A Model Test of Cargo Leak Rate through a Small Crack of Semi-Membrane Tank for an LPG Carrier : A Study of Tank Type B of Semi-Membrane Tank for an LPG Carrier

Abstract

This paper deals with the leak test for designing a partial secondary barrier of Semimembrane tank system (Tank type B) for an 100,000 m^3 LPG / NH_3 carrier. The leak test was performed using the liquid flon 12 (R-12). The material of the specimen used is KT-50N to be used for cargo tank. Several size of fatigue through cracks were made in the specimen and the leak rate was measured for each. During the measurement, three different static membrane tensile stresses and four different liquid pressures were applied to the specimen corresponding to the actual condition of the tank in service. In addition, the static bending stress was also applied in some cases to see its influence on the leak rate. The leak rate of actual cargo was estimated based on the result of the leak test.