Jeff House, Applications Manager for Baxi Commercial Division, considers the uptake of BIM and implications of the Government Construction Strategy.
Back in May 2011, the Cabinet Office published the Government Construction Strategy; a document with far reaching implications for the entire building industry. According to this document the construction sector accounts for some 7% of UK GDP (£110bn per annum) with 40% of this activity being public sector work.
Government believes that, as the industry’s biggest customer, it does not receive full value from public sector construction; with this in mind the strategy document outlines a series of measures designed to achieve a 20% saving (£8.8bn per annum) by the end of this parliament.
Amongst the package of measures proposed to deliver this saving is the adoption of fully collaborative 3D BIM (Building Information Modelling) by 2016. Therefore provision of electronic co-ordinated, collaborative project and asset data will become a pre-requisite requirement for public sector contracts.
As a concept BIM is not new, indeed software tools to aid model creation and design processes have been available for over a decade. However, achieving Government’s desire for full collaboration will require buy-in from the entire construction supply chain. The message is clear, adopt BIM working practices or be left behind. This has led to a groundswell of interest over the last year from construction industry companies, many of which may not have previously worked in a collaborative BIM environment.
What is BIM?
Conceptually BIM can be defined as an integrated process of designing, engineering, constructing and maintaining a building based on a collaborative model including both graphical and non-graphical information. Simply put, BIM enables all of the design disciplines involved in a project to work together to construct a fully co-ordinated, virtual representation of the finished building. This model is enriched with key specification data about each of the building components, thereby allowing much simpler exchange of information and a more controlled project outcome.
As the contract progresses the information contained within the model grows, with input from main contractors, specialist contractors and commissioning engineers eventually leading to a wholly accurate digital representation of the asset being handed to the client. The BIM process does not finish at hand over stage, as building operators can continue work with the information model to inform planned maintenance regimes, manage building extensions or change of use with more certainty and, using dynamic simulation tools, derive estimated versus actual in use energy consumption or CO2 emission data for reporting purposes.
BIM is not just a software tool; it is a cultural shift in the way construction teams traditionally operate in the UK. Adoption of fully collaborative BIM working practices can deliver significant benefits all through the supply chain. At design stage, ease of information retrieval, co-ordination and clash detection can increase productivity. It is possible to virtually construct the building many times over and assess the impact of modifications to structure or systems much more quickly.
What are the benefits?
Up front visualisation can improve client understanding of what the project is intended to deliver. At construction stage, the information model can be used to fine tune both the build programme and co-ordination of trades on site, simplifying the estimation of materials, with more accuracy resulting in less site waste. BIM lends itself well to pre-fabrication and off site assembly with the potential to use co-ordinated design models to feed directly into production drawings for such components. Ultimately BIM can help deliver a more predictable project outcome with greater cost and programme control.
To maximise these benefits, the quality of data incorporated into the information model is key. Each building and system component will require embedded data in order to inform the various BIM processes. For more complex items such as boilers, water heaters and low to zero carbon heating technologies this is particularly key. Such plant items typically form the heart of a building services system and are an integral part of the system design calculation process.
It is possible for designers to create models of such plant items, although time and accuracy of data can be a concern. To this end libraries of products are now becoming available with 3D product models and embedded data included. There are generic libraries available for building services equipment; however, pioneering UK manufacturers have begun to provide specific libraries for their products. By importing and using these libraries, designers can not only save time and effort in the draughting process but also be assured that the embedded data provided is robust and accurately represents the item in question.
It is clear that BIM is here to stay in the UK construction sector. Although Government requirement is for projects with a value in excess of £5 million to use BIM by 2016, a number of local authority contracts of lesser value are implementing BIM requirements now.