What is the required distance radon measurement devices must be placed away from exterior walls?

The required distance for placing radon measurement devices away from exterior walls is one foot. This distance is essential to ensure that the measurement is not influenced by ventilation from outside sources or by outdoor air conditions. By positioning the device at least one foot away from exterior walls, the radon levels measured inside a structure reflect the indoor air quality more accurately, rather than being affected by fluctuations in outdoor radon levels or drafts coming from the surroundings. This standard helps maintain the integrity of the test results, providing a reliable assessment of radon concentration within the indoor environment. Proper placement is critical in obtaining precise measurements necessary for evaluating radon risk and determining any needed mitigation actions.