Enhanced Fujita scale damage indicators and degrees of damage, chapter 20


Institutional Buildings (IB)

Typical Construction:

  • Examples are hospitals, courthouses, university buildings, state and federal buildings, jails
  • Range in height from 1 to 10 storeys; balconies, porches and porticos with heavy façade
  • Roofing materials include fully adhered and mechanically fastened single-ply membranes, polyurethane foam, and copper-clad domes
  • Structure is normally reinforced concrete, relatively small windows
  • Walls are masonry with cut stone or pre-cast panels - may be very ornate
Table 20. 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 115 95 140
2 Loss of roof covering (up to 20%) 140 115 175
3 Damage to penthouse roof and walls; loss of rooftop HVAC equipment 150 120 180
4 Broken glass in windows or doors 155 125 185
5 Uplift of lightweight roof deck and insulation; significant loss of roofing material (more than 20%) 185 155 220
6 Façade components torn from structure 190 155 225
7 Damage curtain walls or other wall cladding 210 175 245
8 Uplift of pre-cast concrete roof slabs 230 190 260
9 Uplift of metal deck with concrete fill slab 235 190 275
10 Collapse of some top story exterior walls 240 205 275
11 Complete destruction of all or a large portion of building 340 285 430

*All wind speeds in km/h

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