RICS WLCA Uncertainty Factor Tool (BETA)

This tool is intended to assist with the whole life carbon assessment uncertainty factor calculation, based on the methodology detailed in the RICS Whole Life Carbon Assessment for the Built Environment Professional Standard (2nd edition).

 

Enter the required information into the yellow fields. When done, the results will appear/update in the green field. Care should be taken in selecting the ten products – see the RICS methodology for this.

Title
1. Contingency factor
Project stage
Result (%)

2. Carbon data uncertainty factor
Product% of building emissions (W)GeographyTechnologyProduct SpecificityTemporalGranularityVerificationScore (S)Weighted Score
(Ws = S x W)
100
200
300
400
500
600
700
800
900
1000
Weighted average score (sum of Ws / sum of W):
Result (%)

3. Quantities uncertainty factor
ProductQUL scoreScore (S)Weighted Score
(Ws = S x W)
100
200
300
400
500
600
700
800
900
1000
Weighted average score (sum of Ws / sum of W):
Result (%)

WLCA uncertainty factor
Result (%)

Note that the RICS methodology states that “the carbon data confidence scores/QUL scores for all key products are then averaged, weighted by their embodied carbon impact…”. The intention here isn’t totally clear and we can find no worked examples. Our interpretation is that a weighted average approach should be used – see the formulae in parentheses in the tables above.