Sunday, 18 September 2011

COBie and cost

For the last few minutes of my presentation at the NBS-NLA BIM Conference I looked briefly at the COBie data format that may be produced by exporting structured information from the CAD and specification models.

In the delegate Q+A session that followed there was a question asking where costs fit into COBie?

This is a very good question as it raises thoughts about how costs fit into inter-operable BIM. I'd be interested in others thoughts on this, please feel free to comment below. My thoughts are as follows...

Consider a designer specifying the "Type A Bath", there may be 150 instances of this bath in the building. The designer may look at the manufacturer list price and estimate that this will cost £100 x 150 = £15K. However, the contractor may have an agreed discount with the manufacturer and pay 30% off list price - £70 x 150 = £10.5K. And finally, to replace a single bath that is broken outside of warranty, the owner/operator may have to pay £149.

So COBie has a single column against each "type" item. This is for replacement cost.

Clearly the designer would not make their estimated cost available to tenderers. Equally, the contractor would not share their actual costs with the client.

One further thought, "cost" is not only measured in pounds, shilling and pence. Carbon costs are also high on the agenda now, and the Government BIM strategy paper made it clear that they will be looking to include metrics such as embodied carbon and carbon in use within their final COBie spreadsheet.

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