What is the minimum height at which detectors should be located above the floor?

Detectors should be located a minimum of 20 inches above the floor to ensure that the measurement of radon levels is representative of the breathing zone of the occupants. This height facilitates accurate sampling of the air that people typically inhale, allowing for effective assessment of radon exposure in inhabited spaces. Placing detectors too close to the floor may result in misleading readings due to the stratification of air in a room, where radon gas could accumulate at different levels. Therefore, the guideline to place detectors at or above 20 inches supports consistent and reliable radon measurement practices.