Plug Valve Regular Pattern, Standard Type Wrench Operated Valve. Specification: Class 125 flange dimensions and drilling in accordance with ANSI B 16.1 BSPT "D" AND "F" flange dimensions and drilling in accordance with BS10. These valves have a port area substantially equal to the bore of pipe where full area is not essential economies can be made by the use of short pattern valves having reduced area.