Post 2004 Hurricane Field Survey Evaluation of the Relative Performance of the Standard Building Code and the Florida Building Code

1
Post 2004 Hurricane Field Survey Evaluation of
the Relative Performance of the Standard Building
Code and the Florida Building Code

• Kurt Gurley UF
• Jeff Burton IBHS
• Makola Abdullah FAMU
• Forrest Masters FIU
• Tim Reinhold IBHS

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Project Goal

• Determine if 2002 code change reduced the
  vulnerability of residential single family homes
• Quantitative rather then anecdotal
• Physical damage
• Loss ratio
• Behaviors (mitigation evacuation)
• Stratify results by wind speed and code

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Additional Objectives

• Include and contrast structures in each of the
  areas impacted by 2004 storms
• Subject targets site built single family
• Post Andrew, pre-Florida Building Code
• 1994 2001 (old)
• Post Florida Building Code
• 2002 2004 (new)

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Methodology

• Pre-arranged appointments with randomly selected
  homeowners to gather damage information
• Interview homeowner
• Inspect property
• Prior knowledge of
• home details ( Yr of construction, Roof / Wall
  type, etc.)
• home location relative to peak 3-second wind
  speeds
• NO prior knowledge of damage
• no visual bias to sample selection
• to determine average damage and loss

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Tools

• Access to wind swath maps
• Vickery Applied Research Associates
• Powell NOAA
• Access to county databases
• Home location
• Homeowner
• Year of construction
• Roof cover (asphalt, tile)
• Roof type (hipped, gable)
• Wall type (masonry, wood frame)
• Appraised value pre-2004 storm season

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Wind Swath Maps
Ivan
Frances
Jeanne

• Charley

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GIS Database - Charlotte County

• All Single family units 2002 - 2004 new

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GIS Database Stratifications

• old units with tile roofs Punta Gorda Isles

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Stratified Sampling Procedure

• Overlay wind swath maps with homes that fit
  desired characteristics (age, roof cover, etc.)
• Randomly select homes across desired wind swath
  contours
• The homeowners contacted by phone in random order
  (25 success rate)

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Survey Details Inspection

• Digital photograph s
• All angles and corners of subject
• Surrounding terrain
• Distance to adjacent large objects in all
  directions
• Sketch elevations and plan view

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Survey Details Inspection

• Attic inspection
• Sheathing type and thickness
• Sheathing nail size, edge and field spacing
• Gable end bracing
• Roof to wall strap installation
• Garage inspection
• Pressure rating, bracing
• Location, size and type of every window and door
• includes protection details damage

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Survey Details Interview

• Evacuation behavior
• Mitigation behavior (shutters)
• Indicate damage on elevation sketches
• Water penetration
• Roof cover failure
• Soffit failure
• Window and / or shutter failure
• Scan any damage pictures
• Insurance reimbursement information

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Survey Details Interview

• Data entered directly into
• handheld PDA
• Upload to access database

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Charley Surveyed Homes
Charley 126 Surveyed Homes
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Frances and Jeanne
Frances Jeanne 33 Surveyed Homes
2002-2004
1994-2001
3-Sec Gust (MPH)
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Wind speed verified through portable weather
stations
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Ivan Surveyed Homes
Ivan 36 Surveyed Homes
2002-2004
1994-2001
3-Sec Gust (MPH)
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Survey Demographics
Total samples 195 Total samples 195 Charley Total 126 Charley Total 126 Charley Total 126 Ivan Total 36 Frances / Jeanne Total 33
Total samples 195 Total samples 195 Zone 8 110 - 120 Zone 10 130 - 140 Zone 11 140 - 150 Zone 8 110-120 Zone 8 110 - 120
Old code SBC 94 98 1 22 10 10 5
Old code SBC 99 01 10 23 14 10 12
New code FBC 02 04 11 12 23 16 16
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Water Penetration Charley (All)
New
Old
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Water Penetration Charley (11)
New
Old
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Water Penetration All stormsZone 8 (110 120
mph 3 sec. gust)
New
Old
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Water Penetration All stormsType of penetration
New
Old
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Water PenetrationResults Summary

• Water penetration by code
• It is not clear from the study that the FBC
  provides improvement in preventing water
  penetration.
• 1994 1998 more likely to have ceiling damage

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Window Protectionby storm and age
New
Old
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Window Damage 110 120 (8)by storm per window
New
Old
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Window Damage Charley data by zone per window
New
Old
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Window Protection 2004 and Future Use
Window protection use in 2004 and future storms
of homes in that region that used left column protection in 2004 ( that intend to use protection in future seasons) of homes in that region that used left column protection in 2004 ( that intend to use protection in future seasons) of homes in that region that used left column protection in 2004 ( that intend to use protection in future seasons)
Charley Ivan Frances / Jeanne
No protection 60 (11) 58 (33) 16 (16)
Plywood 7 (13) 36 (36) 13 (6)
Shutters 27 (74) 6 (27) (53) (72)
Impact Glass 7 (3) 0 (3) 19 (6)
New
Old
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Window ProtectionResults Summary

• Mitigation effectiveness shutter use
• A significant percentage (3 - 4) of unprotected
  windows were damaged in the highest wind zone
  (140 150 mph) in Charley, while protected
  windows experienced significantly less damage.
• At the lower wind zone 8 (110 120 mph gust),
  protected windows permitted almost no damage,
  while the percentage of damaged unprotected
  windows was small but consistent among storms.

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Soffits by Age Group All data
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Soffit DamageResults Summary

• Soffit performance with age of construction
• Increased likelihood of soffit damage with
  increasing age of structure (over the surveyed
  range 1994 2004).

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Roof Cover Charleyby zone and cover type
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Roof Cover (all types) Charleyby age and
quantity
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Roof Cover (Tile) Charleyby age and quantity
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Roof Cover (Shingle) Charleyby age and quantity
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Roof Cover (Tile) Charley (11)by age and
quantity
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Roof Cover - TileResults Summary

• Tile roof cover performance
• Few surveyed tile roof homes of any age group had
  no cover damage
• Higher probability of field tile loss in 94
  01 homes compared to new construction
• 2002 2004
• 15 had tile damage exceeding 5, (mostly ridge
  cap loss)
• 1999 2001
• 60 had over 5 damage
• 44 over 10 damage
• 22 over 25 damage
• 1994 1998
• 60 had 6-25 damage

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Roof Cover (Shingle) Charley (10)by age and
quantity
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Roof Cover - Shingle Results Summary

• Shingle roof cover performance by age of
  construction
• For highest wind zone 140 - 150
• Distinct difference in shingle performance by age
• 1994 - 1998 significant quantities of shingle
  damage
• 1999 2001 less damage
• 2002 2004 small quantity of damage on average
• 1994 1998 Every shingle house surveyed in zone
  11 had shingle damage, all had at least 10
  shingle loss, and most had between 25 and 50
  loss.
• 2002 2004 30 of shingled houses had no shingle
  damage, and the wide majority of those that had
  damage lost less than 5 of their shingles.

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Shingles Regional Comparison
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Roof Cover - ShingleResults Summary

• Shingle roof cover performance by wind speed
• Charlotte County
• 110 120 mph 32 of homes had shingle damage
• 130 140 mph 65
• 140 150 mph 79

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Roof Cover (Shingle) Charley (8)by age and
quantity
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Roof Cover (Shingle) Ivan (8)by age and quantity
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Roof Cover (Shingle) Frances (8)by age and
quantity
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Roof Cover - Shingle Results Summary

• Shingle roof cover performance by region
• 110 120 mph 3 sec. gust
• Charlotte County (32 of homes damaged)
• St. Lucie County (80)
• Escambia County (50)
• Charlotte County suffered less quantity of damage
  on average than those in the Ivan and Frances /
  Jeanne regions.

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Concluding Remarks

• Major findings
• Demonstrate
• Effectiveness of window protection
• Improvement in shingle performance
• Tile older more likely to experience field tile
  damage
• Some aging effects on roof cover performance
• Support efforts to improve
• Water Intrusion standards
• Tile roof cover installation standards
• Ridge cap installation standards
• Soffit installation standards