Uniclass 2 : A brief introduction

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February 28, 2015 │

Uniclass is a classification system defined as a unified classification for the construction industry, initially published in 1997, United Kingdom. The system aims to organize library materials and to structure the product literature and project information.

The last official version released was the Uniclass 1.4, ‘criticized for not being genuinely unified, for inconsistencies between the labeling and depth of tables, for poor integration of civil engineering and building works and for being an essentially paper-based system.’ Therefore, Uniclass 2 has been proposed as a dynamic and electronic system, offered in several formats, pretending to be available to support all the stakeholders during the entire life-cycle of the building.

While in previous versions of Uniclass the information was not linked, because each table was developed individually, Uniclass 2 provides a structured approach to classifying the building information by organizing information based upon common characteristics. Uniclass goes further and defines also guidelines for all aspects of the built environment, rather than only the facility.

‘Uniclass2 groups like information in tables and these tables can be viewed in a hierarchy of increasing detail, where complexes comprise entities, entities comprise elements, elements comprise systems, and systems comprise products. It also provides tables that can be used to classify activities and spaces. Buildings comprise spaces, and activities take place in these spaces.’


Following this logic, the tables are structured as:

  • Co                    - Complexes
  • En                    - Entities
  • Ac                    - Activities
  • Sp                    - Spaces
  • Ee                    - Elements
  • Ss                    - Systems
  • Pr                    - Products
  • WR                  - Work results

‘Each table has groups of similar information and follows a hierarchy that expands with increasing levels of detail from a two digit code to six digits. For example, in the Administrative and Commercial group of the entities table Commercial Administrative Buildings are classified as 25-50 with small single office buildings having a lower level classification of 25-50-70. This principle of increasing specialization applies to all tables as can be observed from this example from the Product table: Openings are classified by group 60 of the Product table, Windows are a sub-group as classified by 60-98 with Hardwood Windows being 60-98-36.’

But how are the tables connected?

‘The unified nature of Uniclass2 means that just a single table (the Work results table) can be used to cover the entire project timeline. It includes civil and process engineering too so it can be used on multi-disciplinary projects. Connections between the Work results table and other Uniclass2 tables become evident when the codes are examined. For example, the last 2 digits of each work results code directly correspond to the Uniclass2 elements, i.e. the 25 in the code of work results section 05-90-25 Wall and barrier elements relates directly to the 25 group of elements in the Elements table. This unified approach is very powerful as it connects related information together.’

‘The Work sections Table includes sections for systems. The Table does not include the systems themselves, however. These would be held in the project specification. Logically, the proposed new Uniclass Systems Table would have a parallel classification of systems. The Systems Table can exactly parallel the Work sections Table down to the third level. Below this (Level 4 in the Uniclass Systems Table), the actual systems listed in the Systems table would be those described in system outline clauses in the project specification.’

‘Similarly, the Work sections Table also includes sections for products. Again, the Table does not include the products themselves. These would be held in the project specification. Logically, the proposed new Uniclass Products Table would have a parallel definition of products. The Products Table can exactly parallel the Work sections Table down to level 2. Below this (Level 3 in the Uniclass Products Table), the actual products listed in the Products table would be those described in product clauses in the project specification.’

The Uniclass system is available on

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