BIM is the digital representation of the physical and functional characteristics of a facility. It can be represented as a virtual 3D model or a spreadsheet. The use of a BIM model is intended to create a shared resource enabling decisions about the design and construction of the facility to be taken before it is built and, after construction, to act as a detailed digital operation and maintenance manual during the lifetime of the building.
The BSI defines BIM as:
“… the process of generating and managing information about a building during its entire life-cycle.BIM is a suite of technologies and processes that integrate to form the “system” at the heart of which is a component-based 3D representation of each building element; this supersedes traditional design tools currently in use”.
BIM therefore means both “Building Information Modelling” and “Building Information Management”.
The BIM strategy was launched by the Government in May 2011 and has been gathering pace since. The first significant milestone is the Government’s stated desire to let all of its contracts on a BIM-enabled basis by 2016. It remains to be seen whether that milestone will be achieved. In reality, it is likely that it will seep through the industry at varying speeds depending upon the size, nature and complexity of the project in question but will ultimately become part of the process in much the same way as CAD.
The 2016 milestone is for BIM at Level 2: that is, the process is distinguished by collaborative working – all parties use their own 3D CAD models (known as federated models) but not necessarily working on a single, shared model. The collaboration comes in the form of how
the information is exchanged between different parties and is a crucial aspect at this level. Design information is shared through a common file format which enables any organisation to be able to combine that data with their own in order to make a federated BIM model. Any CAD software that each party uses must be capable of exporting to one of the common file formats.
The contractual relationships that reflect Level 2 BIM are essentially not very different from the existing contractual arrangements in relation to intellectual property, risk and other issues. They are still characterised by a “ring fencing” of liability and risk between the various parties to the design process. As such, Level 2 BIM is not very different from existing contractual and legal relationships and indeed has been described as simply using the existing information available to the industry more efficiently.
The Construction Industry Council (CIC) has issued a BIM protocol, a document designed to be incorporated into the hierarchy of contract documents and which provides the framework for the application of BIM to a construction project. The Protocol envisages the employment of an Information Manager to manage the exchange of BIM-related project information. The Protocol also is based around a Model Production Delivery Table (MPDT) which identifies the Levels of Detail that models need to meet at the various defined project stages or data drops stated in the table.
The detailed technical and contractual provisions underlying the use of BIM on a project can be found in various Publically Available Specifications all of which have been published by the BIM Task Group.
It appears that whilst the CIC BIM Protocol is being used to some degree, it is more common for bespoke protocols to be prepared based upon the CIC Protocol requirements. Fairly minimal amendments need to be made to the main contract terms to incorporate a BIM Protocol.
Work is already under way on Level 3 BIM, although this is at least five years away in terms of implementation. Currently seen as the holy grail, Level 3 represents full collaboration between all disciplines by means of a single, shared project model held in a centralised repository and worked on by all parties in real time. This is known as “Open BIM”. Current nervousness in the industry around issues such as copyright and liability will have to be resolved – the former by means of robust appointment documents and software originated/read/write permissions and the latter by shared-risk procurement routes such as alliancing or partnering.
The annual BIM survey undertaken by the NBS indicates a growing understanding of BIM and what it means throughout the construction industry. There is a general acceptance that this is now a feature of the industry which will expand beyond just the large scale projects on which it is already operating to medium and even smaller size projects. It is the stated aim of the BIM Task Group (and the BIM4SME Working Group) to spread awareness that BIM is scalable and can be used on nearly any size project.
It is also worth remembering that BIM is intended to be used throughout the life cycle of an asset from its initial conception and design through to its demolition or refurbishment for a different purpose. Given that the vast majority of assets in the built estate in this country are already existing rather than new-build, it follows that BIM statistically has a wider application to existing assets. A BIM model can be created through the scanning of an existing building, which can be accomplished very quickly through point cloud or laser scan and to a very high degree of accuracy, and which can then form the basis of a detailed and highly flexible operation and maintenance model. There are obvious time and costs savings in having available in one place enormous amounts of information in relation to every aspect of the built asset from its main structural components down to the make, size and model of the doors.
Whether or not the milestone set by the Government for 2016 is met, an enormous amount of progress has been made in implementing the use of BIM in the industry and there is absolutely no doubt that BIM is here to stay.