IMC Section 403.2.1 - Recirculation of Air

[Designer_82]

The mechanical code Sec. 403.2.1 - Recirculation of Air says that
"The outdoor air required by Section 403.3 (Group R-2, R-3 and R-4 occupancies three stories and less in height above grade) shall not be recirculated."

Does that mean you can't duct the OSA into the return of the air handler?

 

[nuuvox000]

Per the commentary: "The intent of Section 403 is to bring in outdoor air, force it through the occupied space and then discharge an equal amount of air back to the outdoors." There needs to be relief or exhaust. You can duct it to the return; per code definitions: "Recirculated Air: Air removed from a conditioned space and intended for reuse as supply air."