So far in our series about Building Information Modelling, we’ve discussed the basics of what BIM is and looked at why you should be using it. In this post we look at how the Government has been involved in establishing and mandating this process as well as the type and format of information required.
In 2011 the Government published their Construction Strategy which set out their intentions towards BIM, amongst other strategies. All of these aim to modernise UK construction with a main focus of reducing the capital cost and carbon emissions of the built environment by 20%. They have stated that they required that all public construction projects to be built using BIM from 2016, calling for the adoption of Level 2 BIM within the design and build process. Following on from the implementation of this mandate, the aim is to move towards level 3 BIM within the industry. This is now down to the Construction Industry who were handed over the task from the Government in October 2016. The different levels are discussed in a bit more detail later but basically the Level 2 BIM comprises 3D Domain Models, 2D pdfs and COBie data sets for the project. Level 2 means that there will be managed 3D data for each object, which is formatted in a common way so that they can be integrated with the rest of the design.
A BIM Task Group was established to support the Government’s Construction Strategy. They define BIM as “essentially value creating collaboration through the entire life-cycle of an asset, underpinned by the creation, collation and exchange of shared 3D models and intelligent, structured data attached to them.”
To start with the Government’s construction strategy requests that all the data for each object is provided in COBie (Construction Operations Building Information Exchange) format, as this is a vendor neutral format. This means that it is not a proprietary system that depends on a particular brand of software, instead it can be used by many different types of CAD software. This is similar to the way that the HTML code in webpages can be understood by a number of different browsers. COBie is a simplified subset of the IFC (Industry Foundation Class) which doesn’t contain any drawings or diagrams and the information provided can be contained in a spreadsheet. More information on COBie requirements can be found in its specifically focused standard BS 1192-4:2014 Collaborative production of information Part 4: Fulfilling employers information exchange requirements using COBie – Code of practice.
The data for each object can be held in locations such as the NBS National BIM library, a free online resource which contains both generic BIM objects as well as more specific ones which are provided by manufacturers and contain exact information about the object. Our BIM objects can be found on the library, as well as on our website. The use of a library allows the BIM objects to be easily found and downloaded for use in a project.
BIM Maturity Levels
The Government have specified that the data provided on public construction projects to be provided at maturity level 2 now, with the aim to progress towards Level 3. The levels are as follows:
• Level 0 – Flat CAD with no 3D info (traditional drawings)
• Level 1 – Managed in CAD in 2D or 3D with a collaboration tool providing a common data environment.
• Level 2 – Managed 3D environment held in separate discipline ‘BIM tools’ with attached data. Commercial data is managed by various software tools.
• Level 3 – Fully integrated, interoperable BIM
These levels are not intended as a target which should be achieved and that’s it, rather they are designed as a guideline with the intention that BIM will continue to develop and evolve as we use it. Level 2 should not be the be all and end all, merely a step in the journey.
The advantage of using these models at a more mature level of information means that the effects of altering one element of the design can be reflected throughout the model and in all views that display that element, for example if a wall is altered then all the views that display that element, from the CAD drawings to the 3D model can be intelligently altered by the model, because they are all from the same underlying information.