British Land 5 Broadgate Embodied Carbon Tracking Report

Transcription

1 Issue 28 October 2014 This report takes into account the particular instructions and requirements of our client. It is not intended for and should not be relied upon by any third party and no responsibility is undertaken to any third party. Make Architects Job number Ove Arup & Partners Ltd 13 Fitzroy Street London W1T 4BQ United Kingdom

2 Document Verification Job title Job number Document title File reference Document ref Revision Date Filename BG ECO2 Construction Phase report.docx Draft 1 24 Jul 2014 Description First draft Prepared by Checked by Approved by Name Amy Leitch Jonathan Ben-Ami Jonathan Ben-Ami Signature Draft 2 Issued 10 October October 2014 Filename BG ECO2 Construction Phase report.docx Description Second draft Prepared by Checked by Approved by Name Amy Leitch Jonathan Ben-Ami Jonathan Ben-Ami Signature Filename 5BG ECO2 Construction Phase report.docx Description Issued Prepared by Checked by Approved by Name Amy Leitch George Vergoulas Jonathan Ben-Ami Signature Issue Document Verification with Document

3 Contents 1 Introduction 11 2 Approach 22 Page 2.1 British Land Sustainability Brief 22 3 Methodology Design phase Integrated sustainable procurement process Construction phase 55 Appendices Appendix A Construction Phase Embodied Carbon Tracking Template Appendix B Calculation References / Assumptions 4 Results Design phase Construction phase Comparison 77 5 Lessons Learned 88 Tables Table 1 Lessons learned during Design and Construction Figures Figure 1 British Land Sustainability Brief and project approach to eco 2 Figure 2 Whole life carbon footprint (as of 10/2011) Figure 3 Mitigation of construction carbon footprint (as of 10/2011) Figure 4 Material evaluation sheet template Figure 5 Construction phase embodied carbon tracking table Figure 6 Example of Cradle-to-Gate eco2 tracking table inputs Figure 7 Example of Gate-to-Site eco2 tracking table inputs Figure 8 Design case facade and structural CO 2 e modelled emissions Figure 9 Design case 'whole life' CO 2 e modelled emissions Figure 10 Design case and As-built facade and structural CO2e emissions Figure 11 Constructed 'whole life' reported CO 2 e emissions Figure 12 Embodied carbon dioxide emissions per square metre of compared to similar projects reported in the WRAP database (A1 A5 lifecycle emissions).*

4 1 Introduction Why did we calculate embodied carbon dioxide emissions in the design and construction of? In 2009, the construction and operations of buildings accounted for roughly 43% of all the UK s carbon dioxide emissions. 1 New building construction is an inevitable necessity to support a vibrant economy and growing cities, but the materials required to construct new buildings are a major consumer of resources and can produce large quantities of carbon dioxide (CO 2 ) emissions through the production / manufacture, transportation and installation of materials. As methods for reducing operational carbon emissions become standard practice, British Land anticipates that embodied carbon dioxide emissions (eco 2 ) could become the next focus for the construction industry. 2 Indeed, in addition to raising requirements to reduce operational CO 2 emissions from developments, the London Mayor s 2014 Sustainable Design and Construction Supplementary Planning Guidance elevates planning guidance to prioritise materials with low embodied energy to a Mayor s Priority from a Preferred Standard in the replaced 2006 guidance. However, there are few examples where new developments have undertaken a detailed interrogation of their construction materials and supply chain to understand opportunities to promote materials with low embodied energy (and, as a proxy, low eco 2 emissions) across the design and construction of new buildings. While building modelling to track eco 2 emissions has become increasingly sophisticated and conventional within the building design engineering sector over the last decade, this level of sophistication and detail has not extended as readily to tracking and reporting the eco 2 emissions from the constructed building. In response, British Land selected as a pilot project to track eco 2 emissions and mitigation efforts from design through construction as a core opportunity to learn from real-world project experience, and demonstrates British Land s commitment to innovation and leadership in engaging the construction supply chain. Between 2011 and 2015, British Land anticipates its development programme will contribute 1.2 billion to the UK economy, including over 2 million square feet of development programme in central London that represents roughly 6% of the wider London construction programme. 3 Lessons learned from the practical, real-world engagement with the Construction Trades and experiences calculating the eco 2 emissions from 5 Broadgate will support future British Land projects, provide lessons for the broader construction supply chain, and help inform assumptions in design phase eco 2 modelling. 1 UK Department for Communities and Local Government. Accessed October < 2 British Land. Sustainability Brief for Developments. Version 3: July Accessed October < Land/documents/sustainability_brief_for_development.pdf>. 3 British Land. Accessed October < What method did we use to calculate embodied carbon emissions? The team pursued opportunities to identify and reduce eco 2 emissions throughout the design, tender and construction project phases. The team leveraged design phase eco 2 modelling to predict embodied and whole-life CO 2 emissions and identify opportunities to incorporate design changes to mitigate impact. Design phase effort prioritised on refining design options to reduce material demands and incorporate materials with lower eco 2. During the tender phase, the team worked closely with bidding Contractors to clearly communicate project goals and encourage responding firms to suggest additional opportunities to reduce eco 2 emissions. Effort focused on coordinating messaging across tender documents, establishing clear criteria for evaluating responses, and providing incentives for respondents to pursue options to further reduce eco 2 emissions in a competitive environment before contracts were awarded. During construction, the team worked to track and report eco 2 emissions of key materials to compare modelled projections with the constructed building. Construction tracking prioritised effort on tracking eco 2 emissions associated with the manufacture and production ( Cradle-to-Gate emissions) and the transportation ( Gate-to-Site emissions) of the steel, concrete and façade elements used in the construction of. What did we find? The total tonnes of carbon dioxide equivalent emissions (tco 2 e) for the constructed carbon footprints (super-structure, sub-structure and façade) reported for the design and construction phases are: Design phase modelled emissions: 39,800 tco 2 e Construction phase tracked and reported emissions: 46,324 tco 2 e The reported eco 2 emissions from construction (shell and core construction) accounted 56% of the construction carbon footprint (including site activities and fit-out), compared to 53% in the design case. This represented 27% of the whole life carbon footprint of the development, compared to 25% in the design case. The reported construction phase footprint is 6,524 tco 2 e greater than the design phase model; a 16% increase. Described in more detail in the report, this increase likely illustrates the complexity in defining assumptions for modelling as well as differences in emission factors between modelling and as-built reporting used to calculate eco 2 contributions from materials and activities. What did we learn? The construction phase tracking represented the first time many of the key Trades had engaged with their supply chain to understand and record eco 2 emissions associated with the manufacturing and transport of their procured construction materials. In this way, the experiences of the project team are advancing understanding of the opportunities and challenges tracking as-built eco 2 emissions across the project supply chain as well as informing comparison of constructed totals to design phase models to better refine assumptions in future models. Jason Hawkes / Barcroft Media Make Architects Picture 1 Street-level view north: design rendering with Broadgate Circle to the left. Picture 2 Aerial view south west: during construction with Broadgate Circle to the right. Page 1

5 2 Approach The Base Build project team has been committed to pursuing and realising a high level of sustainable performance in the design and construction of 5 Broadgate from an early stage. This was driven by British Land project goals and informed by the British Land Sustainability Brief for Developments and Agreement for Lease targets developed to ensure compliance with UBS sustainability aspirations. 2.1 British Land Sustainability Brief British Land Sustainability Brief The British Land Sustainability Brief for Developments (Figure 1) was used to develop a Project Sustainability Brief (Step 2 of the Brief), identify areas for project innovation (Step 3 of the Brief) and develop the project sustainability objectives, targets and aspirations (Step 4 of the Brief). These targets and aspirations were informed by British Land s 37 ongoing sustainability objectives and 2011/2012 core targets (included in Appendix 1 of the Sustainability Brief for Developments) which include a specific energy objective to understand and minimise the amount of embedded carbon in the development and the supply chain. A sustainability tracker was developed to track project progress and regular project team meetings were held to coordinate and communicate effort to embed sustainability targets within detailed design (Step 5 of the Brief). As project goal to pilot construction-phase eco 2 tracking, the project team committed to an aspirational target (beyond British Land / UBS / BREEAM requirements) in the sustainability tracker to monitor the reduction in eco 2 associated with the structure and façade over the baseline reference building. This helped guide the development of project-specific tools to inform decisionmaking to identify and evaluate the potential eco 2 savings alongside impacts on cost and programme. The project team pursued a coordinated, proactive effort to communicate sustainability targets during procurement (Step 6 of the Brief) and encourage contractors to interrogate their supply chain to identify opportunities to improve the project sustainability performance in a competitive environment. In recognition of the team s efforts, the integrated sustainable procurement process has been conditionally approved by the BRE as a BREEAM Innovation Credit, contingent on final evidence of the building s sustainability performance. The Base Build sustainability team worked closely with Trades during construction to track and report eco 2 emissions for comparison against the design phase model results (Step 7 of the Brief). As the project moves into close-out and lessons learned in 2015, Step 8 of the Brief will be implemented. This will be instrumental in building a knowledge base around the practicalities and opportunities to track and report construction phase eco 2 emissions. This will help encourage additional projects to track asbuilt eco 2 emissions and inform assumptions during design phase eco 2 modelling to generate more accurate predictions. Figure 1 British Land Sustainability Brief and project approach to eco 2 Page 2

6 3 Methodology 3.1 Design phase Design considerations British Land commissioned a whole life eco 2 model for. This enabled predictions to be made of the eco 2 emissions from design, construction and operations and maintenance (excluding deconstruction/demolition) based on an anticipated 60-year operational lifetime (Figure 2). With energy saving measures incorporated into the scheme, carbon mitigation efforts focused on the structural and façade elements. Mitigation measures in design Using modelling analysis, the team conducted a series of Hot spot studies for façade and structural elements to identify viable carbon savings and evaluate the potential carbon savings alongside impacts on cost and programme. Incorporated measures were shown to mitigate over 3,300 tonnes carbon dioxide equivalent (tco 2 e) emissions compared to the initial design, resulting in an 8% reduction of the construction carbon footprint (Figure 3). 4 Primary design measures identified to reduce the sub and superstructure carbon footprint include 5 : Low carbon concrete (2,300 tco 2 e mitigated): Working with the supply chain enabled the specification of higher levels of cement replacement. This results in lower carbon concrete without detrimental impact on construction programme. Overall structural carbon footprint reduced by 7%. Reduced façade skin thickness (360 tco 2 e mitigated): Efficient design resulted in the façade skin being reduced from 4mm aluminium skin to 2mm stainless steel skin. This avoided requirement for future replacement resulting in 5% reduction in cladding carbon footprint over 60 year life. Double primary beams (360 tco 2 e mitigated): Demonstrated carbon benefit of utilising improved structural double beam solution compared to typical use of single primary beams. The cost neutral action results in 12% reduction in weight and 8% reduction in carbon impact for the steel floor structure. Raft foundation system (300 tco 2 e mitigated): Complex analysis work enabled structure to be amended to raft solution from initial typical London piled solution. Reduction in concrete volume enables 5% drop in substructure concrete footprint. Figure 2 Whole life carbon footprint (as of 10/2011) 4 In calculations reported 15 November 2011, Buro Happold states design phase mitigation of construction carbon footprint results in a 4% reduction. Arup has identified an error in the calculation and reports an 8% carbon footprint reduction. Buro Happold reports total mitigation savings = 3,300 tco 2 e (= 360 tco 2 e from reduced façade skin thickness tco 2 e from double primary beams + 2,300 tco 2 e from low carbon concrete tco 2 e from raft foundation system). Buro Happold reports the total construction carbon footprint = 39,800 tco 2 e (= super-structure + sub structure + façade; as per Buro Happold calculations, construction carbon footprint excludes site activities and fitout.). (3,300/39,800)* 100 = 8.34%. [NB: (3,300/phase total 75,900)* 100 = 4%)] 5 tco 2 e savings and summaries provided by Buro Happold. Figure 3 Mitigation of construction carbon footprint (as of 10/2011) Page 3

7 3.2 Integrated sustainable procurement process Responsible sourcing Responsible sourcing of materials was a key consideration throughout deign development. To assist the meeting performance requirements, Make established a set of material evaluation sheets (Figure 4) to interrogate the performance of Base Build against a range of criteria, including comparing the eco 2 of different materials (using the ICE database see Appendices). These evaluation sheets were used to establish achievable targets and allowed the team to focus on quick wins before performance requirements were embedded into the tender and contract documentation. Integrated sustainable procurement process The sustainable procurement process expanded the British Land Sustainability Brief requirements (Step 6 of the Brief, Figure 1) to include three additional steps: Step 1 Tender sustainability submittals: Sustainability submittals were tailored for each individual package and issued as part of the tender documentation to highlight requirements. Each contractor was expected to review the criteria, confirm compliance and propose improvements where possible. Step 2 Mid tender interviews: Interviews helped ensure bidding contractors understood requirements and were reminded they must complete the environmental submittals to achieve compliant bid status. Step 3 Tender analysis: The contractor submittals were considered as part of the bid analysis (scoring process) and provided an opportunity for the client and design team to consider alternatives, including additional costs associated with improvements proposed in submittals. As part of the tender submittal, an eco 2 tracking table was issued to the packages which had the highest eco 2 impact identified through the design phase eco 2 modelling; concrete (piling, substructure and superstructure), steel and cladding (Figure 5). The tracking table identified the CO 2 e associated with each package material generated through Cradle-to-Gate (manufacturing and production) and Gate-to-Site (transportation) activities. Submitting contractors for these packages were requested to consider any mitigation measures during procurement and were made aware that a full assessment of the package materials in the tracking table would be a construction phase requirement. The tracking template Mitigation measures in procurement Through clear communication of sustainability requirements during the tender phase and active engagement with relevant submitting contractors, primary mitigation measures identified during procurement to reduce the sub and superstructure carbon footprint include 6 : their factory to the stainless steel subcontractor s factory. This reduced the need to transport the stainless steel from the north of Germany to the south and back again, mitigating 48 tco 2 e. Blockwork: the winning blockwork contractor proposed to reduce transportrelate emissions by transporting the 2,750 tonnes blockwork by rail instead of road, which avoided the need for 150 lorries to each drive 92 miles, mitigating 7 tco 2 e. Piling: the winning piling contractor proposed changing from the six 2- meter diameter hand dug under-ream piles specified in the tender design to meter micro piles, mitigating 150 tco 2 e. This was also considered a safer alternative by eliminating confined space working. Feedback from Trade Contractors To capture experiences and lessons learned, the design team sought feedback from Trade Contractors in recognition of the increased engagement and scrutiny of the integrated sustainable procurement for. Two selected quotations are below: Michael Walsh - Swift Block (Blockwork package) The rigorous analysis of the sustainability criteria for the Blockwork we undertook during the tender process resulted in us changing the specified Block. This exceeded the specification requirements and had the added benefit of reducing our embodied carbon through transportation Peter Smith - Cementation Skanska (Piling package), "We are currently developing our own tender sustainability summary sheets to use on future tenders, which will include the statistics for the embodied carbon and water footprints that are associated with our bids. It is good to see that British Land has taken the initiative by actively engaging in sustainability on tenders and considering improvements as part of its bid process. Figure 4 Material evaluation sheet template Cladding stainless steel: The winning cladding contractor identified a measure to mitigation emissions through reduced transportation. For the first time, Seele proposed and have moved their beadblasting machine from Figure 5 Construction phase embodied carbon tracking table 6 tco 2 e savings and summaries provided by Make. Page 4

8 3.3 Construction phase Contractor training In advance of the construction phase eco 2 data collection, the team held a training workshop for Contractors to review project goals and requirements, introduce the tracking template and instructions and provide initial troubleshooting for data collection and reporting. The workshop included representatives from the sustainability team (M3, Mace, Arup and Mace) and contractors from the targeted construction packages (Skanska, Byrne Bros, and Severfield-Rowan). Seele was not required to attend the training as they had submitted an initial completed tracker and was in concurrent discussions with Arup and Make on comments and revisions. Following the workshop, the contractors initiated work to track and report the required information. The sustainability team reconvened a review workshop midway through the reporting process to review initial calculations and provide more detailed troubleshooting advice. At the review workshop, each of the participating contractors had submitted initial calculations, with ranges in completion from final touches to initial collection. Tracking Cradle-to-Gate eco 2 emissions Contractors were requested to report the CO 2 e associated with the manufacturing and production of relevant materials (Figure 6). Contractors were instructed to source this information directly from manufacturers or on-line where possible (e.g. product-specific Environmental Produce Declarations (EPD). Where product-specific information was not available, contractors were instructed to use default values reported from the Inventory of Carbon & Energy (ICE) (2011) (see Appendices). Tracking Gate-to-Site eco 2 emissions Contractors were requested to report the CO 2 e associated with the transportation of relevant materials from the point of final manufacture / production to the 5 Broadgate site (Figure 7). For consistency contractors were instructed to 1) source transportation distances from directions provided from Google Maps, 2) report assumptions on the percent fullness of the vehicle payload and 3) report only direct delivery distances, not distances reflecting multiple stops or return trips. In practice, delivery vehicles may make detours to deliver materials to other sites before arriving at the project site and payloads may include materials for other deliveries, or may have a low percent fullness from large, bulky or fragile materials. The calculation boundaries enabled the team to consistently capture the most actuate direct impacts from transport-related emissions. Figure 6 Example of Cradle-to-Gate eco2 tracking table inputs Contractors were requested to source the CO 2 e associated with the relevant vehicle types from the Guidelines to Defra / DECC s GHG Conversion Factors for Company Reporting (2012) (see Appendices). NB: revised emissions figures were issued by both the ICE and Defra/DECC s databases during the construction phase tracking of the project. However, to maintain consistency across calculations, Trades were requested to refer to the versions referenced in the Appendices and not to take account of subsequent reports. Figure 7 Example of Gate-to-Site eco2 tracking table inputs Page 5

9 4 Results 4.1 Design phase Key findings of this high level review were aimed at informing design decisions to reduce the project s construction eco 2 emissions. Buro Happold conducted a series of iterative carbon footprinting models to identify opportunities and understand the impact of design decisions. Through this effort, the team was able to reduce the initial eco 2 footprint (Figure 8). At the completed design, the carbon modelling showed that eco 2 emissions from construction (shell and core construction) were anticipated to account for over half (53%) of the construction carbon footprint (including site activities and fit-out) and a quarter (25%) of the whole life carbon footprint of the development (including eco 2 emissions resulting from building operation and maintenance based on 60 year life time). Emissions from building operations were anticipated to account for 53% of whole life carbon emissions (Figure 9) Mitigation measures pursued through design (described in Section 3.1) reduced the construction carbon footprint by 8% from the initial design, representing 2% of the overall whole life carbon emissions of the project (Figure 9). Figure 8 Design case facade and structural CO 2 e modelled emissions [Graphics show results as of November 2010 (left), November 2011 (right).] Figure 9 Design case 'whole life' CO 2 e modelled emissions Page 6

10 4.2 Construction phase As discussed in Section 3.2, tracking and reporting of construction phase CO 2 e focused on embodied emissions relating to the building shell and core and included all the associated steel, concrete and façade components delivered to the project site. Eighty four per cent of the reported construction carbon footprint related to the sub and super structure, compared to 80% in the design case (Figure 10). The reported eco 2 emissions from construction (shell and core construction) accounted 56% of the construction carbon footprint (including site activities and fit-out), compared to 53% in the design case. This represented 27% of the whole life carbon footprint of the development, compared to 25% in the design case (Figure 11). Mitigation measures pursued through materials procurement and delivery (described in Section 3.2) reduced by 160 tonnes, representing 0.33% of the construction carbon footprint 4.3 Comparison The total constructed carbon footprints (super-structure, sub-structure and façade) reported for the design and construction phases are: Figure 10 Design case and As-built facade and structural CO2e emissions [Modelled emissions as of November 2011 (left); emissions reported by Trades (right).] Design: 39,800 tco 2 e Construction: 46,324 tco 2 e The reported construction phase footprint is 6,524 tco 2 e greater than the design phase model; a 16% increase. Explanations for this difference include: Different carbon factors used for the design phase model (2006 and 2009 factors) and the construction tracking (2011 and 2012 factors); Different material assumptions compared to the constructed building (e.g., the carbon model is based on generic materials whereas the construction tracking is based on delivered materials, and the construction tracking includes both product-specific material information from EPDs as well as default values provided in guidance documents); Different assumptions about material delivery to the project site (e.g., transport mode, payload capacity, distance travelled, etc.); Potential omissions or calculation errors in reported values (e.g., human error). The close match represents a well-received outcome for the project team. Figure 11 Constructed 'whole life' reported CO 2 e emissions Page 7

11 5 Lessons Learned Lessons learned by the project team for other projects represents an innovative attempt to closely engage the construction supply chain to conduct detailed interrogation and reporting of all the steel, concrete and façade components delivered for a new construction project developed by British Land. The construction phase tracking represented the first time many of the key Trades had engaged with their supply chain to understand and record eco 2 emissions associated with the manufacturing and transport of their procured construction materials. The close engagement and collaboration with the project Trade Contractors helped to build team relationships and facilitated the collection and reporting of construction phase eco 2 emissions. The process also led some Trades to change manufacturing or transport processes to make further reductions in eco 2 emissions. Mace is also building on the data collected to interrogate further aspects of eco 2 impacts in new construction projects, including exploring tracking eco 2 associated with different packages and building services. At this project stage, the sustainability design team has held two project workshops to review project progress, experiences and lessons learned; one concluding the design phase and one midway through the construction phase. Error! Reference source not found. summarises lessons learned raised by the project team relating to efforts to understand and mitigate the project s eco 2. Design Phase Worked well Challenges Future improvements Initial Brief Specify eco 2 targets in initial project brief. Agreement for Lease RIBA D/E Stage Construction Phase Pre-construction Consideration of whole life carbon and materials is rare on development projects. Include eco 2 in AFL targets. eco2 tracking (like WRAP for recycled content) would be good to compare intent against performance. Worked well Challenges Future improvements Aligning the wording in the specs / tender documents across disciplines close potential for conflict / omission in requirements. 1 point of contact (Arup) to review the CWM plan, trade requirements (including eco 2 requirements) and BREEAM requirements closed gaps Make pulled out key tender requirements via a template to raise the profile of the requirements and expectations. Mace developed a project specific contractual document covering a variety of sustainability requirements which was transferred to each subcontract. By agreement with the relevant commercial manager, the project sustainability manager was able to ensure that a robust register of items was recorded in the subcontract order. The team recognised the need to use a set of standard contractual clauses which could then be modified to suit each subcontract package and tailored to the client s requirements. Provide agreed set of templates to go to contractors at the tender phase to coordinate targets and expectations. Mobilisation and Construction Mid-Tender Phase interviews helped to flag environmental requirements It was important to ensure that the subcontract directors were aware of the content of the clauses, and Mace held a series of meetings prior to contractual relations being finalised to discuss client requirements in detail. Mace delivered site start up meetings with subcontract supervisors and operatives at the time of arrival to site, briefing attendees on the exacting requirements of the project and client. Two dedicated eco 2 training workshops with the people involved in collecting the data and reporting the information. Creating a collaborative atmosphere of troubleshooting. Reminding Trades of project requirements, opportunity for leadership and opportunities for new service offerings to keep motivation high. Mace has undertaken a lot of effort in training the people involved in delivering project goals. Table 1 Lessons learned during Design and Construction Ensuring trades are clear on the requirements during the bid phase (agreement is not always an indicator that the requirements for resourcing to deliver are appreciated) A major problem throughout any project is that operatives and supervisors will arrive on site with very little or a complete absence of any sustainability knowledge or training. There is often a major breakdown in subcontractors own communications and internal processes, Mace found on that despite their best efforts expended during pre-contractual negotiations and in pre-start meetings, the site staff who actually attend to carry out the works are usually completely unaware of project sustainability requirements. Challenge connecting the measuring / reporting side with action to improve performance. Goal not to report just to report but to affect improvement. Idea for contract broker to manage trade performance Hold separate eco 2 design workshops Work with contractors to confirm there is a dedicated resource, and facilities available (e.g., desk space) to conduct data collection and reporting. Linking performance in sustainability delivery to financial performance. This would require KPIs for each contractor and close monitoring of performance. Page 8

12 Emerging industry benchmarks In April 2014, the Waste & Resources Action Programme (WRAP) and the UK Green Building Council (UK-GBC) launched the UK s first free, publically available eco 2 database. The database provides performance benchmarks for a range of project types based on data points submitted through self-reporting project information. At the time of the review, the WRAP database incorporated 24 data points for constructed new build office buildings in London. 7 The comparison plots the lifecycle eco 2 emissions reported for for the constructed superstructure, sub structure and façade per square meter (46,324 tco 2 e / 92,903 m 2 GFA) against the data points reported in the WRAP database for eco 2 emissions for A1 A5 life cycle stages from per square metre for new office build offices in London (Error! Reference source not found.). The A1 A5 life cycle stages are defined by British Standards EN and EN 15804, 8 and represent building life cycle information. The stages describe product stages (A1 A3) and construction process stages (A4 A5). These stages compare to the Cradle-to-Gate and Gate-to-Site life cycle stages that formed the scope of eco 2 construction phase reporting, and so represent an appropriate comparison. Robustness: the WRAP embodied carbon database is a database of self-reported eco 2 figures, and while provides guidance on reporting emissions in relation to building system, lifecycle phase, and source database, responding projects use a range of methodologies to scope and calculate eco 2 emissions. While WRAP provides methodology guidance to promote consistency amongst reported data, the submissions are not independently verified. The overall trend for the A1-A5 WRAP data shows a decreasing trend in eco 2 emissions per square meter as overall project GFA increases. This reflects efficiency gains with scale. In comparison to the WRAP reference points, 5 Broadgate tracks a lower eco 2 /m 2 ratio than the overall trend (46,324 tco 2 e / 92,903 m 2 GFA) Considerations in interpreting comparison results Scope: While shows a significantly decreased eco 2 /m 2 ratio than the overall trend, this is largely attributed to differences in scope used for the reporting projects. The eco 2 is based on eco 2 emissions for concrete, steel and façade, as selected priority materials as a pilot exercise. These materials represent the most significant sources of eco 2 emissions for, but do not represent a comprehensive holistic footprint of the project. While broadly comparable to the A1 A5 life cycle stages reported in the WRAP database, the scope of the assessment does not address the entirety of the WRAP scope and so is likely under reported. Emissions factors: emission factors represent the volume of CO 2 e emitted per unit of material or activity measured. Emission factors are regularly updated by the issuing body to reflect changes such as a decrease in the eco 2 intensity of the electricity grid, changes in manufacturing processes or changes in transportation or construction processes. The WRAP database includes footprints calculated over a nineteen year period, with a range of emission factors used. Seemingly small changes in emission factors can result in large differences in calculated CO 2 e emissions. Figure 12 Embodied carbon dioxide emissions per square metre of 5 Broadgate compared to similar projects reported in the WRAP database (A1 A5 lifecycle emissions).* *See considerations in interpreting comparison results, left. 7 WRAP. Embodied Carbon Database. Accessed October < 8 EeBGuide Project. Accessed October < Page 9

13 Appendix A Construction Phase Embodied Carbon Tracking Template

14 A1 Construction Phase Embodied Carbon Tracking Template A1.1 Steel Page A1

15 A1.2 Concrete Page A2

16 A1.3 Facade Page A3

17 A1.4 Mitigation Page A4

18 Appendix B Calculation References / Assumptions

19 B1 Design Phase Assumptions / References 9 Model Systems Boundaries Whole life carbon performance model will measure from cradle to grave. CO2 emissions for the model will be calculated from commencement and including demolition of the existing building up until and not including hypothetical end of life of proposed building. i.e demolition at end of life not included. Whole life Carbon Performance Model Will include predicted CO2 emissions associated with the following: Demolition activities Production of raw materials Transport of materials to site Construction activities Operational energy consumption (heating, lighting cooling, small power, based on design emissions from BER, and predicted actual emissions including non-regulated uses) B2 Construction Phase Assumptions / References Site-to-Gate Boundaries Use product-specific information where possible Gate-to-Site Boundaries Assume delivery trip only (i.e., not to include return) Request Trade / Supplier to estimate % volume of delivery payload Use Google Maps directions function to determine transport distances (i.e., exclude multiple-stop trips) References Embodied carbon factors - Hammond, G., Jones, C. (2011). Inventory of Carbon & Energy (ICE). Version 2.0. Transport carbon factors Defra / DECC. (2012). Guidelines to Defra / DECC s GHG Conversion Factors for Company Reporting. Version References Embodied carbon factors - Hammond, G., Jones, C. (2006). Inventory of Carbon & Energy (ICE). Version 1.6a Beta Transport carbon factors Defra / DECC. (2009). Guidelines to Defra / DECC s GHG Conversion Factors for Company Reporting. Version 1.0. Life expectancy: BCIS. (2006). Life Expectancy of Building Components. 2nd ed. London: Connelly-Manton (Printing) Ltd. Study Methodogy PAS 2050:2008 Specification for the assessment of the life cycle greenhouse gas emissions of goods and services, British Standards Institution, London Applied Decarbonisation scenario - DECC Medoim applied 9 Provided by Buro Happold Page B1