Section 450.141 - Screens(A) Each window and door used for ventilation to the exterior shall have tight-fitting screens with a minimum of 16 mesh per square inch. Each screen door shall be equipped with a self-closing device unless the door is designed to slide from side to side.(B) Every required window screen other than those in a food preparation, service or storage area shall be in place and in good repair from April 15 through October 30.