Enhanced Fujita Scale Damage Indicators and Degrees of Damage

Small Retail Buildings (SRB)

Typical Construction:

  • Best example is fast-food restaurant
  • Flat, hip, gable, mansard or mono-slope roof
  • Asphalt shingles, metal panels, slate, tile, single-ply or BUR roof covering
  • Plywood/OSB roof decking
  • Wood or metal roof structure consisting of trusses or rafters and joists
  • Wood or metal stud walls
  • Typically have large areas of window glass and double entry doors
  • Canopies, covered walkways or porches
  • Wood, brick veneer, metal or vinyl siding, concrete blocks, EIFS or stucco wall cladding

Notes:

  • With hip roof, use upper bound wind speed for degree of damage 4 and degree of damage 6
Table 8. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage10587130
2Loss of roof covering (less than 20%)126105158
3Broken glass in windows and doors138116166
4Uplift of roof decking; significant loss of roof covering (20% or more)158130192
5Canopies or covered walkways destroyed158134183
6Uplift or collapse of entire roof structure192163225
7Collapse of exterior walls; closely spaced interior walls remain standing222193256
8Total destruction of entire building269230311

*All wind speeds in km/h