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Chapter 5 — WATER HEATERS

509.2 Connection to Venting Systems.

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.

Except as permitted in Section 509.2.1 through Section 509.2.7, all appliances shall be connected to venting systems. [NFPA 54:12.3.1] 509.2.1 Appliances Not Required to be Vented. The following appliances shall not be required to be vented: (1) A single listed booster-type (automatic instanta neous) water heater, when designed and used solely

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(1) A single listed booster-type (automatic instanta neous) water heater, when designed and used solely for the sanitizing rinse requirements of a dishwashing machine, provided that the appliance is installed with the draft hood in place and unaltered, if a draft hood is required, in a commercial kitchen having a mechanical exhaust system. Where installed in this manner, the draft hood outlet shall not be less than 36 inches (914 mm) vertically and 6 inches (152 mm) horizontally from any surface other than the appliance. [NFPA 54:12.3.2(5)] (2) Other appliances listed for unvented use and not pro vided with flue collars. [NFPA 54:12.3.2(10)]

(2) Other appliances listed for unvented use and not pro vided with flue collars. [NFPA 54:12.3.2(10)] 509.2.2 Maximum Input Rating. Where any or all of the appliances in Section 509.2.1(1) and Section 509.2.1(2) are installed so the aggregate input rating

exceeds 20 (Btu/h)/ft 3 (207 W/m 3 ) of room or space in which it is installed, one or more shall be provided with venting systems or other approved means for conveying the vent gases to the outdoors so that the aggregate input rating of the remaining unvented appliance does not exceed 20 (Btu/h)/ft 3 (207 W/m 3 ). [NFPA 54:12.3.2.1] 509.2.3 Adjacent Room or Space. Where the calculation includes the volume of an adjacent room or space, the room or space in which the appliances are installed shall be directly connected to the adjacent room or space by a doorway, archway, or other opening of comparable size that cannot be closed. [NFPA 54:12.3.2.2] 509.2.4 Ventilating Hoods. Ventilating hoods and exhaust systems shall be permitted to be used to vent appliances installed in commercial applications and to vent industrial appliances, particularly where the process itself requires fume disposal. [NFPA 54:12.3.3] 509.2.5 Well-Ventilated Spaces. The operation of industrial appliances such that its flue gases are discharged directly into a large and well-ventilated space shall be permitted. [NFPA 54:12.3.4] 509.2.6 Direct-Vent Appliances. Listed direct-vent appliances shall be installed in accordance with the manufacturer’s installation instructions and Section 509.8.2.

[NFPA 54:12.3.5] 509.2.7 Appliances with Integral Vents. Appliances incorporating integral venting means shall be installed in accordance with the manufacturer’s installation instructions, Section 509.8 and Section 509.8.1. [NFPA 54:12.3.6]

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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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