Which of these is not a method of release detection?

• A. Overfill alarm
• B. Interstitial monitoring
• C. Vapor monitoring
• D. Pressure testing

Answer: (A)

Release detection methods are ways to find leaks in the tank, piping, or containment so you can respond quickly. An overfill alarm is designed to prevent spills by sounding when the tank is nearly full during filling. It doesn’t monitor the tank’s integrity or look for leaks in the soil, vapor, or containment space, so it doesn’t perform leak detection itself. In contrast, interstitial monitoring checks for leaks in the space between double walls; vapor monitoring looks for hydrocarbon vapors in the surrounding soil or air; and pressure testing (tightness testing) directly assesses whether the system holds pressure without leaking. Because of that focus on detecting leaks rather than preventing overfill, the overfill alarm is not a release detection method.