Equipment Used for Single Family Homes
and Real Estate Transactions
Continuous Radon Monitoring (CRM) - Provides Hourly Tracking of Radon Levels
The Continuous Radon Monitoring (CRM) is used in single-family homes or other small testing projects that only require 1 or 2 testing locations. This electronic device is 3" x 5" x 7" inches and usually sits on a tripod but can also sit on a counter or table, which is convenient if small children live in the home.
The Recon CRM, manufactured by Rad Elec Inc. is an electronic device that uses two independent sensors to take continuous readings of the alpha particles discharged by the radon gas. The continuous readings result in an extremely accurate and detailed report that shows (using graphs) the fluctuations in radon levels over the test period. In addition to the radon levels, the monitor also takes continuous environmental readings of the air temperature, humidity, and barometric pressure. The environmental data, when paired with the hourly radon levels, is used to assess if anything unusual occurred during the test that skewed the results. Things like unusually severe weather (i.e. tornado activity) can cause radon levels to spike resulting in an invalid test. The data can also tell us if the mandatory closed building conditions were not maintained and someone left windows / doors opened in an attempt to air out the house - thus invalidating the results. The CRM is also equipped with sensors that will tell if the device had a power disruption or was moved. All test run a minimum of 48 hours but can be longer, depending on the time-sensitivity of the results.
Sample Report for Single-Family Home
Equipment Used for Large Projects
E-PERM (Electret Ion Chambers)
Electret Ion Chambers (also called E-PERMs) are used for large projects that require many locations to be tested simultaneously such as: schools, multifamily properties, or assisted living facilities. These devices are about the size of a tennis ball and can be set on a shelf or hung from an interior wall. E-PERMs contain no chemicals and are completely safe to occupants, including children and pets.
These devices can be used for either short-term measurements (2 - 90 days) or long-term measurements (91 - 365 days), depending on how the chamber is configured.
The device is made up of two basic parts: the chamber and the detecting mechanism called an electret. The electret, which screws into the bottom of the chamber, has a surface voltage that is measured before and after deployment. While deployed the chamber is opened allowing radon in the air to enter the device and since radon is radioactive it gives off alpha and beta particles. These electrically charged particles reduce the surface voltage of the electret. When the devices are retrieved, the chambers are closed and returned to our in-house lab where the voltage drop is calculated. From this data and the length of deployment the average radon concentration during the exposure can be calculated. Ambient gamma radiation is also factored into the calculations the appropriate adjustments made.
Advantages of E-PERMS over Charcoal Test Devices.
E-PERMS have several significant advantages over the use of charcoal test devices.
- More Accurate Results. E-PERMS provide a true integrated average over the entire deployment period. With charcoal devices the results are biased to the radon concentrations of the last 12 - 24 hours of the deployment. Charcoal devices do not provide a true average.
- Faster Results. E-PERMS are analyzed at our own analytical lab and results can be obtain within hours of retrieval. E-PERMS are not mailed to a third party lab. Charcoal canisters have to be mailed off to a lab so obtaining results can take several days, there is also the concern of the devices being lost or delayed in the mail.
- More Flexible Testing Durations: Occasionally the testing period needs to be extended due to severe weather or some other unforeseen circumstance. If needed, E-PERMS can remain deployed for extra days or even weeks without any problem. Charcoal devices have a limited deployment time (usually 48-96 hours) and have to arrive at the lab within a certain number of days, otherwise the sample is invalid, and the entire testing process has to be repeated.
- Less Waste: There is no packing material or waste when using E-PERMS. Some charcoal device manufactures have a significant amount of plastic and cardboard that has to be disposed of with each device.
Charcoal canasters (Activated Carbon) are valid testing devices that provide useful data. They are an economical choice and easy to use for the DIY homeowner or non-skilled radon technician. However, as professional radon specialist we at Radon Testing Services choose to use Electret Ion Chambers (E-PERM), which have been shown to be the most accurate and reliable passive radon test device, based on EPA-led research over the last three decades.
