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<ul><li>Thermal performance </li></ul><ul><li>and building codes </li></ul>
Thermal performance <ul><li>λ  wall mix is 0.0697W/m.k  </li></ul><ul><li>R-value of 12” wall is 24 </li></ul><ul><li>R-va...
Hygro-thermal properties <ul><li>Hemcrete ®  does not behave like a lightweight insulation material </li></ul><ul><li>The ...
Thermal mass <ul><li>Hemcrete ®  has the lowest diffusivity of any material </li></ul><ul><li>It is slow to change tempera...
Diffusivity ( λ / ρ c ) <ul><li>Expanded polystyrene ≈  18.4 x 10 -7  m 2 /s </li></ul><ul><li>Mineral fibre ≈  14.4 x 10 ...
Dynamic thermal performance
->  187 Q 24h  [kJ/m 2 ] ->  146 ->  410 ->  229 ( Cement concrete   ->  3163  )
Effective U-value of 250mm Hemcrete ®   <ul><li>187,000 J/m 2  lost in 24 hours </li></ul><ul><li>1W = 1J/s </li></ul><ul>...
Amplitude suppression and phase displacement
Dampening factor Time shift at 25 cm at 25 cm  25cm = 1-(  25cm /   init )  25cm = t max,25cm - t max,init   [-] [h] M...
Air-tightness <ul><li>The monlithic nature of Hemcrete ®  makes it inherently air tight </li></ul><ul><li>There are no com...
Comfort and Health <ul><li>High vapour permeability and absorption coefficicient allow Hemcrete ®  to buffer high humidity...
Thermal bridging <ul><li>The timbers within a Hemcrete ®  wall do not behave as thermal bridges. </li></ul><ul><li>This gi...
Thermal bridging <ul><li>U-value of a 500mm Hemcrete ®  wall (ignoring the timber frame) is 0.134 W/m 2 .K </li></ul><ul><...
The Lime Technology Office
Before
 
 
Sprayed  Hemcrete ®
Spray Limetec ®  render
The finished office
 
External recorded temperature – April to September 2007
Addition of 24hourly average external temperature trend line
Existing offices (monitored June onward) showing high internal temperature swing
By comparison, the Hemcrete offices show a low internal temperature swing, which is characteristic of heavyweight structur...
 
 
 
The finished office
 
 
Tradical ®  Hemcrete ® <ul><li>Good thermal conductivity – 0.07 W/m.K </li></ul><ul><li>No thermal bridging </li></ul><ul>...
Structure <ul><li>Tradical ®  Hemcrete ®  is not a structural material.  The structural requirements are performed by the ...
Tradical ® Hemcrete ®   is non structural
ModCell Hemp <ul><ul><ul><ul><ul><li>Modular panel </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Typically 3m x 2m...
Fire Safety <ul><li>Tests have been carried out at the CSTB in France </li></ul><ul><li>250mm thick wall constructed of bl...
 
 
 
 
 
 
The best way to predict the future, is to create it !
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North carolina 2 jan 2009

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Transcript of "North carolina 2 jan 2009"

  1. 1. <ul><li>Thermal performance </li></ul><ul><li>and building codes </li></ul>
  2. 2. Thermal performance <ul><li>λ wall mix is 0.0697W/m.k </li></ul><ul><li>R-value of 12” wall is 24 </li></ul><ul><li>R-value of 20” wall is 40 </li></ul><ul><li>Depending on finishes/framing </li></ul>
  3. 3. Hygro-thermal properties <ul><li>Hemcrete ® does not behave like a lightweight insulation material </li></ul><ul><li>The latent heat of water phase changes within the material contribute to its performance </li></ul>
  4. 4. Thermal mass <ul><li>Hemcrete ® has the lowest diffusivity of any material </li></ul><ul><li>It is slow to change temperature </li></ul><ul><li>This gives it a thermal inertia like a high thermal mass material </li></ul>
  5. 5. Diffusivity ( λ / ρ c ) <ul><li>Expanded polystyrene ≈ 18.4 x 10 -7 m 2 /s </li></ul><ul><li>Mineral fibre ≈ 14.4 x 10 -7 m 2 /s </li></ul><ul><li>Polyisocyanurate ≈ 5.7 x 10 -7 m 2 /s </li></ul><ul><li>Polyurethane ≈ 5.6 x 10 -7 m 2 /s </li></ul><ul><li>Brick ≈ 4.1 x 10 -7 m 2 /s </li></ul><ul><li>AAC ≈ 3.0 x 10 -7 m 2 /s </li></ul><ul><li>Insulating aerated blocks ≈ 2.3 x 10 -7 m 2 /s </li></ul><ul><li>Timber ≈ 1.6 x 10 -7 m 2 /s </li></ul><ul><li>Hemcrete ® ≈ 1.4 x 10 -7 m 2 /s </li></ul><ul><li>Water (10 o C) ≈ 1.4 x 10 -7 m 2 /s </li></ul>
  6. 6. Dynamic thermal performance
  7. 7. -> 187 Q 24h [kJ/m 2 ] -> 146 -> 410 -> 229 ( Cement concrete -> 3163 )
  8. 8. Effective U-value of 250mm Hemcrete ® <ul><li>187,000 J/m 2 lost in 24 hours </li></ul><ul><li>1W = 1J/s </li></ul><ul><li>There are 86,400 seconds in 24 hours </li></ul><ul><li>The temperature difference was 20 o C </li></ul><ul><li>Real heat loss was 0.11W/m 2 k </li></ul><ul><li>Theoretical U-value is 0.29W/m 2 k </li></ul>
  9. 9. Amplitude suppression and phase displacement
  10. 10. Dampening factor Time shift at 25 cm at 25 cm  25cm = 1-(  25cm /  init )  25cm = t max,25cm - t max,init [-] [h] Material ______________________________________________ LHC – “Wall” mixture 98,5 15 Wood 98,8 16 Cellular concrete 95 10,5 Mineral wool 77,5 6 CEM concrete 89,5 7
  11. 11. Air-tightness <ul><li>The monlithic nature of Hemcrete ® makes it inherently air tight </li></ul><ul><li>There are no complicated details/junctions </li></ul><ul><li>Figures below 2m 3 /m 2 /hr at 50 pascals are achievable </li></ul>
  12. 12. Comfort and Health <ul><li>High vapour permeability and absorption coefficicient allow Hemcrete ® to buffer high humidity, combat condensation and improve air quality </li></ul><ul><li>Low effusivity makes Hemcrete ® walls feel wall and make the internal environment feel comfortable </li></ul>
  13. 13. Thermal bridging <ul><li>The timbers within a Hemcrete ® wall do not behave as thermal bridges. </li></ul><ul><li>This gives Hemcrete ® a significant advantage over most other construction materials </li></ul>
  14. 14. Thermal bridging <ul><li>U-value of a 500mm Hemcrete ® wall (ignoring the timber frame) is 0.134 W/m 2 .K </li></ul><ul><li>Including 15% timber framing reduces the </li></ul><ul><li>U-value to 0.137 W/m 2 .K </li></ul><ul><li>Difference is 0.003 W/m 2 .K </li></ul><ul><li>Rounding error is bigger than this difference </li></ul>
  15. 15. The Lime Technology Office
  16. 16. Before
  17. 19. Sprayed Hemcrete ®
  18. 20. Spray Limetec ® render
  19. 21. The finished office
  20. 23. External recorded temperature – April to September 2007
  21. 24. Addition of 24hourly average external temperature trend line
  22. 25. Existing offices (monitored June onward) showing high internal temperature swing
  23. 26. By comparison, the Hemcrete offices show a low internal temperature swing, which is characteristic of heavyweight structures.
  24. 30. The finished office
  25. 33. Tradical ® Hemcrete ® <ul><li>Good thermal conductivity – 0.07 W/m.K </li></ul><ul><li>No thermal bridging </li></ul><ul><li>Low diffusivity </li></ul><ul><li>Low effusivity </li></ul>
  26. 34. Structure <ul><li>Tradical ® Hemcrete ® is not a structural material. The structural requirements are performed by the frame. </li></ul><ul><li>The Hemcrete ® stiffens the frame </li></ul>
  27. 35. Tradical ® Hemcrete ® is non structural
  28. 36. ModCell Hemp <ul><ul><ul><ul><ul><li>Modular panel </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Typically 3m x 2m </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Fast-track construction </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Off-site construction </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Can be structural </li></ul></ul></ul></ul></ul>
  29. 37. Fire Safety <ul><li>Tests have been carried out at the CSTB in France </li></ul><ul><li>250mm thick wall constructed of blocks made from Tradical ® Hemcrete ® </li></ul><ul><li>The mortar joints failed after 1hr 40 mins </li></ul><ul><li>UK tests on a solid panel have run for 3hrs 45 mins </li></ul><ul><li>Full testing to run in February 2009 </li></ul>
  30. 44. The best way to predict the future, is to create it !
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