IFC objects classification: how to classify IFC model entities with the OmniClass system
Do you need to classify the entities of an IFC project or to read a classification associated with the entities present in an IFC file? This post is all about OmniClass classification system.
We’ll be taking a closer look at what OmniClass classification is, what it is used for and how to use it in order to classify and add information to the entities of an IFC model. We’ll also provide you an example in IFC format that will allow you to classify objects with the aid of usBIM.viewer+ (the freeware to easily manage IFC files).
What is the OmniClass classification system?
OmniClass is a system adopted in North America (according to ISO 12006-2 international standard) and used for organizing and retrieving of information throughout the full facility life cycle, from conception to demolition. The system adapts to all levels of detail of a work: be it industrial, commercial or residential, from materials to construction systems.
OmniClass consists of 15 tables, each of which deals with different construction information.
Each table can be used individually or in combination with others to classify more complex information, while the system can always be updated with the addition of new elements.
The tables organization draws its definitions from ISO 12006-2:
- tables 11 to 22 describe construction results
- tables 23-33-34-35 and partly 36 and 42 classify information on construction resources
- tables 31 and 32 organize the construction processes and phases throughout the construction life cycle.
The chart below shows some examples to better understand how to classify an entity with the OmniClass system.
|Table cod.||Number cod.||Description||Example|
|Table 11||11-00 00 00||Entities of the construction system (classified by function)||Private residences, hotels, congress centres, bus stations, motorways, etc.|
|Table 12||12-00 00 00||Entities of the construction system (classified by shape)||Apartment houses, skyscrapers, bridges, landing platforms, etc.|
|Table 13||13-00 00 00||Spaces (classified by function)||Bedrooms, offices, gyms, motorways, etc.|
|Table 14||14-00 00 00||Spaces (classified by shape)||Courtyards, patios, recesses, interspaces, etc.|
|Table 21||21-00 00 00||Elements (including designed elements)||Exterior walls, stairs, roof, furniture, etc.|
|Table 22||22-00 00 00||Activity results||Metal carpentry, concrete casting, ceramic coating, lighting system, plumbing pipes, railroad tracks, etc|
|Table 23||23-00 00 00||Products||Concrete, bricks, mortar, windows, boilers, manholes, etc.|
|Table 31||31-00 00 00||Phases||Defining the project concept, preparing documents to obtain a building permit, the construction phase, disposing of construction waste, etc.|
|Table 32||32-00 00 00||Services||Planning, the offer, construction estimating, site surveying, etc.|
|Table 33||33-00 00 00||Disciplines||Architecture, construction company, structural engineering, administration, etc.|
|Table 34||34-00 00 00||Organizational roles||Site engineer, designer, plant designer, BIM manager, real estate agent, process manager, etc.|
|Table 35||35-00 00 00||Tools||Scaffolding, work tools, design and calculation software, construction site fencing, vehicles, formwork, etc.|
|Table 36||36-00 00 00||Informations||Project files, building regulations, property titles, maintenance and management manuals, site journal, etc.|
|Table 41||33-00 00 00||Materials||Steel, wood, concrete, plastic, etc.|
|Table 49||49-00 00 00||Properties||Colour, area, length, transmittance values, fire resistance, etc.|
Each information is classified and detected by a six-digit identification code which refers to the table.
The first two digits indicate the reference table while the subsequent pairs of numbers identify the typology for each level.
For example, a foundation wall is identified by the code 21-01 10 10 10, corresponding to:
- table 21 – Elements
- level 1 – Substructures
- level 2 – Foundations
- level 3 – Standard foundations
- level 4 – Foundation wall.
In this way, by reading the code and the classification system adopted, it is possible to uniquely identify an entity and retrieve more information about it.
How to classify IFC entities with usBIM.viewer +
Here are the steps to follow to classify IFC entities, according to the OmniClass classification system:
- download and install usBIM.viewer+ for free
- click File>Open and select the IFC to upload (you can use the example that we’ve prepared for you or any other IFC file)
- click Edit IFC>Edit to model the file
- select (either manually or with the help of selection groups) the objects to classify
- in the Select Classification section on the toolbar click on Edit
- in the pop-up dialog, select the type of classification, in our case OmniClass, and the subcategories to associate with the selected entity
- once the operation is complete, click on Confirm.
This is how you can classify an entity or group of entities according to the OmniClass system.
Below the steps of the process for classifying an element according to the OmniClass standard.
For further testing you can download the IFC file for free and view a project classified according to the OmniClass system.
To verify the entity classification in an IFC file you can use again usBIM.viewer+.
Follow these simple steps:
- open the file with usBIM.viewer+
- select an entity (for example a door, a wall, a slab, etc.)
- read the information relating to the classification on the Properties toolbox on the right-hand side:
IfcClassificationReferencewill report the code;
IfcClassificationwill specify the information relating to the type of classification system adopted (in this case OmniClass).
Remember that with usBIM.viewer+ you can classify objects according to the main classification systems:
- NBS Create
- UniClass (versione 2)
- UniClass 2015