This standard covers steel@ alloy steel@ and stainless steel plug valves with flanged or butt-welding ends and ductile iron plug valves with flanged ends in sizes NPS 1 through NPS 24@ which correspond to nominal pipe sizes in ASME B36.10M. A steel valve body may have one flanged end and one butt-welding end. This standard covers steel@ alloy steel@ and stainless steel valves in Classes 150-2500@ as specified in ANSI B16.34. The valves shall conform to all the requirements of ANSI B16.34 and to all additional requirements specified in this standard. This standard also covers ductile iron valves in Classes 150 and 300@ as specified in ANSI B16.42. This standard covers both lubricated and nonlubricated valves that have two-way coaxial ports; threeway and four-way plug valves are not discussed in this standard. This standard includes requirements for valves fitted with internal body@ plug@ or port linings or applied hard facings on the body@ body ports@ plug@ or plug port. The extent of linings and the materials of which they are made are not covered in this standard. Plug valves covered in this standard belong to one of four general design groups that@ in many cases@ have different face-to-face and end-to-end dimensions. Some types of plug valves are not made to all patterns. The four groups are described in 1.1.4.1 through 1.1.4.4. The short-pattern design is found only in Classes 150 and 300 where flanged plug valves match the face-to-face dimensions of steel flanged gate valves in NPS 1 V2 through NPS 12. Although the body of the regular-pattern design is designed for streamline flow@ it does not match the shape of a venturi throat because the plug ports are larger than those in the venturi pattern. In the regular pattern@ the plug port area is substantially greater than in the venturi pattern. Valves of the venturi pattern are designed for minimum pressure loss consistent with the reduced port area used in this type of valve. Venturi valves have a conjunction of body and plug ports that approximates a venturi throat. The round-port full-bore pattern has a circular port through both the plug and the body that is not smaller than that specified in Annex A of ANSI B16.34 for the inside diameter of a flanged fitting. The standard nomenclature for valve parts is shown in Figures 1@ 2@ and 3. Although Figure 1 illustrates a lubricated valve@ nonlubricated valves without a sleeve or lining may be similar except for the omi~sion of the lubrication groove and the substitution of a mechanical means for freeing the plug.