 feet (610 mm) above the surface of the cooking top where the combustible material is not completely shielded by high shelving, a warming closet, or other system. Reduced combustible material clearances are
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2025 CALIFORNIA MECHANICAL CODE 209
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INSTALLATION OF SPECIFIC APPLIANCES
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919.4 Floor-Mounted Units. Floor mounted units shall be
installed in accordance with Section 919.4.1 and Section
919.4.2.
919.4.1 Clearances. Floor-mounted household cooking appliances, where installed on combustible floors, shall be set on their own bases or legs and shall not interfere with combustion air, accessibility for operation, and servicing. [NFPA 54:10.13.3]
919.4.2 Vertical Clearance Above Cooking Top. Household cooking appliances shall have a vertical clearance above the cooking top of not less than 30 inches (762 mm) to combustible material or metal cabinets. A minimum clearance of 24 inches (610 mm) shall be permitted where one of the following is installed:
(1) The underside of the combustible material or metal cabinet above the cooking top is protected with not less than [1] ⁄ 4 of an inch (6.4 mm) insulating millboard covered with sheet metal not less than 0.0122 of an inch (0.3099 mm) thick.
(2) A metal ventilating hood of sheet metal not less than 0.0122 of an inch (0.3099 mm) thick is installed above the cooking top with a clearance of not less than [1] ⁄ 4 of an inch (6.4 mm) between the hood and the underside of the combustible material or metal
cabinet, and the hood is not less than the width of the appliance and is centered over the appliance.
(3) A listed cooking appliance or microwave oven installed over a listed cooking appliance shall be in accordance with the terms of the upper appliance’s listing and the manufacturer’s installation instructions. {NFPA 54:10.13.3.1} Microwave ovens shall comply with UL 923.
919.5 Built-In Units. Built-in units shall be installed in accor dance with Section 919.5.1 and Section 919.5.2.
919.5.1 Installation. Listed built-in household cooking appliances shall be installed in accordance with their listing and the manufacturer’s installation instructions. The installation shall not interfere with combustion air, accessibility for operation, and servicing. Unlisted builtin household cooking appliances shall not be installed in or adjacent to combustible material.
CMC § 0.4719 Medium relevance — show source text
1 cubic foot per minute = 0.4719 L/s
508.5.1.4 Medium-Duty Cooking Appliances. The minimum net airflow for hoods used for cooking appliances such as electric and gas hot-top ranges, gas open-burner ranges (with or without oven), elec
TYPE OF HOOD AIRFLOW (cubic foot per minute
per linear foot of hood)
Backshelf/pass-over300
Double island canopy (per side)300
Eyebrow250
Single island canopy500
Wall-mounted canopy300 TABLE 508.5.1.5
LIGHT-DUTY COOKING APPLIANCE AIRFLOW
TYPE OF HOOD AIRFLOW (cubic foot per minute
per linear foot of hood)
Backshelf/pass-over250 Double island canopy (per side) 250
Eyebrow250
Single island canopy400
Wall-mounted canopy200 For SI units: 1 foot = 304.8 mm, 1 cubic foot per minute = 0.0283 m [3] /min,
1 cubic foot per minute = 0.4719 L/s
508.5.2 Noncanopy-Type Hoods. Noncanopy-type commercial cooking hoods shall be installed and sized in accordance with the manufacturer’s installation instruc tions, and Section 508.5.2.1 and Section 508.5.2.2.
Exception: Listed hood assemblies designed and installed specifically for the intended use.
tric and gas flat griddles, electric and gas doublesided griddles, electric and gas fryers (including open deep fat fryers, donut fryers, kettle fryers, tortilla chip fryers, and pressure fryers), electric and gas smokers, and electric and gas conveyor pizza ovens shall be in accordance with Table 508.5.1.4.
TABLE 508.5.1.4
MEDIUM-DUTY COOKING APPLIANCE AIRFLOW
For SI units: 1 foot = 304.8 mm, 1 cubic foot per minute = 0.0283 m [3] /min,
508.5.1.5 Light-Duty Cooking Appliances. The minimum net airflow for hoods used for cooking appliances such as gas and electric ovens (including standard, bake, roasting, revolving, retherm, convection, combination convection/steamer, rotisserie, countertop conveyorized baking/finishing, deck, and pastry), discrete element ranges (with or without oven), electric and gas steam-jacketed kettles less than 20 gallons (76 L), electric and gas pasta cookers, electric and gas compartment steamers (both pressure and atmospheric), electric and gas cheese melters, electric and gas tilting skillets (braising pans) electric and gas rotisseries, and electric and gas salamanders shall be in accordance with Table 508.5.1.5.
TABLE 508.5.1.4
MEDIUM-DUTY COOKING APPLIANCE AIRFLOW
For SI units: 1 foot = 304.8 mm, 1 cubic foot per minute = 0.0283 m [3] /min,
CMC § 10.11.2 Medium relevance — show source text
** Floor-mounted food service appliances, such as ranges for hotels and restaurants, deep fat fryers, unit broilers, kettles, steam cookers, steam generators, and baking and roasting ovens, shall be installed not less than 6 inches (152 mm) from combustible material except that at least a 2 inch (51 mm) clearance shall be maintained between a draft hood and combustible material. Floor-mounted food service appliances listed for installation at lesser clearances shall be installed in accordance with its listing and the manufacturer’s installation instructions. Appliances designed and marked, “For use only in noncombustible locations,” shall not be installed elsewhere. [NFPA 54:10.11.2] 917.3 Mounting on Combustible Floors. Floor-mounted food service appliances that are listed specifically for installation on floors constructed of combustible material shall be permitted to be installed on combustible floors in accordance with its listing and the manufacturer’s installation instructions. [NFPA 54:10.11.3.1]
917.3.1 Not Listed for Mounting on Combustible Floors. Floor-mounted food service appliances that are not listed for installation on a combustible floor shall be
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such as to interfere with combustion air and accessibility. Unlisted room heaters shall be installed with clearances from combustible material not less than the following:
(1) Circulating type room heaters having an outer jacket surrounding the combustion chamber, arranged with openings at top and bottom so that air circulates between the inner and outer jacket, and without openings in the outer jacket to permit direct radiation, shall have clearance at sides and rear of not less than 12 inches (305 mm).
(2) Radiating type room heaters other than those of the circulating type described in Section 915.3.3(1) shall have clearance at sides and rear of not less than 18 inches (457 mm), except that heaters that make use of metal, asbestos, or ceramic material to direct radiation to the front of the heater shall have a clearance of 36 inches (914 mm) in front and, where constructed with a double back of metal or ceramic, shall be permitted to be installed with a clearance of 18 inches (457 mm) at sides and 12 inches (305 mm) at rear. Combustible floors under unlisted room heaters shall be protected in an approved manner.
915.3.4 Wall-Mounted Room Heaters. Wall mounted room heaters shall not be installed in or attached
to walls of combustible material unless listed for such installation. [NFPA 54:10.21.4]
915.4 Solid-Fuel Type Room Heaters. Solid-fuel type room heaters shall comply with UL 1482.
916.0 Unit Heaters.
916.1 Application. Unit heaters shall be listed in accordance with ANSI Z83.8/CSA 2.6 and installed in accordance with the manufacturer’s installation instructions. [NFPA 54:10.24.1]
916.2 Support. Suspended-type unit heaters shall be safely and adequately supported, with due consideration given to their weight and vibration characteristics. Hangers and brackets shall be of noncombustible material. [NFPA 54:10.24.2]
916.3 Clearance for Suspended-Type Unit Heaters. Suspended-type unit heaters shall comply with the following requirements:
CMC § 508.5.1.4. Medium relevance — show source text
tric and gas flat griddles, electric and gas doublesided griddles, electric and gas fryers (including open deep fat fryers, donut fryers, kettle fryers, tortilla chip fryers, and pressure fryers), electric and gas smokers, and electric and gas conveyor pizza ovens shall be in accordance with Table 508.5.1.4.
TABLE 508.5.1.4
MEDIUM-DUTY COOKING APPLIANCE AIRFLOW
For SI units: 1 foot = 304.8 mm, 1 cubic foot per minute = 0.0283 m [3] /min,
508.5.1.5 Light-Duty Cooking Appliances. The minimum net airflow for hoods used for cooking appliances such as gas and electric ovens (including standard, bake, roasting, revolving, retherm, convection, combination convection/steamer, rotisserie, countertop conveyorized baking/finishing, deck, and pastry), discrete element ranges (with or without oven), electric and gas steam-jacketed kettles less than 20 gallons (76 L), electric and gas pasta cookers, electric and gas compartment steamers (both pressure and atmospheric), electric and gas cheese melters, electric and gas tilting skillets (braising pans) electric and gas rotisseries, and electric and gas salamanders shall be in accordance with Table 508.5.1.5.
TABLE 508.5.1.4
MEDIUM-DUTY COOKING APPLIANCE AIRFLOW
For SI units: 1 foot = 304.8 mm, 1 cubic foot per minute = 0.0283 m [3] /min,
1 cubic foot per minute = 0.4719 L/s
2025 CALIFORNIA MECHANICAL CODE 113
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EXHAUST SYSTEMS
508.5.2.1 Installation. Noncanopy-type commercial cooking hoods shall be installed with the edge of the hood set back not more than 1 foot (305 mm) from the edge of the cooking surface, and the vertical distance between the lip of the hood and the cooking surface shall not exceed 3 feet (914 mm). 508.5.2.2 Capacity. In addition to other requirements for hoods specified in this section, the volume of air exhausting through a noncanopy-type hood to the duct system shall be not less than 300 cubic feet per minute per lineal foot [(ft [3] /min)/ft)] [0.464 (m [3] /s)/m] of cooking equipment. Listed noncanopy exhaust hoods and filters shall be sized and installed in accordance with the terms of their listing and the manufacturer’s installation instructions.
508.5.3 Labeling. Type I hoods shall bear a label indicating the exhaust flow rate in cubic feet per minute per lineal foot [(m [3] /s)/m].
508.6 Solid-Fuel Hood Assemblies. Where solid-fuel cooking equipment is to be used, the solid-fuel hood assembly shall be in accordance with Section 517.0.
508.7 Exhaust Outlets. An exhaust outlet within an unlisted hood shall be located so as to optimize the capture of particulate matter. Each outlet shall serve not more than a 12 foot (3658 mm) section of an unlisted hood.
CMC § 25.4 Medium relevance — show source text
(1) Unit heaters shall be installed with clearances from combustible material of not less than 18 inches (457 mm) at the sides, 12 inches (305 mm) at the bottom, and 6 inches (152 mm) above the top where the unit heater has an internal draft hood, or 1 inch (25.4 mm) above the top of the sloping side of a vertical draft hood. A unit heater listed for reduced clearances shall be installed in accordance with its listing and the manufacturer’s installation instructions.
(2) Clearances for servicing shall be in accordance with the manufacturer’s installation instructions. {NFPA 54:10.24.3}
916.3.1 Floor-Mounted-Type Unit Heaters. Floormounted-type unit heaters shall comply with the following requirements:
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208 2025 CALIFORNIA MECHANICAL CODE
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
INSTALLATION OF SPECIFIC APPLIANCES
permitted where protected in accordance with Table 303.10.1.
[NFPA 54:10.11.5] 917.6 Use with Casters. Floor-mounted appliances with casters shall be listed for such construction and shall be
installed in accordance with the manufacturer’s installation instructions for limiting the movement of the appliance to prevent strain on the connection. [NFPA 54:10.11.6]
917.7 Level Installation. Floor-mounted food service appliances shall be installed level on a firm foundation.
[NFPA 54:10.11.7]
917.8 Ventilation. Means shall be provided to properly ventilate the space in which a food service appliance is installed to permit proper combustion of the gas. [NFPA 54:10.11.8]
918.0 Food Service Appliances, Counter Appliances.
918.1 Application. Food service counter appliances shall be listed in accordance with ANSI Z83.11/CSA 1.8. [NFPA 54:10.12.1]
918.2 Vertical Clearance. A vertical distance of not less than 48 inches (1219 mm) shall be provided between the top of all food service hot plates and griddles and combustible material. [NFPA 54:10.12.2]
918.3 Clearance for Listed Appliances. Listed food service counter appliances such as hot plates and griddles, food and dish warmers, and coffee brewers and urns, where installed on combustible surfaces, shall be set on their own bases or legs and shall be installed with a horizontal clearance of not less than 6 inches (152 mm) from combustible material, except that not less than a 2 inches (51 mm) clearance shall be maintained between a draft hood and combustible material. Food service counter appliances listed for installation at lesser clearances shall be installed in accordance with their listing and the manufacturer’s installation instructions.
918.4 Clearance for Unlisted Appliances. Food service counter appliances, where installed on combustible surfaces, shall be installed with a minimum horizontal clearance of 6 inches (152 mm) from combustible material, except that at least a 2 inch (51 mm) clearance shall be maintained between a draft hood and combustible material. Food service counter appliances listed for installation at lesser clearances shall be installed in accordance with the manufacturer’s installation instructions. [NFPA 54:10.12.3]
CMC § 916.4 Medium relevance — show source text
vent instead of the rear wall of the unit heater. A unit
heater listed for reduced clearances shall be installed in accordance with its listing and the manufacturer’s installation instructions.
(2) Floor-mounted-type unit heaters installed on combustible floors shall be listed for such installation.
(3) Combustible floors under unlisted floor-mounted unit heaters shall be protected in an approved man ner.
(4) Clearances for servicing shall be in accordance with the manufacturer’s instructions.
916.4 Combustion and Circulating Air. Combustion and circulating air shall be provided in accordance with Section 701.0. [NFPA 54:10.24.4]
916.5 Ductwork. A unit heater shall not be attached to a warm air duct system unless listed and marked for such installation. [NFPA 54:10.24.5] 916.6 Installation in Commercial Garages and Air- craft Hangars. Unit heaters installed in garages for more than three motor vehicles or in aircraft hangars shall be installed in accordance with Section 303.11 and Section 303.12. [NFPA 54:10.24.6]
916.7 Oil-Fired Unit Heaters. Oil-fired unit heaters shall comply with UL 731 and installed in accordance with the manufacturer’s installation instructions.
917.0 Food Service Appliance, Floor-Mounted. 917.1 Application. Floor-mounted food service appliances shall be listed in accordance with ANSI Z83.11/CSA 1.8.
[NFPA 54:10.11.1] 917.2 Clearance for Listed Appliances. Floor-mounted food service appliances, such as ranges for hotels and restaurants, deep fat fryers, unit broilers, kettles, steam cookers, steam generators, and baking and roasting ovens, shall be installed not less than 6 inches (152 mm) from combustible material except that at least a 2 inch (51 mm) clearance shall be maintained between a draft hood and combustible material. Floor-mounted food service appliances listed for installation at lesser clearances shall be installed in accordance with its listing and the manufacturer’s installation instructions. Appliances designed and marked, “For use only in noncombustible locations,” shall not be installed elsewhere. [NFPA 54:10.11.2] 917.3 Mounting on Combustible Floors. Floor-mounted food service appliances that are listed specifically for installation on floors constructed of combustible material shall be permitted to be installed on combustible floors in accordance with its listing and the manufacturer’s installation instructions. [NFPA 54:10.11.3.1]
917.3.1 Not Listed for Mounting on Combustible Floors. Floor-mounted food service appliances that are not listed for installation on a combustible floor shall be
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such as to interfere with combustion air and accessibility. Unlisted room heaters shall be installed with clearances from combustible material not less than the following:
(1) Circulating type room heaters having an outer jacket surrounding the combustion chamber, arranged with openings at top and bottom so that air circulates between the inner and outer jacket, and without openings in the outer jacket to permit direct radiation, shall have clearance at sides and rear of not less than 12 inches (305 mm).
CMC § 120.8 Medium relevance — show source text
8, 120.8(a), 120.8(d) Supply 140.4(e)1, 140.4(f)2, 170.2(c)4C, D, O Temperature 140.4(b)2, 140.4(b)3, 140.4(j), 150.0(h), 160.3(b)2, 170.2(c)2, 170.2(c)4H Ventilation 120.1(d), 120.6(c)7, 160.2(b)2A, 160.2(c)5 Wattage 120.6(c), 120.6(d)3, 120.6(j)3, 120.9(b), 140.4(k)6, 160.4(e)2, 170.2(c)4I Zone 140.4(d), 170.2(c)4B Designated Efficiency 120.1(c)1B, 150.0(m)12C, 160.2(b)1C, 160.2(c)1B Designated Solar Zone 110.10(b)1A, 110.10(b)1B Diagnostic Evaluation 140.3(a)9, 141.0(b)2Q Diagnostic Testing 10-103(a)5, 110.1(c), 120.4(g)1, 141.0(b)2D, 141.0(b)2E, 150.0(m)1, 150.0(m)11, 150.0(m)13, 150.0(o), 150.1(c)7, 150.1(c)9, 150.1(c)10, 150.2(b)1D, 150.2(b)1E, 150.2(b)1F, 150.2(b)1M, 160.2(a)1, 160.2(b)2B, 160.3(b)5, 160.3(c)2H, 170.2(c)3B, 180.1(b)3, 180.2(b)2, 180.2(b)5 Differential Pressure 140.4(k)6, 170.2(c)4I Dimming Controls 150.0(k)2, 160.5(a)2 Direct Digital Control (DDC) 110.12(b), 120.1(d), 120.2(b), 120.2(e), 120.2(i), 120.2(j), 120.2(k), 140.4(c)2, 140.4(d), 140.4(k)6, 160.3(a)2, 170.2(c)4A, B, I Direct Expansion (DX) 140.4(a), 140.4(e)2, 140.4(m), 170.2(c)4K Direct Expansion (DX) Unit Requirements for Cooling Stages and Compressor Displacement Table 140.4-H, Table 170.2-H Direct Sunlight 130.1(d), 140.3(a)6E, 140.3(d), 140.4(e)2D, 150.1(c)4, 160.5(b)4D, 170.2(a)3B, 170.2(c)4C Directional Inlets 110.4(b) Directory 110.0(b), 110.1(b), 150.
Frequently asked questions
Can I reduce the 30‑inch clearance over a household range?
Yes — a 24‑inch clearance is permitted only where one of the protections in § 919.4.2 (floor‑mounted) or § 919.5.2 (built‑in top) is provided: either insulating millboard + sheet metal, a metal ventilating hood meeting the thickness/spacing criteria, or a listed upper appliance installed per its listing.
Do electric ranges have the same clearance rules as gas ranges?
The CMC requires electric household cooking appliances be installed per the manufacturer and listed (UL 858 for ranges) — § 919.2 — but the vertical‑clearance rules above (§ 919.4.2 / § 919.5.2) apply to household cooking appliances generally; always check the appliance listing and instructions for any manufacturer‑specific clearances.
What does “listed” mean here?
“Listed” means the appliance is evaluated and marked for sale and installation in accordance with the referenced standard (for household cooking appliances: CSA/ANSI Z21.1/CSA 1.1) as required by § 919.1.
Can I install an unlisted built‑in cooktop next to wood cabinets?
No. Unlisted built‑in household cooking appliances shall not be installed in or adjacent to combustible material per § 919.5.1. Use only listed appliances or follow an approved alternate method.
Do I need to level the appliance?
Yes. The code requires cooking tops, broiler pans, and oven racks to be level — § 919.6.
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