An "occupied structure" is any building, structure, appurtenances to buildings and structures, land, water or air vehicle, or similar place adapted for overnight accommodation of persons, or occupied by persons for the purpose of carrying on business or other activity therein, or for the storage or safekeeping of anything of value. Such a structure is an "occupied structure" whether or not a person is actually present. However, for purposes of chapter 713, a box, chest, safe, changer, or other object or device which is adapted or used for the deposit or storage of anything of value but which is too small or not designed to allow a person to physically enter or occupy it is not an "occupied structure".
Iowa Code § 702.12
84 Acts, ch 1247, §1