Radon Measurement & Testing
Radon is measured in picocuries per liter, abbreviated pCi/L. The average levels found outdoor air in the United States is 0.4 pCi/L and average indoor air is 1.3 pCi/L. The guidance from the EPA recommends mitigation be considered in homes where testing finds levels at or above 4.0 pCi/L.
The EPA provides two distinct protocols for radon measurement in residential homes: real estate and non-real estate. The real estate protocols recognize the time critical nature of the inspection period in a property transaction. Guidance for real estate measurement is covered in the EPA’s Home Buyer’s and Seller’s Guide to Radon and is an excellent source of information providing answers to many common radon questions. The Citizen’s Guide to Radon offers strategies for testing your home for radon and discusses what steps to take after you have measurement results.
We are capable of conducting both real estate and non-real estate radon measurement procedures following the appropriate protocol for the situation. In all real estate measurements we use continuous radon monitors and can conduct a test in as little as 48 hours. Our monitors measure and report radon levels in hourly increments and an average of the hourly results are reported as the final measurement. This is ideal for real estate transactions because we can deliver results immediately upon completion of the testing period. We do not need to send samples to a laboratory and wait for analytical results.
We strictly follow the EPA short term measurement protocols when conducting a typical real estate 48-hour measurement. It is very important that closed house conditions are maintained throughout the testing procedure to ensure accurate results. Closed house conditions must begin 12 hours prior to the beginning of the 48-hour testing period. Because of this we start all of our tests in the morning and ask that closed house conditions begin the night before. All outside vents and windows must not be opened. All outside doors should be closed except for normal entry and exit. Ask your project manager for additional details on closed house conditions.
We will pickup the monitoring device at the completion of the 48-hour measurement period. The monitor will be transported back to our SE Portland office and the data will be downloaded to our system. The data will be interpreted and a report generated for our client. If the average radon level during a real estate testing period is at or above 4.0 pCi/L we will recommend the installation of a radon mitigation system (link to mitigation page).
The EPA specifies several options for non-real estate transaction radon testing. When you the time constraints of a real estate transaction don't exist, the testing period can be extended out to as much as one year. Typically we will recommend an initial short term measurement lasting anywhere from 48 hours to 90 days. Once results are received we can recommend the follow up testing if necessary. If the initial test is less than 4.0 pCi/L, follow-up testing is probably not needed. If the initial short term test is at or above 4.0 pCi/L, follow-up test should be performed. If the initial test is between 4-10 pCi/L, the EPA recommends a long term follow-up test be conducted. If the initial test result is over 10 pCi/L, the EPA recommends that a second short-term test can be performed to verify the initial measurement. If two short-term tests were done, mitigation recommendation will be based on the average of the two tests. If a long term test was conducted, the results of the long-term will determine the need for mitigation. Mitigation is recommended if 4.0 pCi/L or higher.
For an accurate radon measurement, it is necessary that closed house conditions begin 12 hours prior to our arrival and are maintained throughout the testing period.
Closed house conditions include:
- All exterior doors should be closed except for normal entry and exit;
- All exterior windows must be closed and window fans turned off. If window air conditioner units are installed they must operate on recycle mode or be turned off;
- Outside vents, such as foundation crawlspace vents, must be closed unless designed to remain open;
- Internal-external air exchange systems must be turned off, unless they are part of a building’s engineered design;
- Whole house fans should be turned off, however attic fans intended to control only attic conditions should continue to operate.