Friday, 31 January 2014

Three Keys to Achieve Lean Design in BIM

Following on from my previous post on the importance of improving on value-creating process linkages, it’s worth looking at the lean design process in more detail.
I want to give you three major practical principles for BIM to help in optimising the design process.

To explain them, I’d like to highlight a different kind of model. It was developed in a package called ExtendSim, a software tool that allows you to simulate a range of processes. The authors of the paper, Application of Lean Principles to Design Processes in Construction Consultancy used this tool to map the building design process.

The Bottom Line

Why this matters is that when applied to the design process of a major engineering consultancy in Egypt, the simulation showed that, by applying lean principles, the time required to deliver projects could be reduced by 7 per cent. The average staff utilisation increased from 0.4309 to 0.5116. That, my friends, represents serious money!

Design Phases

The researchers identified three phases. In the diagrams below, I’ve highlighted with a blue box those steps which create no value, but are unavoidable. The red box indicates steps which create no value and are avoidable.
The Project Initiation Phase corresponds to the RIBA Plan of Work Stage 0 and 1 or the AIA Phases 1 and 2. As we at HOK know, workshops are critical to ensuring that the project gains client approval. Obviously, significant value is lost if a design is completely rejected, or returned to the Workshops stage.


The Core Design Phase commences after the preliminary project design gains client approval to proceed:

In the simulation, the architectural design was set to develop to 60 per cent before the structural and mechanical design effort was engaged. By way of contrast, Integrated Project Delivery (IPD) would involve earlier inter-disciplinary design effort. One of the benefits of an IPD contract is that it permits the HVAC and Structural Design integration to proceed long before the Architectural Design is 60 per cent complete.
In all cases, what is important is the Batching block at the end of this phase. It’s about ensuring that all work-streams are combined to present a coherent design package, bringing together the contributions of each discipline. In lean thinking terms, what you are trying to avoid is unnecessary delay.

The Finalisation and Closing phase looks like this.

As indicated by the boxes, wherever information Flow can be impeded, there is the potential for costly delay. Remove those hindrances and you accelerate the value stream. So, this is where BIM can make a difference and here are my three practical principles:
1. Expedite Coordination by Inquiry in BIM.
A key concept in Lean Thinking is Pull: no activity should produce a service until the next process downstream asks for it.
Since documentation is downstream of coordination, views and sheets derived from the models of each discipline can be regularly reviewed in the BIM environment in order to instigate coordination inquiry. From early on in the project, we use Revit and Navisworks to identify design elements that are either absent, poorly defined, inconsistently presented, or uncoordinated with other elements and interfaces.
By querying these discrepancies or omissions with the relevant team member(s), the BIM Coordinator can prompt their resolution. Early on, I’m often asking questions like: ‘Why is that revolving facade door in the middle of the grass verge?’; ‘How is that cantilever supported?’; ‘Why do those ceilings over-sail the facade?’; ‘Where’s the access to the sheave space above the elevator?’
It’s my job, so I keep asking until I get answers.
2. Propagate Design Fixity
Once you have answers, commit them to the model.
On Barts and Royal London Hospitals, the BIM environment (at that time, Architectural Desktop) was used to capture design fixity. Design fixity is a consensus on a design issue that enables the project to progress. It is not ‘design freeze’, but it does provide an agreed basis for making and communicating decisions.
It is attained by what’s known as “Last Responsible Moment” (LRM) decision-making. The LRM is that phase review decision-point beyond which the cost of delay outweighs the benefit of delay. While that moment is the Project Manager’s judgement call, the decision is informed by several factors, including the lead-time for the documentation phase. We can run all the client workshops that we want, but at that LRM, the design team must commit to a decision or begin to lose money.
In order to disseminate design fixity as quickly as possible, the BIM Coordinator must ensure that the project team promptly propagate to all models any aspect of design fixity that affects them. As BIM experts, we need to drive this part of the process.
The lack of immediate propagation of design fixity to the value chain is probably the most significant hindrance to adding value.
 3. Prepare and Provide Early for Drawing Production
The BIM Coordinator should set up the bulk of numbered sheets and implement consistent view templates in accordance with agreed drawing presentation standards long before the deadline looms. This will ensure that, once the design is complete and coordinated, production information is delivered as quickly as possible.
The last-minute implementation of project-wide BIM standards and templates is to be avoided as it will invariably compromise the agreed delivery timescales.
As HOK buildingSMART Managers and BIM Coordinators, we are fortunate to inherit great processes from the hard work of our senior buildingSMART staff. They make our work a lot easier. As we apply them, let’s just remember to prioritise these three key activities that can accelerate the addition of value to our projects.

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