2　Terms and Symbols

2.1　Terms

2.1.1　Fixed roof tank

A type of tank that is equipped with a roof whose shell is rigidly connected to the top of tank shell.

2.1.2　Floating roof tank

A type of tank that is equipped with a roof that floats on the surface of the stored liquid，and rises and falls with the liquid level in the tank，including external floating roof tank and internal floating roof tank.

2.1.3　Slope protected foundation

A type of foundation that comprises a concrete or gravel revetment outside the tank as well as the packing layer，sand cushion and asphaltic sand insulation layer inside the revetment.

2.1.4　Ringwall foundation

A type of foundation that comprises a reinforced concrete ringwall under the tank shell as well as the packing layer，sand cushions and asphaltic sand insulation layer inside the ringwall.

2.1.5　Outside ringwall foundation

A type of foundation that comprises a reinforced concrete ringwall outside the tank as well as the packing layer，sand cushion and asphaltic sand insulation layer inside the ringwall.

2.1.6　Pile foundation

A type of foundation that comprises cast-in-place piles or pre-cast piles and the reinforced concrete pile cap connected to pile tops as well as the packing layer，sand cushion and asphaltic sand insulation layer on the pile cap.