Sustainable Building 2010, Prague Sustainability of Polyurethane Thermal Insulation – Performance Assessment at building and component level in “low energy” buildings Shpresa Kotaji 30/06/ /199

2 Sustainable development EU’s target By 2020: –20 % decrease in energy consumption –20 % reduction in greenhouse gas emissions –20 % share of renewable Key drivers: –Environment: climate change mitigation –Economic: energy supply security –Social: job creation

3 Buildings Europe’s highest contribution potential  Between 280,000 and 450,000 new jobs by 2020 Source: COM(2006)545 final, 2006 Energy consumption (Mtoe) 2005 Energy saving potential (%) 2020

4 Sustainable Construction The crucial role of insulation Economic: –highest negative abatement costs (savings of € 29 billion by 2015) –increases energy supply security and keeps value chain in EU –short pay back periods and lower energy bills Environmental: –highest CO 2 savings potential Social: –Reduces fuel poverty and creates jobs within the EU –Comfort, well-being Source: CEPS, Tackling Climate Change Insulation

5 Insulation for environmental sustainability Key selection criteria #1Design building with low thermal conductivity to optimise energy and CO 2 savings #2Maintain thermal performance over building lifetime – reduce failure risks by using fit for purpose insulation and adequate detailing #3Assess life cycle environmental performance at building or building component level Insulation critical design issues

6 PU-Europe study: LCA and LCC of low energy buildings Third party: BRE (UK Building Research Establishment) –Choose model house, insulation solution and construction materials from BRE LCA and LCC databases –“simulate” designer approach 3 case studies –Case 1: whole new building at fixed u-values for pitched roof, cavity wall and ground floor –Case 2: refurbishment of wall with internal lining at fixed thickness –Case 3: warm deck flat roof at fixed u-value 3 climate zones –Temperate Mediterranean –Temperate Oceanic –Cool Continental Heating energy source: natural gas

7 Building insulation - The basics U = λ d Heat loss rate (W/m 2. K) Thermal conductivity (W/m.K) Thickness (m)  Two possible functional references can be used to compare insulation solutions: –Same U-value –Same insulation thickness (design constraints) Standard houseLow energy house R = 1 U Thermal resistance (m 2. K/W)

8 Case study 1: Whole building 3-bedroom, 2-storey detached house U-values: roof=0.13, wall=0.15, ground floor=0.18 Fixed internal floor area of 52 m 2 and fixed attic volume Polyurethane (PU) Stone wool (SW) Glass wool (GW)

9 Case study 1: Whole building LCA Results - Normalised data Construction materials and insulation  Similar environmental performance for all insulation solutions Environmental Indicators GWP global warming potential (kg CO2 eq) ODP ozone depletion potential (kg CFC11 eq) EP eutrophication potential (kg PO4) AP acidification potential (kg SO2 eq) POCP photochemical ozone creation potential (kg ethene eq)

10 Case study 1: Whole building LCA Results - Normalised data Energy use, Construction materials and insulation Normalized to EU citizen Energy use Cool continental Energy use Temperate Oceanic Energy use Temperate Mediterranean Construction materials Insulation materials GWP ODP EP POCP AP  Insulation has limited impact on total building environmental performance  Construction materials dominate AP, POCP and EP impacts

11 Case study 1: Whole building LCC Results Cavity wall SW and GW solutions 4% more costly: more external brick wall, longer wall ties and larger foundation Pitched roof SW and GW solutions 20% more costly: deeper rafters and larger roof covering surface area Note: the study excluded the cost of additional land unable to be utilised because of larger building footprints  PU solution more cost effective Cumulative discount rate Temperate oceanic climate

12 Case study 1: Whole house Conclusions LCA –All insulation solutions give similar environmental performance –Insulation material has limited contribution to overall building environmental performance –Energy use GWP dominates over material GWP contribution –Construction material related AP, EP and POCP dominate over energy AP, EP and POCP contribution LCC –PU solution lowest life cycle cost

13 Case study 2: Insulation of wall with internal lining U-value Polyurethane (PU)0.36Stone wool (SW)0.54 Expanded Polystyrene (EPS)0.47Glass wool (GW)0.54 Insulation thickness:5 cm, wall surface: 134 m

14 Case study 2: Internal lining LCA Results - Normalised data Energy use, lining installation materials and insulation (temperate continental climate)  Similar environmental performance for all insulation solutions Environmental Indicators GWP global warming potential (kg CO2 eq) ODP ozone depletion potential (kg CFC11 eq) EP eutrophication potential (kg PO4) AP acidification potential (kg SO2 eq) POCP photochemical ozone creation potential (kg ethene eq)

15 GW solution Energy use Installation material Insulation PU solution Energy use Installation material Insulation SW solution Energy use Installation material Insulation EPS solution Energy use Installation material Insulation Case study 2: Internal lining LCA Results expressed as normalised data Analysis of energy and material contribution Example temperate oceanic climate GWP ODP EP POCP AP

16 Case study 2: Internal lining LCA Results expressed as characterized data Analysis of energy and material contribution Characterized data (relative to maximum value in each impact category) Example temperate oceanic climate GW solution Energy use Installation material Insulation PU solution Energy use Installation material Insulation SW solution Energy use Installation material Insulation EPS solution Energy use Installation material Insulation  The greater energy saving achieved with PU offsets the higher environmental impacts of the PU material itself GWP ODP EP POCP AP POCP

17 Case study 2: Internal lining LCC Results Temperate oceanic Cool continental  PU solution most cost effective Cumulative discount rate

18 Case study 2: Internal lining Conclusions LCA –All insulation solutions give similar environmental performance –The greater energy saving achieved with PU offsets the higher impacts of the PU material itself for all impact indicators LCC –PU solution has the lowest life cycle cost

19 Case study 3: Warm deck flat roof Polyurethane (PU) Stone wool (SW) Expanded Polystyrene (EPS) U-value = 0.15 W/m 2 K

20 Case study 3 – Flat roof LCA Results - Normalised data Roof material and insulation InsulationPUEPSSW Density kg/m Lambda Thickness mm Roof surface m 2 64 Weight kg  PU solution has low GWP, POCP and AP

21 Case study 3 – Flat roof LCC results  PU solution more cost effective Cumulative discount rate, 50 years)

22 Case study 3: Flat roof Conclusions LCA –Where specific mechanical properties need to be achieved, the use of polyurethane, with its low density and low thickness brings environmental performance improvement LCC –PU solution has the lowest life cycle cost

23 Overall conclusions Insulation is a key contributor to sustainable construction Insulation material selection cannot be disconnected from the specific building context The choice of the insulation materials has limited impact on the overall building environmental footprint There is not sufficient publicly available LCA data on “natural” plant or animal derived insulation materials to perform meaningful LCA comparisons Insulation density and thermal conductivity are critical properties to consider in LCA and LCC assessment since they define the material intensity and knock-on effects on the building structure and footprint, hence the overall building performance Where specific mechanical properties need to be achieved, such as in a flat roof, the use of polyurethane can bring both environmental performance improvement and cost benefits From a life cycle cost perspective, PU is a logical choice to consider in low energy buildings

24 Recommendations for choosing insulation for sustainability 1#Perform insulation choice based on the insulation ability to optimize efficiently the building thermal performance, especially where there are thickness constraints 2#Make sure the choice will provide adequate performance longevity by taking into account potential failure risks – for any type of insulant specify grades which are fit for the application, are moisture resistant, are dimensionally stable, will not slump or sag and will not be affected by adverse and extreme weather conditions 3#Assess cost performance over the life time for the whole component or building in order to take into account any hidden and additional costs related to the insulation specific installation requirements 4#Assess environmental performance at the building life cycle level

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