R317-560-3. Design and Construction Requirements

3.1 All vault privies shall have vaults or receptacles which are watertight and shall be constructed of reinforced concrete, metal or other material of equal durability which has been approved by the local health department. Inside and outside surfaces of metal vaults shall be thoroughly coated with a good quality asphalt-base material.

3.2 For all earthen pit privies, pit cribbing shall be installed in the pit to prevent caving of soil into the pit and to insure a firm foundation for the building. The pit cribbing shall fit firmly, be in uniform contact with the earth walls on all sides, and shall descend to the full depth of the pit and rise flush with the ground surface.

3.3 All vault privies and earthen pit privies shall comply with the following:

A. A sill or foundation constructed of concrete or treated lumber shall be placed on the ground surface around the vault or pit so as to underlie the floor area of the privy building.

B. A floor and riser of impervious material shall be placed over the sill and vault or pit in such a manner to prevent access of rodents and insects into the vault or pit.

C. The privy building shall be firmly anchored, rigidly constructed, free from hostile surface features such as sharp edges and exposed nail points, and shall afford complete privacy and protection from the elements. The building shall be of fly-tight construction. The door(s) shall be self-closing and provided with an inside latch. Interior floors, walls, ceilings, partitions, and doors shall be finished with readily cleanable materials resistant to wastes and cleaners.

D. The building shall be ventilated by leaving approximately 4-inch openings at (1) the top of two opposite walls just beneath the roof, and (2) at the bottom of two opposite walls just above the floor, all of which are screened with 16-mesh screen or smaller of durable material. Hardware mesh with 1/4" openings may be placed on the inside and outside of the screened openings to protect the smaller mesh screen. Direct line of sight into the building through the bottom ventilation openings shall be effectively obstructed with a louver or other suitable means.

E. Each vault or pit shall be vented to atmosphere with a minimum of 100 square inches of vent area for each seat connected to the vault. (One hundred square inches is equivalent to two 8-inch pipes, or one 12-inch pipe.) Roof vents must extend at least 12 inches above the highest point of the roof and shall be provided with a rain cap and screened with 16-mesh screen or smaller of durable material. Venting to an attic vent may be provided for by utilizing the space between an inside and outside wall if that space provides sufficient area.

F. The seat should be so spaced as to provide a minimum clear space of 24 inches between each seat opening in multiple unit installations, and should provide 12 inches clear space from the seat opening to the sidewall in single and multiple units. In multiple unit installations, partitions should be provided between risers to afford user privacy.

G. The seat riser should have an inside clearance of not less than 21 inches from the front wall and not less than 24 inches from the rear wall of the privy building.

H. The seat top should be not less than 12 inches nor more than 16 inches above the floor.

I. The seat opening shall be covered with an attached, movable toilet seat and lid of easily cleanable, impervious material that can be raised to allow sanitary use as a urinal and can be closed when not in use. Privy buildings for public use shall be provided with open-front seats.

J. Commercially preconstructed vault privy buildings not incorporating all of the requirements of these rules may be evaluated for approval on a case-by-case basis by local health departments.