Minimising the embedded environmental footprint of construction using concrete

Transcription

1 Minimising the embedded environmental footprint of construction using concrete Rushlight event September 26 th 2012 Elaine Toogood BA(HONS) Grad Dip Arch RIBA Regional Architect

2 Responsible sourcing Low waste solution Low Carbon operation Reducing ECO 2 through specification Material efficient Recyclable Use of waste materials Flood prevention and resilience Support biodiversity Long life

3 Free guides for specifiers examining issues and providing guidance

4 Guidance for concrete specification including: Reduction of ECO 2 Use of recycled content Material efficiency Responsible sourcing

5 There are many forms and applications for the use of concrete Versatility leads to a multitude of manufacturing and specification options Range of corresponding embodied environmental factors Depends upon concrete mix, form, overall specification and location

6 Concrete components Man-made inorganic and inert conglomerate Mixture of cement, water, air, fine aggregates (eg. sand) and course aggregates (eg. gravel or crushed stone) May include steel reinforcement, pigments, additives Most of the mix is naturally occurring Approx average mix by volume

7 Reduced Carbon Cements Cement contributes majority of ECO 2 to concrete Carbon footprint of cement production has reduced by nearly 45% since 1990 UK Climate Change Agreement target for 2010 reached 4 years in advance Use of cementitious replacements can reduce ECO 2 further. Eg: GGBS, Fly Ash or lime

8 Westminster City College Schmidt Hammer Lassen / Burohappold Persistence Works, Sheffield Fielden Clegg Bradley Studios Angel building AHMM / AKT The Shard

9 Aggregates Major component of concrete by volume Inherently low carbon Mostly naturally occurring, local resource Potential self-sufficiency in UK aggregates for many thousands of years

10 Use of Recycled and secondary aggregates Recycled Aggregates are efficiently used as hardcore and in landscaping Consistency of supply and source material are necessary for use in concrete 28% of all aggregate in UK is recycled or secondary aggregate (3 x average in Europe) Local virgin aggregates will have lower ECO 2 than recycled aggregate transported more than 15KM by road

11 Concrete is a Local Material Self-sufficiency in UK of raw materials for concrete Average journeys of concrete to the construction site Ready Mix: km Precast: 119km (but with double tonnage) Local production is a key sustainability principal

12 Concrete Industry Commitment to sustainability Sustainable Construction Strategy for the UK Concrete Industries. July 2008 Pan industry pledge for comprehensive industry strategy Extensive data collection and annual reporting Published performance targets Continual improvement

13 Sustainability Performance Report 4th pan-industry sustainability report Measures data and sets targets over various sustainability criteria

14 Responsible Sourcing Concrete is the leading construction material for responsible sourcing 92% all concrete production is BES-6001 accredited

15 Net consumer of waste In 2011 the concrete industry used 63 x more waste than it produced Waste to landfill reduced by 72% since 2008 Concrete is 100% recyclable Specification and design solutions can further optimise material efficiency Waste and by-product material is used to make cement and concrete

16 Concrete industry 2020 Strategy Commitments Contribute to the delivery of a zero carbon built environment Life Cycle Assessment data provision Material and Resource Efficiency Programme development Low Carbon Freight initiative development Water strategy development Continuous improvement of sustainable production performance and annual reporting

17 New concrete industry targets By 2020: 90% reduction in waste to land from 2008 baseline 30% reduction in C0 2 emissions from concrete production from 1990 baseline 95% of production certified to responsible sourcing standard BES % relevant production sites with action plans for stewardship and biodiversity

18 Innovations Permeable concrete Alternative cements Pollution eating and self cleaning concrete Insulating concrete Dives in Misericorda Church, Rome. Architect: Richard Meier

19 Material comparisons Component/Material ECO2 KG/M³ Dense Concrete Aggregate Block (1) 147 Aerated Concrete Block (1) 121 Generic Lightweight Aggregate Block (2) 168 Gen 1: Concrete Foundations (3) 173 RC40: Structural Concrete (3) 372 RC50: High Strength Concrete (3) 436 Structural Steel (4) Timber, UK Forest Softwood (5) 141 Timber, UK Forest Hardwood (5) 353 Chipboard, UK Forestry (5) 512 (1) BRE Environmental Profiles Database (2) The Environment Division, BREEAM Centre, BRE (3) Concrete Centre Study (4) Steel Construction Institute (5) Thesis in School of Environment, University of Brighton

20 Embodied CO 2 Study

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22 Embodied CO 2 Study results

23 Material efficiency Concrete structure can can provide the final finish Avoiding additional finishing materials and embodied impacts at installation and during life of the building Often exceeds minimum fire resistance and sound insulation requirements without additional finishing Optimises thermal mass effect Lincoln Museum Panter Hudspith

24 Embodied CO 2 study - housing Report commissioned by NHBC to investigate % split between operational and embodied CO 2 in new build housing 24 scenarios appraised using SAP for operational CO 2 and BRE Global s Environmental profile methodolgy for ECO 2 Research was carried out by BRE, with assistance from several leading housing developers

25 Source: NHBC report 2011: Operational and Embodied CO2 in new build housing. A reappraisal

26 Source: NHBC report 2011: Operational and Embodied CO2 in new build housing. A reappraisal

27 Results * Extract from executive summary

28 Embodied CO 2 v Operational CO 2 research Science Direct case studyhousing. Extract in CQ Autumn 2006

29 DTI Research Carried out by Arup in 2005 Timber Frame Brick & Block Dense Concrete & Plaster Plasterboard Insulation Plywood Airspace Plasterboard Mediumweight block Insulation Airspace Dense plaster Dense concrete Insulation Brick slips Brick Brick U Value 0.25 W/m 2.K U Value 0.25 W/m 2.K U Value 0.25 W/m 2.K Thermal Mass: Storage of energy WITHIN the wall

30 CO 2 Emissions (tonnes) CO2 produced (tonnes) 220 Arup Research: 200 Summary results Heavy Medium-Heavy Medium Light Lightweight house Mediumweight house Additional embodied CO 2 offset in about 11 years Year Year

31 CO 2 Emissions (tonnes) CO2 produced (tonnes) 220 Arup Research: 200 Summary results Heavy Medium-Heavy Medium Light Lightweight house Heavyweight house Additional embodied CO 2 offset in about 21 to 25 years Year Year

32 Long life Embodied environmental impacts effectively reduced by extending life of building Concrete structures are durable and robust Design for long life, loose fit to enable re-use robust structural frame adaptable layouts tall floor to ceiling heights Park Hill refurbishment, Sheffield, Urban Splash

33 Long life