Enhanced Fujita Scale Damage Indicators and Degrees of Damage

List of 31 Damage Indicators (Canadian DIs prefaced with ‘C’)

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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)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage10585129
2Loss of wood or metal roof panels11998146
3Collapse of doors134109164
4Major loss of roof panels145126177
5Uplift or collapse of roof structure150124177
6Collapse of walls156130192
7Overturning or sliding of entire structure159134190
8Total destruction of building180151211

*All wind speeds in km/h

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One- or Two- Family Residences: 100-500m2 (FR12)

Typical Construction:

  • Asphalt shingles, tile, slate or metal roof covering
  • Flat, gable, hip, mansard or mono-sloped roof or combinations thereof
  • Plywood/Oriented Strand Board (OSB) or wood plank roof deck
  • Prefabricated wood trusses or wood joist and rafter construction
  • Brick veneer, wood panels, stucco, Exterior Insulation and Finish Systems (EIFS) vinyl or metal siding
  • Wood or metal stud walls, concrete

Notes:

  • With hip roof, use upper bound wind speed for degree of damage 4 and degree of damage 6
Table 2. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXPLBUB
1Threshold of visible damage10585129
2Loss of roof covering material (less than 20%), gutters and/or awning; loss of vinyl or metal siding127101156
3Broken glass in doors and windows154127183
4Uplift of roof deck and loss of significant roof covering material (20% or more); collapse of chimney; garage doors collapse inward; failure of porch or carport156130187
5Entire house shifts off foundation195166227
6Large sections of roof structure removed; most walls remain standing196167229
7Exterior walls collapsed212182246
8Most walls collapsed, except small interior rooms245204286
9All walls collapsed274229319
10Destruction of engineered and/or well-constructed residence; slab swept clean322266354

*All wind speeds in km/h

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Manufactured Homes: Singe Wide (MHSW)

Typical Construction:

  • Steel undercarriage supported on concrete block piers
  • Metal straps and ground anchors (frame and/or over-the-top strap anchors)
  • Asphalt shingles or one-piece metal roof covering
  • Wood roof joists; metal, vinyl or wood siding
  • Wood stud walls and partitions
Table 3. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXPLBUB
1Threshold of visible damage9882122
2Loss of shingles or partial uplift of one-piece metal roof covering11998148
3Unit slides off block piers but remains upright140116166
4Complete uplift of roof; most walls remain standing143117180
5Unit rolls on its side or upside down; remains essentially intact158135183
6Destruction of roof and walls leaving floor and undercarriage in place169140198
7Unit rolls or vaults; roof and walls separate from floor and undercarriage175154206
8Undercarriage separates from unit; rolls, tumbles and is badly bent190163219
9Complete destruction of unit; debris blown away204177238

*All wind speeds in km/h

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Manufactured Homes: Double Wide (MHDW)

Typical Construction:

  • Steel undercarriage supported on concrete block piers
  • Multi-unit connection at roof, floor and end walls
  • Frame straps and ground anchors spaced 3 - 4 metres apart
  • Flat, gable or hip roof shape; asphalt shingles or metal roof panels; plywood/OSB roof decking; wood rafter or shallow joist construction; metal, vinyl or wood siding
Table 4. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXPLBUB
1Threshold of visible damage9882122
2Loss of shingles or other roof covering (less than 20%)122100142
3Damaged porches or carports126108154
4Broken windows134109153
5Uplift of roof deck and loss of significant roof covering material (20% or more)142121174
6Complete uplift of roof; most walls remain standing150124177
7Unit slides off CMU block piers151126175
8Removal of entire roof structure leaving most walls standing156129188
9Complete destruction of roof and walls leaving undercarriage in place182150211
10Unit rolls, displaces or vaults183132209
11Undercarriage separates from floor, rolls and tumbles, badly bent204175238
12Complete destruction of unit; debris blows away216192248

*All wind speeds in km/h

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Apartments, Condominiums and Townhouses: 3 Storeys or less (ACT)

Typical Construction:

  • Flat, gable, hip or mansard roof
  • Asphalt shingles, tile, metal or BUR roof covering
  • Plywood/OSB (Oriented Strand Board) roof decking
  • Light-framed wood or metal roof trusses
  • Wood, metal or vinyl panels, stucco brick veneer or EIFS wall covering; combinations of wall coverings
  • Wood or metal stud walls; wood floor diaphragms
  • Sliding patio doors; balconies

Notes:

  • With hip roof, use upper bound wind speed for degree of damage 3 and degree of damage 4
Table 5. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXPLBUB
1Threshold of visible damage122101153
2Loss of roof covering (less than 20%)159132195
3Uplift of roof decking; significant loss of roof covering (20% or more)200172235
4Uplift or collapse of roof structure leaving most walls standing222193254
5Most top story walls collapsed254222296
6Almost total destruction of top two stories290249330

*All wind speeds in km/h

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Motels (M)

Typical Construction:

  • Less than or equal to four storeys
  • Facility made up of one or more multi-storey, rectangular buildings
  • Flat, gable, hip or mansard roof
  • Asphalt shingles, tile, slate or built up roof (BUR) roof covering
  • Plywood/OSB roof decking, wood or metal prefabricated roof trusses
  • Wood floor diaphragms, wood or metal stud walls
  • Stucco, EIFS, wood, metal or brick veneer wall cladding
  • Canopy over driveway at entrance; exterior walkways or balconies

Notes:

  • With hip roof, use upper bound wind speed for degree of damage 4 and degree of damage 6
Table 6. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXPLBUB
1Threshold of visible damage10687134
2Loss of roof covering (less than 20%)129108159
3Broken windows or patio doors143119172
4Uplift of roof decking; significant loss of roof covering (20% or more); loss of EIFS wall cladding153129187
5Uplift or collapse of canopy over driveway159130190
6Uplift or collapse of roof structure leaving most walls standing198166230
7Collapse of top story exterior walls222195251
8Collapse of most top story walls230204261
9Collapse of top two floors of three or more stories274232298
10Total destruction of entire building306262349

*All wind speeds in km/h

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Masonry Apartments or Motels (MAM)

Typical Construction:

  • Less than or equal to four storeys
  • Facility made up or one or more multi-storey, rectangular buildings
  • Flat, gable, hip or mansard roof
  • Asphalt shingles, tile, slate or BUR roof
  • Light steel roof framing with metal deck and lightweight insulation
  • Pre-cast or hollow-core concrete roof and floor system
  • Concrete Masonry Units (CMU) non-bearing walls
  • CMU load-bearing walls
  • Stucco, EIFS, or brick veneer wall cladding
  • Exterior walkways or balconies
Table 7. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXPLBUB
1Threshold of visible damage10587130
2Loss of roof covering (less than 20%)129108163
3Uplift of lightweight metal roof decking153130187
4Uplift of concrete roof decking195166230
5Collapse of top storey walls214185241
6Collapse of top two floors of three or more storeys251212290
7Total destruction of a large section of building290257330

*All wind speeds in km/h

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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

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Small Professional Buildings: Single Storey, less than 500 m2 (SPB)

Typical Construction:

  • Flat, gable, hip, mansard or mono-slope roofs with or without parapet walls
  • Asphalt shingles, tile, slate, metal panels, single-ply or built-up roof covering
  • Light-frame steel construction, steel joists and formed metal decking
  • Load-bearing masonry construction with steel or wood roof structure
  • Timber post and beam construction
  • Wood or metal stud walls, non-bearing masonry walls
  • Metal or vinyl panels, stucco or EIFS cladding
  • Skylights and/or clearstories

Notes:

  • With hip roof, use upper bound wind speed for degree of damage 5 and degree of damage 7
Table 9. 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 windows, including clear story windows or skylights143119172
4Exterior doors fail161132190
5Uplift of roof decking; significant loss of roof covering (20% or more); loss of rooftop HVAC equipment161135188
6Collapsed façade or parapet walls166137198
7Uplift or collapse of entire roof structure200169233
8Collapse of exterior walls; closely spaced interior walls remain standing232198266
9Total destruction of entire building253238322

*All wind speeds in km/h

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Strip Malls (SM)

Typical Construction:

  • Large, rectangular single-storey building with large surrounding parking lots
  • Flat roof with parapet wall
  • Built-up roofing or single-ply roof membrane with rigid insulation
  • Wood or metal deck, wood-fiber cement panels
  • Light-frame steel roof support with steel joists or joist girders
  • Brick or concrete block wall construction
  • Large window glass and glass entry doors
  • Covered walkway attached to building
Table 10. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage10587130
2Uplift of roof covering at eaves and roof corners129106161
3Broken windows or glass doors142116169
4Uplift of roof decking163135196
5Collapsed façade or parapet walls166137201
6Covered walkways uplifted or collapsed166138201
7Uplift or collapse of entire roof structure196166230
8Collapse of exterior walls; closely spaced interior walls remain standing225188266
9Complete destruction of all or a large section of building275237319

*All wind speeds in km/h

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Large Shopping Malls (LSM)

Typical Construction:

  • Typically one or two storeys
  • Flat roof; some areas with relatively large spans
  • Skylights and clear stories
  • Single-ply or BUR with or without roof gravel
  • Metal stud walls with brick veneer, stucco or EIFS cladding
  • Light steel structural framing with open web joists, light metal framing or 3-D space framing
  • Glass at entries
Table 11. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage.11495138
2Loss of roof covering (less than 20%)137111169
3Broken skylights, clearstory windows and atrium walls broken148121183
4Uplift of some roof decking; significant loss of roofing material (20% or more); loss of rooftop HVAC174148206
5Wall cladding stripped starting at corners and progressing to other areas179151211
6Roof structure uplifted or collapsed206174241
7Exterior walls in top storey collapsed232200267
8Interior walls of top storey collapse257224298
9Complete destruction of all or a large section of the building328283398

*All wind speeds in km/h.

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Large Isolated Retail Buildings (LIRB)

Typical Construction:

  • Flat roof with BUR and gravel or single-ply membrane roof; generally has a 1m 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)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage10992134
2Loss of roof covering (less than 20%)130109166
3Uplift of some roof decking; significant loss of roofing material (20% or more); loss of rooftop HVAC166140198
4Long roof spans collapsed downward196166232
5Uplift and removal of roof structure216183253
6Inward or outward collapse of exterior walls220190254
7Complete destruction of all or a large section of the building278237323

*All wind speeds in km/h

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Automobile Showrooms (ASR)

Typical Construction:

  • Most showrooms are single-storey buildings with flat roof
  • Roof system is BUR or single-ply membrane
  • Metal roof deck or plywood panels
  • Steel structural framing with open web steel joists
  • Metal stud walls with EIFS, stucco or tilt-up panels
  • Exterior walls on 2 or 3 sides have large glass windows
Table 13. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage10576129
2Loss of roof covering (less than 20%)129108163
3Broken glass in windows or doors140114171
4Uplift of some roof decking; significant loss of roofing material (20% or more); loss of rooftop HVAC163134193
5Cladding stripped off walls180151212
6Uplift or collapse of roof structure190158225
7Exterior walls collapsed203171238
8Complete destruction of all or a large section of the building253222291

*All wind speeds in km/h

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Automobile Service Buildings (ASB)

Typical Construction:

  • Single storey building with flat roof and relatively tall walls with parapet
  • Roof coverings are typically BUR with gravel or single-ply membrane
  • Roof structure is light steel framing or open web steel joists and metal roof deck
  • Exterior walls are concrete masonry or pre-cast tilt-up panels
  • Numerous large metal overhead doors
Table 14. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage10174127
2Loss of roof covering (less than 20%)126105159
3Failure of large overhead doors146124177
4Uplift of some roof decking; significant loss of roofing material (20% or more); loss of rooftop HVAC158129192
5Collapse of non-bearing masonry or tilt-up walls183151216
6Uplift or collapse of roof structure195164230
7Collapse of load-bearing walls206171240
8Complete destruction of all or a large section of the building253222291

*All wind speeds in km/h

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Elementary Schools (ES)

Typical Construction:

  • These buildings are typically single storey with flat roofs; CMU bearing walls with brick veneer, stucco or EIFS cladding; walls can have a large percentage of window glass
  • Building may contain a small gym or cafeteria with moderately long spans between supports
  • Buildings have long interior hallways with bearing or non-bearing walls
  • BUR, single-ply membrane or metal standing seam roof panels; metal or plywood roof decking supporting rigid insulation boards or a lightweight poured gypsum deck
  • Roof structure consists of open web steel joists bearing on exterior walls and steel interior girders; exterior non-bearing walls constructed with CMUs, glass curtain walls or metal studs with brick veneer, stucco or EIFS cladding
Table 15. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage10576129
2Loss of roof covering (less than 20%)127106159
3Broken windows140114171
4Exterior door failures159137190
5Uplift of some roof decking; significant loss of roofing material (20% or more); loss of rooftop HVAC163132195
6Damage to or loss of wall cladding174148204
7Uplift or collapse of roof structure201174238
8Collapse of non-bearing walls224188261
9Collapse of load-bearing walls246209290
10Total destruction of a large section of or entire building283245327

*All wind speeds in km/h

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Junior and Senior High Schools (JHSH)

Typical Construction:

  • Generally large one or two-storey buildings with flat roofs; may contain gymnasiums, cafeteria and auditorium with large structural spans; may have a basement
  • Classroom wings have interior hallways with bearing or non-bearing interior walls
  • BUR or single-ply membrane roof covering with or without gravel; structural system may consist of an all steel structure or an all reinforced concrete structure or a combination of both
  • Roof structure may be light steel construction with open web joists supported on steel beams; corrugated metal roof deck with rigid insulation or poured gypsum deck
  • Exterior walls constructed of concrete or clay blocks with brick veneer, stucco or EIFS; metal and glass curtain walls; walls may have more than 30% windows
Table 16. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage10989134
2Loss of roof covering (less than 20%)127106159
3Broken windows140114171
4Exterior door failures163134195
5Uplift of metal roof decking; significant loss of roofing material (20% or more); loss of rooftop HVAC163137192
6Damage to or loss of wall cladding174148204
7Collapse of tall masonry walls at gym, cafeteria or auditorium183151219
8Uplift or collapse of light steel roof structure201174238
9Collapse of exterior walls in top floor224195246
10Most interior walls of top floor collapsed254214299
11Complete destruction of all or a large section of building309262360

*All wind speeds in km/h

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Low-Rise Buildings: 1-4 Storeys (LRB)

Typical Construction:

  • Generally consist of rectangular modules but can be “odd shaped” in plan
  • Most will have flat roofs but can have gable, hip or mansard shapes
  • Roofing materials include BUR, single-ply membrane, metal panels or standing seam
  • Roof deck is wood or metal deck, poured gypsum deck or concrete slab
  • Steel or reinforced concrete structural frame
  • Glass and metal curtain walls, metal studs with EIFS, non-bearing masonry walls with stucco or brick veneer
  • Examples are office buildings, medical facilities, and bank buildings

Notes:

  • With hip roof, use upper bound wind speed for DOD3 and DOD5
Table 17. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage10989134
2Loss of roof covering (less than 20%)129108166
3Uplift of metal roof decking at eaves and roof corners: significant loss of roofing material (20% or more)163134193
4Broken glass in windows, entryways or atriums163134196
5Uplift of lightweight roof structure214183253
6Significant damage to exterior walls and some interior walls230196269
7Complete destruction of all or a large section of building303259356

*All wind speeds in km/h

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Mid-Rise Buildings: 5-20 Storeys (MRB)

Typical Construction:

  • Generally consist of rectangular shapes but can have curved or triangular footprints
  • Roofs are generally flat; may have an elevator/mechanical penthouse; parapet walls
  • Structural frame is steel or reinforced concrete
  • Roofing materials are BUR or single-ply membrane with or without gravel
  • Penthouse is steel framing with metal panels, or metal studs with stucco or EIFS
  • Exterior cladding is glass or metal curtain walls; pre-cast concrete window wall panels or a combination of the two
  • Roof structure consists of metal deck, poured gypsum deck or concrete slab
  • Examples are office buildings, medical facilities, and residential buildings
Table 18. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage11393138
2Loss of roof covering (less than 20%)134109166
3Damage to penthouse roof and walls; loss of rooftop HVAC equipment148121182
4Damage to parapet walls or coping159134190
5Broken glass in curtain walls; glass in entryways; significant damage to building interior163134193
6Uplift of lightweight roof decking; significant loss of roofing material (20% or more)192158225
7Broken curtain wall panel anchors208177241
8Uplift or collapse of roof structure219190254
9Significant damage to curtain walls and some interior walls233193269
10Permanent structural deformation338291431

*All wind speeds in km/h

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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)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage11393138
2Loss of roof covering (less than 20%)138111172
3Damage to penthouse roof and walls; loss of rooftop HVAC equipment150121179
4Broken glass in exterior walls at 1st and 2nd floors; broken glass in entryways163134193
5Damage to parapet walls or coping167140196
6Broken curtain wall panel anchors208177253
7Significant loss of roofing material (20% or more)230185266
8Significant damage to curtain walls and interior walls233198277
9Uplift or collapse of roof structure256198295
10Permanent structural deformation367306467

*All wind speeds in km/h

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Institutional Buildings (IB)

Typical Construction:

  • Examples are hospitals, courthouses, university buildings, state and federal buildings, jails
  • Range in height from 1 – 10 storeys; balconies, porches and porticos with heavy façade
  • Roofing materials include fully adhered and mechanically fastened single-ply membranes, polyurethane foam, copper-clad domes
  • Structure is normally reinforced concrete, relatively small windows
  • Walls are masonry with cut stone or pre-cast panels – very ornate
Table 20. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage11695142
2Loss of roof covering (less than 20%)138116175
3Damage to penthouse roof and walls; loss of rooftop HVAC equipment148121179
4Broken glass in windows or doors153126185
5Uplift of lightweight roof deck and insulation; significant loss of roofing material (20% or more)183153219
6Façade components torn from structure190156225
7Damage curtain walls or other wall cladding211177245
8Uplift of pre-cast concrete roof slabs229192262
9Uplift of metal deck with concrete fill slab235190274
10Collapse of some top story exterior walls238204277
11Complete destruction of all or a large portion of building338286431

*All wind speeds in km/h

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Metal Building Systems (MBS)

Typical Construction:

  • Examples are warehouses, industrial facilities, small arenas
  • Metal panel walls and standing seam roof
  • Nearly always have a gable roof and relatively tall walls
  • Large overhead doors
  • Large-span single bay rigid frames
  • Z- or C-shaped purlins and girts span between rigid frames
  • Lateral loads resisted by cross-bracing
Table 21. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage10887134
2Inward or outward collapse of overhead doors143121174
3Metal roof or wall panels pulled from the building153126193
4Column anchorage failed188154217
5Buckling of roof purlins190153222
6Failure of cross-braces in the lateral load resisting system222190254
7Progressive collapse of rigid frames230193270
8Total destruction of building249212286

*All wind speeds in km/h

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Service Station Canopies (SSC)

Typical Construction:

  • Modern service stations consist of a very large canopy covering the entire pump area and a small building that houses cashier and retail space
  • Canopy structure constructed of steel beam framework supported on 4 or more tall columns
  • Metal panels cover bottom side of the canopy
  • Light weight fascia materials, either metal or plastic, cover the perimeter of canopy
Table 22. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage10172127
2Fascia material blown from canopy126103154
3Metal roof panels stripped from canopy148119182
4Columns bend or buckle under wind load175142217
5Canopy collapsed due to column foundation failure183145232
6Complete destruction of canopy214177262

*All wind speeds in km/h

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Warehouse Buildings (WHB)

Typical Construction:

  • This category includes all building systems except Metal Building Systems
  • Examples include warehouse, storage and industrial buildings
  • Buildings are generally rectangular in plan with flat, gable or hip roofs
  • Built-up roofs with gravel, single-ply membrane ballasted, mechanicall attached or fully adhered
  • Light-frame steel construction with masonry bearing walls
  • Large overhead doors
  • Pre-cast concrete columns, beams and double tees with tilt-up wall panels
  • Heavy timber construction with stud walls and wood panels
Table 23. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage10989134
2Loss of roofing material (less than 20%)134111169
3Inward or outward collapse of overhead doors142121172
4Uplift of roof deck; significant loss of roofing material (20% or more); loss of rooftop HVAC equipment166142196
5Collapse of other non-bearing exterior walls183150203
6Collapse of pre-cast concrete tilt-up panels200164232
7Total destruction of a large section of building or entire building254211299

*All wind speeds in km/h

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Free-Standing Towers (FST)

Typical Construction:

  • Cell phone pole or tower
  • Microwave tower
Table 24. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage148122182
2Collapsed cell-phone pole or tower214182253
3Collapsed micro-wave tower219187257

*All wind speeds in km/h

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Free-Standing Light Poles, Luminary Poles, Flag Poles (FSP)

Typical Construction:

  • Cantilevered metal pole
Table 25. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage130108161
2Bent pole164137193
3Collapsed pole190159222

*All wind speeds in km/h

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C-1 Electrical Transmission Lines (C-ETL)

Typical Construction:

  • Single wood poles with wood cross arms, 7-35 metres (m) in height and 15-60 centimetres (cm) in diameter (at 2 m above ground)
  • Single steel or concrete poles with metal cross arms
  • Metal trussed towers

Notes:

  • Whether poles go down is related to size, composition (wood / concrete / steel) and load (wire tension, number of transformers)
  • For small diameter (~15-20 cm) or very old wood poles, use lower bound; for large diameter (~45-60 cm) wood poles, use upper bound
  • Keep in mind – one weak or overloaded pole going down can cause other poles along the line to break due to wire tension
  • Trees falling on lines can bring down poles – do not use this DI if this is the case
  • Metal trussed towers where lines change direction are often more strongly reinforced, use upper bound
Table 26. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage130110155
2Broken wood cross member155125175
3Wood poles leaning175135200
4Broken wood poles195145220
5Broken or bent steel or concrete poles210180240
6Collapsed metal truss towers220185255

*All wind speeds in km/h

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C-2 Trees (C-T)

Typical Species:

  • Hardwood: Oak, Maple, Birch, Ash, Beech, Cherry, Hickory, Walnut, Aspen, Elm, Poplar
  • Softwood: Pine, Spruce, Fir, Hemlock, Cedar, Larch, Redwood, Cypress

Notes:

  • General differences in the responses of softwood and hardwood species are less important than other factors
  • Use lower bound wind speed if trees show evidence of significant rot, or if uprooting occurs with saturated ground or very shallow soil
  • In urban and suburban areas, trees broken at the base of the trunk were likely planted too deeply, had mechanical injury, or had girdling roots – use lower-bound wind speed
  • Forests and woodlots composed of even-aged monoculture plantations can be assigned a lower-bound wind speed; forests or woodlots composed of mature, deep-rooted red oak, red maple, beech, hemlock or white cedar can be assigned a upper-bound wind speed
Table 27. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Small limbs broken  (less than 2 cm diameter)705585
2Large branches broken  (2 - 8 cm diameter)9065110
3Intermittent mature trees snapped and/or uprooted12580160
4Numerous mature trees snapped and/or uprooted155100190
5Most mature trees snapped and/or uprooted180120220
6Virtually all mature trees snapped and/or uprooted, trees may be denuded/debarked by missiles with only stubs of largest branches remaining230180275

*All wind speeds in km/h

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C-3 Heritage Churches (C-HC)

Typical Construction:

  • Built with bricks and/or stones
  • Solidly built roof structure
  • May also have one or more bell towers
Table 28. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage8060100
2Loss of roof covering material (less than 20%)11085135
3Loss of significant roof covering material (20 - 45%); light damage on the bell-tower summit145115175
4Large sections of roof structure removed (50 - 75%); collapse of the bell-tower summit (spire); walls remain standing185150220
5Roof structure significantly removed (80% or more) and blown away; walls partly collapsed; bell-tower structure damaged225190260
6Roof structure totally removed; many walls collapsed; bell-tower structure mostly destroyed270230310
7Complete destruction of building315275355

*All wind speeds in km/h

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C-4 Solid Masonry Houses (C-SMH)

Typical Construction:

  • Asphalt shingles, tile, slate or metal roof covering
  • Flat, gable, hip, mansard or mono-sloped roof or combinations thereof
  • Plywood/OSB or wood plank roof deck
  • All exterior walls are solid masonry construction (e.g. double brick)
  • Roof is wood joist and rafter construction
Table 29. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Threshold of visible damage10585129
2Loss of roof covering material (less than 20%), gutters and/or awning; loss of vinyl or metal siding127101156
3Broken glass in doors and windows154127183
4Uplift of roof deck and loss of significant roof covering material (20% or more); collapse of chimney; garage doors collapse inward; failure of porch or carport156130187
5Large sections of roof structure removed; most walls remain standing196167238
6Exterior walls collapsed245210286
7Most walls collapsed, except small interior rooms285247325
8Complete destruction of building315275355

*All wind speeds in km/h

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C-5 Farm Silos or Grain Bins (C-FSGB)

Typical Construction:

Farm silos

  • Cylindrical structures typically 4 - 10 m in diameter and 20 - 50 m in height
  • Construction is wood staves, concrete staves, cast concrete, poured concrete or steel panels

Grain bins

  • Cylindrical structures typically 5 - 20 m in diameter and 5 - 30 m in height
  • Construction is galvanized steel panels and purlins
Table 30. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Empty unanchored grain bin toppled; anchored grain bin damaged; silo cap damaged9070110
2Empty unanchored grain bin rolled or carried through air less than 10 m; anchored grain bin toppled; silo cap removed135110160
3Anchored grain bin rolled or carried less than 10 m; empty portions of stave concrete silos destroyed180150210
4Grain bin carried 10 - 100 m or more; stave concrete silo destroyed225190260

*All wind speeds in km/h

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C-6 Sheds, Fences or Lawn Furniture (C-SFLF)

Typical Construction:

Shed

  • Single storey and less than 12 m2
  • Wood, metal and/or plastic construction
  • Metal, wood, plastic or shingle roof
  • May have wood, metal or vinyl siding
  • May have one or more windows
  • May be unanchored or weakly anchored

Wood fence

  • Wood rails, panels and posts (sunk into post holes)

Lawn Furniture

  • Light wood, metal and/or plastic construction intended for outdoor use

Notes:

  • Use upper bound wind speed for large and/or well-anchored sheds
Table 31. Degree of Damage (DOD) for Expected (EXP), Lower Bound (LB) and Upper Bound (UB)
DODDamage DescriptionEXP*LB*UB*
1Garden shed overturned, wood fence blown down, lawn furniture blown around9070110
2Garden shed rolled or carried through the air less than 10 m, lawn furniture carried through air135110160
3Garden shed carried through air 10 m or more180150210

*All wind speeds in km/h

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Glossary

BUR roof covering
Built Up Roof covering is a continuous, semi-flexible membrane consisting of plies of saturated felts, coated felts, fabric or mats assembled with alternate layers of bitumen and surfaced with mineral aggregate, bituminous material or granule surface sheets.
Clerestory
A pronounced high wall with a band of wndows along the top. It usually rises above an adjoining roof.
CMU walls
Concrete Masonry Unit walls are forms of portland cement and aggregates made to various shapes, typically 20 cm high by 40 cm wide. CMUs can be either normal or heavy weight for load-bearing conditions. Light weight units are intended for non load-bearing conditions such as veneers.
DOD
Degree of Damage
EIFS
Exterior Insulation and Finish Systems are multi-layered exterior wall systems built for commercial and residential buildings. EIFS consists of insulation board secured to the exterior wall surface by adhesive or mechanical attachment. There is a water-resistant base coat applied on top of the insulation and reinforced with fiber glass mesh. There is a finish coat applied to the exterior.
EXP
Expected value for 3-second gust wind speed at 10 m in flat, uniform, open terrain
Floor Diaphragm
A wood frame floor system consisting of joists, sheathing overlaid on joists, rim joists. Studs below provide a load path to the rim joists. Building codes may only require floor diaphragms to be fastened along continuously supported panel edges, often called an unblocked diaphragm. A fully blocked diaphragm means that each panel segment edge not on a joist is supported by a block.
Gable roof

A roof having two sloping sides that come together at a ridge, creating end walls with a triangular extension, called a gable, at the top

  Gable roof

Girt
A secondary horizontal structural member attached to sidewall or endwall columns to which a wall covering may be attached.
Hip roof

A roof that slopes back from all four sides to a single point, or line, at the top

Hip roof

HVAC
Heating, Ventilation and Air-Conditioning
ICF
Insulating Concrete Forms are used with poured concrete to produce permanent walls. Forms are made of foam insulation and a steel frame. Concrete occupies the interior of the form. ICF panels are connected with plastic ties.
LB
Lower Bound value for 3-second gust wind speed at 10 m in flat, uniform, open terrain
Mansard roof

A type of hip roof where each sloping section is divided in two to create maximum space under the roof; the first section near the walls rises steeply while the second section continues at a milder pitch toward the center.

Mansard roof

Open web joist
A structural system designed to bear loads with a minimum of mass. It consists of structural wood top and bottom chords or steel tube webs with interconnecting pins.
OSB
Oriented Strand Board, similar to plywood but uniform and cheaper. A manufactured 4' X 8' wood panel made up of 1" - 2" wood chips and glue.
Parapet wall
A low wall or railing along the edge of a platform, terrace or roof.
Polyurethane foam roof
Roof decking is sprayed with an elastic, closed-cell foam and then covered with an additional coating. The final cover is several inches thick.
Poured gypsum roof deck
A gypsum concrete roof deck consisting of gypsum concrete that is mixed with either wood fibers or mineral aggregate.
Purlins
Channel-shaped steel structures used to span roof trusses of metal buildings and serve to support the roof deck. Common Purlins come in Z and C shapes.
Single-ply membrane roof
Consists of a single waterproof membrane laid on a roof deck and attached by mechanical or adhesive fastenings. The membrane edge is tucked inside a metal perimeter flashing.
Standing seam roofing
Composed of preformed or field formed pans, usually 45 to 60 cm wide. These pans run parallel to the roof and are joined to adjacent pans with double-locked standing seams. The seams have cleats 30 cm apart which locks the panels on the deck. Metal (e.g., copper) roofing may exhibit this type of construction.
Tilt-up concrete panel
A prefabricated concrete wall panel, often containing openings for windows and doors, that is hoisted into place by a crane or other mechanism. The roof diaphragm acts as a connector between the panels. However, the panels typically are not connected to each other to allow for expansion and contraction.
UB
Upper Bound value for 3-second gust wind speed at 10 m in flat, uniform, open terrain

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EF-Scale Canada

Table 32. Enhanced Fujita Scale - Canada
EF-Scale RatingEF-Scale Wind Speed
Rounded to 5 km/h
090-130
1135-175
2180-220
3225-265
4270-310
5315 or more

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Acknowledgments

  • Damage indicator information for DI 1-26 from McDonald, J. and K. C. Mehta, 2006: A Recommendation for an Enhanced Fujita Scale (EF-Scale), Revision 2. Wind Science and Engineering Research Center, Texas Tech University, Lubbock, TX, 111 pp.
  • Damage indictor information for DI C-3 (C-HC) was adapted from a ‘Churches’ Damage Indicator developed by Keraunos for France (provided by Dr. Emmanuel Wesolek, see http://www.essl.org/ECSS/2011/programme/presentations/111.pdf)
  • Most glossary information from NOAA’s Warning Decision Training Branch (see http://www.wdtb.noaa.gov/)

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