Description - Figure 4 - Recommended radon measurement location in multi-story buildings

These images illustrate the recommended measurement locations in multi-story buildings specifying the floors to be tested based on room occupancy. All occupied rooms on the lowest floor in contact with the ground should be tested.  If there are no occupied rooms on the level(s) in direct contact with the soil then all occupied rooms on the first occupied level are to be tested. Only rooms that are, or might be, occupied by someone for a period greater than 4 hours a day should be  tested.