According to the ANSI-AARST radon mitigation standards, what is the minimum diagnostic work required before starting a mitigation job?

The correct answer reflects the requirement for a visual inspection of the building, which is crucial before initiating any radon mitigation measures. A visual inspection allows the mitigation specialist to identify potential entry points for radon, such as cracks in the foundation, gaps around pipes, and areas where the building contacts the ground. Observing the overall condition of the structure and assessing its ventilation also plays a vital role in planning an effective mitigation strategy.

Conducting a visual inspection helps to determine the level of risk associated with radon entry into the building, as well as informing which mitigation techniques may be most appropriate. It lays the groundwork for further actions by pinpointing specific areas that may require further attention or detailed analysis.

In contrast, while full structural analysis, comprehensive radon level testing, and soil testing may be important components of a comprehensive radon assessment, they are not the minimum diagnostic requirement stipulated by the ANSI-AARST standards before starting a mitigation job. These methods may follow the visual inspection, helping to provide a deeper understanding of radon levels and specific mitigation needs, but they do not replace the initial importance of a visual inspection.