Each underground valve box shall be fitted with a Locking and Sealing Lid, described as follows:
The Lid shall be molded of Engineering Grade Polymer Materials. It shall consist of a circular disc top, with a cylinder projecting from the underside for support from the valve box lid seat.
Around the perimeter of the cylinder and in close proximity to the top disc is an elastomeric seal, which is designed to span the gap between the lid and valve box, thereby preventing the passage of dirt, debris, and insects.
In the center of the lid's top surface is a conventional pentagon nut, attached to a course pitch, left-handed thread bolt, which extends out of the lower side of the lid. Threaded onto this bolt is a follower block, which is connected to three sets of pivotal arms which extend radially outward, such that rotation of the pentagon nut causes the follower block to descend on its bolt, and the pivotal arms to rise at their outermost extension, thus making contact with the lower rim of the lid seat of the valve box, thus affectuating locking.
Locking is complete as soon as contact is felt. Unlocking is accomplished by turning the pentagon nut counter-clockwise until the first resistance is encountered. The pivotal arms have thus been moved to a sufficiently small diameter to allow removal of the lid.
The top circular disc of the lid shall contain two recesses at opposite sides of the perimeter, as pry slots. Two screwdrivers or small pry bars can be used for final removal.
Polymeric materials used in the lid construction shall contain additives for protection against ultraviolet light degradation and ozone attack. All metal components shall be stainless steel, bronze, or other corrosion resistant composition.