ANSI/FCI Standard 70-2
ANSI/FCI Standard 70-2, from the American National Standards Institute and the Fluid Controls Institute, defines leakage classifications specifically for control valves.
Scope
ANSI/FCI 70-2 is the industry standard for control valve leakage.
Classifications
ANSI/FCI 70-2 defines six classifications of control valve leakage, providing test procedures and the maximal allowable leakage (MAL) for each.
CLASS |
MAL |
TEST MEDIUM |
TEST PRESSURE |
I |
Not specified |
No test required |
No test required |
II |
0.5% rated capacity |
Air or water at 50°F to 125°F |
Lower of 45 to 60 psig or maximum operating differential |
III |
0.1% rated capacity |
Same as Class II |
Same as Class II |
IV |
0.01% rated capacity |
Same as Class II |
Same as Class II |
V |
0.0005 ml per minute of water per inch of port diameter per psi differential: “Effectively zero leakage” |
Water at 50°F to 125°F |
Maximum service pressure across valve plug not to exceed ANSI rating |
VI |
Milliliters or bubbles per minute based on nominal port diameter |
Air at 50°F to 125°F |
Lower of 50 psig or maximum rated pressure across valve plug |
A full copy of ANSI/FCI 70-2 can be purchased from the American National Standards Institute