The Illinois Department of Nuclear Safety (IDNS) has developed protocols for homeowners who wish to test their homes for the presence of naturally occurring radon gas. These testing protocols are summarized in simplified form in the table below. This summarized protocol applies to both residents testing their own dwellings and to professional measurement licensees testing home environments. The testing options outlined are intended to be used by the homeowner to determine if steps should be taken to reduce the radon concentration in the home.

Because of the unique nature of real estate transactions, the IDNS has designed special protocols for radon testing in real estate transactions. If you expect to be selling your house in the near future, we recommend that you contact the Illinois Department of Nuclear Safety (IDNS) Radon Program for a copy of [the] fact sheet, "Rdon Testing Guidelines for Real Estate Transactions."

Conduct a short-term radon test in each of the lowest structural levels of the home. For instance, if the house has one or more of the following foundations: basement, crawl space, slab-on-grade; a test, in accordance with this protocol, in each area is required for professional measurements and highly recommended when a resident tests his or her own dwelling.

* Short term tests may last between two and 90 days. Most last between two and seven days. Tests between seven and 90 days are usually impractical for real estate transactions, but are fine for homeowners assessing their own radon situation.
Examples of short-term detectors include: activated charcoal canisters, charcoal liquid scintillation vials, elecret chambers and continuous radon monitors.

** Long-term tests last between 91 and 365 days, and are strongly recommended by the IDNS for all homeowner (that is, non-real estate transaction) testing. Long-term tests give a better estimate of the year-round radon concentration in the home. The closer the test duration is to a full year, the closer the test result will be to the actual average.
An example of a long-term test is an alpha track detector.

*** If your first and second short-term tests are not in agreement (or if you're not sure whether or not they agree), contact the IDNS Radon Program or your registered radon measurement professional. You will probably want to conduct a long-term test, or have a radon professional conduct testing to confirm your radon levels. An example of radon measurements that are "in agreement" is a result of 11 pCi/L on the first test and 9 pCI/L on the second. An example of measurements not in agreement is 15 pCi/L on the first test and 2 pCi/L on the second. Radon levels do vary from day to day, but rarely by more than a few pCi/L.

The only time radon test results can be averaged is when two test results are placed simultaneously or sequentially. Test results from different areas such as above the crawl space and in the basement are considered two different tests. Results are each independent of the other and are reported independently such as basement result of 4.2 pCi/L and family room over crawl space of 6.1 pCi/L. With an elevated radon level in any one of the lowest structural areas, the recommendation is to fix the house.

• Hire an IDNS-licensed radon measurement professional.
• Be sure that IDNS radon testing protocols are followed.
• Use tamper indicators on all windows and doors not used for normal entry and exit during short-term tests.
• Conduct a long-term radon test, the longer the better, up to one year.
• Call the IDNS Radon Program if you are uncertain about anything regarding radon testing.

Short-term and long-term test kits can be purchased at most hardware and department stores, and some other stores. The IDNS Radon Program can provide a list of licensed radon measurement professionals, and a list of businesses which offer testing kits throught the mail.

Be aware that any tests lasting less than a week (that is, most short-term tests) require closed-house conditions. Closed-house conditions mean keeping all windows closed, keeping doors closed except for normal entry and exit, and not operating fans or other machines which bring air in from outside (except for fans that are part of a radon reduction system, or small exhaust fans that operate for only short periods of time).

• Before Testing: Begin closed-house conditions at least 12 hours before the start of the short-term test.
• During Testing: Maintain closed-house conditions during the entire duration of the short-term test, especially for tests less than one week in duration. Operate home heating or cooling systems normally during the test. For tests lasting less than one week, only operate air conditioning units that recirculate interior air.

Place the detector or detectors in the lowest level containing a room that is used regularly, such as:

• a family room, living room, den, playroom, or bedroom; and/or
• in the lowest level suitable for occupancy, even if it isn't currently used but could be, without renovating.

For instance, if the house has one or more of the following foundations - basement, crawl space, or slab-on-grade, a test should be performed in the basement and in at least one room over the crawl-space and slab-on-grade area. If an elevated radon level is found in one of these areas, fix the house.

• in kitchen, laundry room and bathroom (because fan systems and humidity may affect some detectors); or
• in crawl-spaces, on floor or wall cracks, or right next to a sump pump, as this may cause a false high reading.

Call the IDNS Radon Program. Staff there can provide you with names and addresses of licensed mitigation professionals that are trained to reduce radon levels. We also recommend that you contact IDNS for a copy of [the] brochure, Illinois Department of Nuclear Safety (IDNS) Guide to Radon Mitigation. Measurement professionals are precluded by the Rule from performing mitigation at the same address they have performed a measurement. If you prefer, the IDNS can provide you information on how to fix the radon problem yourself.

Perform another short-term test, following the IDNS protocols outlined here, to ensure that the radon reduction system is effective. Make sure the system is operating during the entire test.

• Information about radon and radon testing;
• Names of licensed radon measurement professionals;
• Names of licensed radon mitigation professionals trained to reduce radon

Additional information about radon measurement and mitigation can be found in your local library.
Call the IDNS Radon Program at: 1 (800) 325-1245