What is the minimum distance a radon measuring device should be placed from the ceiling?

The minimum distance for placing a radon measuring device from the ceiling is established to ensure that the device can accurately measure the radon concentration within the breathing zone of individuals in the room. When a device is positioned near the ceiling, it may not effectively capture the air that occupants breathe, as radon gas tends to accumulate closer to the ground due to its density. Placing the device too high could lead to misleading readings, as the concentration of radon closer to the floor might be significantly higher.

The guideline of a minimum of 12 inches from the ceiling ensures that the device is positioned at a height where it can detect more representative levels of radon gas that individuals are exposed to in their everyday environment. This height allows for a better assessment of radon exposure risk in residential and other indoor settings.