What is BIM?

De-coding BIM

Last week, chief construction adviser Paul Morrell said that in five years time, practically every single government construction project will be built using 3D building information modelling (BIM). We already knew that it was likely to become mandatory for projects over £50m, but Morrell wants it extended down to much smaller jobs. BIM will therefore ripple through the supply chain right down to SME minnows. But what is BIM? Rather than imagining a software package, it’s better to think of it as a new way to use existing software to build up a detailed 3D model of a project with common sets of data that everyone working on it can see. If used correctly, it should save time and money by preventing clashes between different sets of designs. It should also give facilities managers more information about how to maintain the building once complete. Yet many in the industry are understandably concerned about the costs and what, in practice, the roll out wil mean for them.

How much will BIM cost?

As BIM is a new way of working rather than a software package, the bulk of the costs are likely to come from training. Chris Gilmore, design and marketing director at BAM Construct, says that “to implement one seat with BIM - hardware, software and training - is around £10,000”. But he adds that there will need to be someone to coordinate the transition to BIM. “On top is the cost of a staff member - say [a] BIM co-ordinator - which will allow the model to be built by the contractor,” he says. Overall BAM is spending £700,000 this year preparing for BIM, training 70 employees, and they will have to continue to invest millions more up to 2015.

It’s almost impossible to estimate how many people will need training and to what extent, says Richard Brinley, group director of membership and professional groups at RIBA, but it will be everyone involved in the design, development, and the later operation of the building. New architecture and engineering graduates are trained to use BIM from day one, but others are in “varying stages of training,” says Brinley. “It’s fair to say that there’s very few people using BIM fully”. A survey by RIBA of 400 people from across the industry last September and October found that only 13% were using BIM, and 43% were unaware of the method.

How much could BIM save?

The system’s advocates think that the industry will notice a difference in months, not years. Rachel Done, deputy director at the UK Contractor’s Group, thinks that within weeks users will see “earlier establishment of more accurate costs for projects” and “better exchange of higher quality information between all parties”. A trial project run in 2006 on Costain’s £30m PalaceXchange mixed-used development in Enfield, north London, showed good returns but not double digit percentage savings. The project spent £10,000 on a consultant to implement BIM plus 24 weeks of training and £6,000 on educating subcontractors. Capita Symonds estimates that £500,000 was saved, under 2% of construction costs, as a result of not having to do remedial works, and it claims about “man months” of work were saved largely because of time saved preparing information for issue.

Could it affect how buildings operate?

Because BIM effectively collates all the different information the supply chain has about a building, this should make it much easier for the facilities manager to service it after it is built. “You can treat a building in the same way as a car or aeroplane [by running regular MOTs when needed] rather than just wandering around waiting for things to fail,” says Joe Martin, a member of the RICS BIM group. A complete model of the building before work has even started allows full performance analysis of how it will operate even before construction starts, says David Philp, director of technical services at Balfour Beatty.

What does it mean for QSs?

BIM could mean less work for QSs in the most traditional sense, because it can automate some tasks, such as taking quantities and schedules off drawings. But consultants will still be essential to check these sums, argues Martin. “If you want your measurements to come out of it [BIM] you’re going to need someone intelligent to interpret these numbers to make sure they make sense,” he says. However, preliminary results from a RICS survey into BIM show that “most [QSs] don’t really know what [BIM] is.”

What does it mean for contractors?

Philp says that BIM helps prevent the design brief constantly changing, meaning that “there’s better understanding throughout the supply chain”. It may disproportionately benefit bigger contractors, like Balfour Beatty, as Philp says: “The big savings are when it’s a PFI building”. However, contractors have so far had one of the lowest rates of BIM uptake in the sector: a McGraw Hill report published last year found that just 11% were frequent users, compared with 60% of the rest of the supply chain. Done says this is to do with the differing roles within the supply chain: “Consultants have the option of choosing which software systems carry out their primary design, [whereas] contractors are not frequently in charge of which design system is used.”

Does it work for refurbishment?

The jury’s out. David Mathieson, head of public sector at Turner & Townsend, argues that with some refit work the costs of surveying the building would be too high to justify using the system. “On a fit-out or refit job, the cost of getting it on the system might be very high,” he said, adding that this lighter work was typical of most government accommodation projects. “I don’t think a blanket mandate would be appropriate.” However, Philp disagrees. “There are really no jobs that you wouldn’t do it on,” he says, adding that it is even cost effective to build a BIM model of a building using laser scanning, which can then be used to improve energy efficiency and carbon output - even if no actual building work takes place. Morrell has said BIM won’t apply to projects where it won’t save money, but when asked what these might be, he said he was “struggling to think of obvious examples”.

What does it mean for architects?

The impact on how architects work will be “dramatic”, according to Brinley. “It will completely change the way you start off the design process. There will be much more up front work to be done building the model and testing it works.” This will save money and time in the long run because the actual process of construction will then be far easier. Architects will have to work much more closely with the entire design team, including facilities managers, to create the BIM model before construction. Brinley hopes that this won’t stifle imaginative design - in fact, it could do the opposite: “Because you can test things early on, clients and contractors will take risks because you prove it will work beforehand,” he argues.

Source: Building.co.uk