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Chapter 13 — FUEL GAS PIPING

1308.4 Sizing of Gas Piping Systems.

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.

Gas piping systems shall be of such size and so installed as to provide a supply of gas sufficient to meet the maximum demand and supply gas to each appliance inlet at not less than the minimum supply pressure required by the appliance. [NFPA 54:5.4.1]

1308.4.1 Maximum Gas Demand. The volumetric flow rate of gas to be provided shall be the sum of the maximum input of the appliances served. The volumetric flow rate of gas to be provided shall be adjusted for altitude where the installation is above 2 000 feet (610 m).

[NFPA 54:5.4.2.1 – 5.4.2.2] Where the input rating is not indicated, the gas supplier, appliance manufacturer, or a qualified agency shall be contacted or the rating from Table 1308.4.1 shall be used for estimating the volumetric flow rate of gas to be supplied.

The total connected hourly load shall be used as the basis for piping sizing, assuming all appliances are operating at full capacity simultaneously. Exception: Sizing shall be permitted to be based upon established load diversity factors. [NFPA 54:5.4.2.3] 1308.4.2 Sizing Methods. Gas piping shall be sized in accordance with one of the following: (1) Pipe sizing tables or sizing equations in this chapter. (2) Other approved engineering methods. (3) Sizing tables included in a listed piping system man ufacturer’s installation instructions. [NFPA 54:5.4.3] 1308.4.3 Allowable Pressure Drop. The design pressure loss in any piping system under maximum probable flow conditions, from the point of delivery to the inlet connection of the appliance, shall be such that the supply pressure at the appliance is greater than or equal to the minimum pressure required by the appliance. [NFPA 54:5.4.4]

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▸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
  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
    Overview
    1. 1301.1 Applicability. The regulations of this chapter shall
    2. 1302.1 General. Coverage of piping systems shall extend
    3. 1302.2 Piping System Requirements. Requirements for
    4. 1302.3 Applications. This code shall not apply to the followin…
    5. 1303.1 Inspection Notification. Upon completion of the
    6. 1303.2 Excavation. Excavations required for the installation o…
    7. 1303.3 Type of Inspections. The Authority Having Jurisdiction …
    8. 1303.4 Inspection Waived. In cases where the work authorized b…
    9. 1304.1 Issuance. Whereupon final piping inspection, the
    10. 1304.2 Gas Supplier. A copy of the certificate of such final
    11. 1304.3 Unlawful. It shall be unlawful for a serving gas suppli…
    12. 1305.1 Authorized Personnel. It shall be unlawful for a
    13. 1305.2 Outlets. It shall be unlawful to turn on or connect gas
    14. 1306.1 Disconnection. The Authority Having Jurisdiction
    15. 1306.2 Notice. Where such disconnection has been made, a
    16. 1306.3 Capped Outlets. It shall be unlawful to remove or
    17. 1307.1 General. Where temporary use of gas is desired, and
    18. 1308.1 Installation of Piping System. Where required
    19. 1308.2 Provision for Location of Point of Delivery.
    20. 1308.3 Interconnections Between Gas Piping Sys-
    21. 1308.4 Sizing of Gas Piping Systems. Gas piping systems shall …
    22. 1308.5 Acceptable Piping Materials and Joining
    23. 1308.6 Gas Meters. Gas meters shall be selected for the
    24. 1308.7 Gas Pressure Regulators. A line pressure regulator shal…
    25. 1308.8 Overpressure Protection. Where the serving gas
    26. 1308.9 Pressure Limitation Requirements. Where piping systems …
    27. 1308.10 Overpressure Protection Devices. Overpressure protecti…
    28. 1308.11 Backpressure Protection. Protective devices
    29. 1308.12 Low-Pressure Protection. A protective device
    30. 1308.13 Shutoff Valves. Shutoff valves shall be approved
    31. 1308.14 Expansion and Flexibility. Piping systems shall
    32. 1309.1 General. Where automatic excess flow valves are
    33. 1310.1 Piping Underground. Underground gas piping shall
    34. 1310.2 CSST Piping Systems. CSST piping systems shall
    35. 1310.3 Installation of Aboveground Piping. Piping
    36. 1310.4 Concealed Piping in Buildings. Gas piping in
    37. 1310.5 Piping in Vertical Chases. Where gas piping
    38. 1310.6 Maximum Operating Pressure in Buildings.
    39. 1310.7 Appliance Overpressure Protection. The maximum operatin…
    40. 1310.8 Gas Pipe Turns. Changes in direction of gas pipe
    41. 1310.9 Drips and Sediment Traps. For other than dry gas
    42. 1310.10 Outlets. Outlets shall be located and installed in
    43. 1310.7 Appliance Overpressure Protection. The maxi- [NFPA 54:7…
    44. 1310.12 Prohibited Devices. Devices shall not be placed
    45. 1310.13 Systems Containing Gas-Air Mixtures Out-
    46. 1310.14 Systems Containing Flammable Gas-Air
    47. 1310.11 Manual Gas Shutoff Valves. An accessible gas
    48. 1311.1 Pipe and Tubing Other than CSST. Each aboveground porti…
    49. 1311.2 Bonding of CSST Gas Piping. CSST gas piping
    50. 1312.2 Suspended Low-Intensity Infrared Tube
    51. 1312.3 Use of Nonmetalic Gas Hose Connectors.
    52. 1311.3 Arc-Resistant Jacketed CSST. CSST listed with
    53. 1311.4 Prohibited Use. Gas piping shall not be used as a
    54. 1311.5 Lightning Protection System. Where a lightning
    55. 1311.6 Electrical Circuits. Electrical circuits shall not util…
    56. 1311.7 Electrical Connections. All electrical connections
    57. 1312.1 Connecting Appliances and Equipment.
    58. 1312.4 Injection (Bunsen) Burners. Injection (Bunsen)
    59. 1312.5 Connection of Portable and Mobile Industrial
    60. 1312.6 Appliance Shutoff Valves and Connections.
    61. 1312.7 Quick-Disconnect Devices. Quick-disconnect
    62. 1312.8 Gas Convenience Outlets. Appliances shall be
    63. 1312.9 Sediment Trap. Where a sediment trap is not incorporate…
    64. 1312.10 Installation of Piping. Piping shall be installed in
    65. 1312.11 Liquefied Petroleum Gas Facilities and Pip-
    66. 1313.1 Piping Installations. Prior to acceptance and initial o…
    67. 1313.2 Test Preparation. Test preparation shall comply
    68. 1313.3 Test Pressure. This inspection shall include an air,
    69. 1313.4 Detection of Leaks and Defects. The piping system shall…
    70. 1313.5 Piping System Leak Test. Leak checks using fuel
    71. 1313.6 Purging Requirements. The purging of piping
    72. 1314.1 General. The following regulations, shall comply
    73. 1314.2 Volume. The hourly volume of gas required at each
    74. 1314.3 Gas Appliances. Where the gas appliances to be
    75. 1314.4 Size of Piping Outlets. The size of the supply piping o…
    76. 1315.1 Pipe Sizing Methods. Where the pipe size is to be
    77. 1315.2 Sizing of Gas Piping Systems. Sizing of piping
    78. 1315.3 Sizing Equations. The inside diameter of smooth
    79. 1315.4 Sizing of Piping Sections. To determine the size
    80. 1315.5 Engineering Methods. For conditions other than
    81. 1315.6 Variable Gas Pressures. Where the supply gas
  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

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