9.28.030 - Rat stoppage requirements—Minimum.
The following regulations shall constitute minimum requirements in equipping a business building with rat stoppage:
A. The material shall be approved and the installation supervised by the director of the department of environmental services or his authorized representative.
B. Solid sheet metal, expanded metal and wire cloth used in the installation shall have a rust-resisting protective coating of hot-dip zinc galvanizing or equal.
C. All foundation wall ventilator openings shall be covered for their entire height and width with perforated sheet metal plates of a thickness not less than fourteen gauge, or with expanded sheet metal of a thickness of not less than eighteen gauge, or with cast iron grills or grates, with any other material of sufficient strength and equal rat-resisting properties. The openings therein shall be small enough to prevent the ingress or egress of rats, and in no instance shall be larger than one-half of an inch.
D. All foundation, exterior wall and roof openings (excluding doors, windows and those openings used for the purpose of ventilation and light) such as those openings around pipes, electric cables, conduits, openings due to deterioration or damage, broken masonry or concrete or other openings which may allow the ingress or egress of rats, shall be protected by closing such openings with cement mortar, concrete or masonry, or close-fitting sheet metal, or suitable size pipe flanges, or other material with equal rat-resisting properties, which shall be securely fastened in place.
E. All exposed edges of the lower eight 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 against the gnawing of rats by covering such doors and jambs with solid sheet metal of not less than twenty-four 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.
Doors, door jambs and sills of coal chutes and hatchways that are constructed of wood shall be covered with solid sheet metal of twenty-four guage or heavier, or they may be replaced with metal chutes of twenty-four gauge or heavier, installed in such manner as will prevent the ingress or egress of rats.
All buildings with side and rear door entrances shall be provided with fly screen and hardware cloth doors. These doors shall be provided with suitable automatic self-closing devices.
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 sill shall not be greater than three-eighths of an inch.
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 of this chapter.
F. All windows and other openings for the purpose of light or ventilation, located within thirty inches above the existing ground or roof level immediately below such openings, shall be covered for their entire height and width, including frames, with wire cloth of nineteen gauge or heavier, having a mesh of not larger than one-half of an inch.
All windows and other openings for the purpose of light or ventilation in the exterior walls, which may be accessible to rats by way of exposed pipes, wires, conduits and other appurtenances, shall be covered with guards of wire cloth of nineteen gauge or heavier, having a mesh of not larger than one-half of an inch, in metal frames of twenty-four-inch galvanzied iron (called Sims frames), or, in lieu of wire cloth covering, such pipes, wires, conduits and other appurtenances shall be blocked from rat usage by installing sheet metal guards of twenty-four guage or heavier. Such guards, when used on horizontal pipes, wires, conduits or other appurtenances, shall be placed in a vertical position and shall be snugly fitted araound the pipe, wire, conduit or other appurtenance. Such guard shall measure not less than twelve inches beyond and on all sides of the pipe, wire, conduit or other appurtenance where the intervening space between the wall and pipe permits, and shall extend thirty inches in an upward direction and twelve inches in a downward direction, and shall be securely fastened to the pipe, wire, conduit or other appurtenance, and also to the adjcent wall wherever practicable, so that the guard will remain in a vertical position at all times.
Such guards, when used on vertical pipes, wires, conduits or other appurtenances, shall be fitted snugly around the pipe, wire, conduit or other appurtenances, shall be placed in a horizontal position (right angle to pipe) and shall extend horizontally from the pipe, wire, conduit or other appurtenance for a minimum distance of twelve inches beyond and on all sides of the pipe, wire, conduit or other appurtenance and also to the adjacent wall wherever practicable, in such manner that the guard will remain in a horizontal position at all times.
G. Light wells with windows in exterior walls that are located below the outside ground level shall be protected from the ingress and egress of rats by one of the following methods:
1. Installing over light wells cast iron or steel grills or steel gratings or other material of equal strength and rat-resisting properties, with openings in grills or gratings not to exceed one-half of an inch in shortest dimension.
2. Installing securely to and completely covering existing metal grills that are broken or have openings larger than one-half of an inch in shortest dimension, or otherwise defective, with expanded metal of eighteen gauge or heavier, having openings not greater than one-half inch in shortest dimension, or with sixteen gauge or heavier wire cloth with one-half of an inch mesh.
At the option of the person in custody of the business building, the opening in the wall of the building below the grate may be entirely closed with brick or concrete or partially closed and the remaining open space covered with nineteen guage or heavier wire cloth with mesh not to exceed one-half of an inch.
H. Business buildings constructed on piers having wooden floors with sills less than twelve inches above the surface of the ground shall have the intervening space between floor sill and ground protected against the ingress or egress of rats by installing a solid masonry or concrete wall not less than four inches thick, around the entire perimeter of the business building, extending the curtain wall to a depth of not less than eighteen inches below the surface of the ground level, with a twelve-inch shelf extending outward from the wall, and fastening securely to the exterior wall of the business building in such manner as will prevent rats from entering the building, except in instances in which the soil will allow rats to burrow more than twelve inches into the ground, in which instance the depth of the curtain wall shall not be less than thirty-six inches.
In lieu of the installation of curtain walls all ground floors of wood construction may be replaced with concrete of not less than three inches in thickness, with the exterior walls protected for a height of twenty-four inches above the concrete floor with masonry concrete or solid sheet metal of twenty-four gauge or heavier. Such exterior wall protection shall be securely tied into the concrete floor at all points.
Business buildings constructed on piers having the lower surface of wooden floor sills more than twelve inches above the ground level shall have the intervening spaces between floor sill and ground protected against the ingress or egress of rats by installing curtain walls in accordance with the preceding paragraph, or by protecting such business building against the ingress or egress of rats by installing solid sheet metal coverage of twenty-four gauge or heavier snugly around each pipe, cable, wire, conduit or other utility service passing through wooden ground floor. The diameter of such metal coverage shall not be less than eight inches larger than diameter of pipe, cable, wire, conduit or other utility service, and shall be securely fastened to the wooden floor. All other openings in wooden ground floors through which rats may gain entrance into double walls or the interior of business buildings, such as openings that may exist in floors and double walls above sills, shall be closed with twenty-four gauge or heavier solid sheet metal or sixteen gauge or heavier wire cloth of one-half-inch mesh, or with concrete or masonry. If the distance from the top of the floor sill to the under surface of a wooden floor is less than twelve inches, rat stoppage treatment as provided in other sections of this chapter shall be used. Wood frame constructed business buildings having concrete or masonry foundation wall shall have ventilators in foundation walls protected as herein provided in subsection D of this section. All miscellaneous wall openings, doors and windows shall be protected in accordance with this chapter.
(Ord. 16812 § 20 (part), 2007; prior code § 12-56)
