Method for constructing triple-shell tank

A method for constructing a triple shell tank including an inner tank, an intermediate tank, and an outer tank each having a roof and a side plate, the method comprising processes of:

• as construction entrances, opening a first construction opening in the outer tank side plate when installing the outer tank side plate, a second construction opening in the inner tank side plate when installing the inner tank side plate, and a third construction opening in the intermediate tank side plate when installing the intermediate tank side plate;
• and
• sealing the second construction opening after completion of work inside the inner tank, then sealing the third construction opening after completion of work inside the intermediate tank, and subsequently, sealing the first construction opening after completion of work inside the outer tank,
• wherein the first construction opening, the second construction opening, and the third construction opening are opened so as to at least partially overlap with one another in a circumferential direction and a height direction of the triple shell tank, and
• the first construction opening and the second construction opening are opened so as to satisfy a relationship of
• AR
• ⁢
• 1
• ≥
• AR
• ⁢
• 2
• where AR1 is an opening area of the first construction opening and AR2 is an opening area of the second construction opening.