Radon Testing: What Are the Different Types of Radon Testing?
Radon Testing Colorado Springs are important parts of a complete home inspection. Radon is a dangerous gas that can cause lung cancer.
It enters buildings through floor cracks, construction joints, wall cavities, and service pipes. A radon test is the only way to find out the levels in your home.
The Electret Ion Detector (EIC) measures the amount of radon gas in a room. It does this by using an electrostatically charged disk in a chamber into which radon and its decay products may diffuse. The ionization of the disk caused by radon and its progeny reduces the surface voltage of the electrode, which can then be measured in the laboratory. A calibration factor then relates the reduction in voltage to the concentration of radon in the room.
The EIC is one of the most accurate radon detectors available to the consumer market. It has the advantage of being easy to use. Its performance has been demonstrated in a number of field tests, and its reliability is well documented. The method is very sensitive to humidity, however, and must be calibrated at different levels of humidity. This is especially important if the device will be used in locations that experience high temperatures and/or humidity.
A preferred embodiment of the Electret Ion Detector consists of a housing 100 with a handle 102 and an ionization chamber with a cylindrical electret holder 120 at its lower end. The cap 102 has a hole 106 through which the electret holder can be read. When the cap is threaded off, a spring 132 lifts the plunger 130 to a position close to the electret. The ionization of the chamber by the alpha particles produced by radon causes the discharge of electrons from the electrostatically charged disk, thereby reducing the surface voltage of the electret. The plunger is moved back to the original position by a spring to a new, lower position each time the ionization chamber is read. The difference in the electric charge of the electron before and after irradiation, called Dgamma, provides a measure of the exposure to gamma radiation.
The ionization chamber can be placed anywhere in the home, but it is most effective when located in the lowest living area of the house. It should be positioned away from drafts and severe heat sources. During the testing period, the homeowner must ensure that all windows and outside doors are closed and kept closed as much as possible. Also, the test should not be conducted during times of unusually severe weather, such as storms and high winds.
Alpha Track Detector
In this method of radon testing, a layer of plastic film is used to catch alpha particles. As these particles fly through the air, they etch marks onto the plastic. These etchings can then be analyzed by a professional inspector, and the number of tracks is indicative of the level of radon in your home. The device is also capable of being used for long-term monitoring, lasting from 90 days to a full year. This type of radon testing is commonly used by radon professionals to provide real-time readings and a more accurate picture of radon levels in a dwelling over a long period of time.
There are a handful of different ways to perform a radon test, but the most common methods include charcoal canisters, liquid scintillation detectors, alpha track devices, and continuous monitors. Each of these tests requires the device to be kept in the home for a specific period of time, typically no longer than 90 days, and then sent to a lab for analysis.
A radon test can only provide an indication of the radon levels in your home if it is performed properly. This means 12 hours of closed-house conditions before beginning the test, placing the device in the lowest occupied level of the building, and keeping it away from fans, heating and cooling systems, and anything else that could interfere with the test results.
The EPA recommends the use of short-term tests when purchasing a home and long-term monitoring for those looking to take steps to lower their radon levels. A combination kit, The Bundle, is available that includes a Rapidos short-term test and three Radtrak3 long-term testers to allow homeowners to get a complete picture of their radon levels in their home.
When selecting a company to conduct a radon test, make sure the inspector is certified through the Canadian National Radon Proficiency Program (C-NRPP). This ensures that the testing technician has met all requirements set by Health Canada and that the company adheres to the international quality standard ISO 17025.
Charcoal Canister
A canister of charcoal granules is used to absorb radon and its byproducts, then the sample is sealed and sent to a lab for analysis. Results may take two to seven days and include a lab fee.
A short-term test requires the homeowner to follow strict instructions, including closing all windows and outside doors, operating heating or air conditioning fans that re-circulate the air, and not painting or remodeling the home during the testing period. The homeowner must also keep the canister out of the reach of children and pets and ensure that it is placed at least 3 feet from exterior doors and windows. The EPA recommends that the shortest duration possible be chosen for the test.
The charcoal is weighed to determine how much radon has been adsorbed, and the lab technician counts iodine spots on a photographic film to calculate the concentration of radon in the canister. This method is prone to errors caused by the user, the lab technician, or the equipment, and results can be delayed by up to three months.
During the radon testing period, it is important that the homeowner not open the windows or doors, operate any type of fan or fireplace, or paint or remodel the home during the test. If the charcoal canister is disturbed or tampered with in any way, a new test must be performed. It is important to note that a homeowner can receive a high radon reading if the radon test was taken on the upper level of the house, while a lower reading could be present in the basement.
Advanced continuous radon monitors can detect movement of the device, changes in temperature and barometric pressure that indicate a person opened a window in an attempt to throw off the test, and even send a text to a phone or computer when the tampering occurs. A continuous monitoring system can also report any significant movement or tampering to the home inspector and the homeowner, saving time, money, and the frustration of falsely inflated radon levels.
While the charcoal canister is a great tool for a home buyer to get an idea of the radon levels in a potential new home, it is also easy for unscrupulous real estate agents or homeowners to tamper with these tests when they are not being watched. A continuous radon monitor cannot be moved or hidden from view and can document any movement or tampering that occurs.
Liquid scintillation medium
The radon testing procedure uses a liquid scintillation medium to measure radon gas. This method is more accurate than other methods because it measures a radon atom’s decay product, which produces photons. The scintillation medium contains a mixture of chemicals that react with the radon atom and emit photons. This measurement is used by laboratories to identify radon levels in homes. This is the most common type of radon test.
A radon test using a liquid scintillation medium can be conducted in a home, office, or school. The test takes only about 90 days and is easy to do. It’s also less expensive than other radon tests. You can buy a radon test kit from many hardware stores. The kits include a container filled with activated charcoal to absorb radon and a special tube to collect the charcoal for laboratory analysis.
Activated charcoal absorbs alpha particles emitted by radon. When the charcoal is used up, it can be resealed and sent to a lab for processing. The results are then recorded on a graph and used to determine radon levels in the building. This is the most accurate type of radon test.
Another type of radon test is the liquid scintillation chamber, which is a special glass container that contains a water-soluble cocktail and a color quenching agent. The scintillation counter then counts the resulting photons and converts them to a concentration of radon gas in Bq/m3.
This method is very sensitive to environmental interference, such as radionuclides that are soluble in the scintillation solution or water. These radionuclides could affect the measured result by changing the decay constant of 222Rn in the scintillation cocktail. In addition, the radon detection sensitivity is influenced by the water’s salinity and temperature.
In order to obtain a good measurement, the sample must be in a closed room in a controlled environment. The room should be located in the lowest inhabited area of the house and should meet other requirements such as keeping windows, doors, and vents closed; not using air conditioning or heating; and not conducting any activity that would disturb the test. The radon concentration in the water-soluble cocktail must be corrected for air-water volume, air and water permeability, water salinity, and temperature.
