Where should a post-mitigation test be conducted according to standards?

Conducting a post-mitigation test in the lowest livable area above a crawlspace is in alignment with best practices for radon measurement after a mitigation system has been installed. This location is significant because radon typically enters buildings from the ground and can accumulate in lower levels of a structure. Testing in this area allows for a more accurate assessment of the mitigation system's effectiveness in reducing radon levels where they are most likely to be problematic.

The choice of the lowest livable area is also supported by the principle that radon is a heavier gas and tends to collect in the lower parts of residential buildings. After mitigation, it is crucial to ensure that the levels in these areas are within safe limits, indicating that the system is operating effectively.

In contrast, testing in other areas, such as the attic or specific rooms like the living room, may not provide a comprehensive understanding of the radon reduction achieved by the mitigation system. Attics are typically not considered livable spaces where people spend significant amounts of time, making them less relevant for testing purposes. Testing in any livable space could yield results that do not accurately reflect the performance of the mitigation system, especially if that space is not the area with the highest risk for radon accumulation. Therefore