Restaurant Gas Piping: Low-Pressure Test and Appliance Connections
A restaurant tenant build-out has a new 1-inch black-iron gas line from the meter, a 40-foot run to a 150,000 Btu/hr range, and a 3/4-inch branch 20 feet to a 40,000 Btu/hr water heater. The contractor air-tests the entire system at 5 psi for 10 minutes and reports no gauge drop. The range has no sediment trap; the water heater is connected with a 7-foot flexible appliance connector. A shutoff valve is installed upstream of the connector. The contractor says the pressure test is “more than enough” because the system is small and the gauge held. The inspector also sees that the gas piping is supported only by the appliance connector at the water heater and is not protected where it passes through a metal stud.
1. Is the 5 psi/10-minute air test acceptable? State the test the inspector should require.
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No. A 5 psi test held for 10 minutes is below the usual UPC gas-piping test requirement. The code commonly requires a test pressure of not less than 10 psi for at least 15 minutes, using a gauge of appropriate range, with the system isolated from the meter and all joints exposed for inspection. The exact pressure and duration must be verified against the adopted edition and any local amendment, but 5 psi for 10 minutes is not a substitute.
The fact that the system is small does not matter; the test verifies the integrity of every joint and connection. A low-pressure test can miss a leak that would show at the required pressure. The inspector should not accept the contractor’s gauge reading alone. The contractor should correct the piping defects, isolate the system, test at the required pressure for the required time, and the inspector should witness or verify the test before approving the gas piping.
2. Identify the gas-piping installation defects and the corrections.
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Several defects are visible. The range lacks a sediment trap; a sediment trap is generally required at the inlet of each appliance unless the appliance has an integral trap, installed downstream of the shutoff and ahead of the appliance controls. The 7-foot flexible connector exceeds the usual 6-foot maximum for an appliance connector; it should be replaced with a shorter connector or hard-piped closer to the water heater.
The piping is supported only by the appliance connector, which means the connector is carrying the weight of the gas piping. The pipe must be independently supported, and the connector must not be subjected to strain, kinks, or sharp bends. The piping passing through the metal stud needs protection against abrasion or corrosion, such as a sleeve or grommet, and must not be concealed in a way that prevents inspection.
The inspector should also verify sizing against the adopted gas tables, shutoff accessibility, and that the range and water heater have the required clearances and venting. Corrections should be complete before reinspection and before the gas supply is turned on.
3. How should the inspector handle the contractor’s claim that the test is adequate because the system is small and the gauge held?
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The inspector should evaluate the test against the adopted code, not against the contractor’s judgment about system size. A small system can still have a leaking joint, and a gauge that holds at a lower-than-required pressure does not prove compliance. The test method must use the required pressure and duration, and the gauge must be suitable for the range and in good condition.
The inspector should document the observed test pressure, duration, gauge range, and whether the system was isolated. If the test does not meet the code, the inspector should issue a correction notice and require a retest after the piping defects are corrected. The inspector should also verify that all joints were exposed for inspection, because a pressure test does not excuse concealed or improperly supported piping.
Approval should be withheld until the required test is passed and the sediment trap, connector length, support, and protection defects are corrected. The final record should show the test results and the reinspection.