Dampness, Flooding, and the Effect on Occupant Health

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Dampness, Flooding, and the Effect on Occupant
Health

• Linking Building Physics, GIS, and Epidemiology
• Height and Flights Conference, Oxford
• July 8th, 2009
• Jonathon Taylor
• Department of Civil, Environmental, and Geomatic
  Engineering, UCL
• The Bartlett School of Graduate Studies

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Study Background

• Background
• London will experience an increase in flooding
  (and indeed, intensity of moisture) due to
  climate change
• Different buildings will be flooded to different
  heights
• Certain wall types absorb and desorb moisture in
  different ways
• People react to flooding and dampness in their
  homes differently
• Research Questions
• Under natural circumstances, how long will the
  city take to dry? What about under different
  drying scenarios?
• What sociodemographic groups will be exposed to
  high levels of damp? Will this cause an increase
  in chronic damp-related health issues?
• How does the length of exposure to damp effect
  the health of previous flood victims?
• How long will temporary accommodation need to be
  provided for victims?
• What are the natural microbial fauna that exist
  in flooded London buildings, and how might this
  effect the health of the population?

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Flooding has a range of health implications

• Acute Problems
• Drowning
• Trauma
• Electrocution
• Poisoning/Disease
• Chronic Problems
• Increase in all-cause deaths in year following
  flooding (50, Bristol, 1969)
• Mental health (Social Flood Vulnerability Index)
• Dampness and Mould related symptoms
• Asthma
• Respiratory diseases
• Toxic building syndrome

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Flooding has a range of health implications

• Acute Problems
• Drowning
• Trauma
• Electrocution
• Poisoning/Disease
• Chronic Problems
• Increase in all-cause deaths in year following
  flooding (50, Bristol, 1969)
• Mental health (Social Flood Vulnerability Index)
• Dampness and Mould related symptoms
• Asthma
• Respiratory diseases
• Toxic building syndrome

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Research Area Greater London

• OS Mastermap building shapefiles
• Cities Revealed building age and type
• Address Layer 2 to identify residential buildings

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Research Area Greater London

• Cities Revealed LiDAR provides height data
• Heights used to create DTM
• Determine building heights

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Environment Agency Data 1/200 Flood Map
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GIS Data Describes
Dwellings, Dwellings in a building, of
premises in building
Age of Buildings
Structure of Buildings
Height of flooding for buildings
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Building Physics

• An applied science that studies the hygrothermal,
  acoustical, and light-related properties of
  building components, rooms, buildings, and
  building assemblies (Hens, 2008)
• Hygrothermal Heat, air, and moisture transport
  in materials, components and buildings, and
  buildings and the outdoor environment
• Interested in
• Water Content The amount of water (kg/m3) of
  water in the wall
• Relative Humidity The amount of water vapour in
  the air, relative to the total amount the air
  could hold (saturation) at a specific temperature
• Crucial for mould growth

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Assumptions can be made about walls from age and
structure
Supplemented by data from English Housing
Condition Survey and the Census
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Flood Models in Different Wall Types
9 Masonry wall with 1cm plaster
Cavity wall with mineral wool insulation and 1cm
plaster
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Wall Types and Moisture

• Sensitivity analysis shows
• Drying time is dependent on wall type, flood
  height, wall orientation, time of year of flood
• Less sensitivity to wall coverings (render, wall
  paper)

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How to integrate GIS and building moisture models

• Each moisture calculation takes up to 20 minutes
• Unrealistic to do for the 305,000 buildings in
  the study area
• More efficient to create curves for drying time
  and relative humidity
• Can be based on depth-damage curves used by the
  insurance industry

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Next Steps

• Generate curves for range of flood heights, wall
  types, climate and drying scenarios
• Apply the curves to past events and future flood
  scenarios
• Apply epidemiological models for dampness
  exposure to examine chronic respiratory disease
• Use as level and length of exposure indicator for
  chronic health studies
• Apply mould growth model to moisture model

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Finally

• Flooding is a good place to start
• 3D model, but basically 2D1
• Defined moisture levels, all or none saturation
  levels, no roof shapes required
• More may be possible in the future
• Intensity of rainfall is expected to increase
• City models are becoming more detailed, with roof
  shapes
• Building stock information is improving
• Potentially research impact of climate change on
  existing building stock, and health consequences
  from this.

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Conclusion

• Known chronic health impacts from dampness and
  flooding, but no length or level of exposure
  information
• Building Physics and GIS can help bridge the gaps
  in epidemiological models
• Building attribute and height data is crucial to
  be able to do this