The short answer
- Underground runs are usually polyethylene gas pipe with a tracer wire, coming up out of the ground through a steel riser.
- Every outdoor gas appliance needs an accessible shutoff valve, and a portable grill should connect through a listed quick-disconnect with its own shutoff.
- Many grills ship for propane. Running one on natural gas takes the manufacturer's conversion kit, or a natural gas model.
- Outdoor gas lines are permitted work, and the line you bury is yours. 811 will not mark it later.
Plan the gas before the hardscape
The easiest outdoor gas line is the one planned before the pavers, the island or the pergola go in. Once a patio is poured, getting a pipe under it means boring, cutting or going the long way around.
Settle three things early: what will burn gas (grill, side burner, fire pit, fire table, patio heater, pool heater), the BTU rating of each, and where each one will sit. The line is sized for the total, and adding a fire pit later to a line sized only for a grill can starve both.
Underground: PE pipe and a tracer wire
Most buried gas runs are yellow polyethylene (PE) pipe. It does not corrode, it comes in long lengths with few joints, and it is approved for underground gas. It is only allowed underground. Above ground and inside walls, PE is not permitted.
Plastic pipe cannot be found with a metal detector, so the code requires a tracer wire buried with it, brought up at the ends where a locator can clip onto it. The fuel gas code generally calls for at least 12 inches of cover, or 8 inches for an individual line to an outdoor appliance like a grill or a gas light. Many installers go deeper where a mower aerator, a fence post or a garden bed might go.
Risers, shutoffs and connections
Where the line leaves the ground it comes up through a riser, usually an anodeless riser that carries the PE inside a steel casing and transitions to steel pipe above grade. Above ground the pipe is steel, protected and supported.
- A shutoff valve at each appliance, where you can reach it without moving the grill or reaching across a burner.
- A sediment trap where the appliance calls for one.
- For a built-in grill in an island, a connector rated for the purpose, and vent openings in the island where the manufacturer requires them, so leaked gas cannot collect inside the cabinet.
- For a freestanding grill on wheels, a listed quick-disconnect with an automatic shutoff and a listed outdoor gas hose, so the grill can be unplugged and moved.
Natural gas or propane: conversion kits
Many grills and fire tables sold in stores are set up for propane. Propane and natural gas run at different pressures and need different orifices and regulators, so a propane grill on a natural gas line will not burn properly, and a natural gas grill on propane can be dangerous.
Check before you buy. Some manufacturers sell a natural gas version of the same model; others sell a conversion kit for specific models; some grills cannot be converted at all. Only use the manufacturer's kit for your exact model, and have the conversion done by someone who will check the flame and the connections afterward.
Permits, clearances and covered porches
An outdoor gas line is new gas piping, and it needs a permit and an inspection from whichever building department covers your address: the City of Spartanburg inside city limits, or Spartanburg County Building Codes in unincorporated areas such as Boiling Springs. The line is pressure-tested before it is connected.
Grill manufacturers set minimum clearances to combustible walls, railings and overhead structures, and many say their grills are not for use under a covered porch or roof at all. Read that section of the manual before you decide where the island goes. Fire pits and fire tables have their own clearance rules, usually to anything above them.
When to call a pro
Call a licensed gas contractor while the outdoor kitchen is still a plan, so the line can be sized for every appliance and routed before the hardscape goes in. The line needs a permit, a pressure test and an inspection before anything is lit.