FCI 70-2-2006 & 70-3-2004 Set

FCI 70-2-2006:
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 valveswith "O" rings or similar gapless seals, among others.

FCI 70-3-2004:
This standard applies to pilot operated and direct acting pressure reducing, pressure relieving (back pressure), differential pressure and temperature regulators.
Selection of a leakage class is not restricted as to regulator design, but acceptable values for various commercially available designs are suggested for each class under Section 4.
The standard cannot be used as a basis for predicting leakage at conditions other than those specified.
This standard is similar to FCI 70-2.
This standard does not apply to pressure regulators as defined in the following standards:
- ANSI Z21.18/CSA 6.3
- ANSI Z21.80/CSA 6.22
- ANSI Z21.78/CSA 6.20