Contractor Trades: Gas Piping Pressure Test Failure
You are the inspection authority for a residential combination project. The plumbing contractor installed 1/2-inch and 3/4-inch black steel gas piping and performed a 10 psig air pressure test on the system, holding it for 10 minutes. The gauge dropped from 10 psig to 8.5 psig during the test. The contractor says the drop is from temperature change and that the system 'held fine' on a previous test. The mechanical contractor has already connected a new furnace and water heater, and the homeowner wants the gas turned on today. The piping includes a run through a concealed ceiling chase and a connection to an exterior grill.
1. Should the pressure test be accepted? Explain the reasoning.
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No. A 1.5 psig drop over 10 minutes is a failure, not a temperature effect. Temperature-induced gauge variation is small and would not produce that magnitude of loss over that interval. The test must be repeated after the leak is located and repaired, and the test duration and pressure must meet the applicable code requirements for the system size and type. The inspector should document the failed test, the gauge readings, and the required retest. The judgment point is that a pressure drop is evidence of a leak until proven otherwise, and the contractor's explanation does not override the gauge.
2. What concerns arise from the concealed chase and the exterior grill connection?
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Concealed piping must be inspected and tested before concealment; if the chase is already closed, the inspector cannot verify joints, supports, or protection, and the piping may need to be exposed or otherwise verified. The exterior grill connection introduces additional requirements for the piping material, protection from corrosion and physical damage, and a shutoff valve at the appliance. Both conditions must be resolved before the gas is turned on. The judgment point is that accessibility and appliance-specific requirements are part of the inspection, not afterthoughts.
3. The homeowner wants gas today. What is your response?
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The gas cannot be turned on until the system passes a proper pressure test and the concealed and exterior portions are verified. Explain the failed test and the required retest to the homeowner and contractor, document the deficiency, and schedule reinspection. Do not authorize energizing a system with an unresolved leak test. The judgment point is that occupant convenience does not justify energizing a system that has not demonstrated integrity.