These standards cover the sanitary aspects of disc-
type valves having a one- or two-piece body and
disc with the disc rotating between the closed and
open positions, as used on tanks or vessels that hold
the product or solutions and as installed in product
and solution pipelines. The stem that rotates the disc
does not penetrate the seal face or seal seat insert of
the valve. The disc-type valve begins at the product
inlet connection and ends at the product outlet
connection. These Standards do not include
butterfly-type valves which may use two- or three-
piece bodies and gaskets as sandwich seals and seal
faces in combination with a disc and in which the
stem penetrates the elastomer seal.
In order to conform to this 3-A Sanitary Standard,
disc-type valves shall conform to the following
design, material, and fabrication criteria, and
applicable documents referenced herein.