When inspecting double wall tanks, what specific area is focused on during checks?

During inspections of double wall tanks, a significant area of focus is the interstice. The interstice refers to the space between the inner tank and the outer tank. This area is crucial because it serves as a secondary containment system, designed to detect leaks from the inner tank. If a leak occurs, the interstitial space is engineered to capture any leaked substance, preventing it from entering the surrounding environment.

Monitoring the interstice is essential not only for compliance with regulatory standards but also for ensuring the safety and environmental protection associated with storing potentially hazardous materials. Inspectors check for signs of leaks, the presence of liquid, and other indicators that may suggest a breach in the inner tank.

While aspects such as the inner tank, outer tank, and the top of the tank might be inspected as well, the primary emphasis during inspections specifically for double wall tanks is on the interstitial area because it directly relates to the tanks' leak detection and containment capabilities. This focus helps in maintaining the integrity of the UST system and preventing environmental contamination.