Reducing Radon Exposure in homes and other buildings

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Reducing Radon Exposure in homes and other
buildings

• Jack Bartholomew Jr.

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Introduction

• My name is Jack Bartholomew Jr.
• I have been providing energy, ventilation and
  radon related research and installation services
  since 1984 starting in Washington, Oregon, Idaho,
  Montana and later in Minnesota, Wisconsin and
  Iowa.
• I have installed successful systems in over a
  1000 single family residences, and a managed few
  handfuls of schools, commercial, public and
  multi-family buildings and campus installations.
• I provide training in radon mitigation methods
  and preparation for the certification exam for
  the Midwest Universities Radon Consortium (MURC),
  through the University of Minnesota, one of four
  initial USEPA national training centers and have
  been doing so since 1989. Recently began to serve
  in Canada through Dalhousie University in
  Halifax.

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PURPOSE / INTENTION

• To stop and/or reduce the migration of radon and
  other soil gases into the occupied building.
• To improve the indoor working and living
  environments for most people of all ages.
• To do no harm to the outdoor and public
  environment when applying this knowledge.

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National Tribal Forum on Air Quality 2009

• This session is focused to the process after
  initial radon testing has been completed and
  confirmed to be a hazard in the building.

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Reduce indoor radon as low as reasonably
achievable

• At 4 pCi/L, the risk of lung cancer from radon
• 62 of 1,000 ever smokers will die from radon
• 7 of 1,000 never smokers will die from radon
• Reduction of home radon from 4 to 2 pCi/L
• Smokers risk drops by about half
• Nonsmokers risk drops by about 40
• Reduction of home radon from 4 to 1.3 pCi/L
• Smokers risk drops by about two-thirds
• Nonsmokers risk drops by about 70

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So you have tested and the results are above 4
pCi/L and you know you should to do
something.WHATS NEXT?Lets review some
radon entry basics
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Location, location, location

• There is no zero reading for radon, just a range
  from very rare to less and more. The average
  outdoor background level is 0.4 pCi/L.

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Sources

• Sources for radon gas exists almost everywhere we
  live on the earth.
• Air flowing from the soil into the building is
  the greatest contributor to indoor radon.
• If you have tested for radon in air and your
  levels are high, and your water comes from a
  well, you should test the water for radon and
  other radioactive elements.

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Radon Entry Variesfrom Building to Building
All Homes Should be Tested!
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Geology Based on Early Mapping

• Granites
• Shales
• Phosphates
• Based largely upon uranium exploration experiences

Geology does not tell the whole story.
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1993 Map of radon potential

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Averaged Contributions from Radon Sources in U.S.
Homes

• The movement of soil gas into a home is the
  predominant way radon enters the home.

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To have high radon levels,

• you need a strong enough soil source and
• pathways connecting the radon source to other
  soil air that is flowing indoors
• and driving forces like heating a building when
  it is cold out or pulling air out of a room with
  a fan and the wind.
• Change any one of them and you can reduce radon
  levels indoors. Hmmm..what can we control?

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The Predominant Driving Force Is Building
Induced Soil Suction

• Buildings can create vacuums that will draw in
  soil gas
• These vacuums or under-pressures are very small
  and are referred to as air pressure differentials

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Wind Can Cause Several Effects

• Building negative pressure
• Bernoulli effect, and down-wind openings
• Building positive pressure with upwind openings
• Soil positive
• Wind pushing beneath or into porous layer of an
  exposed hillside

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Whats NEXT?

• Review test results.
• Walk through the building and map radon entry
  points and sources for indoor negative pressure.
• Learn about your options for reducing exposure.

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Review Radon Test Results

• What can we learn from the first tests?
• Length of test
• Short term average (2-90 days)
• Long term average (91 days)
• Continuous hourly
• Test location
• Lived in room upstairs
• Lowest livable level
• Near large holes in the floor
• Conditions during the test.
• Windows closed or open
• Weather, wind, rain
• Ventilation fans operating or not
• What were the conditions during the test?

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This is the effect of one door closing and
opening between basement and upstairs with the
furnace blower operating continuously
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Take a walk through the building

• What do we need to know?
• Where are the holes leading to the soil?
• Where are the sources of indoor depressurization?
• Is there more than one foundation type?
• Where can we locate a fan and safely discharge
  the radon?

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Entry Routes

• Radon enters the building from the soil through
  the below grade spaces and seams of foundation
  construction.
• Some examples are
• Where the floor meets the perimeter wall / cold
  joints
• Around pipe penetrations through floors and walls
• Underneath a bathtub on a slab floor
• Open sump basin connected to perforated
  drain-tile
• Unvented crawlspaces next to the soil under floors

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Examples of Entry Points
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Negative pressure sources

• Older gas and oil furnaces and water heaters use
  house air for combustion and venting.
• An open filter slot can allow a lot of air to be
  pulled from the room and cause negative pressure
  and increase radon entry

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Developing Priorities
Air from the soil contains water vapor and things
other than radon that contributes to lung and
other breathing diseases. Reducing radon and soil
air entry can also help with moisture problems,
if the soil is a strong moisture source.
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Reducing Indoor Radon Exposure

• It does not mean you have to spend a lot of money
  .
• Simple lifestyle adjustments like
• moving a bedroom upstairs during the winter or
  sleeping near an open window under a good blanket
  can reduce exposure.
• Less radon exposure means less potential for lung
  cancer in ones lifetime, for both smoker and
  nonsmoker.

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Sealing is not a Stand Alone Radon Reduction
Technique

• There are too many openings in a home to be able
  to totally seal out radon.
• However, sealing enhances standard radon systems.

pCi/L
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Reducing Indoor Radon

• Most common method is to reduce radon entry from
  the soil by sealing holes open to the soil and
  active soil depressurization.
• Active soil depressurization (ASD) means creating
  lower pressure in the soil below and around the
  building foundation and reversing the direction
  of airflow between the house and the soil.
• If you cant reduce radon entry with ASD, then
  dilution is the solution to the pollution using
  ventilation.

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A typical radon vent system often begins by
cutting a hole through the floor to the soil.
PFE Vacuum cleaner diagnostics proves the pit
location is good or marginal. Excavating a pit
should improve PFE.
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Digging Out Suction Pit is Very Important

• Increasing the surface area of the suction point
• Usually decreases resistance to air flow at the
  suction point and, thus
• increases pressure field extension.
• The tighter the subslab, the larger the suction
  pit should be

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Can you install a membrane in this crawlspace?
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Unit 3. ASD Installation D. Submembrane
Depressurization Basement with EPDM Membrane
Seal to walls and seams with polyurethane
caulking
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Vent Pipe Routing May Be Interior or Exterior
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Locate ASD Fan Where Radon Leakage will not Enter
Home

• Unacceptable locations
• In the conditioned space of home, e.g., basement
• In an occupied attic
• In a crawl space beneath home
• In a garage with living space above
• Acceptable locations
• Unoccupied attic
• Outside of home
• In garage, unless there is occupied space above
  it

Important
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Fans are commonly installed in attics or outside
the house
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Radon Mitigation Discharge Requirements
12 inches above the roof (good practice but not
RMS) Above the roof eave (RMS) Minimum 10
feet from (RMS) - any opening less than 2 feet
below discharge - any adjacent building - public
or private access - above grade
Radon fan
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Labeling and monitoring system performance
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Combustion spillage

• Certified mitigation providers are required to
  make sure the radon system installed does not
  interfere with the proper drafting of the
  chimneys.

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Installation time period

• Most simple fan and vent systems can be installed
  in one day or less.
• Other approaches may involve additional
  diagnostics be performed to understand the radon
  relationship between a crawlspace and a basement,
  define pressure field extension or take steps
  that focus to a specific foundation zone in homes
  with multiple foundation types and test the
  effectiveness after each step.

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Contractor installed

• The investment to reduce average radon exposures
  in most smaller homes below 4 pCi/L or 150 Bql/m3
  tends to range from 700 to 2500, including any
  special diagnostics, electrician, and follow-up
  testing.
• Fan and parts costs are often under 400.

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Finding a good mitigator

• To find a certified person, go online to the
  National Radon Proficiency Program /National
  Environmental Health Association or consult with
  your state radon office.
• Folks certified by the national radon training
  programs and members of the radon industry
  association (AARST) are most informed about soil
  depressurization systems and the details.
• Use references to qualify the service.

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SUMMARY

• Choose a active system and/or lifestyle strategy.
• Hire or utilize an qualified installer.
• Complete the installation.
• Retest with short term tests.
• Radon exposures well below the original EPA
  guidelines for indoors can be guaranteed and
  achieved with a properly designed and installed
  system.
• Once the system is proven to work there is little
  interaction with the occupants, some electricity
  and reminder to retest every two years just to be
  sure it is still working. Continuous operation of
  the fan is intended and provides the lowest
  indoor exposures year-round.

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QUESTIONS?

• You can reach me at 612 721 8762 to discuss your
  existing or new home project.
• Thank you.