We must harness BIM for carbon estimation and calculation

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The built environment contributes around 40% of the UK’s total carbon footprint, half of this from energy used in buildings. To have a positive impact and meet the demands on the industry to be ever more sustainable, the approach to BIM needs to be overhauled, says Daniel Black, not least because its potential for carbon estimation and calculation is enormous at a time of climate crisis.

So how do we achieve this? First, we need clear intentions. Discussion with the client at the outset about the value of using BIM for ongoing operation as well as design and construction, and actively encouraging it, are crucial. There is a role and indeed a responsibility for BIM experts to support the education process.

We also need to acknowledge that the pandemic has accelerated the digitalisation of our sector. It’s time to embrace technology, data and IoT, to proactively create, manage and leverage intelligent information models to make better operational decisions and more accurate life cycle assessments.

‘We need to see a shift from 3D to 4D to 7D and 8D BIM, which cover sustainability and facilities management’

Daniel Black

Using sensors and IoT, we can feed in as-designed operational performance into the BIM model, and then monitor it for the entire life cycle, evaluating design interventions or enhancements to building services to make improvements year on year. Wider adoption of ratings like NABERS, which focuses on building efficiency in use, will also help.

This use of intelligent information models to facilitate better operational decisions means that BIM needs to progress more quickly. Indeed, the 2020 RICS report The future of BIM: Digital transformation in the UK construction and infrastructure sector says that we have moved beyond BIM Levels and that the maturity of BIM is now defined by the states of information management. We therefore need to see a shift from 3D to 4D to 7D and 8D BIM, which cover sustainability and facilities management respectively. This puts carbon firmly in the list of essentials: design, cost, time and carbon – a game changer in accurately predicting whole life cost and carbon.

Harnessing the potential in carbon reduction

20% of the UK’s building stock is new (according to the UK Green Building Council), so it goes without saying that they should be set up to perform at the highest level. Even for new builds however, most of the carbon estimating tools available, such as AutoBIM, are focused on embodied carbon, which only accounts for 10% of emissions annually (source: UNEP 2021). Building operations are responsible for 27% of emissions annually, so we need more focus on this now, which will also help ensure tools like NABERS are as effective as possible.

Having optimised new buildings, we then need to address decarbonising the 80% that are existing. Many older buildings are in need of retrofit or refurbishment so creating a BIM model as part of that process makes perfect sense. Laser scanning can effectively deliver reality capture and this coupled with digital twin technology enables options testing against an existing building’s exact performance. It can also do so without the need for on-site inspection, optimising time spent on the solutions.

‘New homes will have to be designed to produce 30% less CO2 emissions. Enter BIM to design them, and BIM to monitor them’

Daniel Black

Once the project is handed over, it becomes an invaluable tool for those tasked with efficiency in use – the property and the facilities managers and, by extension, everyone who uses the building. You can only reduce your carbon emissions or change your behaviour if you know what your current performance looks like and its potential for change.

Accelerating adoption

A significant trend in the real estate sector over the last two years, in large part due to COP26 and many protests about the climate emergency, is the astronomical rise of environmental, social and governance (ESG) as a driver in property decisions.

Interestingly, a survey commissioned by Irwin Mitchell and YouGov published in March this year, said that 41% of commercial occupiers would not pay a premium for environmentally sustainable buildings, that they should be sustainable as standard. It also revealed that 26% would pay more in return for savings in service charges or energy bills. Enter BIM! The best tool for accurately calculating and monitoring carbon calculations.

If being smart about our carbon emissions can deliver commercial benefits and ensure we as a society fulfil our responsibility to play our part, great! It’s a win-win and a point well made in two reports produced around COP26 by the European Chapter of the Society of Industrial and Office Realtors (SIOR), in which its members championed the value that comes from responding to ESG criteria.

Alongside the mindset shift, there is also new legislation coming into force via Building Regulations in June 2022, which will mandate the industry to change gear significantly. For instance, new homes will have to be designed to produce 30% less CO2 emissions. Enter BIM to design them, and BIM to monitor them.

The crux of the matter is that we need to cut carbon emissions by 78% by 2035. Too many are still talking about BIM’s value for supporting built assets as a future event. That’s too late; now is the time for operation and ongoing use to take centre stage so we can at least achieve this goal.

Daniel Black is BIM consultant at Plowman Craven.

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  1. I find it a little frustrating that the answer is simply “BIM” and would have liked to see the author elaborate on more on the “how”. Telling the industry to “simply” optimise 20% of the nation’s building stock and then just retrofit the rest – why did nobody ever think of that before?

    Phrases like “shift from 3D to 4D to 7D and 8D BIM … [to put] carbon firmly in the list of essentials: design, cost, time and carbon” is classic BIM-speak that continues to confuse the industry

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