CMC · California Mechanical Code
Incinerators and crematories — field‑constructed vs factory‑built and residential limits
The California Mechanical Code (§ 924.1–§ 924.3) requires you to treat incinerators/crematories by category: field‑constructed commercial incinerators must be built to NFPA 82, factory‑built commercial crematories/ incinerators must be UL 2790 listed and installed per the manufacturer, and residential incinerators must be UL 791 listed and installed per the manufacturer; the CMC sections refer you to those standards for the technical details. **§ 924.1**, **§ 924.2**, **§ 924.3**
Last reviewed: July 6, 2026
What the code requires — plain English
- § 924.0 simply groups incinerator/crematory rules; the operative requirements are in the next sections. § 924.1 requires field‑constructed commercial‑industrial incinerators to be built and installed in accordance with NFPA 82. § 924.2 requires factory‑built commercial crematories (and factory‑built commercial incinerators) to comply with UL 2790 and be installed per the manufacturer’s instructions. § 924.3 requires residential incinerators to comply with UL 791 and be installed per the manufacturer’s instructions. § 924.1, § 924.2, § 924.3 .
The single most important rule: pick the right category (field‑constructed commercial, factory‑built commercial, or residential) and comply with the referenced standard (NFPA 82, UL 2790, or UL 791) and the manufacturer’s installation instructions. § 924.1, § 924.2, § 924.3 .
Requirements in detail
Summary first: the California Mechanical Code does not spell out construction details in these sections — it mandates compliance with nationally recognized standards and manufacturer instructions. The detailed engineering, clearances, stack heights, fire‑resistance, emissions controls, spark arrestors, etc., are found in the referenced standards (NFPA 82, UL 2790, UL 791) or in manufacturer literature; the CMC text directs you to those documents. § 924.1, § 924.2, § 924.3 .
Decision table — which path to follow
| Decision dimension | Typical value / test | Required action | Code Reference |
|---|---|---|---|
| Intended use | Commercial‑industrial incinerator (field‑constructed) | Design and install to NFPA 82 | § 924.1 |
| Product type | Factory‑built commercial incinerator/crematory | Use units listed to UL 2790 and follow manufacturer’s instructions | § 924.2 |
| Occupancy / setting | Residential incinerator (home use) | Use UL 791 listed residential incinerators; install per manufacturer | § 924.3 |
| Installation compliance | Manufacturer’s installation instructions | Mandatory for factory/listed equipment (both § 924.2 and § 924.3) | § 924.2, § 924.3 |
| Where details live | Construction/clearance/emissions metrics | See NFPA 82 (field) or UL 2790 / UL 791 (factory/residential) — CMC does not restate those measurements | § 924.1, § 924.2, § 924.3 |
Notes:
- The CMC text is short and prescriptive about the STANDARD to follow; it does not include the standard text. You must obtain NFPA 82, UL 2790, or UL 791 for the technical criteria referenced in § 924.1, § 924.2, and § 924.3 .
- For factory‑built listed equipment, following the manufacturer’s installation instructions is required by the CMC text for both commercial and residential listed units. § 924.2, § 924.3 .
What the CMC requires you to provide at permit time
- Evidence that the proposed equipment or construction method meets the referenced standard (listing or design submittal) — CMC sections point to the standard rather than listing explicit submittal contents. § 924.1, § 924.2, § 924.3 .
- Manufacturer documentation and installation instructions for factory‑built/listed units; for field‑constructed installations provide drawings and documentation showing NFPA 82 compliance. § 924.1, § 924.2, § 924.3 .
Exceptions & special cases
- The CMC sections do not publish exceptions in those subsections — they defer to the listed standards. If you need an exception (for example, an alternate construction approach, or a unit that is between “residential” and “commercial”), you must consult the referenced standard(s) and the Authority Having Jurisdiction (AHJ). § 924.1, § 924.2, § 924.3 .
- The CMC language is directive (comply with NFPA/UL). It does not itself define detailed operational limits (hours of burning, proximity to hazardous wildland), which may be covered by other codes (e.g., California Fire Code) or local ordinance. The CMC text for § 924 does not contain those operational restrictions; those are outside these specific sections. § 924.1, § 924.2, § 924.3 .
- If a product is not listed to UL 2790 (commercial) or UL 791 (residential), it will need to be treated as either a field‑constructed installation (follow NFPA 82 where applicable) or be denied for the intended use. The CMC does not offer alternative numeric limits in § 924.x; the referenced standards control. § 924.1, § 924.2, § 924.3 .
Common mistakes
- Assuming a generic “incinerator” can be installed anywhere without checking classification: you must decide whether the unit is field‑constructed commercial, factory‑built commercial, or residential and then follow the specific standard named in the code. § 924.1, § 924.2, § 924.3 .
- Relying only on the CMC text for detailed dimensions and clearances — the CMC points to NFPA/UL; it does not reproduce their technical criteria. § 924.1, § 924.2, § 924.3 .
- Installing a factory‑built unit but ignoring the manufacturer’s installation instructions — the CMC explicitly requires installation in accordance with the manufacturer for listed units. § 924.2, § 924.3 .
- Treating UL listing as “all‑inclusive” — while listing is mandatory per § 924.2/924.3 for the categories it covers, AHJs or other codes (fire code, local ordinances) can impose additional requirements not stated in § 924.x. § 924.2, § 924.3 .
Worked example — concrete scenario
Scenario: A small funeral home wishes to install a single‑unit, factory‑built crematory (commercial use) on its site.
Step 1 — classify the unit:
- This is a factory‑built commercial crematory, not a residential incinerator.
Step 2 — apply the CMC rule:
- The CMC requires factory‑built commercial incinerators/crematories to comply with UL 2790 and be installed in accordance with the manufacturer’s installation instructions. That is the controlling rule: § 924.2 .
Step 3 — submittal and installation:
- For plan review submit the UL 2790 listing for the model and the manufacturer’s installation manual (venting, clearances, structural support, access). The CMC text mandates compliance with UL 2790 and the manufacturer’s instructions — the CMC itself does not list the numeric clearances; those will be in the listing/manual and must be followed during installation per § 924.2 .
Example numbers (illustrative only — obtain exact values from the UL listing/manufacturer):
- Manufacturer manual says minimum clearance to combustibles = 24 in and required stack height = 20 ft above ground; you must show these on the plans and install exactly per manual. The CMC requires you to follow the manufacturer’s instructions (installation) for factory‑built units. § 924.2 .
Important: the numeric examples above are hypothetical; the CMC requires compliance with the manufacturer/UL listing, not these specific numbers. The standards (UL 2790 / UL 791 / NFPA 82) contain the technical criteria the inspector will check. § 924.2, § 924.3, § 924.1 .
Related provisions (CMC)
- § 923.0 Illuminating appliances — other appliance installation rules in nearby sections of the same chapter (see table of contents around § 923). § 923.0
- § 925.0 Infrared heaters — another appliance grouping in the same portion of the code (useful when reviewing appliance listing/installation practice). § 925.0
- For exhaust/duct and enclosure testing/listing practice see the CMC material addressing field‑applied vs factory‑built assemblies (example: § 507.4.6 on field‑applied and factory‑built grease duct enclosures) for analogous listing/installation expectations. § 507.4.6
(If you need operational limitations such as hours of burning, spark arrestors, or prohibitions near brush, consult the California Fire Code and local ordinances — those items appear outside § 924.x and are not restated in these CMC subsections.)
Code references
Grounded in the retrieved California Mechanical Code — click a citation to read the verbatim passage:
CMC § 923.5 High relevance — show source text
923.5 Appliance Pressure Regulators. Where an appliance pressure regulator is not supplied with an illuminating appliance and the service line is not equipped with a service pressure regulator, an appliance pressure regulator shall be installed in the line serving one or more illuminating appliances. [NFPA 54:10.14.5]
924.0 Incinerators and Crematories.
924.1 Field Constructed Commercial-Industrial
Incinerators. Field constructed commercial-industrial incin erators shall be constructed and installed in accordance with
NFPA 82.
924.2 Factory-Built Commercial Crematories. Factorybuilt commercial incinerators and crematories shall comply with UL 2790 and installed in accordance with the manufac turer’s installation instructions.
924.3 Residential Incinerators. Residential incinerators shall comply with UL 791 and installed in accordance with the manufacturer’s installation instructions.
925.0 Infrared Heaters.
925.1 Application. Infrared heaters having an input rating of 400 000 Btu/hr (117 kW) or less shall be listed in accordance with ANSI Z83.19/CSA 2.35 or ANSI Z83.20/CSA 2.34. [NFPA 54:10.16.1]
925.2 Support. Suspended-type infrared heaters shall be fixed in position independent of gas and electric supply lines. Hangers and brackets shall be of noncombustible material. Heaters subject to vibration shall be provided with vibrationisolating hangers. [NFPA 54:10.16.2]
925.3 Clearance. The installation of infrared heaters shall comply with the following clearance requirements:
(1) Listed heaters shall be installed with clearances from combustible material in accordance with their listing and the manufacturer’s installation instructions.
(2) Unlisted heaters shall be installed in accordance with clearances from combustible material acceptable to the Authority Having Jurisdiction.
(3) In locations used for the storage of combustible materials, signs shall be posted to specify the maximum per
«
«
«
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«
«
«
«
«
FLAME HEIGHT ABOVE
BURNER HEAD
(inches)MINIMUM CLEARANCE FROM
COMBUSTIBLE MATERIAL
(feet)*Col3
FLAME HEIGHT ABOVE
BURNER HEAD
(inches)HORIZONTAL VERTICAL 12 2 6
183 8
243 10
304 12 For SI units: 1 inch = 25.4 mm, 1 foot = 304.8 mm
- Measured from the nearest portion of the burner head.
2025 CALIFORNIA MECHANICAL CODE 211
), Copyright © 2025 IAPMO, and may not be used for any other purpose or distributed to any other persons or parties.
INSTALLATION OF SPECIFIC APPLIANCES
927.2 Clearance. Refrigerators shall be provided with clearances for ventilation at the top and back in accordance with the manufacturer’s instructions. Where such instructions are
CMC § 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
CMC § 10.14.2.1 High relevance — show source text
(457 mm). [NFPA 54:10.14.2.1(2)]
923.2.1 Open-Flame Type. Clearance shall comply with the following:
(1) Unlisted open-flame illuminating appliances installed outdoors shall have clearances from com bustible material not less than that specified in Table 923.2.1. The distance from ground level to the base of the burner shall be a minimum of 7 feet (2134 mm) where installed within 2 feet (610 mm) of walkways. Lesser clearances shall be permitted to be used where acceptable to the Authority Having Jurisdiction.
(2) Unlisted open-flame illuminating appliances installed outdoors shall be equipped with a limiting orifice or other limiting devices that maintain a flame height consistent with the clearance from combustible material, as given in Table 923.2.1.
(3) Appliances designed for flame heights in excess of 30 inches (762 mm) shall be approved. Such appliances shall be equipped with a safety shutoff device or automatic ignition.
(4) Clearances to combustible material from unlisted open-flame illuminating appliances shall be approved. [NFPA 54:10.14.2.2]
TABLE 923.2.1
CLEARANCES FOR UNLISTED OUTDOOR
OPEN-FLAME ILLUMINATING APPLIANCES
[NFPA 54:TABLE 10.14.2.2]
923.3 Mounting on Buildings. Illuminating appliances designed for installation on a wall or ceiling shall be securely attached to substantial structures in such a manner that they are not dependent on the gas piping for support. [NFPA 54:10.14.3]
923.4 Mounting on Posts. Illuminating appliances designed for installation on a post shall be securely and rigidly attached to a post. Posts shall be rigidly installed. The strength and rigidity of posts greater than 3 feet (914 mm) in height shall be at least equivalent to that of a 2 [1] ⁄ 2 inch (64 mm) diameter post constructed of 0.064 of an inch (1.626 mm) thick steel or a 1 inch (25.4 mm) Schedule 40 steel pipe. Posts 3 feet (914 mm) or less in height shall not be smaller than a 3 ⁄ 4 of an inch (19.1 mm) Schedule 40 steel pipe. Drain openings shall be provided near the base of posts where water collecting inside the posts is possible. [NFPA 54:10.14.4]
923.5 Appliance Pressure Regulators. Where an appliance pressure regulator is not supplied with an illuminating appliance and the service line is not equipped with a service pressure regulator, an appliance pressure regulator shall be installed in the line serving one or more illuminating appliances. [NFPA 54:10.14.5]
924.0 Incinerators and Crematories.
924.1 Field Constructed Commercial-Industrial
Incinerators. Field constructed commercial-industrial incin erators shall be constructed and installed in accordance with
NFPA 82.
924.2 Factory-Built Commercial Crematories. Factorybuilt commercial incinerators and crematories shall comply with UL 2790 and installed in accordance with the manufac turer’s installation instructions.
924.3 Residential Incinerators. Residential incinerators shall comply with UL 791 and installed in accordance with the manufacturer’s installation instructions.
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 § 605.5.1 High relevance — show source text
(a) Appliances employing open flame radiated heat shall have fixed and substantially constructed metallic guards located not less than 10 inches from the radiating flame and the guard members shall be spaced not more than 2 inches apart.
(b) Cabinet type appliances that are not provided with an inner combustion chamber and an air circulating space between the combustion chamber and the outer shell, shall have fixed and substantially constructed metallic guards located not less than 3 inches from the shell and spaced not more than 2 inches apart.
605.5.1 Guard against contact. The heating element or combustion chamber shall be permanently guarded so as to prevent accidental contact by persons or material.
605.5.2 Heating appliance installation and maintenance. Heating appliances shall be installed and maintained in accordance with the manufacturer’s instructions, the California Building Code, the International Fuel Gas Code, the California Mechanical Code and the California Electrical Code.
605.6 Unauthorized operation. It shall be a violation of this code for any person, user, firm or agent to continue the utilization of any device or appliance (the operation of which has been discontinued or ordered discontinued in accordance with Section 605.2) unless written authority to resume operation is given by the fire code official. Removing or breaking the means by which operation of the device is prevented shall be a violation of this code.
605.7 Incinerators. Commercial, industrial and residential-type incinerators and chimneys shall be constructed in accordance with California Building Code and the California Mechanical Code. Unless other approved means are provided for the prompt disposal of rubbish, an approved incinerator shall be provided and maintained for the disposal of combustible waste. Incinerators shall be constructed, located and maintained in such manner that waste material can be safely burned at any hour of the day, where local ordi- nances permit. Fuel-fired and garbage burning incinerators shall be constructed and maintained in conformance with NFPA 82-2019 Incinerators, Waste and Linen Handling Systems and Equipment or UL 791-2006 Standard for Residential Incinerators, whichever is applicable.
605.7.1 Residential incinerators. Residential incinerators shall be listed and labeled in accordance with UL 791.
605.7.2 Spark arrestor. Incinerators shall be equipped with an effective means for arresting sparks.
605.7.3 Restrictions. Where the fire code official determines that burning in incinerators located within 500 feet (152 m) of mountainous, brush or grass-covered areas will create an undue fire hazard because of atmospheric conditions, such burning shall be prohibited.
6-8 2025 CALIFORNIA FIRE CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
BUILDING SERVICES AND SYSTEMS
605.7.4 Time of burning. Burning shall take place only during approved hours.
605.7.5 Discontinuance. The fire code official is authorized to require incinerator use to be discontinued immediately if the fire code official determines that smoke emissions are offensive to occupants of surrounding property or if the use of incinerators is determined by the fire code official to constitute a hazardous condition.
605.7.6 Flue-fed incinerators in Group I-2. In Group I-2 occupancies, the continued use of existing flue-fed incinerators is prohibited.
CMC § 0.5 Medium relevance — show source text
in.|≤ 100 sq. in. =
D-H-90
>100 sq. in.=
D-H-W-90|Not
Permitted|2|Not
Permitted|W-120| |Double fire walls
constructed in
accordance with
NFPA 221|2|1|1|100 sq. in.|≤ 100 sq. in. =
D-H-60
> 100 sq. in. =
D-H-W-60|Not
Permitted|1|Not
Permitted|W-60| |Enclosures for
shafts, interior exit
stairways and inte-
rior exit ramps.|2|2|11/ 2|100 sq. in.b|≤100 sq. in. =
D-H-90
> 100 sq. in.=
D-H-T-W-90|Not
Permitted|2|Not
Permitted|W-120| |Horizontal exits in
fire wallsg|4|4|3|100 sq. in.|≤100 sq. in. =
D-H-180
> 100 sq. in.=
D-H-W-240|Not
Permitted|4|Not
Permitted|W-240| |Horizontal exits in
fire wallsg|3|3|3d|100 sq. in.|≤100 sq. in. =
D-H-180
> 100 sq. in.=
D-H-W-180|Not
Permitted|3|Not
Permitted|W-180| |Fire barriers having
a required fire-
resistance rating of
1 hour: Enclosures
for shafts, exit
access stairways,
exit access ramps,
interior exit stair-
ways and interior
exit ramps; and exit
passageway walls|1|1|1|100 sq. in.|≤100 sq. in. =
D-H-60
>100 sq. in.=
D-H-T-W-60|Not
Permitted|1|Not
Permitted|W-60| |||||||Fire protection|Fire protection||| |Other fire barriers|1|1|3/ 4|Maximum
size tested|D-H-45|3/ 4
h|3/ 4
h|D-H-45h|D-H-45h| |Fire partitions:
Corridor walls|1|1|1/ 3
a|Maximum
size tested|D-20|3/ 4
a|3/ 4
a|D-H-OH-45|D-H-OH-45| |Fire partitions:
Corridor walls|0.5|0.5|1/ 3
a|Maximum
size tested|D-20|1/ 3|1/ 3|D-H-OH-20|D-H-OH-20|7-28 2025 CALIFORNIA BUILDING CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
FIRE AND SMOKE PROTECTION FEATURES
|TABLE 716.1(2)—OPENING FIRE PROTECTION ASSEMBLIES,
CMC § 82-2019 Medium relevance — show source text
Incinerators shall be_ constructed, located and maintained in such manner that waste material can be safely burned at any hour of the day, where local ordi- nances permit. Fuel-fired and garbage burning incinerators shall be constructed and maintained in conformance with NFPA 82-2019 Incinerators, Waste and Linen Handling Systems and Equipment or UL 791-2006 Standard for Residential Incinerators, whichever is applicable.
605.7.1 Residential incinerators. Residential incinerators shall be listed and labeled in accordance with UL 791.
605.7.2 Spark arrestor. Incinerators shall be equipped with an effective means for arresting sparks.
605.7.3 Restrictions. Where the fire code official determines that burning in incinerators located within 500 feet (152 m) of mountainous, brush or grass-covered areas will create an undue fire hazard because of atmospheric conditions, such burning shall be prohibited.
6-8 2025 CALIFORNIA FIRE CODE
on Jul 18, 2025 11:14 AM (CDT) THEREUNDER.
BUILDING SERVICES AND SYSTEMS
605.7.4 Time of burning. Burning shall take place only during approved hours.
605.7.5 Discontinuance. The fire code official is authorized to require incinerator use to be discontinued immediately if the fire code official determines that smoke emissions are offensive to occupants of surrounding property or if the use of incinerators is determined by the fire code official to constitute a hazardous condition.
605.7.6 Flue-fed incinerators in Group I-2. In Group I-2 occupancies, the continued use of existing flue-fed incinerators is prohibited.
605.7.7 Incinerator inspections in Group I-2. Incinerators in Group I-2 occupancies shall be inspected not less than annually in accordance with the manufacturer’s instructions. Inspection records shall be maintained on the premises and made available to the fire code official upon request.
605.8 Gas meters. Above-ground gas meters, regulators and piping subject to damage shall be protected by a barrier complying with Section 312 or otherwise protected in an approved manner.
SECTION 606—COMMERCIAL COOKING EQUIPMENT AND SYSTEMS
[M] 606.1 General. Commercial kitchen exhaust hoods shall comply with the requirements of the California Mechanical Code .
[M] 606.2 Where required. A Type I hood shall be installed at or above all commercial cooking appliances and domestic cooking appliances used for commercial purposes that produce grease vapors.
Exceptions:
Factory-built commercial exhaust hoods that are listed and labeled in accordance with UL 710, and installed in accordance with Section 304.1 of the California Mechanical Code, shall not be required to comply with Sections 507.1.5, 507.2.3, 507.2.5, 507.2.8, 507.3.1, 507.3.3, 507.1.6 and 507.2.10 of the California Mechanical Code .
CMC § 4.420 Medium relevance — show source text
410|≥4.420|NA|AHRI
550/590| |Water
source
electri-
cally
operated
positive
displace-
ment|<75|≤0.7885
FL
≤0.6316
IPLV.IP|≤0.7875
FL
≤0.5145
IPLV.IP|75/655|NA|NA|NA|≥3.550|NA|NA|NA|6.150|6.150| |Water
source
electri-
cally
operated
positive
displace-
ment|≥75
and
<150|≤0.7579
FL
≤0.5895
IPLV.IP|≤0.7140
FL
≤0.4620
IPLV.IP|54/445|≥4.640|≥3.680|≥2.680|NA|≥8.330|≥6.410|≥4.420|NA|NA| |Water
source
electri-
cally
operated
positive
displace-
ment|≥75
and
<150|≤0.7579
FL
≤0.5895
IPLV.IP|≤0.7140
FL
≤0.4620
IPLV.IP|75/655|NA|NA|NA|≥3.550|NA|NA|NA|6.150|6.150| |Water
source
electri-
cally
operated
positive
displace-
ment|≥150
and
<300|≤0.6947
FL
≤0.5684
IPLV.IP|≤0.7140
FL
≤0.4620
IPLV.IP|54/445|≥4.640|≥3.680|≥2.680|NA|≥8.330|≥6.410|≥4.420|NA|NA| |Water
source
electri-
cally
operated
positive
displace-
ment|≥150
and
<300|≤0.6947
FL
≤0.5684
IPLV.IP|≤0.7140
FL
≤0.4620
IPLV.IP|75/655|NA|NA|NA|≥3.550|NA|NA|NA|6.150|6.150| |Water
source
electri-
cally
operated
positive
displace-
ment|≥300
and
<600|≤0.6421
FL
≤0.5474
IPLV.IP|≤0.6563
FL
≤0.4305
IPLV.IP|54/445|≥4.930|≥3.960|≥2.970|NA|≥8.900|≥6.CMC § 205.0 Medium relevance — show source text
CONSTRUCTION DOCUMENTS
Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205.0
For Permits . . . . . . . . . . . . . . . . . . . . . . . 103.3, 104.3.1
CONTAINERS FOR
Grease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 509.2.4.1
Liquid petroleum gas (LP-Gas) . . . . . . . . . . . . . D 104.3
Oil tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D 113.6.2
Refrigerants . . . . . . . . . . (see Refrigerants, containers)
CONTINUOUS ENCLOSURE . . . . . . . . . . . . . . 205.0, 510.7
COOLING
Air system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311.0
Coil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904.8
Evaporative cooling system . . . . . . . . . . . . 207.0, 932.0 System, definition . . . . . . . . . . . . . . . . . . . . . . . . . 205.0
Towers . . . . . . . . . . . . . . . . . . . . . . . Chapter 11 (Part II)
Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205.0, 904.9
COPPER OR COPPER
ALLOY PIPE AND TUBING . . . . . . . . . . . . . . . . . . . 1211.4
CORRUGATED STAINLESS STEEL
TUBING (CSST)
Bonding of . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1311.2
Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205.0
Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1310.3.5
Test pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1313.3
CREMATORIES
Factory built . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 925.3
CROSS-LINKED POLYETHYLENE (PEX)
PIPING OR TUBING
Definition. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 218.0
CMC § 4.3.2 Medium relevance — show source text
accordance with the manufacturer’s instructions and the listing requirements. [NFPA 96:4.3.2 – 4.3.2.2]
507.4.6 Both Field-Applied and Factory Built. Field-applied grease duct enclosures and factory-built
grease duct enclosures shall demonstrate that they provide mechanical and structural integrity, resiliency, and stability when subjected to expected building environmental conditions, duct movement under general operating conditions, and duct movement due to fire conditions.
[NFPA 96:4.3.5]
507.4.6.1 Physical Damage. Measures shall be taken to prevent physical damage to a material or product used for the purpose of reducing clearances.
Exception: Where the duct is protected with a fieldapplied grease duct enclosure or factory-built grease duct enclosure.
507.4.6.2 Specification. The specifications of material, gauge, and construction of the duct used in the testing and listing of field-applied grease duct enclosures and factory-built grease duct enclosures shall be included as minimum requirements in their listing and installation documentation. [NFPA 96:4.3.6]
507.4.6.3 Clearance Options. The following clearance options for which field-applied grease duct enclosures and factory-built grease duct enclosures have been successfully evaluated shall be clearly identified in their listing and installation documentation and on their labels:
(1) Open combustible construction clearance at manufacturer’s requested dimensions.
(2) Closed combustible construction clearance at manufacturer’s requested dimensions, with or without specified ventilation.
(3) Rated shaft clearance at manufacturer’s requested dimensions, with or without specified ventilation. [NFPA 96:4.3.7]
507.4.7 Building and Structural Contact. A duct shall be permitted to contact noncombustible floors, interior walls, and other noncombustible structures or supports, but it shall not be in contact for more than 50 percent of its surface area for each linear foot of contact length. [NFPA 96:4.4.1]
507.4.7.1 Corrosion Protection. Where duct contact must exceed the requirements of Section 507.4.7, the duct shall be protected from corrosion.
[NFPA 96:4.4.2]
507.4.7.2 Zero Clearance. Where the duct is
listed for zero clearance to combustibles or is otherwise protected with a material or product listed for the purpose of reducing clearance to zero, the duct shall be permitted to exceed the contact limits of Section 507.4.7 without additional corrosion protection. [NFPA 96:4.4.3]
507.4.8 Clearance Between Duct and Interior
Surfaces. Clearances between the duct and interior surfaces of enclosures shall meet the requirements of Section 507.4 through Section 507.4.3.3. [NFPA 96:4.5]
507.5 Drawings. For cooking operations in buildings, a drawing(s) of the exhaust system installation along with
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EXHAUST SYSTEMS
CMC § 1220.4.2 Medium relevance — show source text
8|1220.4.2 – 1220.4.6| |1221.7|1221.6| |1308.2 – 1308.4.1|1308.3 – 1308.5.1| |Table 1308.3.1|Table 1308.4.1| |1308.4.2|1308.5.2| |1308.4.2.2 – 1308.6.4|1308.5.2.1 – 1308.7.3| |Table 1308.4.6.2|Table 1308.5.6.2| |1308.6.5 – 1308.13.1|1308.7.7 – 1308.14.1| |1312.1.2 – 1312.1.3|1312.1.1 – 1312.1.2| |Chapter 17|Appendix F| |Chapter 18|Chapter 17| |D 103.2|D 103.1| |E 503.5.6.7|E 503.5.6.6| |E 503.5.7.2 – E 503.5.7.6|E 503.5.7.1 – E 503.5.7.5| |Table E 503.5.7.2|Table E 503.5.7.1| |Table E 503.5.7.6|Table E 503.5.7.5| |Table E 503.5.10.1.2(1)|Table E 503.5.10(1)| |Table E 503.5.10.1.2(2)|Table E 503.5.10(2)| |E 503.5.10.1.2|E 503.5.10| |E 503.5.10.2 – E 503.5.10.2.2|E 503.5.10.1 – E 503.5.10.1.2| |E 503.5.12.1|E 503.5.12| |E 503.5.12.2|E 503.5.12.1| |E 503.6.5.4|E 503.6.5.4.1|
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Uniform Mechanical Code – 2024 Edition:
The Uniform Mechanical Code contains complete requirements for the installation and maintenance of heating, ventilating, cooking and refrigeration systems.
Uniform Mechanical Code Illustrated Training Manual:
CMC § 10.5 Medium relevance — show source text
10.5 and subsections_|||||||||||||||X|||||||||| |1.10.6 and subsections||||||||||||||||X||||||||| |1.11.0 through 1.11.11|||X|||||||||||||||||||||| |1.12.0|||||||||||||||||||||||X|| |1.13.0||||||||||||||||||||X||||| |1.14.0||||||||||||||||||||||||X| |Division II –
Scope and Administration||||||||||||||||||||||||| |101.0 – 104.1||||||||||X|X|X|X|X|X|||||||||| |104.2 (Items 1 – 5)||||X|X|||||||||||||||||||| |104.3 – 107.0||||||||||X|X|X|X|X|X|||||||||| |104.4.3.1|X||||||||||||||||||||||||This state agency does not adopt sections identified with the following symbol: The Office of the State Fire Marshal’s adoption of this chapter or individual sections is applicable to structures regulated by other state agencies pursuant to Section 1.11.0.
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CHAPTER 1
ADMINISTRATION
DIVISION I CALIFORNIA ADMINISTRATION
1.1.0 General.
1.1.1 Title. These regulations shall be known as the California Mechanical Code, may be cited as such and will be referred to herein as “this code.” The California Mechanical Code is Part 4 of thirteen parts of the official compilation and publi- cation of the adoption, amendment, and repeal of mechanical regulations to the California Code of Regulations, Title 24, also referred to as the California Building Standards Code. This part incorporates by adoption the 2024 Uniform Mechan- ical Code of the International Association of Plumbing and Mechanical Officials with necessary California amendments.
1.1.2 Purpose. The purpose of this code is to establish the minimum requirements to safeguard the public health, safety and general welfare through structural strength, means of egress facilities, stability, access to persons with disabilities, sanitation, adequate lighting and ventilation, and energy conservation; safety to life and property from fire and other hazards attributed to the built environment; and to provide safety to fire fighters and emergency responders during emer- gency operations.
1.1.3 Scope. The provisions of this code shall apply to the construction, alteration, movement, enlargement, replace- ment, repair, equipment, use and occupancy, location, main- tenance, removal, and demolition of every building or structure or any appurtenances connected or attached to such buildings or structures throughout the State of California.
Frequently asked questions
Can I build my own incinerator for a business and simply pass inspection?
No. If it is a field‑constructed commercial‑industrial incinerator it must be constructed and installed in accordance with NFPA 82 per § 924.1. Obtain NFPA 82 requirements and show compliance to the AHJ. § 924.1
May I use a residential UL‑791 incinerator for a small commercial operation?
Not under § 924.x alone — § 924.3 limits residential incinerators to UL 791 and residential installation instructions. Commercial uses are addressed by § 924.1 or § 924.2 and require NFPA 82 or UL 2790 compliance. Check the AHJ and the referenced standards for allowed uses. § 924.1, § 924.2, § 924.3
Does the CMC give clearance and stack height numbers for incinerators?
No. The CMC sections for incinerators require compliance with the referenced standards (NFPA 82, UL 2790, UL 791) and manufacturer instructions; the specific numeric clearances and stack heights are in those standards and the manufacturer documentation, not in § 924.1–924.3. § 924.1, § 924.2, § 924.3
What documentation should I submit with my permit application?
At minimum: the product listing (UL 2790 or UL 791 where applicable), the manufacturer’s installation instructions, and engineered drawings showing compliance with NFPA 82 for field‑constructed commercial units. The CMC text requires adherence to those standards and instructions (see § 924.1–924.3). § 924.1, § 924.2, § 924.3
Who enforces compliance beyond the CMC language in § 924.x?
The local Authority Having Jurisdiction enforces the CMC and may require submittals and additional approvals; other codes (for example, the California Fire Code) can add operational and safety requirements beyond § 924.x. The CMC’s § 924.x text itself is limited to the standard/listing requirements. § 924.1, § 924.2, § 924.3
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