Proper placement of Radon Tests
Radon tests should be left undisturbed for the entire testing period and placed approximately two to five feet above the floor. The test should also be placed in a room with moderate temperatures that feel comfortable to the homeowner. Tests should not be placed near furnaces, in laundry rooms, kitchens, bathrooms, near windows. Tests should not placed in the path of direct air flow such as by heat vents or fans (Colorado, 2003).
Closed housed testing conditions requires all windows and doors closed, air conditioners should be set on auto or re-cycle during the testing period. Window fans and swamp coolers need to be turned off. Normal entering and exiting through doors are acceptable; however, this is not the time to be moving furniture in or out of the home. These conditions should be maintained for at least 12 hours prior to the test starting as well as throughout the testing period.
How do the different types of test work?
This type of test is an open faced canister, with activated charcoal, which is placed in the lowest level of the home for a minimum of 48 hours and a maximum of 96 hours. This works by allowing air containing radon to diffuse through the metal screen and into the activated charcoal (Deployment, 2010). The date, time, location, building type, and foundation type should be recorded at the beginning of the test. Upon completion of the test the canisters should be resealed with vinyl type and sent as soon as possible to the respective lab.
AccuStar Labs analyzes closed charcoal canisters by placing it in a gamma detector. Gamma emissions from the decay of radon adsorbed on the charcoal are counted. A calibration factor accounting for exposure time and decay time is used to calculate the radon concentration. A correction factor is applied for any weight gain from moisture absorbed into the charcoal (Laboratory Analysis, 2010).
Charcoal Liquid Scintillation (LS)
LS Tests are small vials that are placed in the lowest level of the home for at least 48 hours. This is considered a passive detector and requires no power. The passive nature of the activated charcoal allows continual adsorption and desorption of radon. The adsorbed radon undergoes radioactive decay during the measurement period. The adsorption of radon onto the charcoal is the same as the activated charcoal, but the difference is that the charcoal LS test undergoes analysis by being treated with scintillation fluid and a scintillation counter is used to analyze the fluid.
Continuous Radon Monitor (CRM)
CRM tests are machines which are placed in the lowest level of the home for 48 hours. The great thing about the machine is that the test start date can be delayed for 12, 24 or 48 hours. This type of machine is calibrated annually and sent in for any problems, making it one of the most accurate radon tests. This is most commonly used test for real estate transactions. This type of test is also the fastest and most efficient for determining radon levels. The machine pumps or diffuses air through a counting chamber. The counting chamber is a scintillation cell or ionization chamber. The scintillation count is processed by electronics and radon concentrations for predetermined intervals are stored in the machine’s memory (www.ncradon.org).
Colorado Vintage Companies, Inc. (2003) Protecting your home from radon (2nd ed). Colorado Springs: Vintage.
Deployment: Activated Carbon Open. (2010). Retrieved October 23, 2015, from AccuStar Labs: http://www.accustarlabs.com/radon-testing-product-specifications/activated-carbon-open.aspx
Laboratory Analysis: Activated Carbon Open. (2010). Retrieved October 23, 2015, from AccuStar Labs: http://www.accustarlabs.com/radon-testing-product-specifications/activated-carbon-open.aspx
NC Radon Program Radon Testing Devices. (2014). Retrieved October 23, 2015 from NC Radon Program: www.ncradon.org