A: All transportation profiles are calculated in line with section 5.1.3 Transport impacts (A4) in the Whole life carbon assessment for the built environment, Professional standard, global, 2nd edition, September 2023.

Please note the following:

Transport impacts must include all stages of the journey of the products following their departure from the final manufacturing plant to the project site, including return journeys, taking into account any interim stops at storage depots and/or distribution centres.

Transport impacts should be calculated as follows:

A4 = material or product mass (a) x transport distance (b) x [carbon conversion factor outward (c1) + (empty running factor x carbon conversion factor return (c2))]

Here are two examples of this is worked out as carbon factors for the profiles in the software.

Carbon only - HGV (all diesel), All rigids, average laden, accounted for the return trip

Source: UK Government GHG Conversion Factors for Company Reporting 2023 - Freighting goods

Then we calculate the full net load:

Km avg / tonkm avg = net average load

0.82313 kg CO2e /km / 0.17819 kg CO2e / tonkm = 4.619395 ton

Finally, we convert the 0% km value to per tonkm value to cover how much is the share of the materials of the empty trip per tonkm:

0.65828 kg CO2e/km / 4.619395 ton x 43% = 0.061276 kg CO2e/tonkm

And this is added to the kg CO2e/tonkm average value

(0.17819 + 0.061276) kg CO2e/tonkm = 0.239467 kg CO2e/tonkm

Carbon only - HGV (all diesel), All HGVs, average laden, accounted for the return trip

Source: UK Government GHG Conversion Factors for Company Reporting 2023 - Freighting goods

Then we calculate the full net load:

Km avg / tonkm avg = net average load

0,87204 kg CO2e /km / 0,096957 kg CO2e / tonkm

=8.994090 ton

Finally we convert the 0% km value to per tonkm value to cover how much is the share of the materials of the empty trip per tonkm:

0,64257 kg CO2e/km / 8.994090 ton x 43% = 0.030721 kg CO2e/tonkm

And this is added to the kg CO2e/tonkm average value

(0,096957 + 0.030721) kg CO2e/tonkm = 0.127678 kg CO2e/tonkm

A: On the results page, after the results summary, you will be able to find this section named "Most contributing materials (Global warming potential - Non-Decarbonised scenario)"

If you scroll further down, you will find this section which shows the top ups and uncertainty scores calculated.

A: There are several mentions of biogenic carbon in the guidelines in sections 2.1, 4.11.1, 4.11.6, 5.2.5, 6.3.5, Appendix K and N.

Figure 2: Building and infrastructure life cycle stages and information modules (adapted from EN 15978, EN 17472 and EN 15643, with additions to illustrate biogenic carbon)

Emissions and removals of all types of carbon (fossil carbon, land use and land use change (LULUC) carbon, and biogenic carbon) are assessed and reported in the modules in which they occur. However, as Figure 2 shows, when reporting upfront carbon (as described below) the sequestered biogenic carbon stored within construction products incorporated into an asset is not included but is reported separately.

The guidelines in section 4.11.1 Biogenic carbon make clear the specifics.

Note: For timber, biobased packaging or timber formwork that is not sustainably sourced, no removal of biogenic carbon must be considered at any point in the life cycle. However, any emission or transfer of sequestered carbon from timber that has not been sustainably sourced must be considered as an emission of carbon arising from land use and land use change (LULUC), considered in the same way as a fossil carbon emission.

If correctly assessed – accounting correctly for all the co-products, waste and combustion of biomass during the production of sustainably sourced timber and other biomass – the sequestered biogenic carbon contained in products and their packaging should be reported as a removal of biogenic CO2 in A1–A3 (i.e. a negative emission of CO2), as an emission of biogenic CO2 for any packaging disposed of in A5, and as an emission of biogenic CO2 in C3 or C4 for the product at end of life. Sustainably sourced biobased product wastage in A5, and any replacement of sustainably sourced biobased products or packaging in B2–B4, will have balanced removals and emissions of biogenic carbon in each module unless methane is emitted during disposal.

Because there should be a biogenic carbon balance over modules A–C, it makes little difference whether biogenic carbon is included in targets for embodied and whole-life carbon, as the removals of biogenic carbon in modules A1–A3 are balanced by emissions in modules C3 and C4.

Biogenic carbon removals and emissions from modules A1–A3 (the sequestered biogenic carbon within products) must not be included in the calculation of upfront carbon, but must be reported separately as the sequestered biogenic carbon stored within the asset in A1–A3.

Biogenic carbon and LULUC carbon must be included with fossil carbon in the calculation of both embodied carbon and WLC.

For timber or other biobased materials (biogenic carbon) that is modelled as reused or recycled at the end of life, the biogenic carbon sequestered within it should be taken into account as a transfer (emission) from C3.

For any net output of biomass into module D, the transferred biogenic carbon should be treated as a removal (a negative emission). Any biogenic carbon sequestered in the substituted product or material in D1 should also be considered in D1. Deducting the impact of the substituted product involves deducting the removal of sequestered carbon in the substituted product, so it will be equivalent to adding it as an emission in D1. If the quantity of sequestered carbon in the recovered and substitute products are the same, this will result in a biogenic carbon balance.

A: The guidelines in section 6.1.4 Accuracy of reporting states the following:

The carbon impacts reported must reflect the accuracy of the calculation, which will depend on the project phases at which the assessor is reporting.

• Early design phase: at building or asset level, calculations and totals should be reported to two significant figures (e.g. 230 kgCO2e/m2 or 1200 kgCO2e/m2 rather than 234.3kgCO2e/m2 or 1234.4 kgCO2e/m2).

• Technical design/construction/post-completion phase: at building or asset level, calculations and totals should be reported to three significant figures (e.g. 234 kgCO2e/m2 or 1230 kgCO2e/m2 rather than 234.3 kgCO2e/m2 or 1234.4 kgCO2e/m2).

Depending on what you have set as the phase of the project of reporting, the subtotals will reflect what the guidelines have stated.

A: The guidelines in Appendix H (H1 Emissions associated with energy usage) states the following:

Energy usage in buildings is responsible for different types of carbon emissions:

It is important to understand the whole energy supply chain when choosing a carbon conversion factor for B6 calculations. For a WLCA over the RSP, carbon conversion factors must include all emissions listed above.

The datapoint for input in B6 is taken from set 1 for design decision-making.

The Energy-supplementary tables for Set 1: Whole-life carbon design decision making, gives the following values.

Adding up the carbon factors (0.2071 + 0.0459 + 0.0179 + 0.0040 + 0.020 + 0.0004), gives 0.2953 kgCO2e/kWh
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The data point currently in the tool reflects this as rounded up to 0.3 kgCO2e/kWh.
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If you look at the detailed calculations, you will find that it is reflected as 0.2953 kg CO2e/kWh.

A: The existing GLA templates are aligned to the previous RICS v1.0 guidelines. It is expected that GLA will issue new guidance to align with the new RICS v2.0 guidelines. This is the current advisory from GLA with regards to GLA submissions:

The RICS WLC methodology's second edition came into effect on 1 July 2024. The GLA WLC guidance document (including benchmarks) and template are underpinned by first edition methodology, so referable applications should provide assessment in accordance with this guidance. Applicants can additionally provide assessments in accordance with second edition methodology if they wish. Revisions relating to second edition methodology are being considered as we look to update GLA guidance in future.

Please see the full RICS 2nd Edition guidance for more details.