Manual of Naval Preventive Medicine
Chapter 1: Food Service Sanitation
VIII: Structural Requirements and Sanitary Controls

Department of the Navy
Bureau of Medicine and Surgery

(See also Chapter 8, NAVMED P-5010, Medical Entomology and MIL-STD-904A, Guidelines for Insect Infestation of Subsistence). Insect and Rodent Accesses. Food service facility openings to the outside must be effectively protected against the entrance of rodents and insects by use of self-closing doors, closed windows, screens, air curtains or other means. Screens must be tight-fitting, free of breaks or tears, and not less than 16 mesh to the inch of screen. Screens are not required in air-conditioned food service spaces where windows or portholes are sealed closed. Air curtains must meet the standards of NSF Standard No. 37 or be equivalent.