Radon Overview Reducing Radon in a Home

Learning Outcomes Upon completion of this module you will be able to:  Recall the most common method to reduce radon in a home  Identify why you can’t just seal the cracks to keep the radon out  Recognize the difference between a passive and active mitigation system

Learning Outcomes Upon completion of this module you will be able to:  Identify the rules for vent pipe location in an interior sub-slab depressurization (SSD) system  Determine where the exhaust fan should be installed in a interior SSD system  Recall what a manometer is, and what it does in a radon remediation installation

How To Fix A House If It Has Elevated Levels?  A Mitigation Contractor can:  Install a system to reduce radon levels  Prevent radon from ever entering the living space  Sealing visible cracks is a basic part of most radon mitigation approaches, but sealing alone is not enough.  Opening doors and windows to dilute the radon may sometimes be effective, but it is not a practical long-term solution.

How To Fix A House If It Has Elevated Levels? Can’t we just seal the cracks?  Radon can enter through very small openings.  Without affecting house pressures, sealing is not a stand-alone technique.

Methods for Reducing Radon in Air 1. Depressurization  Suck air from below basement (slab)  Radon does not enter home  Radon is exhausted away from home 2. Pressurization  Blow air into the basement  Push radon gas out  Radon gas is diluted All methods involve sealing foundation openings

Various Foundations May Require Different Methods

Basement and Slab-on-Grade Options  Most common method: Active sub-slab suction system  Suction prevents radon from entering home  Draws radon from below home and vents radon to pipe(s)  Releases radon to air above home  It is called an active system if we install a fan in the pipe(s)  It is called a passive system if we do not install a fan in the pipe(s)  New homes often have a passive system installed at the time of construction.

Active Sub-slab Depressurization (SSD)  Reliable  Effective in reducing high radon levels  Suction pipes are inserted through the slab into soil or crushed rock below  Vent fan draws radon gas up and releases it outside, above the roof  Works best when air moves easily under slab

Major Requirements of an SSD System  All components should be clearly labeled “Radon Reduction System.”  If the system has an exhaust fan, the fan must be located outside or above the habitable space of the building.  It may be located outside or in an unused attic.

Major Requirements of an SSD System  Any exhaust fan must be located in a vertical run of the vent pipe.  If there is an exhaust fan, there should be a visible or audible warning device to alert occupants if the system fan stops working.  The vent pipe must end at least 12 inches above the surface of the roof.

Major Requirements of an SSD System  The vent pipe must end at least 10 feet from any window or opening into the house and at least 10 feet from any adjoining or adjacent buildings.  Ties or brackets must secure the vent pipes:  Every six feet in a horizontal run of pipe, and  Every eight feet in a vertical run of pipe

Labeling  The system must be clearly labeled as a “Radon Reduction System”  The contractor’s contact information must be attached to the system

Exhaust Fan: Exterior Installation

Exhaust Fan: Interior Installation  Usually more effective and last longer  Fan must be installed in unused and unoccupied space  Fan may not be installed in basement

Visible Gauge Manometer:  Does not measure radon  Alerts residents if fan stops working

Discharge Point: Exterior Installation  The discharge point must be at least 12 inches above the surface of the roof  It must also be at least ten feet from windows and other openings, if it not located at least two feet above such openings

Exhaust Point: Interior Installation  The discharge point must end at least 12 inches above the surface of the roof  It must also be at least ten feet from windows and other openings, if it not at least two feet above such openings

Pressurization Methods  Typically used in homes with dirt or stone foundations  Locations where depressurization would be ineffective  Types  Home/room pressurization  Heat recovery ventilation (HRV), or air-to-air heat exchange

Summary In this module we have discussed:  The most common method to reduce radon in a home  Why you can’t just seal the cracks to keep the radon out  The difference between a passive and active mitigation system

Summary In this module we have discussed:  The rules for vent pipe location in an interior sub-slab depressurization (SSD) system  Where the exhaust fan should be installed in an interior SSD system  What a manometer is, and what it does in a radon remediation installation