1. How can you reduce radon in a home?
Lesson 10
How can you reduce
radon in a home?

2. Brief overview of radon mitigation
Measuring Radon in Residential Properties
How can you reduce radon in a home?
Brief overview of radon mitigation
Mitigation: reducing radon in air or water
Requires trained, registered radon mitigation specialist
See listing at /radon/ Pubs/rpplist.pdf
Graphic:
Typical radon mitigation system
Connecticut Radon Measurement
Training Program 2006

3. Measuring Radon in Residential Properties
How can you reduce radon in a home?
Mitigation design
EPA usually recommends methods that prevent radon from entering the home
Rather than reduce amount already present
Design starts with visual inspection
Identify radon entry paths
Identify relevant construction features
May require diagnostic tests
Photos: and
Connecticut Radon Measurement
Training Program 2006

4. Methods for reducing radon in air
Some methods apply to all foundation types
Sealing foundation openings
Home/room pressurization
Heat recovery ventilation (HRV), or air-to-air heat exchange
Natural ventilation
Some methods depend on home construction, especially foundation design and materials

5. Sealing foundation openings
Method
Seal cracks and other openings to reduce radon entry
Advantages
Reduces loss of heated or cooled air
Makes other methods more effective and cost-effective
Disadvantages
Difficult to identify and permanently seal all places where radon enters
Some areas are not accessible
Normal settling opens new cracks and reopens old ones
Sealing alone does not reduce radon enough

6. Home/room pressurization
Method
Fan blows air from upstairs or outdoors into lowest living levels
Increases pressure to reduce radon entry
Disadvantages
Requires doors and windows on lowest level to be kept closed except for normal entry and exit
Introduces more outdoor air, so may increase moisture and energy costs
Effectiveness limited by
Home construction
Climate
Appliances
Resident lifestyle
Use only with other methods if they do not reduce radon enough

7. Heat-recovery ventilation (air-to-air heat exchange)
Method
Increases ventilation by bringing in outdoor air and removing indoor air
Outgoing indoor air heats or cools incoming air
Most effective when ventilating a limited space, such as a basement
Can be used year-round
Advantage
Can improve overall air quality where there are other indoor pollutants
Disadvantage
Can significantly increase heating and cooling costs

8. Use only as a temporary method
Natural ventilation
Method
Opening windows, doors, and vents on lower levels increases ventilation
Outdoor air mixes with indoor air, diluting radon
Indoor and outdoor air pressure is equalized
Disadvantages
When openings are closed, radon returns to higher level in 12 hours
Greatly increases energy costs because heated and cooled air is lost
May make home uncomfortably hot or cold
May make home less safe
Use only as a temporary method

9. Methods for specific foundation types
Measuring Radon in Residential Properties
How can you reduce radon in a home?
Methods for specific foundation types
Room
partly or completely below ground
Concrete poured at ground level
Shallow unfinished space below first floor
Image: U.S. Environmental Protection Agency, 2003, Consumer’s Guide to Radon Reduction.
Connecticut Radon Measurement
Training Program 2006

10. Basement and slab-on-grade options
Types of suction
Subslab
Active
Passive
Drain tile
Sump hole
Block wall
Suction prevents radon from entering home
Draws radon from below home
Vents radon to pipe(s)
Releases radon to air above home

11. Active subslab suction (or subslab depressurization)
Measuring Radon in Residential Properties
How can you reduce radon in a home?
Active subslab suction (or subslab depressurization)
Reliable
Effective in reducing high radon levels
Suction pipes inserted through slab into soil or crushed rock below
Vent fan draws up radon gas and releases it outside, above the roof eave
Works best when air moves easily under slab
Image: www,takeactiononradon.uiuc.edu/reducing.html
Connecticut Radon Measurement
Training Program 2006

12. Subslab suction Passive
Measuring Radon in Residential Properties
How can you reduce radon in a home?
Subslab suction Passive
Similar to active system but
Instead of fan, natural air pressure differences and air currents draw up radon gas
Less effective in reducing high radon levels
Usually used with radon-resistant features in newly built homes
Image: Take Action on Radon,
Connecticut Radon Measurement
Training Program 2006

13. Measuring Radon in Residential Properties
How can you reduce radon in a home?
Drain tile suction
Drain tiles or perforated pipe direct water away from foundation
Works with a partial or complete loop of drain tiles
Suction pulls radon from soil and vents away from home
Image:
Connecticut Radon Measurement
Training Program 2006

14. Sump hole suction
Used in basement with sump pump designed to remove water
Sump is capped and continues to operate
Sump becomes location for radon suction pipe
Works best when air moves easily to sump from under slab

15. Block wall suction Used in basement with hollow block foundation walls
Requires that major openings be sealed
Removes radon and depressurizes block wall
Often used in combination with subslab suction

16. Crawlspace options Submembrane suction Active depressurization
Crawlspace ventilation

17. Measuring Radon in Residential Properties
How can you reduce radon in a home?
Submembrane suction
Method
Cover earth floor with high-density plastic sheet
Vent pipe and fan draw radon from under sheet and vent to outdoors
Advantage
Most effective method
Graphic:
Connecticut Radon Measurement
Training Program 2006

18. Active depressurization
Method
Fan draws air from crawlspace
Disadvantages
Less effective than submembrane suction
Requires special attention to backdrafts of combustion appliances
Requires sealing crawlspace from rest of home
May increase energy costs because heated or cooled air is lost

19. Crawlspace ventilation
May lower radon by
Reducing suction on soil
Diluting radon beneath a home
Methods
Active: fan blows air through crawlspace
Passive: vents circulate air naturally in crawlspace
Disadvantages
Water pipes, sewer lines, and appliances in crawlspace may need to be insulated against cold
May increase energy costs

20. Various foundations may require various methods
Measuring Radon in Residential Properties
How can you reduce radon in a home?
Various foundations may require various methods
Image:
Connecticut Radon Measurement
Training Program 2006

21. Questions?

22. Removing radon in water from private wells
Point-of-entry system
Removes radon before water is distributed
Treats all water in home
Types
Granular activated carbon
Aeration
Point-of-use system
Removes radon from water at tap
Treats only small percentage of household water
Less effective than point-of-entry

23. Granular activated carbon (GAC) system
Measuring Radon in Residential Properties
How can you reduce radon in a home?
Granular activated carbon (GAC) system
Used to treat radon in water levels from 5,000 pCi/L to below 10,000 pCi/L
Less expensive
Photo:
Filters water through carbon bed, which traps radon and radon decay products
Tank may emit some radiation and may require shielding
Filter must be changed each year
Connecticut Radon Measurement
Training Program 2006

24. Measuring Radon in Residential Properties
How can you reduce radon in a home?
Aeration system
Used to treat radon levels 10,000 pCi/L and above
More expensive
Mixes water with air and vents radon outdoors
System does not become radioactive
Requires yearly cleaning
Photos: and
Connecticut Radon Measurement
Training Program 2006

25. Summary Mitigation should be done by qualified contractor
Mitigation involves
Visual inspection
Consideration of home construction
Possibly diagnostic tests
General mitigation methods
Sealing foundation openings
Home/room pressurization
Heat recovery ventilation
Natural ventilation

26. Summary Methods for slab-on-grade and basement foundations
Subslab suction
Drain tile suction
Sump hole suction
Block wall suction
Methods for crawlspace foundation
Submembrane suction
Active depressurization
Crawlspace ventilation