By Bekir Andrews ,
Associate Director, Group Sustainability, Balfour Beatty PLC
With ambitious targets set by the industry to become carbon Net Zero, supported by our own 2030 targets and 2040 ambitions within our Building New Futures Sustainability Strategy, the requirement to track carbon at all stages of the supply chain is vital.
Calculating the embodied carbon of materials for construction projects is generally quite labour intensive and requires a complete recalculation if the design changes. Some automated software products do exist, but few extract data directly from the BIM model. They are usually expensive, require manual entry, do not allow comparisons of different designs, and do not allow tracking of carbon savings throughout the iterative design process.
To address these shortcomings, Balfour Beatty were keen to develop an add-on module for Autodesk Revit, to pull the quantities of materials from the BIM module and automatically calculates the carbon quantity.
The aim was for designers to be able to adjust the design and get instantaneous carbon figures which would allow them to hone in on an improved solution without having to be a sustainability expert.
In collaboration with Innovate UK, Leeds Beckett University, Hertfordshire University, and White Frog Publishing, Balfour Beatty created a carbon calculation tool for the construction and infrastructure industry – offering a consistent, practical solution for the measurement of embodied carbon.
The AutoBIM Carbon Calculator automatically links BIM data to embodied carbon data from the Inventory of Carbon and Energy (ICE) database, an online source which provides energy and embodied carbon information for construction materials.
In addition, the platform allows users to enter information from environmental product declarations sheets; verified and registered documents that provide transparent and comparable data about the environmental impact throughout the life cycle of a product or material.
During the design phase of a project, the innovative platform allows teams to compare products and materials, provide alternative solutions, and ultimately help those involved make informed, low carbon decisions.
The carbon calculator can demonstrate the benefits of different construction methodologies.
For instance, the general assumption might be that a steel frame has less embodied carbon than a concrete frame. Indeed, in the below example, a steel frame structure shows a 26% reduction in carbon over a standard concrete mix (Mix 1). However, a concrete mix with 55.5% Ground Granulated Blast-furnace Slag (GGBS) (Mix 3) provides a 39% reduction in carbon emissions against a standard mix (Mix 1). Therefore, in this example, a concrete frame with a high GGBS content is more favourable than a steel frame.
At present this tool is not interfaced for use on civils projects, which use different software.