Bonus challenge: Upfront embodied carbon

For decades the focus on carbon in the built environment has been largely centred around operational energy emissions. However as buildings ditch gas and electricity grids around the world decarbonise, we cannot ignore the impact of our material choices. For high performance buildings connected to low emission grids, embodied carbon dominates the whole of life carbon equation. Embodied carbon also has a more immediate impact on global warming as it is released now, rather than somewhere 20-30-100 years in the future. For this reason we are introducing an upfront embodied carbon as an optional challenge. Think of it like extra credit.

Building scope – bridge

Goal

Compared to a baseline façade design, calculate the upfront embodied carbon of your Bridge façade design from Challenge 1.

Design considerations

For this bonus challenge, you will assess the upfront embodied carbon of your façade from Challenge 1 using the NABERS national emissions factors database average values for upfront carbon emissions. If you select a material that is not represented in the database, you must provide an Environmental Product Declaration (EPD).

You will undertake a comparative analysis, using the parameters below for your baseline façade. This design is consistent with minimum building fabric performance requirements as per local building code, the National Construction Code 2022 Volume 2 Section J1-J4 for a Class 3 building in Climate Zone 6.

Baseline façade design parameters:

Steel stud construction spaced 450 mm, 0.75BMT, 92 mm cavity depth
Class 4 vapour permeable membrane
Plasterboard internal finish, mineral wool insulation, Colorbond external cladding, total wall R-2.0
30% window to wall ratio on east and west façades; 0% others
Thermally broken aluminium IGUs, total window U-2.4, SHGC 0.4
500 mm horizontal external aluminium shades at 1000 mm glazing head height

Methodology:

Scope: Bridge façade
System Boundary: upfront carbon, as per EN 15978 modules A1-A3
Functional unit: report impacts per m² of gross floor area served by the façade

Performance targets

There is no minimum outcome required for this challenge, however the higher your reduction, the more points you will be awarded.

Judging criteria

Points will be awarded for: undertaking the challenge regardless of outcome; and demonstrating a reduction of 10% or higher. The team with the highest reduction will receive full points. Remaining teams will be assigned points on a sliding scale. Ties are accepted.