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Chapter 5 — WATER HEATERS

509.5 Masonry, Metal, and Factory-Built Chimneys.

California Plumbing Code (Title 24, Part 5) · 2019 edition · updated 2026-09-10 · California

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

Chimneys shall be installed in accordance with Section 509.5.1 through Section 509.5.3. 509.5.1 Factory-Built Chimneys. Factory-built chimneys shall be installed in accordance with the manufacturer’s installation instructions. Factory-built chimneys used to vent appliances that operate at positive vent pressure shall be listed for such application. [NFPA 54:12.6.1.1] 509.5.1.1 Decorative Shrouds. Decorative shrouds addressed in Section 509.5.4.3 shall comply with UL 103 for factory-built residential chimneys. 509.5.1.2 Listing Requirements. Factory-built chimneys shall comply with the requirements of UL 103 or UL 959. Factory-built chimneys for use with wood-burning appliances shall comply with the Type HT requirements of UL 103. [NFPA 211:6.1.3.1] 509.5.2 Metal Chimneys. Metal chimneys shall be in accordance with NFPA 211. [NFPA 54:12.6.1.2] 509.5.3 Masonry Chimneys. Masonry chimneys shall be in accordance with NFPA 211 and lined with approved clay flue lining, a listed chimney lining system, or other approved material that resists corrosion, erosion, softening, or cracking from vent gases at temperatures not exceeding 1800°F (982°C). Exception: Masonry chimney flues lined with a chimney lining system specifically listed for use with listed appliances with draft hoods, Category I appliances, and other appliances listed for use with Type B vents shall be permitted. The liner shall be installed in accordance with the liner manufacturer’s installation instructions. A permanent identifying label shall be attached at the point where the connection is to be made to the liner. The label shall read: “This chimney liner is for appliances that burn gas only. Do not connect to solid- or liquid-fuel-burning appliances or incinerators.” [NFPA 54:12.6.1.3] 509.5.4 Termination. A chimney for a residential-type or low-heat appliance shall extend not less than 3 feet (914 mm) above the highest point where it passes through the roof of a building and not less than 2 feet (610 mm) higher than a portion of a building within a horizontal distance of 10 feet (3048 mm). (See Figure 509.5.4) [NFPA 54:12.6.2.1] 509.5.4.1 Medium-Heat Gas Appliances. A chimney for medium-heat appliances shall extend at least 10 feet (3048 mm) higher than any portion of any building within 25 feet (7620 mm). [NFPA 54:12.6.2.2] 509.5.4.2 Chimney Height. A chimney shall extend not less than 5 feet (1524 mm) above the highest connected appliance draft hood outlet or flue collar. [NFPA 54:12.6.2.3] 509.5.4.3 Decorative Shrouds. Decorative shrouds shall not be installed at the termination of factory-built chimneys except where such shrouds are listed and labeled for use with the specific factory-built chimney system and are installed in accor

.** A chimney shall extend not less than 5 feet (1524 mm) above the highest connected appliance draft hood outlet or flue collar. [NFPA 54:12.6.2.3] 509.5.4.3 Decorative Shrouds. Decorative shrouds shall not be installed at the termination of factory-built chimneys except where such shrouds are listed and labeled for use with the specific factory-built chimney system and are installed in accor

dance with the manufacturer’s installation instructions. [NFPA 54:12.6.2.4] 509.5.5 Size of Chimneys. The effective area of a chimney venting system serving listed appliances with draft hoods, Category I appliances, and other appliances listed for use with Type B vents shall be in accordance with one of the following methods: (1) Those listed in Section 510.0. (2) For sizing an individual chimney venting system for

a single appliance with a draft hood, the effective

(2) For sizing an individual chimney venting system for

a single appliance with a draft hood, the effective areas of the vent connector and chimney flue shall be not less than the area of the appliance flue collar or draft hood outlet or greater than seven times the draft hood outlet area. (3) For sizing a chimney venting system connected to

two appliances with draft hoods, the effective area of

(3) For sizing a chimney venting system connected to

two appliances with draft hoods, the effective area of the chimney flue shall be not less than the area of the larger draft hood outlet plus 50 percent of the area of the smaller draft hood outlet or greater than seven times the smaller draft hood outlet area. (4) Chimney venting systems using mechanical draft

shall be sized in accordance with approved engi

(4) Chimney venting systems using mechanical draft

shall be sized in accordance with approved engineering methods. (5) Other approved engineering methods. [NFPA

54:12.6.3.1]

(5) Other approved engineering methods. [NFPA

54:12.6.3.1] 509.5.6 Inspection of Chimneys. Before replacing an existing appliance or connecting a vent connector to a chimney, the chimney passageway shall be examined to ascertain that it is clear and free of obstructions and shall be cleaned where previously used for venting solid- or liquidfuel-burning appliances or fireplaces. [NFPA 54:12.6.4.1]

509.5.6.1 Standard. Chimneys shall be lined in accordance with NFPA 211. Exception: Existing chimneys shall be permitted to have their use continued when an appliance is replaced by an appliance of similar type, input rating, and efficiency, where the chimney complies with Section 509.5.6 through Section 509.5.6.3 and the sizing of the chimney is in accordance with Section 509.5.5. [NFPA 54:12.6.4.2] 509.5.6.2 Cleanouts. Cleanouts shall be examined to determine that they will remain tightly closed where not in use. [NFPA 54:12.6.4.3] 509.5.6.3 Existing Chimney. Where inspection reveals that an existing chimney is not safe for the intended application, it shall be repaired, rebuilt, lined, relined, or replaced with a vent or chimney in accordance with NFPA 211, and shall be approved for the appliances to be attached. [NFPA 54:12.6.4.4] 509.5.7 Chimney Serving Appliances Burning Other Fuels. An appliance shall not be connected to a chimney flue serving a separate appliance designed to burn solid fuel. [NFPA 54:12.6.5.1]

509.5.7.1 Gas and Liquid Fuel-Burning Appli- ances. Where one chimney serves gas appliances and liquid fuel-burning appliances, the appliances shall be connected through separate openings or shall

2019 CALIFORNIA PLUMBING CODE 91

WATER HEATERS any other purpose or distributed to any other persons or parti es.

be connected through a single opening where joined by a fitting located as close as practical to the chimney. Where two or more openings are provided into one chimney flue, they shall be at different levels. Where the gas appliance is automatically controlled, it shall be equipped with a safety shutoff device.

[NFPA 54:12.6.5.2] 509.5.7.2 Gas and Solid Fuel-Burning Appli- ances. A listed combination gas- and solid-fuelburning appliance connected to a single chimney flue shall be equipped with a manual reset device to shut off gas to the main burner in the event of sustained backdraft or flue gas spillage. The chimney flue shall be sized to properly vent the appliance.

[NFPA 54:12.6.5.3] 509.5.7.3 Combination Gas- and Oil-Burning Appliances. A single chimney flue serving a listed combination gas- and oil-burning appliance shall be sized to properly vent the appliance. [NFPA 54:12.6.5.4] 509.5.8 Support of Chimneys. All portions of chimneys shall be supported for the design and weight of the materials employed. Listed factory-built chimneys shall be supported and spaced in accordance with the manufacturer’s installation instructions. [NFPA 54:12.6.6] 509.5.9 Cleanouts. Where a chimney that formerly carried flue products from liquid- or solid-fuel-burning appliances is used with an appliance using fuel gas, an accessible cleanout shall be provided. The cleanout shall have a tight-fitting cover and be installed, so its upper edge is not less than 6 inches (152 mm) below the lower edge of the lowest chimney inlet opening. [NFPA 54:12.6.7] 509.5.10 Space Surrounding Lining or Vent. The remaining space surrounding a chimney liner, gas vent, special gas vent, or plastic piping installed within a masonry chimney shall not be used to vent another appliance. Exception: The insertion of another liner or vent within the chimney as provided in this code and the liner or vent manufacturer’s instructions. [NFPA 54:12.6.8.1]

FIGURE 509.5.4 TYPICAL TERMINATION LOCATIONS FOR CHIMNEYS AND SINGLE-WALL METAL PIPES SERVING RESIDENTIAL-TYPE

AND LOW-HEAT APPLIANCE

[NFPA: 54: FIGURE A.12.6.2.1]

509.5.10.1 Combustion Air. The remaining space surrounding a chimney liner, gas vent, special gas vent, or plastic piping installed within masonry, metal, or factory-built chimney flue shall not be used to supply combustion air. Exception: Direct-vent appliances designed for installation in a solid-fuel-burning fireplace where installed in accordance with the manufacturer’s installation instructions. [NFPA 54:12.6.8.2]

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Contents — California Plumbing Code (Title 24, Part 5)
California Plumbing Code (Title 24, Part 5)
  1. Chapter 1 — GENERAL CODE PROVISIONS
  2. Chapter 2 — DEFINITIONS
  3. Chapter 3 — GENERAL REGULATIONS
  4. Chapter 4 — PLUMBING FIXTURES AND FIXTURE FITTINGS
  5. Chapter 5 — WATER HEATERS
    Overview
    1. 501.0 General.501.1 Applicability. The regulations of this cha…
    2. 503.2 Final Water Heater Inspection. This inspection
    3. 504.2 Vent. Water heaters of other than the direct-vent type
    4. 504.3 Clearance. The clearance requirements for water
    5. 504.4 Pressure-Limiting Devices. A water heater installation s…
    6. 504.5 Temperature-Limiting Devices. A water heater
    7. 504.6 Temperature, Pressure, and Vacuum Relief
    8. 505.2 Safety Devices. Storage-type water heaters and hot
    9. 505.3 Oil-Fired Water Heaters. Oil-fired water heaters
    10. 505.4 Indirect-Fired Water Heaters. Indirect-fired water
    11. 506.0 Air for Combustion and Ventilation.506.1 General. Air fo…
    12. 506.2 Indoor Combustion Air. The required volume of
    13. 506.4 Outdoor Combustion Air. Outdoor combustion air
    14. 506.3 Indoor Opening Size and Location. Openings
    15. 506.8 Louvers, Grilles, and Screens. The required size
    16. 506.5 Combination Indoor and Outdoor CombustionAir. The use of…
    17. 506.9 Combustion Air Ducts. Combustion air ducts shall
    18. 506.6 Engineered Installations. Engineered combustion
    19. 506.7 Mechanical Combustion Air Supply. Where
    20. 507.2 Seismic Provisions. Water heaters shall be
    21. 507.3 Appliance Support. Appliances and equipment shall
    22. 507.4 Ground Support. A water heater supported from the
    23. 507.5 Drainage Pan. Where a water heater is located in an
    24. 507.6 Added or Converted Equipment or Appliances. When additio…
    25. 507.7 Types of Gases. The appliance shall be connected to
    26. 507.8 Safety Shutoff Devices for Unlisted LP-GasAppliance Used…
    27. 507.9 Use of Air or Oxygen Under Pressure. Where air
    28. 507.10 Protection of Gas Appliances from Fumes orGases other t…
    29. 507.11 Process Air. In addition to air needed for combustion i…
    30. 507.12 Flammable Vapors. Appliances shall not be
    31. 507.13 Installation in Residential Garages. Appliances
    32. 507.14 Installation in Commercial Garages. Appliances
    33. 507.15 Installation in Aircraft Hangars. Heaters in aircraft h…
    34. 507.16 Venting of Flue Gases. Appliances shall be vented
    35. 507.17 Extra Device or Attachment. No device or attachment sha…
    36. 507.18 Adequate Capacity of Piping. When additional
    37. 507.19 Avoiding Strain on Gas Piping. Appliances shall
    38. 507.20 Gas Appliance Pressure Regulators. Where the
    39. 507.21 Venting of Gas Appliance Pressure Regula-tors. Venting …
    40. 507.22 Bleed Lines for Diaphragm-Type Valves. Bleed
    41. 507.23 Combination of Appliances and Equipment. A
    42. 507.24 Installation Instructions. The installing agency
    43. 507.25 Protection of Outdoor Appliances. Appliances
    44. 507.26 Accessibility for Service. Appliances shall be
    45. 507.27 Clearance to Combustible Materials. Appliances and thei…
    46. 508.0 Appliances on Roofs.508.1 General. Appliances on roofs s…
    47. 508.2 Installation of Appliances on Roofs. Appliances
    48. 508.3 Appliances on Roofs. Appliances located on roofs
    49. 508.4 Appliances in Attics and Under-Floor Spaces.
    50. 509.2 Connection to Venting Systems. Except as permitted in Se…
    51. 509.3 Design and Construction. Venting systems shall
    52. 509.4 Type of Venting System to be Used. The type of
    53. 509.5 Masonry, Metal, and Factory-Built Chimneys.
    54. 509.6 Gas Vents. The installation of gas vents shall meet
    55. 509.7 Single-Wall Metal Pipe. Single-wall metal pipe
    56. 509.8 Through-the-Wall Vent Termination. A mechanical draft ve…
    57. 509.9 Condensation Drain. Provision shall be made to
    58. 509.11 Vent Connectors for Category II, Category III,
    59. 509.12 Draft Hoods and Draft Controls. Vented appliances shall…
    60. 509.15 Obstructions. Devices that retard the flow of vent
    61. 509.13 Manually Operated Dampers. A manually operated damper s…
    62. 509.14 Automatically Operated Vent Dampers. An
    63. 510.1 Single Appliance Vent Table 510.1.2(1) through
    64. 510.2 Multiple Appliance Vent Table 510.2(1) throughTable 510.…
  6. Chapter 6 — WATER SUPPLY AND DISTRIBUTION
  7. Chapter 7 — SANITARY DRAINAGE
  8. Chapter 8 — INDIRECT WASTES
  9. Chapter 9 — VENTS
  10. Chapter 10 — TRAPS AND INTERCEPTORS
  11. Chapter 11 — STORM DRAINAGE
  12. Chapter 12 — FUEL GAS PIPING
  13. Chapter 13 — HEALTH CARE FACILITIES AND MEDICAL GAS AND MEDICA…
  14. Chapter 14 — FIRESTOP PROTECTION
  15. Chapter 15 — ALTERNATE WATER SOURCES FOR NONPOTABLE APPLICATIONS
  16. Chapter 16 — NONPOTABLE RAINWATER CATCHMENT SYSTEMS
  17. Chapter 17 — REFERENCED STANDARDS
  18. Appendix A — RECOMMENDED RULES FOR SIZING THE WATER SUPPLY SYS…
  19. Appendix B — EXPLANATORY NOTES ON COMBINATION WASTE AND VENT S…
  20. Appendix C — ALTERNATE PLUMBING SYSTEMS
  21. Appendix D — SIZING STORM WATER DRAINAGE SYSTEMS
  22. Appendix E — MANUFACTURED/MOBILE HOME PARKS AND RECREATIONAL V…
  23. Appendix F — FIREFIGHTER BREATHING AIR REPLENISHMENT SYSTEMS
  24. Appendix G — SIZING OF VENTING SYSTEMS
  25. Appendix H — PRIVATE SEWAGE DISPOSAL SYSTEMS
  26. Appendix I — INSTALLATION STANDARD FOR PEX TUBING SYSTEMS FOR …
  27. Appendix J — COMBINATION OF INDOOR AND OUTDOOR COMBUSTION AND …
  28. Appendix K — POTABLE RAINWATER CATCHMENT SYSTEMS
  29. Appendix L — SUSTAINABLE PRACTICES
  30. Appendix M — PEAK WATER DEMAND CALCULATOR

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