ABout Mitigation / Radon Mitigation / Guide to Radon Mitigation

IEMA - Guide to Radon Mitigation (Illinois Emergency Management Agency)

Your radon level is 4 picocuries per liter (pCi/L) or higher. What are your options?

Contact a mitigation professional licensed by DNS to reduce the radon levels in your home.

Request two or three price estimates from licensed mitigation professionals. The cost of a radon reduction
system generally ranges from $900 to $2500, depending on characteristics of the house and choice of
radon reduction methods.

Talk to your mitigator and be sure you understand the mitigation design.

Residents of a dwelling may install a mitigation system in their own dwelling; however without proper
equipment or technical knowledge, you could actually increase your radon level or create other potential
hazards.

IEMA Assures Consumer Protection

IEMA-licensed mitigation professionals have passed the U.S. Environmental Protection Agency
(USEPA) radon qualification course and exam, or an equivalent course and exam approved by the
department.

IEMA-licensed radon professionals work to a Quality Assurance Program and a Worker Protection
approved by the department.

IEMA investigates and resolves complaints and non-compliance reports.

IEMA performs performance audits on a regular basis to evaluate individual professional compliance.

IEMA radon regulations ensure that radon measurements and mitigations performed by licensed
professionals are standardized throughout the state

Mitigation Systems Reduce Radon By:

Collecting radon prior to entry into the building and discharging it to a safe location. Modifying building
pressure differentials. Diluting radon concentrations with increased ventilation.

Mitigation Systems In Illinois Must Include:

Effective radon reduction
Unobtrusive and permanent installation
Quiet operation
Energy efficient operation and maintenance
A system function indicator
A primary suction point independent of the sump pit
Sump covers with observation ports
Exhaust above the highest eave
Sub-Slab Pressurisation (SSD)

Active sub-slab suction uses a fan to draw radon from beneath the house. SSD systems collect radon prior
to entry and exhaust it to a safe location above the highest eave.

Sub-Membrane Pressurisation (SMD)

SMD is performed in crawl spaces and areas that are directly in contact with rock or soil. Suction is created:

Under a specified polyethylene or equivalent flexible material (plastic sheet) permanently installed
over exposed soil or rock
By a fan drawing radon from beneath the plastic sheet and exhausting the radon outdoors above the
highest eave.
Discharging Above The Highest Eave

Discharge above the highest eave ensures that there is significant dilution of exhaust by outdoor air to
minimize re-entry into the house and minimize exposure to persons in the yard and neighboring areas. To
ensure public health and safety, IEMA requires that the point of discharge from fan-powered soil
Pressurisation systems be located:

Above the highest eave of the roof;
As close to the roof ridge line as possible;
10 feet from any window, door or other opening (into the building) that is less than 2 feet below the
exhaust point;
10 feet or more from any opening to an adjacent building

Sealing:

Sealing enhances radon reduction techniques, such as SSD, SMD and Heat Recovery Ventilation. Reducing
the loss of conditioned air increases radon reduction system effectiveness and cost efficiency. DNS does not
recommend the use of sealing alone to reduce radon concentrations. Sealing alone has not been shown to
lower radon levels significantly or consistently.

New Construction Systems:

Since 1995, radon control methods have been part of the Council of American Building Officials (CABO)
"One and Two Family Dwelling Code." Several Illinois municipalities have adopted variations of the CABO
code requiring the installation of radon control methods in newly constructed residences. These methods
are known as passive and skeletal new construction systems. Passive or skeletal new construction systems
are not acknowledged mitigation systems and may or may not reduce radon concentrations in homes to
below the USEPA’s Action Level, 4.0 picocuries per liter of air (4pCi/L). IEMA encourages homeowners to
test their home to determine the actual radon levels. With test results of 4 pCi/L or more, passive and
skeletal new construction systems should be converted to active soil Pressurisation systems by mitigation
professionals licensed by IEMA. IEMA recommends that post-mitigation measurements be performed by
measurement professionals licensed by IEMA in order to ensure defensibility and reliability of test results.

Passive New Construction:

Passive new construction systems rely solely on the convective flow of air upward in the vent pipe for sub-
slab Pressurisation. The system consists of a vertical vent pipe routed through conditioned space from the
suction pit to 12 inches above the roof.

Skeletal New Construction:

A skeletal system is a system that is designed for the installation of a vent fan and may consist of multiple
vent pipes. This includes vertical and angled runs that are not necessarily routed through living space that
may be joined to a single termination above the roof or may terminate separately above the roof.
Always Perform a Post-Mitigation Test!

Post-mitigation tests are important evaluators of actual system function:

Professional post-mitigation measurements must be performed to the applicable DNS measurement protocol.
The Adopted Rule, 32 Illinois Administrative Code, Part 422, prohibits mitigation professionals from
performing radon measurements at a residence where they have installed a mitigation system.

For additional information about radon, radon measurement and mitigation, call IEMA at: (800) 325-
1245 or visit the
IEMA website at: Illinois State Radon Information