BIM: what is it, and how does it affect you?
BIM stands for ‘Building Information Modelling’ (or ‘model’) and is already common terminology in the US and parts of Scandinavia. Without doubt it represents the future of construction documentation. Dr Stephen Hamil, director of design and innovation and Head of Building Information Modelling at NBS, explains what it’s all about.
BIM Artlantis rendering by Thierry Tutin
I recently represented NBS at a roundtable discussion on BIM. Many respected experts from UK industry were present, including the government's chief construction advisor, Paul Morrell, and leading voices from Laing O'Rourke, Hilson Moran and BDP. Here is a distillation of some of the main questions posed from the floor, and the experts’ answers.
|1.||What is BIM?
BIM stands for ‘Building Information Modelling’ or a ‘Building Information Model’. It is a rich digital model of a physical building. That model can be used by the design team to design the building, the construction team to model the construction of the building, and then by the building owner to manage the facility, throughout its life.
|2.||Who owns the BIM?
To maximise its full benefits, the building owner must own the BIM.
If an engineer, for example, creates a BIM and doesn’t share it, then the true benefits are not realised. The designs across the design team will not be fully coordinated, the construction team will not have the chance to model the construction process digitally (or will have to re-key the information to do this) and the building owner will be left to manage the facility by relying on box-fulls of paper documents.
To maximise the full benefits the design team must share their information model, pass this to the construction team and then place it in the hands of the building owner.
A very simple analogy would be to compare BIM with commissioning a book or a photography session. If the client only received a physical book or prints at the end of the process then that would be satisfactory, but far better to also receive the copy content and original photographs in digital format. The client could then reuse this content in future, and gain much greater value from it.
|3.||Who will make the most money from BIM?
One might have asked the same question when the construction industry moved from drawing boards and typewriters to the first CAD and word processing systems in the 1980s. The answer then – as now – is that everyone made or saved money, because work processes became more efficient and accurate. If you made a mistake you could undo it. If you had to draw the same window 100 times, each copy was exactly the same as the first. If you wanted to find a particular word or phrase within a 100 page document, you could search for it in seconds.
Now it’s time for the construction industry to move to the next stage of technology and structured data. Designers need no longer spend time retyping data from a 2D CAD model into a Microsoft Excel workbook to produce a 200-instance door schedule, or going through a 150-page specification to identify where they’ve requested that the contractor submit proposals or samples. Contractors themselves will no longer be informed by the structural and M&E engineers about design clashes on site and during construction, and will be able to more efficiently price projects by getting competitive prices when purchasing in bulk, with less waste. Finally, the building owner will be able to manage and alter their facility using an accurate digital model of the physical building.
|4.||What are the legal implications of BIM?
For all of the positives associated with BIM, there are also some uncertainties. Legal questions surrounding BIM’s status as a contract document is one of these.
For a number of years contract documentation has all been on paper. In recent years this has started to turn digital, with PDF (Portable Document Format) being a common medium. We are fortunate that PDF is quite a simple, robust, data format. But consider the example of a contractor referring to the contract specification for the colour of the fašade; the specification refers to the drawing. When the contractor views the drawing in their chosen PDF viewer this fašade is red. However, the designer has changed this to be blue but not coordinated this across the documents. Who will pay the bill for this mistake?
This problem is far more likely to occur if a BIM was to be used for contract documentation. As an interoperable data format, a BIM is a far more complex and far less mature than a simple two-dimensional PDF. What if the model opens differently in the software the contractor is using, with potential financial or health and safety consequences? Who would pay the bill for this mistake?
A recent article in JCT News discusses this very subject. They suggest that collaborative contracts such as JCT Construction Excellence, NEC3 or PPC2000 could be readily adapted to a ’full’ BIM process. These could potentially allow risks to be identified and the process managed closely.
|5.||How does BIM help manufacturers?
Learn more about BIM at the next FREE* Consultancy Days on 18 and 25 October 2011. Stephen Hamil will be offering guidance on how BIM helps manufacturers at the Consultancy Day 2011 event.
Register your interest now.
* Consultancy Days free to subscribers of Premium ribaproductselector.com, CPD Provider and NBS Plus clients only. An event will be available to other clients soon.
Dr Stephen Hamil is director of design and innovation and head of building information modelling at NBS. Dr Hamil led the software development of NBS Building, NBS Plus, NBS Scheduler and NBS Domestic Specification.
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