The procedure involving inserting plugs, connecting an air hose, and pressurizing to 0.5 psi above the test pressure, closing the isolation valve, and timing the pressure drop is used for which test?

• A. Water Test
• B. Air Pressure Test
• C. Exfiltration Test
• D. Alignment Testing

Answer: (B)

When testing a sewer line for leaks, using an air pressure method is the approach that matches this procedure. The line segment is isolated with plugs, an air hose is connected, and the system is pressurized to a pressure slightly above the required test level—here 0.5 psi higher—to make small leaks show up against a small overpressure. After sealing off the section with the isolation valve, you time how long it takes for the trapped air pressure to drop. If the pressure holds, the joints and pipe are likely tight; if it falls noticeably, there’s a leak somewhere in the section being tested. This method specifically uses air and measures the rate of pressure loss to assess integrity, which distinguishes it from a water-filled test. A water test would involve filling the pipe with water, while an exfiltration test focuses on leakage to or from surrounding soil, and alignment testing checks the physical alignment rather than pressure.