At static angles of heel up through 30°, a secondary barrier must

(a) If a complete secondary barrier is required in §154.459, hold all of the liquid cargo in the cargo tank for at least 15 days under the dynamic loads in §154.409(e);

(b) If a partial secondary barrier is permitted in §154.459, hold any leakage of liquid cargo corresponding to the extent of failure under §154.448(a) after initial detection or primary barrier leak for at least 15 days under the dynamic loads in §154.409(e);

(c) If the primary barrier fails, prevent the temperature of the vessel's structure from falling below the minimum allowable service temperature of the steel; and

(d) Be designed so that a cargo tank failure does not cause a failure in the secondary barrier.