1　Scope

This Specification defines the requirements for material selection,design,fabrication,inspection and acceptance of steel vertical vessels supported by skirts(hereinafter referred to as columns)in petrochemical industry.

This Specification is applicable to the design for the columns at design pressures not greater than 35MPa,with height greater than 10m and height-to-diameter ratio greater than 5.

Note:The diameter of columns refers to their nominal diameter.For columns designed with different diameters,the weighed mean diameter shall be assumed as their nominal diameter,as calculated by Equation(1).

where　D—diameter of the column shell;

H—height of the column;

D1,D2,…,Di—nominal diameter of each columnsection;

h1,h2,…,hi—height of each column section.

This Specification is not applicable to the design of the following columns:

a)Guyed columns;

b)Non-metallic lined columns;

c)Columns in row or column groups connected by operation platforms;

d)Jacketed columns.