1.1 This specification covers mechanical end-face seals for centrifugal and positive displacement pumps for shipboard use. 1.2 The following types of seals are not included in this specification: lip seals, oil seals, circumferential seals, labyrinth seals or gas seals. 1.3 Lineal dimensions and units of force in this specification are expressed as inches and pounds respectively. A companion metric standard is in the process of preparation. 1.4 Special requirements for U.S. Navy Shipboard Pump Applications are included in Supplement S1.