BIM: What you need to know

Steven Parham takes looks at BIM: Building Information Modelling. To a vast number of engineers, the subject is somewhat polarising. Some have embraced the changes that this legislation will eventually bring to civil engineering projects and the wider world, whereas others dread the impact that this legal requirement for large scale civil projects is having.

So, what is BIM, why has it been implemented, and what will this mean for current and future building projects?



The date is the 31st May 2011. The Cabinet Office publishes one of the most far reaching documents in the history of construction in the United Kingdom.

The reason? To modernise the construction industry in terms of how information is recorded, stored and retrieved on any building to be built, from its initial conception and throughout its entire lifespan, right through to decommissioning and demolition. The process is known as Building Information Modelling, and in 2016, BS1192:2007 officially became an industry wide standard and project requirement.

The aim of BIM is threefold: to reduce costs, the effect on the environment and introduce efficiencies that improve construction and buildings in general. Keeping capital costs down in any project is difficult, so by using BIM processes, the key players in construction and infrastructure projects can monitor costs and apply alternatives as and when the need arise.

The upshot of this is that all buildings will have a virtual model, and within that model, is the three dimensional design (a Computer Aided Design model), built part-for-part with its real world counterpart, and those parts will have metadata, that is, information about that part. So the information model literally is like a database – each component is composed of sub component data, and that in turn has component data. But that’s not all. The idea is to produce what is known as a 5D model – the fourth dimension in this case is time: not in terms of time travel, but the whole life cycle of that building as an entity. The fifth dimension in this instance is cost.

The carbon footprint of a building or site can be reduced as well, the materials used can be monitored in terms of where they come from, what their properties are, who manufactured them, their cost, and how much it would cost to replace them. Sounds complicated and too much hassle? Lets look at some examples in engineering, where the principles of BIM, albeit in name, have been used for years.

BIM affects the construction and lifecycle of all future public buildings from schools to prisons, airports, railways and housing. So how does it affect you, and how will it affect industry?

A quick history of the BIM concept

The actual idea behind BIM has been around since the 1970s. However, it wasn’t until 1992 that the term Building Information Model itself was first used in an academic paper by Nederveen and Tolman, and the acronym BIM itself didn’t really get used much until 2002 when Autodesk, the software house behind AutoCAD published a paper entitled ‘Building Information Modelling’. Some say the very first practical implementation of BIM happened way back in 1987 using ArchiCAD. Over the years, the BIM process has encompassed not just the 5D model principle, but other considerations, such as the special relationships between structures, geographical information, bills of quantities, light and sound analysis. A whole plethora of metadata that could be incorporated into the whole model.

The BIM is therefore an abstraction of the real world, where discipline specific data is held and can be interrogated by all parties concerned at will in an ideal world. The other advantage of using a BIM for a project is that the information that is held within that model is the be all and end all. If the ownership of the model is changed for some reason, there is no information lost in the transfer.

In 2007, the British Standards published the first BIM standard code of practice: BS1192:2007, which will be the yardstick from which everybody should be working to by 2016. BS1192 is the official methodology and discipline for the distribution and the quality of construction information. This covers CAD systems, databases, planning and tendering. Nearly every area of the building supply and demand chain will be affected by the requirement by law to comply with this standard. BS1192 has therefore been bolstered by the Code of Procedure for the Construction Industry. The standard now has teeth.

Lessons learned

The aftermath of the July 7th bombings in London. A six carriage Hammersmith and City line train was badly damaged when a suicide bomber detonated his device, taking six people with him in one of four attacks on the tube, and one on a London bus. In total, 52 innocent people lost their lives throughout the network.

Transport for London then had the daunting task of reassembling some of the carriages damaged in the bombings. Rather than recycling the damaged carriages, they decided it was more appropriate to rebuild them from scratch to match the rest of the fleet. One problem: sourcing the right components, and more importantly, where to build it. There was nowhere left in the UK with the capability. So, the assembly work was completed in Hungary by Bombardier, from spare parts, new components and scratchbuilt copies of the original parts that were not available as spares.

One of the difficulties involved in the task was the process of sourcing the design information for the trains themselves. These were originally built in 1969 and 1977 by Metro Cammell, and that had gone by 1989, bought out by Alsthom, who then closed the remaining works in 2005 before the terrorist attacks. Most of the drawings for the C69 and C77s, the trains involved were on paper, in various locations all over the place. These were drawn on paper by draughtsmen, long before CAD became commonplace. Then there were the stakeholders of the relevant information. London Undergrounds maintenance teams had the majority of the knowledge and skillbase to repair the trains, but not the facilities to build them. Metro Camell no longer existed, and Alsthom probably had no real legal reason to keep the original drawings if they still had them. Some of the component manufacturers had also gone. The replacement carriages were introduced into service in 2007 with the new designation C08 (C Class 2008). All of the C class on the Metropolitan and City line have now been officially decommissioned and replaced with the S7 Class trains earlier this year.

Another analogy to BIM on an engineering level is the modern day (yes, modern day) Spitfire. Many people will be surprised to learn that most of the Spitfires flying at air displays and during events, are in fact privately owned, and probably less than 20 years old. In 1939, the average cost of a Mark 1 Supermarine Spitfire was £12,604; it’s modern day counterpart, the Mark 26b costs approximately ten times that. Mike O’Sullivan, an Australian enthusiast, first made his Spitfire copy in 1994, and then due to the demand, made further planes, and making improvements as he reintroduced the classic to the world. At the end of it’s official military life in 1961, it had reached Mark 19. It was the last piston based fighter used by the Royal Air Force. The Mark 26B is lighter, with a different engine and modern instrumentation and safety features, about 90% the size of the Mark 1. The people that fly and buy these are enthusiasts, the data and models are modern representations of the original RJ Mitchell design, realised in three dimensions on CAD drawings and models. A classic design, reborn using modern techniques and methods.

What can be learned here? Any machine or system is made up of parts and more importantly, information. Buildings are the same, they have a life cycle, from the very first drawing and documented proposal. All parts and the people involved in the building have a history, whether it is the boiler to go in the basement, to the windows on the top floor. A pipe will consist of a size, diameter, material, length, manufacturer and lifespan. The last factor is important. Things wear out and need to be replaced.

How does BIM affect you?

In order to fully realise the benefits of using BIM, the owner of the building or infrastructure must own the model itself. If that information isn’t shared however, it is effectively useless, as the true benefits will not be realised and the cost efficiencies across the whole system will be wasted. Think of BIM as giving everybody involved on a project, complete access to everybody elses’ design information, the resulting collaboration improves and refines that model throughout its existence.

Collaboration and co-ordination are the key elements of the BIM process, along with the reduction of that old bugbear, duplication of effort. Why draw one type of window 100 times, when you can copy and paste it along the model. If each window takes one hour to draw, you can either draw it one hundred times and pay the costs for it, or if the model is co-ordinated, draw that one window in 3D in one hour, make a model of it with the metadata attached, then place it on the database so that all parties involved can access it. The engineers and architects for technical reasons such as clashes and mechanical problems, the environmental people for efficiency reasons, the auditors for costing reasons. For the sake of an extra quarter of an hour on the modellers part, that window can now be copied and pasted into the hundred other locations within the model, and the costs for the design of that one item alone are initially reduced by 98.75%. That is the aim of BIM in a nutshell: complete referential transparency.

Who will profit the most from BIM?

An interesting question. Are we talking in terms of profits or in terms of savings that increase profits. Both is the simple answer, yet the cost of implementing BIM in industry will reduce these benefits initially. Also, some companies and institutions are dragging their heels a bit in terms of implementation. Some of the old school of engineers don’t like the idea of three dimensional computer models, and refuse to use them, even though they know that ultimately they will save them time. Prejudices still exist in the industry towards the notions and concepts that BIM ultimately embraces.

On the legal front, there are also implications. Many would say that you can’t go wrong with a 2D print and a folder full of paperwork. But who is to blame if there are errors within that model? Who pays the costs for a mistake if say, all windows on the 3D model are tinted one shade, yet the specification clearly states that they are all different shades, whereas the CAD model shows also, quite clearly that they are uniform? And what if there is a disaster where, say, a building is destroyed in a fire? The BIM then becomes a virtual expert witness, allowing the courts or any enquiry to interrogate that model to determine probable causes of the catastrophe. And then the blamestorming between the stakeholders can begin until a probable cause or culprit can be found, be it natural failure or professional incompetence.

And what of the insurance implications. What if your building or facility was built pre BIM? How does that affect any claims that you, as the owner make?

Yet, would you rather carry around a big A4 binder on site, or an IPad with a camera and GPS enabled, so that you can look at an object on site, which is then identified by software, and then gives you every piece of metadata on that item, from design drawings, manufacturer’s specifications, through to maintenance history. BIM has the potential to be this powerful, both as a methodology and an indispensable tool. Because all of this information can be at your fingertips, a facilities manager will find servicing a building that much easier, giving the building regular once overs rather than waiting for failures and problems to occur. The model of the building imitates its real life counterpart, so problems in the virtual world should manifest themselves as much as in the real word, allowing the owner of the model to notice and deal with problems before they occur.

BIM for small companies

Most of the companies that will be affected by the implementation of BS1192 probably already are and are unaware of it. Many don’t even know of its existence outside the construction and engineering industries. For projects over £50million, project compliance to BS1192 is mandatory. Some want the extension of that mandatory status filtered down to even smaller jobs. By 2020, it looks like it will have an effect on the housing industry and any parts of the building supply and demand chain. Some companies are already investing hundreds of thousands of pounds in training in order to be ready for compliance with the new standard. People who are pro BS1192 believe that savings will be noticeable on projects within months, not years, and many man months will be saved as a result of getting things right the first time round, and not having to resort to remedial works to correct errors on projects.

University students in architecture and structural engineering studies are already being given a firm grounding in BIM and BS1192 already. Others within the industry are either being trained up in the methodologies and techniques, or are having to conform to the new order as it is implemented from cold. According to a survey by the Royal Institute of British Architects, only 13% of engineers, technicians and architects are using BIM, while even more disturbing, 43% were not even aware of what BIM was or what BS1192 implied for their work.

For architects and structural engineers, the impact has already been astonishing. The whole design process has changed, and as a result of creating a BIM, there will be more modelling, more testing to see what works, what doesn’t, how things can be improved, long before any construction engineer even gets to look at it. As a result though, construction of the building or the infrastructure will be a lot easier, as problems will have been identified and dealt with at an early stage. And far from stifling the creative process, it may even produce more staggering designs, because those involved can test new ways of doing things, long before the construction phase of the project.

Quantity Surveyors should be alarmed, as BIM can automate a lot of the tasks associated with surveying. Even so, a qualified QS will be needed to analyse and corroborate any results the model generates. In short, the model will only ever be as intelligent as the people involved in its inception. And, according to a recent Royal Institute of Chartered Surveyors survey, most Quantity Surveyors don’t really know what BIM or BS1192 is or involves.

For early adopters, BS1192 and the concepts involved in BIM means a better understanding of the way others use and implement their processes and why, and how they can effectively implement those processes on a smaller scale to help save them time and money. Why should BIM be the preserve of some multi-million Public Finance Initiative project, when it can be applied to say, a £10million pound housing development? The savings may not be as much as they would be in a PFI project, but they will be there to be taken. Contractors and consultants who are wise enough to run with the ball, will try to keep up, and stay on top of things. Contractors have less of a say in which a project is run, so they will have to adapt in order to survive.

For building refurbishers, new toys can come into play. Laser surveys can build up a points cloud of a building, inside or out, that can be used within a CAD system to generate a 3D model. Even if the job isn’t a refit, the data provided from the laser scan means that energy efficiencies and environmental modifications can take place to change the carbon footprint of a building.

Another recent survey, conducted by the National House Building Council Federation, they found that 64% of the major housebuilding companies that were members of the Federation were not currently implementing a BIM program. About 25% hadn’t heard of it. The consensus amongst housebuilding companies is that BIM only benefits large scale or PFI based projects with large budgets. After the recent recession, many companies involved in the housing market don’t want to be burdened by what they believe will ultimately hinder their progress to recover from the recession.

The cost and benefits of BIM

The initial outlay for BIM systems is substantial. For companies serious about implementing these changes, they will have to invest in high end PCs and CAD software, and the training associated with it. Some companies have suggested that the initial outlay for a CAD Technician to be trained to BS1192 standard is roughly £10,000. That’s a reasonable sum per head for large scale capital projects, where multi-million pound budgets are involved, and a decent return on investment is up for grabs – not so good, when you’re looking at smaller budget projects.

Compared to the cost of implementing the computer hardware, the software training costs, BIM pays for itself in the long term due to the savings it creates. For the companies that want to tackle the bigger projects, or form joint ventures with those that can implement BIM, the long term rewards will be substantial. Construction problems can be spotted and rectified before a building is even constructed. Bills of Quantities for a development can be generated in mere seconds rather than calculated over a period of weeks by three or four people double checking their figures several times over.

And this brings us back to metadata: the ability to layer not just drawings with sets of information, but to layer information with other substrates of information. One tag of information, will connect to another list and so on, a bifurcating stream of building information that can be interrogated along any point in that stream. The overall approach with BIM is a holistic one, encouraging all stakeholders in a project to take an active interest.

Manufacturers are gearing up for the change, making 3D CAD models of their products readily available for those that can use them. Companies such as Unistrut and Halfen that make metal channels and fittings supply CAD drawings ready to download in order to encourage companies to use their products. Anything from bricks to soffits, roof joists and steel beams, it’s out there, ready to be downloaded and used in a project.

The cost of the software is slowly coming down, as well as technology with BIM applications in general. In the last couple of years, the cost of 3D printers are now virtually accessible and affordable to the man in the street. There is no reason why smaller companies cannot begin to take the principles of Building Information Modelling onboard now, before this becomes mandatory eventually to smaller building projects rather than PFI led concerns. There are a number of processes that small companies can put in place now that will help them to work with bigger companies that are BIM capable. The National Federation of Builders and the National House Building Council have put together excellent resources for small builders to read and gain an understanding of BS1192 and its implications. It will be interesting to see the changes in housing design over the next twenty years, and where BIM will take us.

Steven Parham

A property developers guide to planning permission

Useful Links

NFB: Building Information Modelling

LYNDA (an excellent video training site for all things BIM related)