Control Valve - ANSI / FCI 70-2
•ANSI/FCI
70-2
–This standard
establishes six classes of seat leakage for control valves. Also defined are
specific test procedures to
determine the appropriate class. Included are
classes commonly associated with double-port, double-seat or balanced
single-port control valves with a piston ring seal or metal-to-metal seats;
commercial unbalanced single-port, single-seat
and balanced single-port valves
with extra tight piston rings or other sealing means and metal-to-metal seats;
valves for
critical applications where the control valve may be required to be
closed, without a blocking valve, for long period of time;
and resilient
seating control valves with "O" rings or similar gapless seals, among
others.
