Enhanced Fujita scale damage indicators and degrees of damage, chapter 19

High-Rise Buildings: Greater than 20 Storeys (HRB)

Typical Construction:

Generally consist of rectangular shapes but can have curved or triangle footprints
Roofs are generally flat but may have a more complex roof shape as part of aesthetic statement; roofing material single-ply membrane fully adhered, polyurethane foam roof, metal or copper clad roof covering
Structural frame is steel or reinforced concrete; penthouse is steel framing with metal panels
Exterior cladding is glass or metal curtain walls or pre-cast concrete window panels
First floor often has very large glass areas that are susceptible to debris impact
Atriums with overhead glazing or tall window walls
Examples are hotels, office buildings, and condominiums

Table 19. 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	110	170
3	Damage to penthouse roof and walls; loss of rooftop HVAC equipment	150	120	180
4	Broken glass in exterior walls at 1st and 2nd floors; broken glass in entryways	165	135	195
5	Damage to parapet walls or coping	165	140	195
6	Broken curtain wall panel anchors	210	175	255
7	Significant loss of roofing material (more than 20%)	230	185	265
8	Significant damage to curtain walls and interior walls	235	200	275
9	Uplift or collapse of roof structure	255	200	295
10	Permanent structural deformation	365	305	465

*All wind speeds in km/h