“HUD does not consider RV’s as permanent living quarterssince it exempted RV’s from the building codes. With the small size of RV’s, it is virtually impossible to build a structure that can meet HUD residential building codes, and still be able to drive down a highway and handle necessary wind shear requirements. RV Consumers are still protected by ANSI A119.2 standards when they purchase an RV from an RVIA member and NHTSA’s Federal Motor Vehicle Safety Standards.”
In the document linked below, the Recreational Vehicle Dealers Association comments on the Federal Reserve’s requirements regarding loans for dwellings versus RVs, and also comments on permanent versus temporary living structures.