Enhanced Fujita scale damage indicators and degrees of damage, chapter 12


Large Isolated Retail Buildings (LIRB)

Typical Construction:

  • Flat roof with BUR and gravel or single-ply membrane roof; generally has a 1-m parapet
  • Open web joists and steel girders or joist girders supported by tall pipe columns
  • Metal deck with rigid insulation or lightweight concrete fill slab
  • Large windows on front side of building
  • CMU walls, tilt-up concrete panels, metal stud walls covered with EIFS or combinations of these
Table 12. 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 110 90 135
2 Loss of roof covering (up to 20%) 130 110 165
3 Uplift of some roof decking; significant loss of roofing material (more than 20%); loss of rooftop HVAC 165 140 200
4 Long roof spans collapsed downward 195 165 230
5 Uplift and removal of roof structure 215 185 255
6 Inward or outward collapse of exterior walls 220 190 255
7 Complete destruction of all or a large section of the building 280 235 325

*All wind speeds in km/h

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