In Division 7 we discussed radon gas and mitigation. There are several acceptable methods currently being used to measure radon in air and in water. Some test kits are available through local hardware stores (see Chart 13.1). It is important to follow the manufacturers instructions precisely.
Radon Testing in an Existing Structure
The general procedure for radon air testing, regardless of the type of kit used, is:
• Close the home for a minimum of 12 hours before beginning the test and keep it closed throughout the testing period. You may enter and leave the house as long as the doors are not left open.
• Place the sampler about 30 inches above the floor and at least two feet away from the wall in the area being tested. Keep the sampler away from doors, windows, fireplaces, outside walls, corners, and any other places where drafts or stagnant air may exist. These precautions are necessary to ensure that the sampler is exposed to a representative sample of air.
• Accurately record the starting and stopping time. This information, along with the date, must be included with the sample when it is returned to the lab. Without precise recording information, the results cannot be considered valid.
A typical radon test kit costs less than $25. After each individual test, the kit must be returned to a laboratory for analysis. Multiple testing or continuous monitoring can be carried out with electronic radon monitors.
Radon Land Test
Radon mitigation is most effective and least costly when incorporated into the construction of the home. If you are building a new home and there is reason to suspect a radon problem, a land test is advisable. Although the test will not provide a definitive answer as to what the radon levels will ultimately be in the finished home, it is nevertheless an indicator that will help you decide whether mitigation measures should be included in your construction plans.
The test kit available for measuring radon in the soil requires placing a special collection box with its open side over the soil to be tested. Mound soil around the lip of the box to form a tight seal and keep the box in place. Radon gas is trapped and concentrated in a carbon medium and can then be measured by a testing apparatus. Record the starting time and date. After the prescribed period of time (usually 48 hours), push the soil away, retrieve the tester, and return it to its foil pouch. Record the stop time and send it with the other information and materials to the lab for analysis.
Radon Water Testing
Radon found in water poses a health threat when released into the air and inhaled. Hot, steamy baths or showers with water that has high radon content can be a serious source of exposure. Since the EPA requires municipal water sources to screen for radon, it is necessary to test only well water. Small amounts of radon can be removed with special carbon filters. A high radon content (5,000 pico – curies per liter or greater) is more difficult and costly to remove. (See Chart 13.1 for test kits for radon in water.)