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Plumbingaka: gas lineaka: CSSTaka: natural gas piping

Gas Piping

In Plain English

The pipe system that carries natural gas or propane from the supply source to appliances like furnaces, water heaters, and stoves.

Definition

The system of pipes, fittings, valves, and equipment used to distribute natural gas or propane from the utility meter or storage tank to gas appliances. Gas piping materials include black steel pipe, corrugated stainless steel tubing (CSST), and approved flexible connectors. All gas work must be pressure tested before concealment and inspected by the authority having jurisdiction.

Why It Matters in Bidding

Gas piping scope sits at the boundary of plumbing and mechanical, so estimators must pin down exactly who carries it to avoid double-counting or a scope gap that surfaces at award. Material selection (black steel versus CSST) and the required pressure test and AHJ inspection drive labor hours and schedule sequencing, since lines cannot be concealed until they pass.

Example

Reviewing the mechanical addendum, an estimator confirms the plumber owns gas piping to the rooftop units and adds 120 linear feet of black steel plus a pressure test allowance after the HVAC sub's bid excluded it.

Related Terms

ValvePressure RegulatorMain Shutoff ValveRough-In

Frequently Asked Questions

It depends on the specification division and local custom. Plumbers often run gas piping, but mechanical contractors may carry it to HVAC equipment. Always read the trade scope notes and addenda, then confirm in the subcontract; an unclaimed gas line is a common award-stage scope gap that triggers a change order.
CSST installs faster with fewer joints, lowering labor on long or concealed runs, while black steel costs less per foot but needs more threading and fittings. Bonding and listing requirements differ too. Estimators should price the material the drawings specify rather than substituting, since the AHJ inspects against the approved system.
Gas lines must pass a pressure test and AHJ inspection before being concealed, so estimators carry labor for the test, gauges, and any retest, plus schedule float. Missing this can stall drywall and finish trades downstream, creating delay claims and cash-flow strain if rework is needed.

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