Enter a value in a field below, then press 'convert' to show equivalent values.

cubic foot
cubic inch
gallon US
cubic meter
liter
gallon UK
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Enter a value for temperature
in either field, then press 'convert' to show converted values.

Centigrade
Fahrenheit
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Flow coefficient (Cv)
is the number of US gallons per minute that flow through a valve at 60F with a pressure drop of 1 PSI across the valve.

The metric equivalent - called the flow factor (Kv) is the number of cubic meters per hour of water at 20C which will flow through the valve with a pressure drop of one Bar.

For typical Cv and Kv values for standard Gemco Valve apertures, click below:

Show Values

 

There are six different seat leakage classifications as defined by
ANSI FCI 70-2. The most commonly used by Gemco Valve are CLASS I, CLASS IV and CLASS VI.

CLASS I is also known as "dust tight" and can refer to metal or resilient seated valves.

CLASS IV is also know as "metal to metal". This is the kind of leakage rate you can expect from a valve with a metal shut-off disc and metal seat.

CLASS VI is known as a "soft seat" classification. Soft Seat Valves are those where either the seat, shut-off disc or both are made from some kind of resilient material such as Teflon.
View All Classifications

 

ANSI VALVE LEAKAGE
STANDARDS


There are six different seat leakage classifications as defined by ANSI FCI 70-2. The most commonly used by Gemco Valve are CLASS I , CLASS IV and CLASS Vl

Control Valve Seat Leakage Classifications - ANSI FCI 70-2 superseding ANSI B16.104


Leakage Class Designation I
also know as dust tight and can refer to metal or resilient seated valves

Maximum Leakage Allowable: N/A

Test Medium: N/A

Test Pressure:
N/A

Testing Procedures Required for Establishing Rating:

No test required provided user and supplier so agree.

Leakage Class Designation II

Maximum Leakage Allowable:
0.5% of rated capacity

Test Medium:
Air or water at 50-125 F (10-52C)

Test Pressure:
45-60 psig or max. operating differential whichever is lower.

Testing Procedures Required for Establishing Rating:

Pressure applied to valve inlet with outlet open to atmosphere or connected to a low head loss measuring device full normal closing thrust provided by actuator.


Leakage Class Designation III

Maximum Leakage Allowable:
0.1% of rated capacity

Test Medium:
Air or water at 50-125 F (10-52C)

Test Pressure:

45-60 psig or max. operating differential whichever is lower.

Testing Procedures Required for Establishing Rating:

Pressure applied to valve inlet with outlet open to atmosphere or connected to a low head loss measuring device full normal closing thrust provided by actuator.


Leakage Class Designation IV
also known as metal to metal. It is the kind of leakage rate you can expect from a valve with a metal shut-off disc and metal seat.

Maximum Leakage Allowable:
0.01% of rated capacity

Test Medium:
Air or water at 50-125 F (10-52C)

Test Pressure:
45-60 psig or max. operating differential whichever is lower.

Testing Procedures Required for Establishing Rating:

Pressure applied to valve inlet with outlet open to atmosphere or connected to a low head loss measuring device full normal closing thrust provided by actuator.


Leakage Class Designation V

Maximum Leakage Allowable:
0.0005 ml per minute of water per inch of port diameter per psi differential

Test Medium:
Water at 50 to 125F (10 to52C)

Test Pressure:
Max service pressure drop across valve plug, not to exceed ANSI body rating.

Testing Procedures Required for Establishing Rating:

Pressure applied to valve inlet after filling entire body cavity and connected piping with water and stroking valve plug closed. Use net specified max actuator thrust, but no more, even if available during test. Allow time for leakage flow to stabilize.


Leakage Class Designation VI
Known as a soft seat classification. Soft Seat Valves are those where the seat or shut-off disc or both are made from some kind of resilient material such as Teflon.

Maximum Leakage Allowable:

Not to exceed amounts shown in the table below based on port diameter.

Test Medium:

Air or nitrogen at 50 to 125F (10 to 52C)

Test Pressure:

50 psig or max rated differential pressure across valve plug whichever is lower.

Testing Procedures Required for Establishing Rating:

Actuator should be adjusted to operating conditions specified with full normal closing thrust applied to valve plug seat. Allow time for leakage flow to stabilize and use suitable measuring device.

Control Valve Seat Leakage Classifications

NOMINAL PORT DIAM. LEAK RATE
Inches Milli-
meters
ml per
Minute
Bubbles
per
minute*
3 75 0.9 6
4 100 1.7 11
6 150 4 27
8 200 6.75 45
10 250 9 63
12 300 11.5 81



*Bubbles per minute as tabulated are a suggested alternative based on a suitable calibrated measuring device, in this case a 0.25-inch OD X 0.032-inch wall tube submerged in water to a depth of from 1/8 to 1/4 inch. The tube end shall be cut square and smooth with no chamfers or burrs. The tube axis shall be perpendicular to the surface of the water. Other measuring devices may be constructed and the number of bubbles per minute may differ from those shown as long as they correctly indicate the flow in milliliters per minute.

 

 

Change size Rate information

 

Grit Size:
click buttons below for specifications.
Size conversion:
input a value into either field the press 'convert' to show equivalents.
#7 #4 #2
micro inches
micrometers
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Use this tool to find
approximate equivalent grit sizes.

US (CAMI)
150
.00363
mesh size
avg. dia. in.
EUROPE (FEPA)
92
none
mesh size
avg. dia. micron

 

Mass conversions:
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