Does Wood Burn ? The Fire Safety of Solutions in Wood<br />David Barber<br />Arup<br />Fire Group Leader - Australasia Reg...
David BarberDoes Wood Burn ? The Fire Safety of Solutions in Wood<br />
Does Wood Burn ?<br />I have the hardest job - convince the audience that it is ok to have elements within a building that...
Does Wood Burn ?<br />Wood burns – how it burns is important <br />
Concept 1:Can Fire Performance Be Predicted ?<br />
Concept 1:Can Fire Performance Be Predicted ?<br />Fire performance of wood has been studied for many years:<br />Research...
Concept 2:Not All Wood Is The Same<br />
Concept 2:Not All Wood Is The Same<br />
Concept 2:Not All Wood Is The Same<br />
Concept 2:Not All Wood Is The Same<br />
Concept 2:Not All Wood Is The Same<br />I<br />Scale Matters !<br />
Concept 3:How Does Wood Burn ?<br />
Concept 3:How Does Wood Burn ?<br />Char:<br />Natural protection for wood<br />Allows for continued, but diminishing stre...
Concept 3:How Does Wood Burn ?<br />The importance of char:<br />
Concept 4:Expected Fire Performance<br />
Concept 4:Expected Fire Performance<br />National Construction Code:<br />Performance Requirement CP 1 - <br />“A building...
Concept 4:Expected Fire Performance<br />Concrete:<br />- Inherent protection<br />In a fire:<br /><ul><li> Spalling (>600C)
 Exposed steel
 Bending
 Failure is very rare</li></li></ul><li>Concept 4:Expected Fire Performance<br />Protected Steel:<br /><ul><li> Reliant on...
 Protection limits heat
 Unlikely to collapse
Need replacement</li></li></ul><li>Concept 4:Expected Fire Performance<br />Structural Wood:<br /><ul><li> Inherent protec...
 Unlikely to collapse
 Need replacement</li></li></ul><li>Concept 4:Expected Fire Performance<br />Summary:<br />Concrete – fire resistive, elem...
Concepts:Summary<br />Concepts for fire performance of wood:<br />Fire performance is well understood<br />Not all wood is...
What Does the NCC Allow for Solutions in Wood ? <br />
What Does the NCC Allow for Solutions in Wood ? <br />Summary of limitations:<br />Type A construction (non-combustible) i...
Class 2 or 3 (residential) – Rise in storeys of 3 or more</li></ul>Type A - all elements must be non-combustible (except a...
What Does the NCC Allow for Solutions in Wood ? <br />So, how is wood used in buildings ?<br />NCC allows fire engineering...
Solutions in Wood - Facades<br />
Solutions in Wood – Facades<br />
Solutions in Wood – Internal Elements<br />
Case Study – 5 Storey Building<br />
Case Study – 5 Storey Building<br />Could be concrete, steel or solid wood structure<br />NCC - 120 mins FRL to structure,...
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Fire Safety Engineering by David Barber

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Fire Safety Engineering

David Barber, Principal, Australasia Fire Leader, ARUP

Internationally and locally, timber and wood products are increasingly specified for major construction projects as a fire safe building material. Integrating design principles and fire engineering can ensure the required performance and compliance with relevant building codes.

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Fire Safety Engineering by David Barber

  1. 1.
  2. 2. Does Wood Burn ? The Fire Safety of Solutions in Wood<br />David Barber<br />Arup<br />Fire Group Leader - Australasia Region<br />
  3. 3. David BarberDoes Wood Burn ? The Fire Safety of Solutions in Wood<br />
  4. 4. Does Wood Burn ?<br />I have the hardest job - convince the audience that it is ok to have elements within a building that burn, even the structure<br />
  5. 5. Does Wood Burn ?<br />Wood burns – how it burns is important <br />
  6. 6. Concept 1:Can Fire Performance Be Predicted ?<br />
  7. 7. Concept 1:Can Fire Performance Be Predicted ?<br />Fire performance of wood has been studied for many years:<br />Research dates back to 13th century<br />Solid wood has highly predictable performance in fire<br />Little variability between countries in species type<br />Knowledge = data = confidence<br />
  8. 8. Concept 2:Not All Wood Is The Same<br />
  9. 9. Concept 2:Not All Wood Is The Same<br />
  10. 10. Concept 2:Not All Wood Is The Same<br />
  11. 11. Concept 2:Not All Wood Is The Same<br />
  12. 12. Concept 2:Not All Wood Is The Same<br />I<br />Scale Matters !<br />
  13. 13. Concept 3:How Does Wood Burn ?<br />
  14. 14. Concept 3:How Does Wood Burn ?<br />Char:<br />Natural protection for wood<br />Allows for continued, but diminishing strength during a fire<br />Well studied and well understood and is predictable<br />Different wood – different char (due to density and water content)<br />
  15. 15. Concept 3:How Does Wood Burn ?<br />The importance of char:<br />
  16. 16. Concept 4:Expected Fire Performance<br />
  17. 17. Concept 4:Expected Fire Performance<br />National Construction Code:<br />Performance Requirement CP 1 - <br />“A building must have elements which will, to the degree necessary, maintain structural stability during a fire appropriate to.......”<br />Structural wood needs to provide an equivalent level of performance as concrete or steel<br />
  18. 18. Concept 4:Expected Fire Performance<br />Concrete:<br />- Inherent protection<br />In a fire:<br /><ul><li> Spalling (>600C)
  19. 19. Exposed steel
  20. 20. Bending
  21. 21. Failure is very rare</li></li></ul><li>Concept 4:Expected Fire Performance<br />Protected Steel:<br /><ul><li> Reliant on inherent </li></ul> strength and applied <br /> protection<br />In a fire:<br /><ul><li> Will deflect (>550C)
  22. 22. Protection limits heat
  23. 23. Unlikely to collapse
  24. 24. Need replacement</li></li></ul><li>Concept 4:Expected Fire Performance<br />Structural Wood:<br /><ul><li> Inherent protection</li></ul>from char<br />In a fire:<br /><ul><li> Will deflect
  25. 25. Unlikely to collapse
  26. 26. Need replacement</li></li></ul><li>Concept 4:Expected Fire Performance<br />Summary:<br />Concrete – fire resistive, elements may need replacement after a major fire<br />Steel – fire resistant with additional protection, will need replacement after a major fire<br />Structural wood - fire resistant, will need replacement after a major fire<br />
  27. 27. Concepts:Summary<br />Concepts for fire performance of wood:<br />Fire performance is well understood<br />Not all wood is the same - scale matters<br />Solid wood chars – which has predictable performance in fire<br />In a fully developed fire, wood can perform equivalent or better than steel<br />
  28. 28. What Does the NCC Allow for Solutions in Wood ? <br />
  29. 29. What Does the NCC Allow for Solutions in Wood ? <br />Summary of limitations:<br />Type A construction (non-combustible) is required for:<br /><ul><li>Class 5 (office) – Rise in storeys of 4 or more
  30. 30. Class 2 or 3 (residential) – Rise in storeys of 3 or more</li></ul>Type A - all elements must be non-combustible (except a mezzanine), hence no wood permitted....... <br />
  31. 31. What Does the NCC Allow for Solutions in Wood ? <br />So, how is wood used in buildings ?<br />NCC allows fire engineering solutions for areas of non-compliance (so called “performance based” approach)<br />Fire engineering solutions will need a good fire engineer, who understands structural wood solutions, understands the process of approval and design implementation<br />
  32. 32. Solutions in Wood - Facades<br />
  33. 33. Solutions in Wood – Facades<br />
  34. 34. Solutions in Wood – Internal Elements<br />
  35. 35. Case Study – 5 Storey Building<br />
  36. 36. Case Study – 5 Storey Building<br />Could be concrete, steel or solid wood structure<br />NCC - 120 mins FRL to structure, separations<br />Many different fire protection options <br /><ul><li>Fire rated compartmentation
  37. 37. Smoke detection
  38. 38. Sprinkler protection
  39. 39. Additional stairs</li></li></ul><li>Case Study – 5 Storey Building<br />Wood structure and steel are very similar from a fire safety view point<br />Using sprinklers with a trade off in fire ratings, reducing to 60 minutes FRL<br />Structural wood was determined as the better option<br />Wood elements can be pre-assembled off site for quicker construction<br />
  40. 40. Case Study – 5 Storey Building<br />Solid wood structure of columns and beams, inherent FRL with load bearing capacity in excess of 60 mins FRL<br />Wood assumed to not have any plasterboard protection (not required to be maintained)<br />Steel would require protective coating (sprayed or paint) to achieve 60 mins FRL (requiring maintenance)<br />
  41. 41. Case Study – 5 Storey Building<br />Designing details<br />Assist with detailing for:<br /><ul><li>Connections
  42. 42. Floor and structure connections
  43. 43. Edge details</li></ul>Penetrations for building services are complex to solve<br />Facade interface with wood edge beams are problematic<br />
  44. 44. Case Study – 5 Storey Building<br />Case study summary:<br />Performance requirements of the NCC can be met using structural wood<br />Designs can gain approval, provided the engineering is substantive<br />Similar approach to any other fire engineered solution<br />
  45. 45. Summary<br />Wood does burn – but we understand how<br />Structural wood is equivalent or better than structural steel in many built situations<br />A lack of understanding of the fire performance of wood by many<br />Wood can be used, but you need a fire engineering solution <br />
  46. 46. Does Wood Burn ? The Fire Safety of Solutions in Wood<br />Questions?<br />David Barber<br />Arup<br />Fire Group Leader – <br />Australasia Region<br />

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