Another level v one dimension

This article was first published in the Civil Engineering Surveyor, who have agreed to Simmons & Simmons making it available to elexica subscribers.

Building Information Modelling is one of those subjects where everyone has something to say…

“It’s great, we should all be doing it”

“It’s expensive, it excludes SMEs”

“what’s all the fuss about, it’s just a proper design process”

Regardless of the debate, this is the year in which the UK Government has said it will mandate the use of level 2 BIM on all of its projects. Looking forwards, in two years or so the UK Government wants to step up the use of BIM to level 3. What does that mean though, and is it the right thing to do? Is there something else that could or should be done, or is it better to just let the industry get the hang of this step first?

BIM levels

BIM is, primarily, ranked according to levels. Those levels denote an amount of collaboration or integration of the design process ranging from level 0, where there is no collaboration and the design is produced on paper (or possibly stone tablets!) through to level 3, involving fully collaborative electronic design, in real time, on a single model. The point along that journey that we have now reached, BIM level 2, is based on having electronic designs carried out separately, but joined together at various stages of the design process to build a joint (federated) model. The essence of the step from level 2 to level 3 BIM is to go from designing on your own systems, in what could be called collaborative isolation, to the design team all working on the same model together.

The benefits of the step up to BIM level 3 are perceived to be that it will spot problems with a design model more quickly and therefore reduce wasted time. By getting the whole design team working together, at every stage of the design process, it is also thought that you will maximise the opportunity for innovation and value engineering in the design.

BIM dimensions

In this context, the dimension of the model is used to denote the amount of information that is placed into the model. The first three dimensions are fairly simple (height, width and depth). The next dimension (4D) considers time as part of the design, particularly the time to construct. The one after that (5D) consider costs as part of the design, generally taken as just the capital build cost. Next comes a dimension (6D) to deal with whole life costing within the design. While you don’t have to add these dimensions successively (ie you could just add cost) there is value in adding them in sequence to enable control and understanding of the design and the impact of any change.

Most design models still focus on being 3D but there is real benefit in the additional information being available. Adding dimensions for time and cost allow everyone in the project to see the full consequence of changes very rapidly. In particular, it will be able to model very quickly the impact of using, for example, bespoke over standard fixtures and fittings. Where the main aim and perceived benefit of additional dimensions is additional collaboration and innovation opportunity extra dimensions provide control and guidance. While not intended to stifle innovation they do provide it with context.

Purpose of BIM

The primary drive for BIM is efficiency and possible reliability. How do we achieve better value in our projects and how do we ensure that, once the process has started, it remains controlled. The efficiency and reliability primarily comes from a more collaborative and “joined-up” design, avoiding errors that have to be fixed in the construct phase.

However, the efficiency will also come from everyone in a project understanding the real impact of a change. While it may seem minor to alter Widget A for Widget B or to move Flange X from Location Y to Location Z, the design implications, and the knock on construct implications, can be significant.

Risks and opportunities

There is a tendency to focus on what might be achieved, perhaps in a rather utopian setting rather than looking at what might go wrong and what extra risks might be being introduced through dimensions or levels of BIM. If one follows the BIM protocol produced by the CIC for level 2 BIM then it is clear that the intent is for risk in the use of the BIM process actually to filter up the chain to rest with the Employer, on the basis that he takes the benefit of the BIM process.

However, certain risks remain, particularly around the use of software and managing change. These risks would increase at BIM level 3 as broader access is given to a complete design model, putting pressure on the integrity and security of the BIM system (there have been a series of cases of cyber-attacks via building management systems which would be equally possible via a BIM model). In addition to the more process driven risks there will be a heightening of risks around intellectual property and design liability where you have multiple individuals working on a single model and tracing back where a problem started and who contributed what to a loss could prove difficult.

If there are some risks to be considered in increasing the level of BIM there are at least as many to be considered when adding additional dimensions. Who is taking responsibility for the costs that form the cost model, what if the underlying market changes? Who takes responsibility for time within the model, does all of the risk simply get past to the contractor as last man on site?

In relation to all of the above, from a designers perspective, it is not yet clear how the insurance market will react to these new potential risks. Will they set exclusions (or will existing exclusion bite in an unexpected way) or perhaps premiums will jump or become unpredictable. Maybe even the nature of the market will change fundamentally shifting the insurance burden from the design team to the project. With unpredictability comes risk and with risk comes cost so there is some thought that needs to go into these risks yet before stepping up to the next level or adding dimensions.

What best achieves the purpose

The drive by the UK Government is focussed on achieving BIM level 3 but why? There is no need to be at BIM level 3 before extra dimension are added. It is perfectly feasible to have a 6D BIM level 2 model. The question is what are you trying to achieve.

Almost without a doubt, building in time and cost information will generate more efficiency and greater control of the project spend and completion date than would be achieved by adding more integration to the design. The difficulty is that adding dimensions will also slow down the initial design process and make it more costly, as more work will need to be done. It may also limit innovation as process will take over.

While there should be an overall saving when using additional dimensions, the project becomes front end loaded with cost, whereas the trend has been to push cost back down the process, along with risk. This may allow the project to start more quickly but it increases both the cost (because of additional risks being transferred) and the potential for error and changes.

The step from level 2 to level 3 BIM is legally, and practically, complex. It generates significant risks around intellectual property and poor performing design team members. On the other hand, it does retain the same structure and timing of a more traditional design process. Adding dimensions creates its own risks around warranting time and cost information. It also raises an issue of who owns the intellectual property in that information where it is attached to a specific design. However, the information has the potential to drive the efficiencies everyone is looking for.

An increase in the BIM level or number of dimensions used has advantages. However, those advantages will only be truly captured when a different style of contracting is adopted for the whole of the project. We have to move forward but let’s not just jump at a technological fad, let’s really look at how the obvious advantages can be drawn into the construction process as a whole so that we don’t take a step forward just to fall on our faces.