Gaps and Disadvantages The BLCA represents an important part of these evaluation methods. Lots of previous studies have allowed the BLCA tools to be reviewed (Zabalza Bribián et al., 2009, Nibel et al., 2005, Haapio and Viitaniemi, 2008a, Erlandsson and Borg, 2003b). Nevertheless, there are some gaps regarding the environmental indicators, easily understandable presentation of the BLCA results to its users, simplification, and adaptation to various purposes or applications (e.g. early design phases) (Zabalza Bribián et al., 2009, Todd et al., 2001b). LCA was mainly developed for designing low environmental impact products. As products, buildings are special since: They have a comparatively long life They undergo changes often (especially offices and commercial buildings) They often have multiple functions They contain many different components They are locally produced They are normally unique are not often many of the same kind) They cause local impacts They are integrated with the infrastructure, system boundaries are not clear, etc. This implies that making a full BLCA is not a straightforward process as it is for many other consumer products (Zabalza Bribián et al., 2009). Both retrospective and prospective BLCAs have methodological limitations. In a retrospective BLCA, for example, there seems to be no general, objective basis for the definition of subsystems or the choice of allocation methods. In these respects, the retrospective BLCA methodology relies on the establishment of standards when a detailed standardisation of the methodology is required. An example of such a convention for this type of BLCA is the product-specific rules (PSR) in the Swedish system for EPD (PSR, 2001, PSR, 2000, Ekvall et al., 2005). The need for conventions is emphasised by the fact that the PSRs for different types of products do not have the same conventions for calculating the average data for electricity production (Ekvall et al., 2005).
4.4 Comparison of Building Design and Decision-support Tools Considering the principal goal of this research, this section covers the comparison of the BLCA in Level 2 of the ATHENA classification, which is equivalent to Class 2 of the IEA Annex 31 (environmental LCA tools for buildings and building stocks). This level is defined as ‘whole building design or tools’ (Trusty, 2000, Haapio and Viitaniemi, 2008b), and includes: ATHENA™, BEAT 2002, BeCost, Eco-Quantum, Envest 2, EQUER, LEGEP® and PAPOOSE (Table 4.1). Table 4.1: Whole building design and decision-support tools (Haapio and Viitaniemi, 2008) Name Developer References ATHENA™ Environmental Impact Estimator ATHENA Sustainable Materials Institute; Canada ATHENA Institute (2003); ATHENA™(2007); DOE (1996/2006a); Trusty and Meil (2002a,b) BEAT 2002 Danish Building Research Institute (SBI), Denmark BEAT (2002 ); Forsberg and von Malmborg (2004); Hansen (2005); IEA Annex 31 (2001); Petersen (2002) BeCost (previously known as LCA-house) VTT, Finland BeCost; (2004); IEA Annex 31 (2001)
Table 5.3: Spreadsheet: calculation of the total EE, EC, and the total environmental impact of construction in the simulated buildings Building Component Value Units (m2) Weight (kg) EE (MJ/kg) EC (kg CO2) Total EE for each material (MJ) Total EC for each material (kg CO2) Total environmental impact for each material/Eco- point ConcSlab_OnGround 50 35415 0.95 0.13 33644.25 4603.95 … Plaster_Insulation_Suspended (General Insulation in this case) 61.05 811.66 45 1.86 36524.7 858.52 … SolidCore_PineTimber (General Timber in this case) 1.89 41.58 8.5 0.46 353.43 19.1268 … BrickTimberFrame(General in this case) 135.15 31435.62 3 0.22 94306.86 6915.836 … SingleGlazed_TimberFrame 12.96 133.695 15 0.85 2005.425 113.6408 … MetalDeck (Sheet-Virgin in this case) 50.515 796.119 31.5 2.51 25077.75 1998.259 Total Total EE for Building (MJ) Total EC for Building (kg CO2) for construction 191912.4 14509.33 …. Consequently, this framework suggests benefitting from a combination of the different calculation approaches, which benefits from the output of the different BLCA tools, programmes, and databases, and which aims to calculate the total EE, EC, and Eco-point (environmental impact) of buildings in the case studies. The results reveal the higher sensitivity and level of confidence of this methodology (refer to the next chapter). Moreover, different of materials can be considered in the spreadsheet. This shows the flexibility of the measurement approach to include virgin (or materials, recycled materials, and eco-agro materials (including lower embodied energy and high construction performance) in design scenarios.
emission and total environmental impact of the building during its service life are calculated. In the next stage, the results of this spreadsheet through the case study for the different geographical scenarios (different locations in the UK) were compared in a statistical approach (using Microsoft Excel/SPSS). Therefore, the impact of geographical variation and climatic change on the BLCA was highlighted (refer to Chapter 8). Hence, as a principal goal of this research, the level of confidence that might be expected from the BLCA was determined. 5.3 A More Detailed Explanation of the Measurement Phases in the New Spreadsheet The measurement spreadsheet to demonstrate the guideline of the new framework introduced by this research was developed established on calculation of the following values (see figure 5.3): section detail material area (m2) height (m) volume (m3) density (kg/m3) total weight (in kg and tonnes) EE per m3 EC per m3 EE Total EC OE (resulting from the Ecotect 2011 modelling) Eco-point (resulting from the Envest 2 modelling). Figure 5.3: The new spreadsheet introduced by this research
Another advantage of this methodology is the flexibility to add/remove building components and details and EE and EC profiles as much as required for the various ranges of projects. Moreover, the materials of the building utilities such as boilers, coolers, and security systems can be added according to the decision of designers and building in projects. Furthermore, whole phases of building maintenance during the building’s service life can be added, including the materials for devices and utilities (table 7.1). Table 7.1: Total EE, EC, OE, and Eco-point in scenario 1, The Arts Tower of Sheffield The Arts Tower of Sheffield, Scenario 1 Energy (MJ) EC (Kg) Embodied (EE) Operational (OE) Basement floor/FL-BT 43,168,557 75,565.44 43,244,122.44 2,358,341 42,058 Ground floor/FL-GR 6,525,120 116,524.80 6,641,644.80 393,510.3 4,141 Mezzanine floor/FL-MZ 6,027,637.60 120,181.00 6,147,818.60 370,861.3 5,618 Floors 273,348,263 967,195 274,315,458.10 14,299,211 935,838 Floor 19 15,112,604 129,173.00 15,241,777.00 837,030.8 11439 Roof 12,402,373 33,135.84 12,435,508.84 801,804 6,870 Total for Building 356,584,555 1,441,775.18 358,026,329.78 19,060,758 1,005,964 Figures 7.3 to 7.5 reveal comparisons of EE, OE, Total energy, EC, and Eco-point in the design sections of The Arts Tower of Sheffield in pie charts. Figure 7.3: Comparison of EE and OE in the design sections of The Arts Tower of Sheffield: Scenario1
The height of the ceiling areas is 3-4 metres; however some tenants prefer just to paint the concrete slab and have exposed installations (see figure 7.20). Preliminary Modelling of the building block scenarios in HAP Scenario 1: The first position of the building with a rectangular floor plan is with a north–south orientation in its longer facades (more details in Appendix A). The result shows that the building will require 1,248 tons of refrigeration, which is equivalent to 15,833.4274 joules/hour (see figure 7.21). Figure 7.21 Modelling of scenario 1 in HAP: 1,207 tons of refrigeration (screenshot). Scenario 2: The second scenario has a square floor with a north–south orientation in two of its sides. The result shows that the building will require 1,207 tons of refrigeration, which is equal to 15,314.2887 joules/hour. Scenario 3: Prototype 3 has a circular shape with a northward orientation. The result shows that the building will require 1,149 tons of refrigeration, which is equal to 15,339.6125 joules/hour. 7.8 presents the results of the primary OE modelling in HAP. Table 7.8: A comparison of the case study scenarios in terms of OE. shape Tons of refrigeration joules/hr Scenario 1 square floor plate 1,207 15,314.2887 Scenario 2 rectangular floor plate 1,248 15,833.4274 Scenario 3 circular floor plate 1,149 15,339.6125