Taking off quantities and BIM

As part of the Government Construction Strategy 2011 it was announced that from April 2016 all central-government-funded projects must be BIM enabled to level 2. What does that mean?

BIM Level 1

Working at this level is common within the U.K. construction industry and generally comprises a mixture of 3D CAD and 2D for drafting production information with models not being shared between the project team.

BIM Level 2

This was the level chosen by the UK government as the minimum target for all work on public-sector work, by 2016. The big difference between level 1 and level 2 is that level 2 involves collaborative working with all parties working and contributing to a shared single model. All parties can access and add to a single BIM model.

What impact will BIM have on quantity surveying practice?

Not for the first time the quantity surveyor has been threatened with obsolescence, this time by BIM and it has even been suggested that quantity surveyors are deliberately dragging their heels in adopting BIM in an act of self-preservation.

10 years on from the announcement by government, what impact has BIM had on quantification? First it must be said that the target set in 2011 has not been met, as it appears government is either unwilling or unable to enforce their mandated goal.

One thing is certain, BIM will not herald the death of the quantity surveyor.

According to the RICS, BIM will “enhance rather than damage” the quantity surveying profession. Others within the profession warn that BIM won’t kill the quantity surveying profession, but firms that don’t embrace the changes will lose relevance. The ability of BIM models to automatically generate quantities and cost estimates doesn’t lessen the need for an expert to interpret the vast amounts of data produced, or to distil it into a form that clients, contractors and sub-contractors can use to make informed decisions just as in the past they have been used to interpret drawings Equally, the quality of the data you get out of a BIM model depends on what data you put into it and quantity surveyors are uniquely qualified to input and analyse output of data. Professional insight and judgement will be needed to produce quantities from models and will be for the foreseeable future.

There is no doubt that BIM is capable of producing generic quantities more quickly than traditional techniques. although other systems such as digitisers are capable of producing quantities quickly and efficiently. However, quantity surveyors are required to interpret and check BIM models, just as in the past they have been used to interpret drawings. Professional insight and judgement are needed to produce quantities from models and will be for the foreseeable future. BIM models can generate quantities quickly but, what they can’t do yet is to present the quantities in a format that is of wider use to the client, design team and industry.

Duncan Cartlidge


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