Measuring the carbon impact of a structure
2020
Tekla Structural Designer
Measuring the carbon impact of a structure
Global impact of construction industry
According to The Institution of Structural Engineers (IStructE):
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Buildings and construction account for about 40% of energy related CO2 emissions
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Manufacture and disposal of materials used in structures accounts for about 11% of all greenhouse gas emissions
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Analysis suggests that inefficiency in material use of up to 50% is common
Typical emissions at each stage of the structure's life
In order to reduce carbon emissions it is first necessary to measure them. This can be done in different ways - in the UK for example by using BS EN 159781 the life cycle of the structure can be split into four stages as shown below, and the emissions assessed at each stage.
The distribution of emissions at each stage breaks down in approximately in these proportions:
| Stage | Typical distribution of emissions |
|---|---|
| Product Stage | 50% |
| Construction Stage | 5% |
| Use Stage | 43% |
| End-of-Life Stage | 2% |
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:
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Raw material extraction
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Transport of raw materials to manufacturing facilities
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Manufacture
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 enables model material data to be exported to One Click LCA, which:
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is a widely used cloud-based software for life-cycle assessment and the calculation of embodied carbon.
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complies with a large number of standards including BREEAM and LEED.
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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.
Note: The One Click LCA service can only be used if you have a One Click LCA account.
This feature enables 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.