Last edited 16 Mar 2017


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:

The OmniClass Construction Classification System, also known as OmniClass™ or OCCS, is a classification system used for the organising and retrieving of information for the construction industry. It is the North American equivalent of Uniclass.

It covers the full facility lifecycle from conception to demolition or reuse, and all types of construction in the built environment. It is useful for Building Information Modelling (BIM), organising reports and object libraries.

Similar to Uniclass, OmniClass is derived from internationally-accepted standards developed by the International Organisation for Standardisation (ISO) and the International Construction Information Society (ICIS) and has been developed from the early-1990s to the present.

OmniClass comprises 15 tables, some of which focus on buildings and landscapes, and some of which also serve civil and/or process engineering. Each table can be used independently to classify a particular type of information, or entries on it can be combined with entries on other tables to classify more complex subjects.

The tables are as follows:

  • Construction Entities by Function – Table 11.
  • Construction Entities by Form – Table 12.
  • Spaces by Function – Table 13.
  • Spaces by Form – Table 14.
  • Elements (includes Designed Elements) – Table 21.
  • Work Results – Table 22.
  • Products – Table 23.
  • Phases – Table 31.
  • Services – Table 32.
  • Disciplines – Table 33.
  • Organisational Roles – Table 34.
  • Tools – Table 35.
  • Information – Table 36.
  • Materials – Table 41.
  • Properties – Table 49.

OmniClass incorporates other extant systems currently in use, such as; MasterFormat™ for work results, UniFormat for elements, and Electronic Product Information Cooperation (EPIC) for structuring products.

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