Measuring the carbon impact of a structure
Global impact of construction industry
According to The Institution of Structural Engineers (IStructE):
Buildings and construction account for about 40% of energy related CO2 emissions
Manufacture and disposal of materials used in structures accounts for about 11% of all greenhouse gas emissions
Analysis suggests that inefficiency in material use of up to 50% is common
Typical emissions at each stage of the structure's life
The distribution of emissions at each stage breaks down in approximately in these proportions:
|Typical distribution of emissions
It can be seen that the largest portion of emissions occurs at the Product Stage, and this is the stage that can be targeted by Tekla Structural Designer to make savings.
1. BS EN 15978:2011: Sustainability of construction works. Assessment of environmental performance of buildings. Calculation method. London: BSI, 2011
Measuring Product Stage Carbon
In the UK, the Product Stage is split into modules A1-A3, which are:
Raw material extraction
Transport of raw materials to manufacturing facilities
The carbon impact of materials used in manufacture can then be measured by using an Embodied Carbon Factor (ECF).
This factor is specific to each material and is multiplied by the quantity of that material in order to give a quantity of CO2 emitted in the Product Stage.
Many construction materials have standard ECF values that the engineer can use, and in addition manufacturers may also provide third-party verified Environmental Product Declarations (EPDs) which can be used when the engineer knows exactly which manufacturer the material will be sourced from.
Reporting and export of embodied carbon data
Tekla Structural Designer includes an automated and comprehensive built-in calculation of Embodied Carbon quantities, together with powerful options for graphical review/optimization and reporting of this aspect of design. For more information, see Embodied carbon workflow.
In addition Tekla Structural Designer also enables model material data to be exported to One Click LCA, which:
is a widely used cloud-based software for life-cycle assessment and the calculation of embodied carbon.
complies with a large number of standards including BREEAM and LEED.
includes a huge database of generic and manufacturer-specific Environmental Product Declarations (EPDs)
The data can either be exported to a spreadsheet, or directly to the One Click LCA service, from where the environmental impact of the design can be reviewed and reports can be created.
Both of the above features enable the Engineer to quickly and easily determine the embodied carbon for the part of a project they are responsible for. This also helps them to develop and compare different scheme options. For a selected scheme they can then track progress as they make refinements to drive down the carbon impact.