TYPES OF ABOVEGROUND STEEL TANKS
The type of foundation construction depends on size
and function of AST, bearing capacity of soil, level of underground
water, need of anchorage and possibility of owner.
Tanks with double bottom.
constructed on purpose to prevent the pollution on the soil when
one bottom is punctured.
Tanks with double steel shell. They are applied when:
- the available area
is not very large and it is impossible to construct earth or
- very expensive area, when it is cheaper to
construct second shell;
- in order
to decrease all kinds of outpouring and pollutions if there is leak in
Tank with fixed roof.
They are applied when they store the products which are not volatile
and/or the tanks themselves have the small and medium sized volumes.
The roofs can be of the following kinds:
a) Self-supporting roof:
- cone roof - they are economical
when the volumes are up to 2 000 m3
- dome roof - they
are economical when the volumes are bigger than
2 000 m3. Steel dome roof could be applied when the
volumes are up to 70 000 m3 ( diameter D < 65 m ).
- cone roof
– they can be applied in all existing volumes of the tanks;
roof - they are still experimental.
Tanks with floating roof.
They are applied when store volatile products and/or the tanks
themselves have big volumes, and the using of the fixed roof
increases the weight of the used material.
other side the floating roofs are different types:
a) according to their position:
- external floating roof - when the tanks are open on
- internal floating roof - when
they are erected inside
tank with fixed roof.
b) according to their construction:
- single deck floating roof;
- double deck floating roof.