Yokogawa Product Line

Yokogawa Pressure Transmitters and Temperature Transmitters 2D & 3D CAD models

Unit Conversion Sites

Yokogawa HART and BRAIN Pocket Guides

Control Valve Sizing Program

Digital Yewflo Vortex Flow Meter Sizing Program

ANSI Pressure Ratings

Yokogawa General Specification Data Sheets

Valve Seat Leakage Chart
The Fluids Control Institute (FCI) Standard ANSI/FCI 70.2 establishes a Valve’s allowable seat Leakage Rate. The standard recognizes five degrees of seat tightness.

 

Valve Seat Leakage Chart

The Fluids Control Institute (FCI) Standard ANSI/FCI 70.2 establishes a Valve’s allowable seat Leakage Rate. The standard recognizes five degrees of seat tightness.

ALLOWABLE SEAT LEAKAGE CLASSES Leakage Class	Maximum Seat Leakage	Test Fluid	Test Pressure	Relative Seat Tightness
Class II	0.5% of rated CV	Water	45 to 60 PSI	1.0
Class III	0.1% of rated CV	Water	45 to 60 PSI	5.0
Class IV	0.01% of rated CV	Water	45 to 60 PSI	50
Class IV+	0.0015 ml /min/inch of trim size/ ΔP(PSI)	Water	Max Operating ΔP	150,000
Class V	0.0005 ml /min/inch of trim size/ ΔP(PSI)	Water	Max Operating ΔP	300,000
Class VI	about 0.9 ml/min ∗	Air	50 PSI	600,000