- An internal or external inspection performed to maintain and ensure the integrity of a storage tank.
- Measurement of tank settlement comprises three components: uniform settlement, planar tilt, and out-of-plane settlement. While excessive uniform settlement and uniform settlement may not impair the structural integrity of tanks, they can cause serviceability issues. Out-of-plane settlement can lead to serviceability problems of the tank and also induce localized stress concentration that may cause accelerated corrosion or rupture. Measured settlements need to be evaluated to determine the effects on tanks.