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What is IFC (Industry Foundation Classes) in Construction?

IFC is the short form for Industry Foundation Classes.

It is the main tool for the implementation of OpenBIM workflows; a collaborative approach to the design, construction and operation of budlings based on open standards.

Therefore, IFC is an open file format, that is not controlled by any individual BIM software creators. It is a recognised ISO standard, created and maintained by buildingSMART International to facilitate interoperability between different operators.

Building Information Modelling, IFC and Interoperability

Building information modelling is one of the most innovative digital construction solutions of our age. It describes a collaborative workflow that is aimed at sharing real-time construction project data to aid in decision making. This is made possible by the use of BIM software that relies on IFC to exchange model data without the loss or distortion of the data.

The BIM model is not just a three-dimensional representation of the facility. Not only is it dynamic, but also intelligent in the sense that it contains a range of information that responds to the changes in the geometrical description of the model and updates automatically.

Given that people use different software to author BIM data, it becomes a challenge when that data needs to be exchanged. Proprietary file formats would require you to have the same version of the software that was used to create the file for you to access the model data, and use it for your intended project-related purposes.

This challenge is called the interoperability challenge. There is a need to have a globally standard file format for describing both the geometrical and non-geometrical BIM data in a way that will be universally accessible to any project member regardless of what BIM software they have installed on their computer.

As a result, IFC was developed to cater for such needs. It is, therefore, a global standard used to describe, share and exchange construction and facilities management information.

Further, it is a neutral file format, with an open standard that supports different software systems, even operating systems.

IFC File Types

There are very many file types that are supported by the IFC standard. However, the following are the main types:

  1. .ifc – STEP Physical Format; is the most widely used and the most compact IFC format.
  2. .ifcXML – Extensible Markup Language; provides enhanced readability and is compatible with a broad range of software tools.
  3. .ifcZIP – is a ZIP file with either .ifc or .ifcXML files embedded within.

Why IFC?

Let’s assume you use ArchiCAD or Revit to author your BIM models as an architect, or CostX if you are a quantity surveyor. This means you rely on the software vendors’ native file formats. What if they update their software by removing some features, adding new functionality or removing some data fields that you relied on so much to put together your BIM data?

As a consequence, it might be challenging to read and access data created with earlier software formats using the updated versions.

Also, some important data might be lost if the old BIM metadata and classifications are no longer supported.

However, with IFC, the data structures are publicly maintained and governed by an international ISO standard. That is more reliable compared to an individual native format that the vendor is free to change without consulting you.

Further, IFC provides the rules and guidelines to determine what information is exchanged between software applications while maintaining meaning. It includes but is not limited to geometrical data of physical building elements.

Also, it allows the linking of non-geometrical alphanumeric information, such as properties, quantities and classifications, to building components and a way of maintaining the relationship between these data types.

In the end, standardization makes it possible to work with anyone. According to Acca Software, it results in higher quality, reduction of errors, reduction of costs and saving of time, with consistent data flowing from the design phase through all other phases of the project.


The Architecture, Engineering and Construction industry is increasingly getting digitized. There is no going back as the benefits realised are immense. Collaborative sharing of project information removes the bottlenecks brought about by the fragmented nature of the industry.

Also, IFC as an international OpenBIM standard removes the impracticalities brought about by interoperability problems in the different types of BIM software adopted by construction project members. The benefits are consistency in the data flow, savings in time and costs, inclusivity of project members regardless of the software they use and better collaboration.

The benefits offer a positive move toward making the Architecture, Engineering and Construction (AEC) industry more valuable and profitable. That is a move I happily and enthusiastically welcome and champion for.

I would like to know your thoughts and ideas about IFC, BIM and construction digitization generally. Do you think innovative digital technologies are important for the construction industry or we can do better without them? Let me know in the comments section below.

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