“You can’t play a new game with old rules”
In Stephen Hunt’s view, “There is a disconnect between the client’s expectations of RIBA stages and BIM design methodology.” As MD of a building services consultancy, he is well placed to know. Historically, construction projects followed the RIBA seven stage model. The framework of this runs from feasibility at stage one right through to monitoring of the finished building at stage seven. Although design and build procurement routes have sometimes muddied the waters of who holds the mandate for detailed project design, he considers that, in the main, this has worked well, The RIBA stages have helped ensure that all delivery partners understood their role in the process. But as BIM takes hold, the rules of the game are changing rapidly.
BIM is a game changer
BIM is causing procedural problems as everyone still clings to the old RIBA rule book, trying to implement new working practices without relinquishing old structures. However, in a BIM utopia all delivery partners would be appointed at stage zero (client brief) and work collaboratively through the feasibility (stage one), concept design (stage two) and detailed design (stage three) phases to better equip them to work effectively together throughout the technical design (stage four) construction (stage five), handover (stage six) and monitoring (stage seven) phases.
The Budget Conscious Real World
In the real world of budget conscious BIM projects and traditional definitions of roles and skill sets, this remains a pipe dream that we’re unlikely to realise for some time to come. For most of the construction design and delivery process, this continuation of the traditional status quo, despite the enormous changes to design and delivery methodologies introduced by BIM, does not present too much of a problem. However, there is a significant grey area in terms of responsibility and financial commitment that occurs somewhere between RIBA stages three and four. This is because the client may request a detailed design but the building services consultant can only provide the required level of detail in the model by investing time and resources in a technical design.
Unrealistic Client Expectations
In effect, the client is asking for RIBA stage three, but is expecting stages three and four combined. As a result, the consultant is faced with two equally onerous options: either to provide a performance building services specification that does not meet the client’s expectations; or to complete a full technical specification which exceeds the mandate from the client at that point and involves a significant amount of additional work which has not been accounted for in the fee.
Why Clients are Unrealistic
In Hunt’s view, the reason for this is that clients are applying 2D thinking to a Revit-based 3D design process. As a result, where consultants may, for instance, once have drawn the routes of ductwork and risers into a CAD drawing to scale as part of the detailed design, now these items can only be included in the Revit model if they are fully specified items with product data and pricing.
To address these issues, BSRIA, for example, has identified and attempted to create a Design Framework for Building Services (BG6/2014), which sets out numerous building services design stages aligned to the RIBA stages. This attempts to insert sub stages between RIBA stages three and four, but the disconnect between traditional thinking and Revit delivery remains because Revit is not simply a visualisation tool; it is also a database.
Hunt’s firm has tried to map the RIBA stages alongside the BSRIA stages to provide a client friendly menu of options. This aims to allow them to design to the level of detail client’s require, without over-reaching their budget or undervaluing the firm’s level of work.
Culture Change Needed
It will take time for the culture change needed to adapt working processes, structures and assumptions to BIM. This includes both client and the consultant expectations of what RIBA stages three and four should look like. In Hunt’s view “Only by embedding the BIM principles of communication and collaboration on the scheme can we start to evolve and align those expectations to reflect the new functionality of BIM software and be less encumbered by the old parameters of design stages.”
Whatever your project, the chances are that it will need some degree of technical expertise for it to be buildable. Conceptual designs can be made more ‘buildable’, Building Regulation compliant, and cost effective if the technical structural aspects have been addressed as the design is worked up. Indeed, as noted above, ideally a ‘team working’ approach is desirable and can have significant benefits, especially in the area of energy efficiency.
Visit the Benfield ATT Group website for more information on RIBA Stages & BIM