List code 12 digits mean: it is represented by twelve Arabic numerals, and one to nine digits are unified codes. Among them, one or two digits are appendix sequence codes, three or four digits are professional engineering sequence codes, five or six digits are partial engineering sequence codes, seven, eight and nine digits are subentry project name sequence codes, and ten to twelve digits are list project name sequence codes.

Project code refers to the Arabic numeral identification of the names of partial projects and measures. The project code of bill of quantities shall be represented by twelve Arabic numerals, one to nine digits shall be set according to the appendix of measurement specification, and ten to twelve digits shall be set according to the project name of bill of quantities of the proposed project, and the project code of the same project subject to tender shall not have duplicate codes.

When a bill of quantities of the same bid section (or contract section) contains multiple unit projects and the bill of quantities is based on the unit projects, special attention should be paid to the setting of ten to twelve digits of project codes when compiling the bill of quantities.

For example, the bill of quantities of a bid section (or contract section) contains three unit projects, each of which has solid brick wall masonry with the same project characteristics, and the bill of quantities needs to reflect the quantities of solid brick wall masonry of three different unit projects.

The project code of the solid brick wall of the first unit project should be 010401kloc-0/,the project code of the solid brick wall of the second unit project should be 0 1040 1003002, and the project code of the solid brick wall of the third unit project should be 0/kloc.