chapter  1
Introduction
Pages 1

Abstract Two new types of LNG above-ground storage tank, the prestressed concrete outer tank and in-pit storage tank, are now under construction in Japan. The two tank systems were designed and developed to improve the safety and reliability of above­ ground LNG storage tanks requiring both large capacity and/or located at sites with restrictions such as closeness to residential areas or having limited area. This paper shows the main characteristics and design points of the two types of storage tanks together with construction examples. Keywords: Above-ground storage, aseismic design, in-pit storage, LNG, prestressed concrete, pump barrel, tank, ventilation

About 90% of Japan’s energy is imported, of which some 70% is petroleum-based in the form of petroleum oil, petroleum gas and natural gas. The proportion of natural gas continues to rise as it is increasingly used for both city gas and electric power plants, currently accounting for 10% of total energy consumption. Therefore there is a commensurate need for many LNG storage tanks to hold the gas. Since LNG was first imported in 1969, 136 LNG storage tanks at 13 receiving terminals have been constructed and operated safely, with a further 16 LNG storage tanks now under construction.