Bitesize BIM Blog – Issue 3

Welcome to our latest BIM Blog, written by Rod Arkle who is a Site Manager with Woodhead:

Let us assume you are a small builder offering a design and build service with a small office and a few people in it, how would you approach your business behaving in a BIM like manner? You may have your 2D CAD system and in the course of designing and constructing extensions and houses you accumulate a wealth of information, it would be easy to keep it in a file on a shelf in your workshop, or scattered throughout your computer. However if you catalogued it and kept a good record keeping structure with spreadsheets and good naming protocols etc, this would give you a comprehensive information source easily accessible for future pricing of works and all the other things you have to do as a small builder. This is a BIM approach in its simplest form

Even in its basic form it is easy to see that BIM is a state of mind as much as anything else and not necessarily in its simplest form as difficult to achieve as it may first seem.

Within an SME construction business the levels of information generated are many degrees higher, but the principles remain the same. The BIM approach allows information generating practices to adhere to your companywide conventions.

It is important that the company has a strategy toward standards and conventions and that keeps them under constant review as this BIM approach should be managed and approached as any other business activity.


When Computer aided design first appeared in offices around the country it was used as an upmarket version of the Architects drawing board. You could overlay one floor plan on top of another, you would only need to draw the floor plan once and then you could coordinate and add your variations for any particular floor. BIM is not just a 3D version of CAD it is much more than that. Three dimensional models will give a client a very good idea of what their asset will look like, I am sure you will have seen them on Grand Designs and other such programmes, but within a BIM they are filled with a wealth of information, a lot of it in the form of objects and this is allied with Master Specification Systems. The model and the information contained within it should be verifiably of an open and shared standard.

If you think of a model you may well think of a geometrical model, and while this geometrical or graphical model can tell us the width and height of something, allied to this has always been the written word to describe it in more detail. In the BIM model we will be looking at a 3D information rich model as well as a Master Specification System that includes the non-graphical information such as performance requirements, definitions, perhaps data that is behavioural and allows the object to be positioned and function in the same manner as the product itself.

What are these objects?

Object technology is a wonderful invention. We use them every day of our lives on the web for searches, archiving information and much more. It allows mobile phones, desktops, wireless and GPS systems to work together. In simple terms an object is something that carries information but can also do something. It can also do either of these things in isolation. In the construction discipline these objects can range from building fabric systems to M and E objects and are presented in a 3D format. It allows us within this 3D model to see how things work together, but also gives us the opportunity to place the services etc in the right places.

Let’s just assume that a gas pipe must not run within the same duct as a fire alarm cable. The object that is the gas pipe will have characteristics within it that will tell it all the things it can be with and those it should not, the fire alarm cable will also have this capability. The software would then tell us the gas pipe should not be there alongside the fire alarm cable. We can download these BIM objects free of charge from The National BIM Library. These objects are uploaded by supply chain companies, manufacturers and others and these objects are filled with data on the specifications and use of these products. They have been created to ensure they conform to a standard that all users can be confident in.So by including them within the model, alongside the Master Specification System the virtual design, construction and operation of the asset can be developed and tested as a digital prototype in advance of the construction phase.

Working this way the development team or hub as we have referred to it previously are able to provide certainty over costing, programme duration forecasting, reducing delivery risks and clash detection. Client driven changes if asked for can be checked for compatibility against the model so ensuring they can be accommodated within the construction.

Unless they are prepared to invest in 3D software construction companies will therefore have to have a close relationship with an architectural practice if they wish to move further down the BIM road. They will then have to look at how they will share information with this practice, as they will very likely have differing software platforms and information management protocols that they use.

Industry Foundation Classes

These are object based file formats that are used to facilitate interoperability (working together) in architecture, engineering and construction, essentially aiding exchanges of information between software applications used in these industries.


The specified information set is called a COBie. This is basically a very large excel spreadsheet and stands for Construction Operations Building Information Exchange. Information is entered onto the COBie spreadsheet or into other spreadsheet applications during design, construction and commissioning. The practical application of this is a series of pre planned data drops into whatever spreadsheet is used. At what stages these ‘drops’ are made is decided during the initial stages of the BIM project and is outlined in the PAS. Typically information for the client is contained in drawings, bills of quantities and specifications. When the documentation gets handed over to the client it is PDF’s, paper and other formats which can make it difficult for the client to use. The idea of the COBie is all the information is in one format and can be shared. This then along with the geometric model becomes a valuable asset for the client and the future use of the building.

What is BIM level 2 readiness?

Every company will probably have their own idea of what it is but it can be described as follows:

• Having a clear idea of what the clients information requirements are at every stage of a project.

• Knowing your information marketplace.

• Being clear about the roles and responsibilities of everyone concerned with producing information for the project.

• Having a clear plan for delivering structured and quality controlled information.

• Having a clear view of how the project software platforms interact.

Most successful companies will already be doing this type of thing in their normal everyday business. The difference with the level 2 readiness is they will have to be doing it in tandem with other companies and entities that may well have differing opinions on how to achieve the readiness required, and completely different computer systems and practices. This phase of the governments BIM strategy may well be more difficult to achieve than level 3 as the collaborative problems will have been ironed out during level 2.

The next article will cover the legal, and educational needs of BIM.

In preparing this article we have made reference to and used information from several publications and websites. They are listed below. We recommend you use them for further reference.



The BIM Task Group

Rod Arkle (Site Manager)