Both ‘baseline’ and ‘integrated’ approaches are applicable to option appraisal. A description of each and how they work with the Mat 01/02 Results Submission tool is given below.
A ‘baseline’ approach means building LCA starts after the project team have established an initial building design. Once an initial building design is available, building LCA is used to work out its environmental impact – the ‘baseline’ result. Then various alternative designs are explored to lower the impact compared with the ‘baseline’.
This approach is common where the building LCA work is less integrated with the design process and done as a separate exercise (e.g. by an LCA specialist for example). The alternative designs can be used as the basis of options for options appraisal.
Where this approach is followed for Mat 01, the ‘baseline’ option will typically be the worst performing option and it is logical for it to be included as the 1st option in the Mat 01/02 Results Submission Tool. The subsequent alternative designs explored form the 2nd, 3rd etc. options.
An ‘integrated’ approach means building LCA is integrated into the design process before the design team have established an initial building design (there is no ‘baseline’). From this earlier stage, as alternative designs are explored, building LCA is used to inform the designers on environmental impact performance of each one.
This approach requires the LCA work to be highly integrated within the design process, either by the designers themselves or by a specialist working in parallel. Earlier use and greater integration of building LCA should prove more effective at reducing impacts. For example, compared with the ‘baseline’ approach, there is no initial design that the project team have already spent time developing which may in some respects have become fixed.
Where an ‘integrated’ approach is followed for Mat 01, the differences between options are still expressed as ‘changes’ relative to option 1 in the Mat 01/02 Results Submission Tool. However, this does not mean option 1 is necessarily worse. It is simply a convenient way of declaring the differences between the options – any of the options can be option 1.
For both approaches Mat 01 options can be based on either: –
- Multiple designs developed in parallel
- Significant development points during a single, progressive design process (serial)
- a mixture of both