Last edited 25 Sep 2020


Classification, an introduction describes classification as, ‘what things are called, and how those names are arranged and structured’, or ‘the act or process of dividing things into groups according to their type.’

In the construction industry, classification is used in:

CI/SfB is the Construction Index/ Samarbetskommitten for Byggnadsfragor, a Scandinavian classification system for libraries set up in 1959 and intended for the construction industry.

This system has been used worldwide for technical and trade literature in the construction sector, more recently being used to define layers in computer aided design (CAD) construction drawings. It also formed the basis of the BS 1192-5 Construction drawing practice. Guide for structuring and exchange of CAD data.

In recent years it has been gradually superseded by Uniclass, which has a much wider coverage and is able to encompass new building types and concepts involving energy and environmental issues. However, many architectural libraries are still organised according to the CI/SfB system.

The method of displaying CI/SfB classifications is to use four boxes (or bays) with specific codes that appear in a particular box. References are based on five tables which then fit into the four boxes.

Most construction products do not enter data in all the boxes, and often ignore Tables 0 and 4.

Most products use (3-), which applies to ‘Secondary elements, completion of structure’. Detail can be provided to this, for example:

Composite window and door openings and parts to fill them (31.3)

Window openings only as above (31.4)

With Table 3 - Construction form, the products are classed as components, with the code being X, followed by a code for the material used (such as metal - ‘h’), and a sub-code for the particular type of material (such as aluminium - ‘4’).

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