An automatic line leak detector is defined as a device that:

• A. Is designed to shut down or dramatically reduce the flow to 3 gallons per hour in a pressurized piping system
• B. Is designed to detect a leak of 3 gallons per hour at a line pressure of 15 pounds per square inch
• C. Is designed to detect a leak of 3 gallons per hour at a line pressure of 10 pounds per square inch
• D. Is designed to detect a leak of 3 gallons per hour at a line pressure of 10 pounds per square inch in American style suction systems

Answer: (C)

An automatic line leak detector is defined by the specific condition under which it can reliably identify a leak—a leak rate of 3 gallons per hour when the line is at 10 pounds per square inch. This combination sets the sensitivity and the operating pressure at which the device must detect leaks, ensuring leaks big enough to matter are caught during testing without responding to minor fluctuations. The other descriptions either describe what action the system should take (like shutting down) or specify a different pressure or system type that isn’t part of the standard definition. Therefore, detecting 3 gallons per hour at 10 psi best matches the specification.