The pressure-staged connection
Residential propane delivery requires two-stage pressure reduction:
- Tank pressure (~120 psi at 70°F) → first-stage regulator → ~10 psi in the yard line
- 10 psi yard line → second-stage regulator at house → ~11 in WC for appliances
First-stage regulator installation
Installed directly on the tank's vapor outlet valve. Vents to atmosphere through a small opening that must point downward and remain unobstructed. Includes a freeze protection feature in cold climates to prevent regulator icing during high draw.
Yard line installation
PE (polyethylene) tubing is the modern standard. Trenched 18–24 inches below grade. Tracer wire installed above the line for future locator use. Marker tape buried 6 inches below grade to warn future excavators. Riser at the house transitions PE to copper or steel for above-grade entry.
Second-stage regulator at house
Wall-mounted on the exterior of the home, often near the gas meter location used for natural gas in non-propane homes. Vents to atmosphere downward. Output: ~11 in WC for the house piping system.
House piping
Black iron or CSST piping distributes propane from the second-stage regulator to each appliance. NFPA 54 (National Fuel Gas Code) governs pipe sizing based on appliance BTU loads and pipe length. Each appliance has an individual shut-off valve.
Building entry sealing
The point where the gas line enters the building is sealed against air infiltration and water entry — and against any conceivable path for gas to enter the building envelope outside the intended piping system.
FAQ
Can a propane tank be connected directly to appliances without regulators?
No. Tank pressure is far higher than appliance operating pressure. Direct connection would destroy appliances and create extreme safety risk. Two-stage regulation (first stage at tank, second at house) is required.
How is the yard line protected from freezing?
PE tubing buried below the frost line (typically 18–24 inches in most US climates, deeper in northern climates) doesn't freeze because propane vapor at 10 psi doesn't condense at typical ground temperatures. First-stage regulators in cold climates have freeze-protection features for the regulator itself.