A high-rise mixed-use project with two levels of office and multiple levels of residential is in EPA Zone 1 for radon. All the codes addressing radon mitigation listed in the prerequisite applying to the residential use are for low- to-mid-rise residential only. (For instance, Appendix F of the IRC covers only low-rise residential). The language in the prerequisite also instructs to "design and construct any dwelling unit on levels one through four above grade with radon-resistant construction techniques".
In this project, the first residential level is around 55' above grade, (above the two office levels) while there are some residential uses such as lobby, mail areas, etc on the first floor. The radon mitigation requirements in the stated codes do not seem to apply to this situation. Can an exception be made to this project, since the residential use is not located on grade as in a typical single-family/low-rise residential project?