Gas Range Addition Under a Kitchen Remodel

Total the load, then size every section by the longest length from the meter.

• Total connected load: 80 + 40 + 65 + 35 = 220 CFH (at roughly 1,000 BTU per cubic foot).
• Longest length from the meter to the farthest new appliance is 65 feet. Using the longest-length method (Table 402.4 series in the adopted fuel gas code, 0.5 psi, natural gas):
  • 3/4-inch at 65 feet carries roughly 95 to 100 CFH - far short of 220 CFH.
  • 1-inch at 65 feet carries roughly 190 CFH - still short.
  • 1 1/4-inch at 65 feet carries roughly 390 CFH - adequate.
• So the trunk from the meter must be upsized to 1 1/4 inch, and the existing 3/4-inch pipe cannot be left as the main run.
• The range branch carries only 65 CFH, but it is still sized at the 65-foot longest length, not at its own 30 feet. 1/2-inch at 65 feet carries roughly 45 CFH, which fails. Use 3/4-inch for that branch (about 95 CFH at 65 feet).
• For CSST, use the manufacturer's sizing table, its equivalent lengths for fittings, and its approved bonding and strike protection - do not mix tables.

Test before concealment, and do not confuse a soap test with a pressure test.

• A permit must be obtained before the work by the licensee responsible for it; the homeowner cannot ratify it afterward. The AHJ can require the drywall to be opened or the piping to be exposed for inspection, and unpermitted work is a code violation that can also affect the certificate of occupancy and insurance.
• Test: the piping is isolated at the meter and the appliance regulators and tested with air, nitrogen, or another inert gas (never oxygen) at the pressure and duration the adopted code requires - typically not less than 1.5 times the working pressure and not less than 10 psi for low-pressure systems, held long enough to observe the gauge (commonly 30 minutes). Confirm the exact figures with the AHJ.
• The gauge must be visible to the inspector, of appropriate range, and the test must hold with no drop. Soap bubbles at operating pressure are a leak-finding technique, not a test.
• Do not use the appliance regulator as a test boundary; isolate it so it is not damaged.
• Rough-in inspection before concealment, then a final inspection after appliances are connected and the sediment traps and connectors are in place.

Three separate issues: protection, methods, and appliance connection.

• Concealment and protection: CSST concealed in a wall must be protected per the manufacturer's listing against nails and screws - typically with a heavy-gauge steel striker plate where it passes through framing, and sleeves where it penetrates plates. Some manufacturers and local amendments prohibit certain concealed runs outright; check the listing.
• Support and bonding: follow the manufacturer's support spacing, keep the tubing away from sharp edges, and bond the CSST per the manufacturer's and the electrical code's requirements.
• Sediment trap: required at the appliance connection - installed downstream of the appliance shutoff valve, as close to the appliance inlet as practical, in the direction of flow so dirt and pipe scale drop out before the controls. Range and dryer both need one unless the appliance is listed with an integral trap.
• Connector: the appliance connector must be listed, not exceed the code length (commonly 6 feet for a range), must not be concealed in a wall or floor, and must not be used to make a rigid connection through a cabinet where it can be damaged. Provide a shutoff valve in the same room, accessible, within the code's distance of the connector.
• Grounding and the range: a gas range in a kitchen still requires the electrical bonding and grounding the manufacturer specifies for its ignition and controls; verify the electrician has completed it before the final inspection.