Physical Damages

1
Unit 2

• Physical Damages

2
Methods for Estimating Physical Damages

• Standard Depth-Damage Functions
• Typical Buildings
• Atypical Buildings
• Expert EngineersInfrastructure Projects
• Historic Damage Data

3
Unit 2 Objectives

• After completing this unit, you will be able to
• Estimate building and contents damages using the
  standard DDFs and building replacement values.
• Identify at least three sources of building
  replacement value data.
• Adjust the standard DDFs to more accurately
  reflect atypical situations.

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Unit 2 Objectives (Cont.)

• After completing this unit, you will be able to
• Create an Excel spreadsheet to calculate adjusted
  DDFs.
• Question an expert engineer to obtain estimates
  of infrastructure damages at various flood
  depths.
• Convert historic damage data into their values in
  todays dollars using the Inflation Adjustment
  Calculator.

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Damage Estimates Method 1

• Standard Depth-Damage Functions

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Replacement Value

• Definition
• Building Replacement Value (/sf) is a measure
  of the economic value of a building, including
  the structure and non-structural permanent parts
  of the building, but excluding its contents.
• Replacement value means the cost to provide a
  functionally equivalent structure of the same
  size. Replacement value does not include
  recreating historical or archaic materials,
  finishes, or features.

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Sources of Data on Replacement Value

• Local building officials
• Builders
• Realtors
• Market value of new homes (per sf) minus the
  value of the lots.
• Marshall Swift Residential Cost Handbook
• R.S. Means Square Foot Costs

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Example

• Consider a 1,700 square-feet, one-story house
  with no basement and a replacement value of
  70/sf. Suppose that during a recent flood
  event, the flood depth in the house reached 3
  feet.
• What are typical damages in this situation?

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Example

• Consider a 1,700-square-feet, one-story house
  with no basement and a replacement value of
  70/sf. Suppose that during a recent flood
  event, the flood depth in the house reached 3
  feet.
• What are typical damages in this situation?
• Replacement Value 1,700 sf x 70/sf
• 119,000
• Percentage Damages 27
• (From DDF Table)
• Total Damages 119,000 x .27
• 32,130

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Depth-Damage Functions

• The Depth-Damage Functions provide very good
  estimates of the percentage damages when
• You are evaluating BUILDINGS.
• Flood conditions are TYPICAL.

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Atypical Situations

• Standard DDFs may underestimate percentage
  damages if the situation involves
• Long-duration inundation
• High-velocity flooding or heavy debris or ice
• Contamination
• Soil failure

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Actual Damage Data Sources

• Some sources of actual damage data
• Insurance claims
• Repair receipts
• Contractor estimates

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Estimating Contents Damages Using DDFs

• Percentage Contents Damages are typically 150 of
  Percentage Building Damages.

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Atypical Contents Damages

• Building Contents Damages may be
• Greater than DDF estimates if atypical flood
  conditions exist (e.g., long inundation, high
  velocity).
• Greater than or less than DDF estimates if the
  contents are more or less vulnerable to water
  damage than typical contents (e.g., warehouse
  full of computers vs. warehouse full of bricks).

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Damage Estimates Method 2

• Expert Opinion

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Infrastructure Damages

• Infrastructure is highly variable in terms of
• Vulnerability to flood damage
• Critical flood depths
• Therefore, no standard DDFs exist for
  infrastructure.

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Damage Estimates Method 3

• Historic Data

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Historic Damage Data
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Adjusting Past Damages for Inflation

• Rule of Thumb
• If historic damage data are older than 5 years
  old, they should be converted to their values in
  todays dollars.

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Adjusting for Inflation

Example If you had 15,000 damages in 1992, what
would the damages be in 1999 dollars?
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Adjusting for Inflation
Example If you had 15,000 damages in 1992, what
would the damages be in 1999 dollars?
15,000 X 1.0291 X 1.0261 X 1.0286 X 1.0299 X
1.0229 X 1.0156 X 1.024 17,848 in 1999 dollars
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Common Error To Avoid

• Historic data will only provide an accurate
  estimate of future damages if the flood risk is
  much the same today as it was when the historic
  damage occurred.
• In other words, such estimates will be
  accurateif there have been little or no changes
  in
• Flood hazard
• Property exposed to floods

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Unit 2 Summary

• In this unit, you learned several methods for
  estimating physical damages
• Standard Depth-Damage Functions and Replacement
  Value
• Typical Buildings
• Atypical Buildings
• Expert EngineersInfrastructure Projects
• Historic Damage Data

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Unit 2 Summary (Cont.)

• The Depth-Damage Functions provide very good
  estimates of the percentage damages when
• You are evaluating BUILDINGS.
• Flood conditions are TYPICAL.
• To derive damage estimates using the standard
  DDFs, you must know the replacement value of the
  buildings you are evaluating.

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Unit 2 Summary (Cont.)

• Standard DDFs may underestimate percentage
  damages in certain ATYPICAL situations such as
• Long-duration inundation
• High-velocity flooding or heavy debris or ice
• Contamination
• Soil failure

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Unit 2 Summary (Cont.)

• If you have actual damage data for some of the
  damages that occurred in an atypical situation,
  you can use those data to determine how much to
  adjust the standard DDFs in order to derive more
  accurate damage estimates.
• You can use standard DDFs (multiplied by 1.5) and
  adjusted DDFs to estimate building contents
  damages as well as building damages.

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Unit 2 Summary (Cont.)

• No standard DDFs exist for infrastructure.
• Infrastructure is highly variable in terms of
• Vulnerability to flood damage
• Critical flood depths
• One of the best sources of infrastructure damage
  estimates is an expert engineer familiar with the
  specific type of facility you are evaluating.

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Unit 2 Summary (Cont.)

• Historic damage data can often provide a good
  estimate of future damages.
• If historic damage data are more than 5 years
  old, they should be converted to their values in
  todays dollars using the Inflation Adjustment
  Calculator.
• Damage estimates based on historic data are only
  accurate if the flood risk today is the same as
  the flood risk at the time of the historic
  damages.