(a) All exposed edges of the lower six inches or more, if necessary, of wooden doors and door jambs serving as front, rear or side entrances into business buildings from the ground, basement or cellar floors, and other doors accessible to rats, shall be protected, if necessary, against the gnawing of rats by covering such doors and jambs with solid sheet metal of not less than 24 gauge thickness. The same material shall be used on doorsills or thresholds, or such doorsills or thresholds may be constructed of cement, stone, steel or cast iron.
(b) Doors, door jambs and sills of coal chutes and hatchways that are constructed of wood shall be covered with solid sheet metal of 24 gauge or heavier, or they may be replaced with metal chutes of 24 gauge or heavier, installed in such manner as will prevent the ingress or egress of rats.
(c) All doors on which metal flashing has been applied shall be properly hinged to provide for free swinging. When closed, doors shall fit snugly so that the maximum clearance between any door, door jambs and sills shall not be greater than three-eighths of an inch.
(d) Door jambs and sills constructed of metal, concrete, masonry, stone or cement mortar, or cast iron and steel, when fitting closely to exclude rats, are not required to comply with this provision.
(1964 Code, § 19-358)