Environmental Impacts of Multi-Storey Buildings Using Different ...

- 67 -8000700060005000GWP (t CO2 equiv.)40003000200010000-1000-2000ConcreteSteelBuilding typeTimberTimber+Initial Embodied Maintenance Transport Operational End of Life CO2 storageFigure 6.5: GWP (tonnes CO 2 equivalent) for each stage of the life cycle of all the building types6.3.4.2 Contribution of building componentsIn this section, embodied energy (as distinct from total primary energy) and embodied GHGemissions are analysed (cradle to gate only). However, it should be noted that the calorificvalue, as well as, the stored carbon (that is potential sequestration in the timber) are not takeninto account. These factors are dependent on the end-of-life scenario of the building and aretaken into account in the full life cycle assessments. Especially, the carbon storage shouldonly be considered if the whole life cycle is taken into account because the effect of differentend-of-life scenarios can influence this result significantly, as shown later in section 6.3.5.However, Figure 6.3 has shown that the carbon storage in landfill that can be attributed tospecific materials can be significant, if a landfill scenario is assumed. Refer to section 6.3.3.3on the details how this was calculated.The highest individual energy user is the structure of the Steel building (Figure 6.6Figure6.6Figure 6.6). Aluminium louvres are the largest energy input for the Concrete and Timberbuildings, and the second largest of the Steel building. The TimberPlus building uses woodenlouvres, which are almost 20 times lower in energy than the aluminium louvres used in theother buildings. Window type also makes a significant contribution to embodied energy andagain, the reason the TimberPlus building has a lower figure than the others is because it useswooden frames instead of aluminium. Suspended floors are the next significant embodiedenergy contributor, and this is primarily from Concrete and Steel. The values are much higherthan for the foundations figures, because much more concrete and steel is used in fivesuspended floors.The higher value for the ceiling of the TimberPlus building can be attributed to the largequantities of MDF used in the ceilings.