Skip to content

Chapter 3 — GENERAL REGULATIONS

303.10 Clearances. Appliances and their vent connectors

California Mechanical Code (Title 24, Part 4) · 2022 edition · updated 2026-09-10 · California

Italicized text is a California amendment to the model code, as printed in the official publication.

shall be installed with clearances from combustible material so their operation does not create a hazard to persons or property. Minimum clearances between combustible walls and the back and sides of various conventional types of appliances and their vent connectors are specified in Chapter 8 and Chapter 9. [NFPA 54:9.2.2] Where not provided in this code, listed and unlisted equipment or appliances shall be installed to maintain the required clearances for servicing and to combustible construction in accordance with the listing and the manufacturer’s installation instructions.

303.10.1 Clearance Reduction. Reduced clearances to combustible construction for listed equipment and appliances shall comply with the listing and Table 303.10.1. Where permitted by the manufacturer, and not provided in this code, reduced clearances to combustible construction for unlisted equipment and appliances shall comply with Table 303.10.1.

303.10.1.1 Type I Hood Exhaust System. Reduced clearances for Type I exhaust systems shall be in accordance with Section 507.4.2 through Section 507.4.2.3. Clearances from the duct or the exhaust fan to the interior surface of enclosures of combustible construction shall be in accordance with Section 510.7.3 and clearances shall not be reduced. 303.10.1.2 Product Conveying Ducts. Reduced clearances to combustibles construction for product conveying ducts shall be in accordance with Section 506.10.3 through Section 506.11.6.3.

2022 CALIFORNIA MECHANICAL CODE 49

GENERAL REGULATIONS

303.10.1.3 Solid-Fuel Burning Appliances. For solid-fuel burning appliances, the clearance shall not be less than 12 inches (305 mm) to combustible walls and not less than 18 inches (457 mm) to combustible ceilings. The clearance, after reduction, shall be permitted to be less than 12 inches (305 mm) to combustible walls and less than 18 inches (457 mm) to combustible ceilings. Solid-fuel burning appliances listed for lesser clearances shall be permitted to be installed in accordance with the manufacturer’s instructions and their listing.

Get a plain-English answer with a citation back to this text.

Ask AI about this code
Export this section
▸Contents — California Mechanical Code (Title 24, Part 4)
California Mechanical Code (Title 24, Part 4)
  1. Chapter 1 — GENERAL CODE PROVISIONS
  2. Chapter 2 — DEFINITIONS
  3. ▸Chapter 3 — GENERAL REGULATIONS
    Overview
    1. 301.1 Applicability. This chapter covers general requirements …
    2. 301.2 Approval. Equipment or appliance shall be approved
    3. 301.3 Design of Equipment. The installer or contractor
    4. 301.4 Electrical Connections. For equipment regulated
    5. 301.5 Oil-Burning Appliances. The tank, piping, and
    6. 301.6 Personnel Protection. A metal guard shall be provided ar…
    7. 301.7 OSHPD 1R [OSHPD 1R]. For OSHPD 1R, refer to
    8. 302.1 Minimum Standards. Listed pipe, pipe fittings,
    9. 302.2 Alternate Materials and Methods of Construc-
    10. 302.3 Alternative Engineered Design. An alternative
    11. 303.1 Listed Appliances. The installation of equipment
    12. 303.2 Closet or Alcove Installations. [Not adopted
    13. 303.3 Unlisted Appliances. Except as otherwise permitted in th…
    14. 303.4 Anchorage of Appliances. Appliances designed to
    15. 303.5 Movement. Movement of appliances with casters
    16. 303.6 Identification of Equipment. Where more than one
    17. 303.7 Liquefied Petroleum Gas Facilities. Containers,
    18. 303.8 Appliances on Roofs. Appliances on roofs shall be
    19. 303.9 Avoiding Strain on Gas Piping. Appliances shall
    20. 303.10 Clearances. Appliances and their vent connectors
    21. 303.11 Installation in Commercial Garages. Appliances installe…
    22. 303.12 Installation in Aircraft Hangars. Heaters in aircraft h…
    23. 304.1 General. All appliances shall be located with respect
    24. 304.2 Sloped Roof. Where equipment or appliances that
    25. 304.3 Access to Appliances on Roofs. Appliances
    26. 304.4 Appliances in Attics and Under-Floor Spaces.
    27. 305.4 Elevator Shaft. Unless required for the functionality
    28. 305.5 Drainage Pan. Where a water heater is located in an
    29. 306.1 General. Heating appliances shall be equipped with
    30. 306.2 Building Automation Systems. [OSHPD 1]
    31. 305.1 Installation in Residential Garages. Appliances
    32. 305.2 Pit Location. Where excavation is necessary to
    33. 305.3 Flood Hazard Areas. For buildings located in flood
    34. 307.1 Fuel-Burning Appliances. Fuel-burning heating
    35. 307.2 Electric Heating Appliances. Electric heating
    36. 307.3 Heat Pump and Electric Cooling Appliances.
    37. 307.4 Absorption Units. Absorption units shall bear a permanen…
    38. 308.1 General. Piping or equipment shall not be so located as
    39. 309.1 Engineering Practices. Design, construction, and
    40. 309.2 Concealing Imperfections. It shall be unlawful to
    41. 309.3 Installation Practices. Mechanical systems shall
    42. 310.1 Condensate Disposal. Condensate from air washers, air-co…
    43. 310.2 Condensate Control. Where any equipment or
    44. 310.3 Condensate Waste Pipe Material and Sizing.
    45. 310.4 Appliance Condensate Drains. Condensate drain
    46. 310.5 Point of Discharge. Air-conditioning condensate
    47. 310.6 Condensate Waste From Air-Conditioning
    48. 310.7 Plastic Fittings. Female plastic screwed fittings shall
    49. 311.1 Source. A heating or cooling air system shall be provide…
    50. 313.7 Gas Piping. Gas piping shall be supported by metal
    51. 311.2 Air Filters. Air filters shall be installed in a heating,
    52. 311.3 Prohibited Source. Outside or return air for a heating o…
    53. 311.4 Return-Air Limitations. Return air from one
    54. 311.5 California Energy Code Requirements for Res-
    55. 312.1 General. Water supply, sanitary drainage, and backflow p…
    56. 313.1 General. Piping, tubing, appliances, and appurtenances s…
    57. 313.2 Material. Hangers and anchors shall be of sufficient
    58. 313.3 Suspended Piping. Suspended piping or tubing
    59. 313.4 Alignment. Piping or tubing shall be supported in
    60. 313.5 Underground Installation. Piping or tubing in the
    61. 313.6 Hanger Rod Sizes. Hanger rod sizes shall be not
    62. 314.1 General. Heating, ventilating, and air-conditioning
    63. 315.1 General. Louvers located in areas within hurricaneprone …
    64. 316.1 General. Piping or tubing passing under or through
    65. 316.2 Installation. Piping or tubing shall be installed so that
    66. 316.3 Corrosion, Erosion, and Mechanical Damage.
    67. 316.4 Protectively Coated Pipe. Protectively coated pipe
    68. 316.5 Fire-Resistant Construction. Piping, tubing, and
    69. 316.6 Steel Nail Plates. Plastic piping or tubing, copper
    70. 316.7 Sleeves. Sleeves shall be provided to protect piping
    71. 316.8 Firewalls. A pipe sleeve through a firewall shall have
    72. 316.9 Structural Members. A structural member weakened or impa…
    73. 316.10 Rodentproofing. Mechanical system shall be constructed …
    74. 316.11 Metal Collars. In or on buildings where openings
    75. 317.1 Trenches. Trenches deeper than the footings of a
    76. 317.2 Tunneling and Driving. Tunneling and driving shall
    77. 317.3 Open Trenches. Excavations required to be made for
    78. 317.4 Excavations. Excavations shall be completely backfilled …
    79. 318.1 Applicability. This part is applicable to health facil-
    80. 318.2 Services/Systems and Utilities. Refer to Section
    81. 319.1 Requirements for Hospitals and Optional Serv-
    82. 319.2 Requirements for Skilled Nursing, Intermedi-
    83. 320.1 Requirements for Hospitals and Optional Serv-
    84. 320.2 Requirements for Skilled Nursing, Intermedi-
    85. 320.3 Requirements for Outpatient Facilities and
    86. 320.4 Telephone and Technology Equipment Centers.
    87. 320.5 Psychiatric Services. [OSHPD 1, 1R, 2, 4 & 5] For
    88. 321.1 (Does not apply to OSHPD 3 surgical clinic.) All heat-
    89. 321.2 All heating equipment and fans necessary to maintain
    90. 321.3 Equipment necessary for humidification of the areas
    91. 321.4 All supply, return, and exhaust fans required to maintain
    92. 321.5 All control components and control systems necessary
    93. 321.6 Alarms for airborne infection isolation rooms and pro-
    94. 322.1 The following conditions shall be met for sensitive
    95. 323.0 Mechanical Equipment Schedules. [OSHPD 1,
  4. Chapter 4 — VENTILATION AIR
  5. Chapter 5 — EXHAUST SYSTEMS
  6. Chapter 6 — DUCT SYSTEMS
  7. Chapter 7 — COMBUSTION AIR
  8. Chapter 8 — CHIMNEYS AND VENTS
  9. Chapter 9 — INSTALLATION OF SPECIFIC APPLIANCES
  10. Chapter 10 — BOILERS AND PRESSURE VESSELS
  11. Chapter 11 — REFRIGERATION
  12. Chapter 12 — HYDRONICS
  13. Chapter 13 — FUEL GAS PIPING
  14. Chapter 14 — PROCESS PIPING
  15. Chapter 15 — SOLAR ENERGY SYSTEMS
  16. Chapter 16 — STATIONARY POWER PLANTS
  17. Chapter 17 — REFERENCED STANDARDS
  18. Appendix A — RESIDENTIAL PLAN EXAMINER REVIEW FORM FOR HVAC SY…
  19. Appendix B — PROCEDURES TO BE FOLLOWED TO PLACE GAS EQUIPMENT …
  20. Appendix C — INSTALLATION AND TESTING OF OIL (LIQUID) FUEL-FIR…
  21. Appendix D — FUEL SUPPLY: MANUFACTURED/MOBILE HOME PARKS AND R…
  22. Appendix E — SUSTAINABLE PRACTICES
  23. Appendix F — GEOTHERMAL ENERGY SYSTEMS
  24. Appendix G — SIZING OF VENTING SYSTEMS AND OUTDOOR COMBUSTION …
  25. Appendix H — EXAMPLE CALCULATION OF OUTDOOR AIR RATE

GoCodebook provides public access, search, citation, multilingual explanation, and practical interpretation of legally adopted building regulations. It is not a substitute for the official ICC or California code publications.