IFC and classification systems: how to add a classification to IFC model entities according to the UniClass 2015 system.
If you need to address the tedious task of having to classify the entities of an IFC project, or do you have to read the classifications associated with the entities present in an IFC file, well today I’ll explain what the UniClass 2015 classification system is and what it is used for, including some useful info on how to use it to classify and add information to IFC Model entities.
I’ve also prepared an example in the IFC format on which you can try to classify objects yourself with usBIM.viewer + (the free software for managing IFC files).
What is the UniClass 2015 classification system?
UniClass (Unified Classification for the Construction Industry) is a classification system that was introduced for the first time in 1997 in the United Kingdom by the Construction Project Committee. It was born as an integration of existing standards such as EPIC (Electronic Product Information Cooperation) and CAWS (Common Arrangement of Work Sections for Building Works).
In the construction sector, UniClass can be defined as a “faceted” classification system, partly with an enumerative approach, which operates a classification method based on 15 tables and according to a hierarchy of tables.
Going into detail, the tables available in the UniClass classification are as follows:
- Complexes: describes a project in overall terms. It can refer, for example, to residential buildings, sports buildings, school buildings, airports, etc.
- Entity: constitutes one of the parts (or areas) of which a work is composed. It can include buildings, bridges or tunnels within a more complex system.
- Activities: represents the activities to be carried out in a complex or in an entity. For example, in a school building, motor, administrative, recreational, training, etc. activities meet. The table also includes investigations, operation, maintenance and services.
- Spaces: they can host one or more activities, inside a building or related to non-punctual works, such as road systems, railway networks, etc.
- Elements: they are the main components of a structure. For example, in a home, the elements coincide with the floors, pillars, walls, etc.
- Systems: are a set of components associated to form an element or to perform a function. For example, the roof system consists of tiles, insulation, vapor barrier, beams, etc.
So the UniClass 2015 system is based on tables. Each of these tables relates to a specific informative aspect and can be used individually or combined with other tables to express more complex concepts.
Here are the main titles and contents of the various tables.
|A||Form of information||The documents are classified either based on the type of content (catalogs, price lists, etc. ) and the media (magazines, videos, etc.).|
|B||Subject Disciplines||The disciplines related to the world of construction.|
|C||Management||Concepts related to decision making.|
|D||Facilities||Civil engineering works.|
|E||Construction Entities||The concepts relating to buildings, pavements, bridges and viaducts.|
|F||Spaces||The concepts relating to building spaces, regardless of whether they are internal or external.|
|G||Elements for buildings||The concepts relating to the elements in place belonging to the world of building production.|
|H||Element for civil engineering works||The concepts relating to the elements in place belonging to the world of civil engineering.|
|J||Work Section for buildings||A classification complementary to that of construction works focused on the “work sections “.|
|K||Work section for civil engineering works||A classification complementary to that of civil engineering works focused on the “work sections “.|
|L||Construction products||The products of construction.|
|M||Construction aids||The equipment of the construction site.|
|N||Properties and characteristics||The properties of the entities subject to classification.|
|Q||Universal decimal classification||Complex concepts, which can be determined by combining different class-specific codes.|
Between 2013 and 2015 the UniClass 2015 classification tables from 15 were reduced to 11.
|Table 1||Co||Complex (complessi)||Project as a whole (villa, university campus etc.)|
|Table 2||En||Entities (Entità)||Buildings according to function|
|Table 3||Ac||Activities (attività)||The activities that are carried out within the spaces|
|Table 4||SL||Space/Locations (spazi)||The spaces (the premises that make up the building)|
|Table 5||EF||Elements/Function (Elementi/Funzioni)||The elements are the single main components of a building (walls, foundations, roofs, etc.)|
|Table 6||Ss||Systems (sistemi)||The set of components of an element (the panels and uprights of a plasterboard wall, the joinery and carpentry elements that make up a door, etc.)|
|Table 7||Pr||Products (prodotti da costruzione)|
|Table 8||TE||Tools and Equipment|
|Table 9||Zz||CAD||The concepts related to computer science applied to construction|
|Table 10||FI||Form of Information|
|Table 11||PM||Project Management|
An element is identified by:
- 1 pair of alphabetic letters referred to the table
- 4 pairs of numbers that identify groups, subgroups, sections and objects.
In the next paragraph I’ll also show you how to classify any entity (for example a roof, a wall, etc.) of an IFC model.
You can try to classify the elements of any 3D model yourself (IFC, DWG, SKP, etc.), using usBIM.viewer + for free. Just open any file, (here you can download an example file) and select the ” Edit ” button in the ” Classification ” section of the ribbon bar.
How to classify IFC entities with usBIM.viewer +
The IFC standard also uses classification systems to catalog the entities of a project and implement the information system associated with them.
How can I actually add new classifications in the IFC language?
Below I show you a practical example to classify a project entity with usBIM.viewer +, according to the UniClass 2015 system.
Simply follow these steps:
- download and install viewer+ for free;
- click on File > Open and select the IFC file to upload;
- to modify the model click on Edit IFC > Edit;
- select (manually or with the help of selection groups) the objects to add a classification;
- from the toolbar, in the Select Classification section, click on Edit;
- from the dialog, select the type of classification, in our case UniClass 2015 (October 2018 version ), and then the subcategories to be associated with the selected entity;
- then click on confirm;
As illustrated in the animated GIF, after selecting the interested entity, you can read the information you just assigned in the right toolbox of the Properties:
- IfcClassificationReference expresses the code to which the type of information we have added corresponds
- IfcClassification expresses the type of classification adopted (in this case UniClass 2015).
For further information, here’s the IFC File example which you can download for free to view a project cataloged according to the UniClass classification system.
In this way you can check the classification assigned to each entity by following these simple steps:
- open the IFC file with usBIM.viewer +
- select an entity (e.g. a door, a wall, an attic, etc.)
- read the classification information in the right toolbox of the Properties:
IfcClassificationReferenceshows the code
IfcClassificationexpresses information on the type of classification system adopted (in this case UniClass 2015).
Remember that since this is not a standard, it is always necessary to reach agreement in advance between the different role players involved the type of classification to be adopted, in order to make the exchange of information univocal.