BIM to help drive prefabrication, expert says
Christine O’Callaghan, commercial manager, Off-Site Engineering Solutions
The emergence of building information modeling (BIM) is influencing design and construction processes and how project teams collaborate. A key benefit of BIM is enabling the increased use of prefabrication and modularisation, which in turn improves worksite productivity and overall project ROI.
‘This is particularly so for multi service MEP modules. BIM helps enable prefabrication of tightly integrated MEP systems, allowing designers to maximize space for other uses in high-tech buildings like hospitals’…As BIM’s use becomes more widespread and sophisticated, it is expected that prefab and modular construction will increase dramatically in the coming years.”
The use of BIM software technology has facilitated the prefabrication coordination process and has increased the potential for prefabrication on multiple levels. Prefabricated MEP sub-assemblies have become a safer and more predictable option since the rise in the usage of BIM coordination.
The installation of MEP systems has historically been very challenging. The coordination process involves diverse design and operations criteria, avoiding clashes in a confined space, and has historically been amongst the most fragmented industries in the world2.
Using BIM software as a tool to assist coordination, documentation and fabrication of MEP systems is an effective approach to overcome these problems3. The BIM collaboration also focused on identification of “functional” clashes in the design, in addition to “physical” clashes between components and in the resulting design is a robust demonstration of the appropriate use of BIM technology, modern methods of construction and an integration of disciplines to produce a collaborative result. Thus conflicts can be discovered and remedied during the design process and not after fabrication and installation.
The recent McKinsey Report4 states that ‘There is an opportunity for parts of the construction industry to move to a production system – and boost productivity up to tenfold.’ In the seven ways to tackle construction’s poor productivity – BIM and prefabrication contributes to 6 out of the 7:
1. Regulation – as evidenced by the UAE government’s BIM mandate
2. Collaboration – by using a common BIM model, move away from the present hostile contracting environment.
3. Design & Engineering – the biggest impact on productivity would come from moving forward thinking about construction as a production system, where possible encouraging off site manufacture and minimizing on-site construction.
4. On-Site Execution – installation of MEP modules as single units on site
5. Technology – make BIM universal within the company
6. Capability building – training in production and lean manufacturing techniques
Early adoption is crucial
The McGraw Hill SmartMarket report5 found that the primary reason for not using modularisation and prefabrication was that the buildings were not designed with this in mind. The benefits of modularisation and prefabrication are often reduced with the added cost and difficulty to redesign eating into gains in productivity and ROI. The Dubai Municipality has already mandated that BIM be used on all large scale projects in the UAE, adding that modularisation be considered and designed in will allow greater productivity and savings to be realised along with all the other benefits of prefabrication.
BIM - a collaborative model
• Enhanced communication = fewer misunderstandings = efficient change management between modules and independent services.
• As changes will be incorporated into the BIM model prior to the production of working drawings these changes can be made with minimal impact on time and productivity in virtual space and the models will form the basis for the working drawings released to the production floor prior to manufacture.
• Early clash detection in the BIM model will save time and rework. By identifying issues before they show up in the field, users can prevent costly mistakes.
Designing in the prefabricated elements
Designing in the prefabrication elements of the building into the BIM model has many advantages. It smoothens and speeds up the approvals processes as these are much simplified and de risked. Shop drawings and Bills of Materials can be exported directly from the model, reducing the handling and redesign for the prefabricated elements and reducing the potential for error.
4D BIM allows for not only 3D design of the building and services but also sequencing and scheduling information allowing for JIT (just in time) purchasing and delivery of material. Decoupling the site work from the prefabricated elements allows for concurrent prefabrication and greatly reduced installation times on site.
Contractors in the UAE must have a BIM model, so why not maximise the investment in this model and benefit from the speed, quality, productivity and other advantages of prefabrication?
1. Prefabrication and Modularization: Increasing Productivity in the Construction Industry SmartMarket Report 2011
2. McKinsey Global Institute – Reinventing Construction: A route to higher productivity
3. Thomas Korman Ph.D. California State Polytechnic
4. McKinsey Global Institute – Reinventing Construction: A route to higher productivity
5. Prefabrication and Modularization: Increasing Productivity in the Construction Industry SmartMarket Report 2011.Pg.7