Enhanced Fujita scale damage indicators and degrees of damage, chapter 1

Small Barns or Farm Outbuildings (SBO)

Typical Construction:

  • Less than 250 square metres (m2)
  • Wood or metal post and beam construction
  • Wood or metal roof trusses
  • Wood or metal panel siding
  • Metal or wood roof
  • Large doors
Table 1. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DOD Damage Description EXP* LB* UB*
1 Threshold of visible damage 100 85 125
2 Loss of wood or metal roof panels (up to 20%) 120 100 145
3 Collapse of doors 135 110 165
4 Major loss of roof panels (more than 20%) 145 125 175
5 Uplift or collapse of roof structure (more than 50%) 150 125 185
6 Collapse of walls 155 130 190
7 Overturning or sliding of entire structure 160 135 190
8 Total destruction of building 180 150 210

*All wind speeds in km/h

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