New Construction Gas Piping in Spartanburg, SC

An addition is new construction tied to an old system, and the old system was sized for the old house. Adding a bedroom wing with a second furnace, or moving to a tankless water heater during a kitchen remodel, can push the total load past what the existing trunk was designed to carry.

We check the existing piping and load before tying in. Sometimes the existing pipe is fine. Sometimes a new trunk from the meter is the cleaner answer, or a 2 psi branch with a regulator to serve the new space. The meter may also need review by the utility if the load jumps.

Remodels also uncover old work: abandoned stubs left uncapped behind cabinets, flexible connectors running through walls, and black steel that has been painted over so many times the fittings are hidden. We fix what the code requires while the walls are open.

Every gas system starts with a load list: each appliance, its BTU input, and where it sits relative to the meter. We add appliances you have not bought yet but probably will, because a capped stub inside an open wall is far simpler than a new run through a finished house later.

From the load and the developed lengths we choose the piping layout and size each run from the fuel gas code tables. The meter location matters too. The utility decides where the meter can go, and it should be on a wall that keeps the main trunk short and away from driveways, windows and other openings.

We give the builder the plan early, so framers can leave chases where the piping needs to pass and nobody notches a joist that the gas line needed.

Most older homes run at low pressure from the meter, a few inches of water column, which is the pressure the appliances use. Low-pressure systems are simple and reliable, but with long runs and big loads the pipe sizes grow quickly, especially trunk lines in black steel.

Many new homes use a 2 psi system instead. The utility delivers gas at 2 psi to the house, a single trunk carries it to a central manifold, and a line regulator at the manifold drops it to appliance pressure. From the manifold, individual CSST runs go to each appliance, one line per outlet. The higher upstream pressure means much smaller pipe can carry the same load, which suits larger homes, tankless water heaters and generators.

A 2 psi system has extra requirements. The regulator must be accessible, it needs a vent or a listed vent limiter, and there must be a shutoff valve ahead of it. The utility must agree to supply elevated pressure at that meter. And the CSST has to be bonded to the electrical grounding system, which Spartanburg County checks at the meter release inspection.

• Low pressure: simplest, larger pipe, best for compact homes and modest loads
• 2 psi with manifold: smaller pipe, home runs to each appliance, suits larger homes and big loads
• Hybrid: a 2 psi trunk to a regulator, then low-pressure branches, common on additions

The rough-in inspection happens with the walls open. The piping is installed, supported, protected with striker plates where it passes through framing, and pressure-tested. Underground runs are tested before they are backfilled or covered by concrete, which in Spartanburg County is its own inspection point.

After drywall, the final stage is the gas meter release. Spartanburg County's residential inspection list calls for a minimum 10 psi air test on the gas lines at that stage, gas appliances in place and vented except the range, dryer and certain water heaters, every other outlet valved and capped, and the gas piping bonded. Other jurisdictions have their own lists, and we work to whichever applies.

Once the building office releases the meter, the utility schedules the meter set. That date is on their calendar, so we push the release as early as the job allows. When the meter is on, we purge the lines, light each appliance and check it.