What is one of the ANSI/AARST fan requirements for radon mitigation?

The ANSI/AARST standard outlines specific requirements for the placement of fans used in radon mitigation systems. One key requirement is that the fan must be installed in a location that efficiently captures radon gas and helps to expel it outside the living space. Placing the fan in the attic or outdoors is a suitable choice because this helps prevent any potential radon from re-entering the living areas of the home. It ensures that the radon is fully vented out of the building, effectively reducing radon levels within the home.

Choosing locations such as under the living space or within the living envelope would not optimize the fan's function, since they would not effectively eliminate radon from the home; this could allow radon to accumulate back into the living areas. Furthermore, installing a fan in every room is impractical and unnecessary for effective radon mitigation, as one properly placed fan can service an entire system designed to lower radon levels throughout the home.