General Properties of Polyurethane Insulation. Chris Ungermand Huntsman Nordic IDA Fyn seminar Odense

Transcription

1 General Properties of Polyurethane Insulation Chris Ungermand Huntsman Nordic IDA Fyn seminar Odense

2 Drivers for insulation growth Mega trends Population (billion) Year billion Growing global need for food, shelter & energy Depletion of egergy recources Climate change

3 Construction sector dimensions Consumes 50% of extracted raw materials Accounts for the 40 % of greenhouse gas emissions Produces 20 to 30% of total waste Environment Economic Social Accounts for ca. 9% of total GDP Employs 8 % of the working population 2 trillion annual turnover People spend 90% of the time indoor, comfort, well being, social integration

4 Energy efficiency driven by EU legislation: From standard house to low enegy house

5 Introduction to Polyurethane Insulation Chemistry PIR (PolyIsocyanuRate). A cyclic reaction product 3 isocyanate groups.

6 PUR versus PIR : A Comparison SIMILARITIES: Low thermal conductivity Low density Closed cell cellullar foam Auto-adhesive to steel Raw material streams = polyol blend, blowing agent, isocyanate DIFFERENCES: PIR recipy has higher isocyanate content Laminator needs high conveyor temperature to process PIR PIR processing window generally more narrow than PUR PIR has excellent fire properties. PIR foam flow is limited : filling of complex cavities is difficult

7 Low Density, Low Lambda & Broad Service Range Low density means lighter building elements and thus easy handling Low lambda means thinner insulation thickness for equivalent performance Broad service temperature range from -200 to +100C Comparative Insulation Values 50 mm PU-rigid foam 80 mm EPS 90 mm mineral wool 100 mm cork 130 mm wood fiber 200 mm softwood Total Weight of Insulation for a Flat Roof (Area = 100 m 2 at a thermal resistance of 3.33 m 2 K/W) Insulant Lambda Thickness (mm) Weight (kg) PUR/PIR EPS SW GW XPS Wood fibre mm light concrete 1720 mm bricks

8 About Thermal conductivity Why PU foam has so good insulation properties? Because heat transmission is very efficient between solids and very poor between gases. In the PU foam, the solid network cover only the 3 % of the total polymer volume! \ Hence PU insulation foam is basically solid gas

9 Thermal conductivity model. Cyclo-pentane foam gr/l)

10 K gas of individual gases Mw dependence K gas at 10C (mw/m.k) AIR (N2/O2) 24.8 mw/m.k CO mw/m.k NP = 13.7 IP = 12.8 CP = Molecular weight (-)

11 Effective Diffusion Coefficient Established values for PU boards Typical values (RT) Practical example Deff m 2 / s 1.0E E E E E E E E E-14 H2O CO2 O2 N2 C5 Foam cube 5cm*5cm*5cm N-pentane / CO2 blown Required time for full gas equilibrium H20 < 1 day CO2 ~ 1 month O2 ~ 15 months N2 ~ 40 months C5 > 200 years

12 Ageing calculation Initial cell gas: 100% CO2 1 D diffusion one month in a 5x5x5 cm foam brick. (aging in one direction only). Extent of gas pressure equilibrium between foam and atmosphere P/Po, The parameter P/Po represents aged pressure over initial pressure. P/P0 = Deff. t / L 2 = => P/P0 =1E-10 *3600x24x30/0,05*0,05 = 0,104 (=10% of the original CO2 gas is still in the foam cells). The above equation can also be used for 3 D ageing. Then 3 such equations must multiplied. P/P0 = (1E-10 *3600x24x30/0,05*0,05) 3 = 7x10-9 (all CO2 is gone after 30 days).

13 Lambda Improves with Thicker Boards Ageing of un-faced board at ambient years at ambient T Lambda Definitions Initial lambda PU foam cooled down after few days Lambda at 10C (mw/m.k) Ageing time at ambient T (years) 80 mm 120 mm 160 mm 200 mm Age lambda measured after certain period (usually higher) Declared lambda Average lambda after 25 years (simulated in ½ years time at 70 C approx. 10 years at 20 C) Conclusions Thicker panels have slower lambda increases, hence lower average / 25 yrs Thicker panels have lower lambda increases after 25 wks / 70 For thick panels lambda after 25 wks / 70 are lower than the average / 25 yrs at ambient temperature 20 cm panels need up to 18 months / 70 to get to the 25 yrs average Source: Andre V.

14 High Strength High strength means resistance to Settling, thinning and compaction Wind uplift Foot traffic (eg flat roofs walkability ) Flat roof Walkability Testing Maximum load level at 2% deformation after 5 cycles Insulant Thicknes s (mm) Load Level (kpa) EPS mm) MW PUR XPS Phenolic Foam Expanded Perlite Board Note: EN826 (load time = common roof density Strength (kpa) kg/m3 32kg/m3 32kg/m3 Cellular Glass SW/GW Compressive Strength Shear Strength Sources: FIW for walkabilty data

15 Walkability Testing Classification of Insulation Products (Marathon Man) Class Criteria (<15% loss CS) Walkabilty: Suitability for roof pedestrian traffic 0 5 No Not suitable 1 5 Yes Limited to occasional traffic during inspection & maintenance 2 10 Yes Good. Frequent traffic for inspection & maintenance OK 3 30 Yes Intensive. Daily pedestrian traffic OK Test results Insulation Membrane Classification MW EPDM 0 MW PVC 1 MW 2xdensity EPDM 1 MW 2xdensity EPS light facer & 2xdensity EPS light facer & 2x density EPS std facer & density EPS very heavy density 2 layer bitumen modified 2 EPDM 1 PVC 2 EPDM 2 EPDM 3 Polyurethane EPDM 3 Sources: BDA Institute (Marathon Man Test Method)

16 Low Moisture Absorption and Air Tight Air leakage: has more impact on energy performance then building element U values performance requirements evolving eg Germany Evolution of German air leakage legislation.. High Low Relative Moisture Absorption EPS (15-30kg/m 3) Mineral/Glass Fibre 32kg/m 3 32kg/m 3 PU Boardstock with Al foil facing Cellular 125kg/m 3 Just 1% of moisture in fibrous insulation reduces the U value by 86% Moderate air speeds 1m/s thru fibrous insulation can double heat loss!

17 Durability of Polyurethane Insulation Test of 28 year old PU Board sample from a pitched roof in Germany fully functional and meeting all declared performance values Property Initial Declared Properties Measured Value (after 28 years) Facing Aluminium multilayer facing on both sides (one side perforated) Thickness (mm) Moisture content Not declared 0.05% (vol) Compressive Strength (kpa) Thermal conductivity Reaction to Fire (DIN ) Class B2 (normally ignitable). No flaming droplets/particles. Source: FIW Germany

18 Good Fire Performance Can be formulated to meet a wide range of range of national & international standards Thermoset.. does not melt or drip like EPS and XPS Forms a protective char layer Fire performance is enhanced by facings such as metal Test Method PUR PIR ASTM D (%wt retained) BS (mm) < DIN 4102 part 1 B3 (a) B2 (b) BS 476 part 7: 1971 Class 4 Class 1 N FP M4 (c) M1 ASTM E-84 Class 2 Class 1 ASTM D (specific optical density) SBI Flexible faced Rigid faced Class E Class B, s2, d0 Class D- s2,d0 Class B- s1,d0 Numerical fire ratings or classifications are not intended to reflect hazards presented by these materials under actual fire conditions

19 Non toxic, Non Irritant & Biologically Neutral Safe and easy to handle: Non toxic: chemically inert Non irritant: non fibrous Extremely low VOC emissions: PU achives the best emission class under schemes such as AgBB. Biologically neutral Does not support bacteria or fungus Non nutritious to vermin PUR Insulation Board Evaluated to AgBB (28 days) Test Measurement TVOC (C 6 -C 16 ) 0 VOC excl. NIK (C 6 -C 16 ) 0 Results [µg/m 3 ] SVOC (C 16 -C 22 ) cancerogens 0 R 1 [-] 0

20 EPD (Environmental Product Declaration) A full range of EDPs for PUR/PIR thermal foam insulation materials as per ISO and EN can be found at PU Europe. EPF for Faced foam boards Naked foam boards Sandwich elements Spray foam

21 PUR/PIR insulation is cost effective. PU 60% more expensive than SW but the total building cost is lower Thin construction saves up to 10 m2 of gross floor space in a 150 m2 passive detached dwelling. Major cost savings in construction materials and labour. Helsinki University of Technology Sustainable Energy Research Programme has found that a passive detached dwelling insulated with costs about EUR 5,000 less to build than a corresponding wool-insulated building. More living space results from renovation construction, directly increasing the value of the building Insulation is effective both with and without vapour barriers Very little need for repair during the life cycle of the building The Building Research Establishment finds that polyurethane has the lowest whole life cycle costs when used for thermal insulation in low energy buildings Source:

22 Summary of Rigid Polyurethane Features and Benefits Low density Easy to handle Low lambda Thinner insulation = more living space High compressive and shear strength No compaction, thinning or settling Low moisture absorption and air tight Long term maintence of perfomance. No need to cover/protect against rain at building site Good fire performance Sustainability Non toxic and non irritant No itching and scratching Biologically neutral Unattractive to vermin etc Versatile manufacture Self adheres Properties adjustable Process by spray or pour in factory or on site Good buildability High structural rigidity Chemically resistant Broad service temperature Easily fixed or cut to shape Design freedom